Publications

Aghayarzadeh, M, Khabbaz, H & Fatahi, B 2019, 'Evaluation of Concrete Bored Piles Behaviour in Saturated Loose and Dense Sand During the Static Load Testing' in New Developments in Materials for Infrastructure Sustainability and the Contemporary Issues in Geo-environmental Engineering, Springer International Publishing, Cham, Switzerland, pp. 75-89.
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Diversity of construction methods is available for the installation of piles; and generally piles are classified into two main groups in terms of their installation method, including non-displacement piles and displacement piles. However, non-displacement piles such as bored piles or drilled shafts cause less disruption to adjacent soil compared to displacement piles. Knowing the behaviour of piles, the load-displacement curve has an important role during the pile load testing. In this study, firstly, the background and concepts of three different constitutive soil models including Mohr-Coulomb, Hardening Soil and Hypoplastic models are discussed. Secondly, using these soil models and finite element software PLAXIS, the load carrying capacity of a single bored pile in saturated dense and loose sand are evaluated. Finally, different factors affecting load-displacement curve including Hypoplastic model parameters are assessed. The most important aim of this study is comparing the capability of different soil models to capture the large strain behaviour observed during the static load testing. The results revealed that all three soil models indicate a reasonable correlation to each other, except when the “Intergranular Strain” concept, defined in Hypoplastic model, is activated. This paper can be useful for the practicing engineers to identify the effect of different soil models in numerical simulation of static pile load testing.

Dong, Y, Fatahi, B, Khabbaz, H & Hsi, J 2019, 'Impact of Initial In-Situ Stress Field on Soil Response During Cavity Expansion Using Discrete Element Simulation' in New Developments in Materials for Infrastructure Sustainability and the Contemporary Issues in Geo-environmental Engineering, Springer International Publishing, Switzerland, pp. 1-10.
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Discrete element method (DEM) is gaining its popularity in investigating many complicated geotechnical related problems due to its discontinuous nature in simulating granular materials. Particularly when simulating the processes involving large deformation and displacement of soil (e.g. pile penetration), DEM demonstrates distinct advantages over other numerical solutions that may confront convergence problems. Despite the facts that DEM analysis has been conducted to study the mechanism of the cavity expansion, there is a very limited number of investigations conducted to study the effects of the initial stress field on the soil response. Hence, in this study, a three-dimensional numerical analysis has been conducted using PFC3D to investigate the soil response under different initial stress conditions during cavity expansion. A large-scale model containing an adequate number of particles has been constructed to simulate the soil medium, in which, microscopic contact properties were calibrated against existing experimental data to mimic the realistic behaviour of a sandy soil. To examine the effects of the initial in-situ stresses, several cylindrical cavities were created and expanded gradually from an initial radius to a final radius, while stress and strain variations were monitored during the entire simulation. It should be noted that the internal cylinder boundary was loaded using a constant strain rate, while the outer boundary was controlled through a servo mechanism to maintain a constant external pressure adopting appropriate subroutines. The results obtained confirmed that the initial stress conditions have significant effects on the soil response during cavity expansion.

Naidu, G, Johir, MAH, Shanmuganathan, S, Listowski, A & Vigneswaran, S 2019, 'Zero Waste Discharge in Wastewater Reclamation System for Small Cities' in Waste Water Recycling and Management, Springer Singapore, pp. 207-215.
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Ngo, HH, Khan, MA, Guo, W, Pandey, A & Lee, D-J 2019, 'Non-conventional Anaerobic Bioreactors for Sustainable Wastewater Treatment' in Energy, Environment, and Sustainability, Springer Singapore, pp. 265-295.
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Ngo, HH, Vo, HNP, Guo, W, Bui, X-T, Nguyen, PD, Nguyen, TMH & Zhang, X 2019, 'Advances of Photobioreactors in Wastewater Treatment: Engineering Aspects, Applications and Future Perspectives' in Bui, X-T, Chiemchaisri, C, Fujioka, T & Varjani, S (eds), Energy, Environment, and Sustainability, Springer Singapore, Germany, pp. 297-329.
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The photobioreactor is an efficient artificial system in terms of biomass cultivation and removing pollutants. Compared to other conventional technologies, its design and operational processes are superior. Therefore, the photobioreactor specifically targets and tailors for the increasing demand for biomass and stringent pollutants removal standards. Since the early 1950s, there has been a variety of photobioreactor types, and these have been addressing the different technical issues over time and others more recently. As well, diverse applications of the photobioreactor process are becoming more widespread, and this opens for a good opportunity for future sustainable developments. This book chapter discusses advances being made in photobioreactor technology, encompassing: (1) modelling; (2) designs and classifications; (3) applications and (4) future perspectives.

Tijing, LD, Yao, M, Ren, J, Park, C-H, Kim, CS & Shon, HK 2019, 'Nanofibers for Water and Wastewater Treatment: Recent Advances and Developments' in Bui, X-T, Chiemchaisri, C, Fujioka, T & Varjani, S (eds), Energy, Environment, and Sustainability, Springer Singapore, Singapore, pp. 431-468.
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Woo, YC, Kim, S-H, Shon, HK & Tijing, LD 2019, 'Introduction: Membrane Desalination Today, Past, and Future' in Current Trends and Future Developments on (Bio-) Membranes, Elsevier, pp. xxv-xlvi.
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© 2019 Elsevier Inc. All rights reserved. In recent decades, many regions of the world have suffered from water scarcity, which is one of the most critical issues in the world. The main challenge is to supply freshwater to water shortage regions. In addition, waterborne illness has been caused through the consumption of the contaminated potable water in these regions. Increasing demands of potable water and the deficiency of surface water resources led to the development of desalination technologies, which obtain freshwater from seawater. This chapter addresses general information on desalination technologies in terms of the historical development, current status, and future prospects. It begins with the description of backgrounds in terms of the development of desalination technologies. Section 2 is an overview of the historical development of desalination technologies, including multistage flash, multieffect distillation, and reverse osmosis. Section 3 focuses on the reduction of energy consumption of the desalination technologies and increase of the permeate volume by energy recovery device, improved membrane, and hybrid conventional process. In Section 4, several alternative desalination technologies, membrane fabrication techniques, and brine management methods are introduced. Future trends of desalination technologies are pointed out in the final section.

Abas, AEP, Yong, J, Mahlia, TMI & Hannan, MA 2019, 'Techno-Economic Analysis and Environmental Impact of Electric Vehicle', IEEE Access, vol. 7, pp. 98565-98578.
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Abas, PE & Mahlia, TMI 2019, 'Techno-Economic and Sensitivity Analysis of Rainwater Harvesting System as Alternative Water Source', Sustainability, vol. 11, no. 8, pp. 2365-2365.
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This paper formulates a rainwater harvesting model, with system and economic measures to determine the feasibility of a rainwater harvesting system, which uses water from the mains to complement the system. Although local meteorological and market data were used to demonstrate the model, it can also be easily adapted for analysis of other localities. Analysis has shown that an optimum tank size exists, which minimizes the cost per unit volume of water. Economic performance measures have indicated that rainwater harvesting system is currently infeasible to be implemented in Brunei; with capital cost and water price being shown to be among the prohibiting factors. To improve feasibility, a combination of rebate scheme on capital cost and raising the current water price has been proposed. It has also been shown that the system is more viable for households with high water demand.

Abnisa, F, Anuar Sharuddin, SD, bin Zanil, MF, Wan Daud, WMA & Indra Mahlia, TM 2019, 'The Yield Prediction of Synthetic Fuel Production from Pyrolysis of Plastic Waste by Levenberg–Marquardt Approach in Feedforward Neural Networks Model', Polymers, vol. 11, no. 11, pp. 1853-1853.
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The conversion of plastic waste into fuel by pyrolysis has been recognized as a potential strategy for commercialization. The amount of plastic waste is basically different for each country which normally refers to non-recycled plastics data; consequently, the production target will also be different. This study attempted to build a model to predict fuel production from different non-recycled plastics data. The predictive model was developed via Levenberg-Marquardt approach in feed-forward neural networks model. The optimal number of hidden neurons was selected based on the lowest total of the mean square error. The proposed model was evaluated using the statistical analysis and graphical presentation for its accuracy and reliability. The results showed that the model was capable to predict product yields from pyrolysis of non-recycled plastics with high accuracy and the output values were strongly correlated with the values in literature.

Adanta, D, ., B, ., W, Quaranta, E & I. Mahlia, TM 2019, 'Investigation of the effect of gaps between the blades of open flume Pico hydro turbine runners', Journal of Mechanical Engineering and Sciences, vol. 13, no. 3, pp. 5493-5512.
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This study will analyze the impact of gap size in two different runners called runner A (five blades) and B (six blades) to provides recommendations in design and manufacture of open flume turbine runners so that maximize the conversion of kinetic and potential energy. There are three methods was used to investigate its: analytical method is used to design the turbine; experimental to determine the actual turbine performance; computational fluid dynamics (CFD) to study the physical phenomena and re-check the velocity triangle on the runner to validate the design and manufacturing process. Using the results obtained, gaps between the blades can alter the velocity vector on the outlet and unbalance the rotation of runner; this imbalance could cause cavitation. Then, the decreasing torque is assumed because water pressure in the draft tube is similar to atmospheric pressure. Two conditions must be satisfied to maximize the performance of the turbine: swirling flow is required after the water flows past the runner in order to minimize the radial velocity on the outlet so that the draft tube can function properly; the dimensions of the blade must be carefully selected to avoid the formation of gaps between the blades.

Ahmed, MB, Hasan Johir, MA, Zhou, JL, Ngo, HH, Nghiem, LD, Richardson, C, Moni, MA & Bryant, MR 2019, 'Activated carbon preparation from biomass feedstock: Clean production and carbon dioxide adsorption', Journal of Cleaner Production, vol. 225, pp. 405-413.
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© 2019 Elsevier Ltd The current methods used for the production of activated carbon (AC) are often chemical and energy intensive and produce significant amount of chemical waste. Thus, clean production of AC is important to reduce its overall production cost and to limit the adverse effect on the environment. Therefore, the main aim of this study is to develop a clean method for AC production from woody biomass with low chemical consumption. Herein, this study reports a facile strategy for reducing chemical usages in the production of high-performance AC, by introducing a crucial pre-pyrolysis step before chemical activation of biomass. The ACs prepared were characterised using scanning electron microscopy, Fourier transform infrared spectroscopy, nitrogen and carbon dioxide gas adsorption measurements. All these characterisations indicated that produced ACs have similar physicochemical properties. The strategy reduced chemical use by 70% and produced high-performance ultra-microporous ACs with excellent carbon dioxide adsorption capacity (4.22–5.44 mmol m −2 ). The facile pre-pyrolysis method is recommended for further research as a cleaner activated carbon preparation method from biomass feedstock.

Akther, N, Lim, S, Tran, VH, Phuntsho, S, Yang, Y, Bae, T-H, Ghaffour, N & Shon, HK 2019, 'The effect of Schiff base network on the separation performance of thin film nanocomposite forward osmosis membranes', Separation and Purification Technology, vol. 217, pp. 284-293.
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© 2019 Elsevier B.V. In this study, Schiff base network-1 (SNW-1) nanoparticles, which are covalent organic frameworks (COFs), were used as fillers in the polyamide (PA) active layer to elevate the performance of thin-film nanocomposite (TFN) forward osmosis (FO) membranes. The TFN membranes were prepared by interfacial polymerization (IP) of m-phenylenediamine (MPD) and trimesoyl chloride (TMC), and the SNW-1 nanoparticles were dispersed in the MPD aqueous solution at various concentrations. The secondary amine groups of SNW-1 nanoparticles reacted with the acyl chloride groups of TMC during the IP reaction to form strong covalent/amide bonds, which facilitated better interface integration of SNW-1 nanoparticles in the PA layer. Additionally, the incorporation of amine-rich SNW-1 nanoparticles into the TFN membranes improved their surface hydrophilicity, and the porous structure of SNW-1 nanoparticles offered additional channels for transport of water molecules. The TFN0.005 membrane with a SNW-1 nanoparticle loading of 0.005 wt% demonstrated a higher water flux than that of pristine TFC membrane in both AL-FS (12.0 vs. 9.3 L m−2 h−1) and AL-DS (25.2 vs. 19.4 L m−2 h−1) orientations when they were tested with deionized water and 0.5 M NaCl as feed and draw solution, respectively.

Akther, N, Phuntsho, S, Chen, Y, Ghaffour, N & Shon, HK 2019, 'Recent advances in nanomaterial-modified polyamide thin-film composite membranes for forward osmosis processes', Journal of Membrane Science, vol. 584, pp. 20-45.
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© 2019 Elsevier B.V. Polyamide thin-film composite (PA TFC)membranes have attained much attention for forward osmosis (FO)applications in separation processes, water and wastewater treatment due to their superior intrinsic properties, such as high salt rejection and water permeability compared to the first-generation cellulose-based FO membranes. Nonetheless, several problems like fouling and trade-off between membrane selectivity and water permeability have hindered the progress of conventional PA TFC FO membranes for real applications. To overcome these issues, nanomaterials or chemical additives have been integrated into the TFC membranes. Nanomaterial-modified membranes have demonstrated significant improvement in their anti-fouling properties and FO performance. In addition, the PA TFC membranes can be designed for specific applications like heavy metal removal and osmotic membrane bioreactor by using nanomaterials to modify their physicochemical properties (porosity, surface charge, hydrophilicity, membrane structure and mechanical strength). This review provides a comprehensive summary of the progress of nanocomposite PA TFC membrane since its first development for FO in the year 2012. The nanomaterial-incorporated TFC membranes are classified into four categories based on the location of nanomaterial in/on the membranes: embedded inside the PA active layer, incorporated within the substrate, coated on the PA layer surface, or deposited as an interlayer between the substrate and the PA active layer. The key challenges still being confronted and the future research directions for nanocomposite PA TFC FO are also discussed.

Ali, SM, Qamar, A, Kerdi, S, Phuntsho, S, Vrouwenvelder, JS, Ghaffour, N & Shon, HK 2019, 'Energy efficient 3D printed column type feed spacer for membrane filtration', Water Research, vol. 164, pp. 114961-114961.
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© 2019 Elsevier Ltd Modification of the feed spacer design significantly influences the energy consumption of membrane filtration processes. This study developed a novel column type feed spacer with the aim to reduce the specific energy consumption (SEC) of the membrane based water filtration system. The proposed spacer increases the clearance between the filament and the membrane (reducing the spacer filament diameter) while keeping the same flow channel thickness as compared to a standard non-woven symmetric spacer. Since the higher clearance reduces the flow unsteadiness, column type nodes were added in the spacer structure as additional vortex shading bodies. Fluid flow behaviour in the channel for this spacer was numerically simulated by 3D CFD studies and then compared with the standard spacer. The numerical results showed that the proposed spacer substantially reduced the pressure drop, shear stress at the constriction region and shortened the dead zone. Finally, these findings were confirmed experimentally by investigating the filtration performances using the 3D printed prototypes of these spacers in a lab-scale filtration module. It is observed that the column spacer reduced the pressure drop by three times and doubled the specific water flux. 2D OCT (Optical Coherence Tomography) scans of the membrane surface acquired after the filtration revealed much lower biomass accumulation using the proposed spacer. Consequently, the SEC for the column spacer was found about two folds lower than the standard spacer.

Altaee, A & Cipolina, A 2019, 'Modelling and optimization of modular system for power generation from a salinity gradient', Renewable Energy, vol. 141, pp. 139-147.
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© 2019 Elsevier Ltd Pressure retarded osmosis has been proposed for power generation from a salinity gradient resource. The process has been promoted as a promising technology for power generation from renewable resources, but most of the experimental work has been done on a laboratory size units. To date, pressure retarded osmosis optimization and operation is based on parametric studies performed on laboratory scale units, which leaves a gap in our understanding of the process behaviour in a full-scale modular system. A computer model has been developed to predict the process performance. Process modelling was performed on a full-scale membrane module and impact of key operating parameters such as hydraulic feed pressure and feed and draw solution rates were evaluated. Results showed that the optimum fraction of feed/draw solution in a mixture is less than what has been earlier proposed ratio of 50% and it is entirely dependent on the salinity gradient resource concentration. Furthermore, the optimized pressure retarded osmosis process requires a hydraulic pressure less than that in the normal (unoptimized) process. The results here demonstrate that the energy output from the optimized pressure regarded osmosis process is up to 54% higher than that in the normal (unoptimized) process.

Altaee, A, Braytee, A, Millar, GJ & Naji, O 2019, 'Energy efficiency of hollow fibre membrane module in the forward osmosis seawater desalination process', Journal of Membrane Science, vol. 587, pp. 117165-117165.
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© 2019 This study provided new insights regarding the energy efficiency of hollow fibre forward osmosis modules for seawater desalination; and as a consequence an approach was developed to improve the process performance. Previous analysis overlooked the relationship between the energy efficiency and operating modes of the hollow fibre forward osmosis membrane when the process was scaled-up. In this study, the module length and operating parameters were incorporated in the design of an energy-efficient forward osmosis system. The minimum specific power consumption for seawater desalination was calculated at the thermodynamic limits. Two FO operating modes: (1) draw solution in the lumen and (2) feed solution in the lumen, were evaluated in terms of the desalination energy requirements at a minimum draw solution flow rate. The results revealed that the operating mode of the forward osmosis membrane was important in terms of reducing the desalination energy. In addition, the length of the forward osmosis module was also a significant factor and surprisingly increasing the length of the forward osmosis module was not always advantageous in improving the performance. The study outcomes also showed that seawater desalination by the forward osmosis process was less energy efficient at low and high osmotic draw solution concentration and performed better at 1.2–1.4 M sodium chloride draw solution concentrations. The findings of this study provided a platform to the manufacturers and operators of hollow fibre forward osmosis membrane to improve the energy efficiency of the desalination process.

Altaee, A, Zhou, J, Zaragoza, G & Sharif, AO 2019, 'Impact of membrane orientation on the energy efficiency of dual stage pressure retarded osmosis', Journal of Water Process Engineering, vol. 30, pp. 100621-100621.
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© 2018 Elsevier Ltd The performance of Dual Stage Pressure Retarded Osmosis (DSPRO) was analyzed using a developed computer model. DSPRO process was evaluated on Pressure Retarded Osmosis (PRO) and Forward Osmosis (FO) operating modes for different sodium chloride (NaCl) draw and feed concentrations. Simulation results revealed that the total power generation in the DSPRO process operating on the PRO mode was 2.5–5 times more than that operating on the FO mode. For DSPRO operating on the PRO mode, the higher power generation was in the case of 2 M NaCl-fresh and 32% the contribution of the second stage to the total power generation in the DSPRO. To the contrast, he total power generated in the DSPRO operating on the FO mode was in the following order 5M-0.6M > 5M-0.7M > 2M-0.01 > 2M-0.6 M. Interestingly, single stage process operating on the FO mode performed better than DSPRO process due to the severe concentration polarization effects. The results also showed that power density of the DSPRO reached a maximum amount at a hydraulic pressure less than the average osmotic pressure gradient, Δπ/2, due to the variation of optimum operating pressure of each stage. Moreover, results showed that the effective specific energy in the PRO process was lower than the maximum specific energy. However, the effective specific energy of the DSPRO was larger than that of the single stage PRO due to the rejuvenation of the salinity gradient, emphasizing the high potential of the DSPRO process for power generation.

Areerachakul, N, Sakulkhaemaruethai, S, Johir, MAH, Kandasamy, J & Vigneswaran, S 2019, 'Photocatalytic degradation of organic pollutants from wastewater using aluminium doped titanium dioxide', Journal of Water Process Engineering, vol. 27, pp. 177-184.
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Asif, MB, Ansari, AJ, Chen, S-S, Nghiem, LD, Price, WE & Hai, FI 2019, 'Understanding the mechanisms of trace organic contaminant removal by high retention membrane bioreactors: a critical review', Environmental Science and Pollution Research, vol. 26, no. 33, pp. 34085-34100.
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© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. High retention membrane bioreactors (HR-MBR) combine a high retention membrane separation process such as membrane distillation, forward osmosis, or nanofiltration with a conventional activated sludge (CAS) process. Depending on the physicochemical properties of the trace organic contaminants (TrOCs) as well as the selected high retention membrane process, HR-MBR can achieve effective removal (80–99%) of a broad spectrum of TrOCs. An in-depth assessment of the available literature on HR-MBR performance suggests that compared to CAS and conventional MBRs (using micro- or ultra-filtration membrane), aqueous phase removal of TrOCs in HR-MBR is significantly better. Conceptually, longer retention time may significantly improve TrOC biodegradation, but there are insufficient data in the literature to evaluate the extent of TrOC biodegradation improvement by HR-MBR. The accumulation of hardly biodegradable TrOCs within the bioreactor of an HR-MBR system may complicate further treatment and beneficial reuse of sludge. In addition to TrOCs, accumulation of salts gradually increases the salinity in bioreactor and can adversely affect microbial activities. Strategies to mitigate these limitations are discussed. A qualitative framework is proposed to predict the contribution of the different key mechanisms of TrOC removal (i.e., membrane retention, biodegradation, and sorption) in HR-MBR.

Aung, Y, Khabbaz, H & Fatahi, B 2019, 'Mixed hardening hyper-viscoplasticity model for soils incorporating non-linear creep rate – H-creep model', International Journal of Plasticity, vol. 120, pp. 88-114.
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© 2019 Elsevier Ltd. This paper focuses on the deformation of soils considering the time-dependent stress-strain evolution. In this paper, a new mixed hardening hyper-viscoplasticity model is proposed for the derivation of the time-dependent constitutive behaviour of soils, with the intention to capture the variation in the shapes of the yield loci by pursuing non-associated flow rules and accounting for kinematic hardening effects. The distinctive departure from the existing viscoplasticity models is the application of thermodynamics, based upon the use of internal variables, to postulate free-energy and dissipation potential functions, from which the corresponding yield locus, isotropic and kinematic hardening laws, flow rules and the elasticity law are deduced in a systematic procedure. The kinematic hardening behaviour of the yield locus is considered using the shift stress, resulting from the additional plastic component of the free-energy function. A non-linear creep formulation is postulated to address the limitation of over-estimating long-term settlement and incorporated into the model for more reliable predictions. The major parameters required for the model are identified, along with the summary of descriptions on how the model parameters can readily be determined. Non-associated behaviour is found to be a natural consequence of this approach, whenever the division between dissipated and stored plastic work is not equal. This study aims to provide a theoretical background and a numerical implementation for those who are interested in the advancement of constitutive modelling of soil behaviour under the framework of hyperplasticity. Validity and versatility of the proposed constitutive model are evaluated against triaxial and oedometer test results available in literature.

Bao, T, Damtie, MM, Yu, ZM, Liu, Y, Jin, J, Wu, K, Deng, CX, Wei, W, Wei, XL & Ni, B-J 2019, 'Green Synthesis of Fe₃O₄@Carbon Filter Media for Simultaneous Phosphate Recovery and Nitrogen Removal from Domestic Wastewater in Biological Aerated Filters', ACS Sustainable Chemistry & Engineering, vol. 7, no. 19, pp. 16698-16709.
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Copyright © 2019 American Chemical Society. Domestic wastewater depth processing and reclamation are essential in the alleviation of global water shortage. In this study, an innovative filter media (i.e., Fe3O4@Carbon filter media [FCM]) was synthesized and subsequently used in a biological aerated filter (BAF) for simultaneous phosphate recovery and nitrogen removal (SPN) from domestic wastewater. The performance of FCM was compared with the commercially available ceramsite (CAC). The results showed that the performance of FCMBAF was better than that of CACBAF; as far as SPN is concerned, the magnetic field of FCMBAF could accelerate the growth rate of biofilm. Moreover, the nitrospira and nirK gene copy numbers of FCMBAF were considerably higher than those of CACBAF. Interestingly, the interconnectivity and uniformity of pores were also suitable for the microdistribution of biofilm, where different aerobic and anaerobic zones of the FCM were formed. This facilitates the microinteraction between the key microorganisms and the filter media that successfully enhanced the nitrogen removal. The phosphate recovery was attained via hydroxyapatite (Ca10(PO4)6(OH)2) formation, which resulted from the reaction between phosphate (PO43-) and FCM. The average effluent concentrations of total organic carbon (TOC), total nitrogen (TN), ammonia nitrogen (NH4+-N), and PO43- were 8.12, 6.18, 0.997, and 0.073 mg/L of FCMBAF, respectively, which were lower than those from the national standard (CODcr ≤ 50 mg L-1, NH4+-N ≤ 5.0 mg L-1, TN ≤ 15 mg L-1, TP ≤ 0.5 mg L-1, GB 18918-2002, first standard). Thus, FCM demonstrated a promising potential for SPN and wastewater recycling of BAF in domestic wastewater treatment.

Barambu, NU, Bilad, MR, Wibisono, Y, Jaafar, J, Mahlia, TMI & Khan, AL 2019, 'Membrane Surface Patterning as a Fouling Mitigation Strategy in Liquid Filtration: A Review', Polymers, vol. 11, no. 10, pp. 1687-1687.
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Membrane fouling is seen as the main culprit that hinders the widespread of membrane application in liquid-based filtration. Therefore, fouling management is key for the successful implementation of membrane processes, and it is done across all magnitudes. For optimum operation, membrane developments and surface modifications have largely been reported, including membrane surface patterning. Membrane surface patterning involves structural modification of the membrane surface to induce secondary flow due to eddies, which mitigate foulant agglomeration and increase the effective surface area for improved permeance and antifouling properties. This paper reviews surface patterning approaches used for fouling mitigation in water and wastewater treatments. The focus is given on the pattern formation methods and their effect on overall process performances.

Bates, H, Zavafer, A, Szabó, M & Ralph, PJ 2019, 'A guide to Open-JIP, a low-cost open-source chlorophyll fluorometer', Photosynthesis Research, vol. 142, no. 3, pp. 361-368.
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© 2019, Springer Nature B.V. Chlorophyll a fluorescence is the most widely used method to study photosynthesis and plant stress. While several commercial fluorometers are available, there is a need for a low-cost and highly customisable chlorophyll fluorometer. Such a device would aid in performing high-throughput assessment of photosynthesis, as these instruments can be mass-produced. Novel investigations into photosynthesis can also be performed as a result of the user’s ability to modify the devices functionality for their specific needs. Motivated by this, we present an open-source chlorophyll fluorometer based on the Kautsky induction curve (OJIP). The instrument consists of low-cost, easy-to-acquire electrical components and an open-source microcontroller (Arduino Mega) whose performance is equivalent to that of commercial instruments. Two 3D printable Open-JIP configurations are presented, one for higher plants and the other for microalgae cells in suspension. Directions for its construction are presented and the instrument is benchmarked against widely used commercial chlorophyll fluorometers.

Biradar, J, Banerjee, S, Shankar, R, Ghosh, P, Mukherjee, S & Fatahi, B 2019, 'Response of square anchor plates embedded in reinforced soft clay subjected to cyclic loading', Geomechanics and Engineering, vol. 17, no. 2, pp. 165-173.
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Plate anchors are generally used for structures like transmission towers, mooring systems etc. where the uplift and lateral forces are expected to be predominant. The capacity of anchor plate can be increased by the use of geosynthetics without altering the size of plates. Numerical simulations have been carried out on three different sizes of square anchor plates. A single layer geosynthetic has been used as reinforcement in the analysis and placed at three different positions from the plate. The effects of various parameters like embedment ratio, position of reinforcement, width of reinforcement, frequency and loading amplitude on the pull out capacity have been presented in this study. The load-displacement behaviour of anchors for various embedment ratios with and without reinforcement has been also observed. The pull out load, corresponding to a displacement equal to each of the considered maximum amplitudes of a given frequency, has been expressed in terms of a dimensionless breakout factor. The pull out load for all anchors has been found to increase by more than 100% with embedment ratio varying from 1 to 6. Finally a semi empirical formulation for breakout factor for square anchors in reinforced soil has also been proposed by carrying out regression analysis on the data obtained from numerical simulations.

Buapet, P, Mohammadi, NS, Pernice, M, Kumar, M, Kuzhiumparambil, U & Ralph, PJ 2019, 'Excess copper promotes photoinhibition and modulates the expression of antioxidant-related genes in Zostera muelleri', Aquatic Toxicology, vol. 207, pp. 91-100.
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© 2018 Elsevier B.V. Copper (Cu) is an essential micronutrient for plants and as such is vital to many metabolic processes. Nevertheless, when present at elevated concentrations, Cu can exert toxic effects on plants by disrupting protein functions and promoting oxidative stress. Due to their proximity to the urbanised estuaries, seagrasses are vulnerable to chemical contamination via industrial runoff, waste discharges and leachates. Zostera muelleri is a common seagrass species that forms habitats in the intertidal areas along the temperate coast of Australia. Previous studies have shown the detrimental effects of Cu exposure on photosynthetic efficiency of Z. muelleri. The present study focuses on the impacts of sublethal Cu exposure on the physiological and molecular responses. By means of a single addition, plants were exposed to 250 and 500 μg Cu L−1 (corresponding to 3.9 and 7.8 μM, respectively) as well as uncontaminated artificial seawater (control) for 7 days. Chlorophyll fluorescence parameters, measured as the effective quantum yield (ϕPSII), the maximum quantum yield (Fv/Fm) and non-photochemical quenching (NPQ) were assessed daily, while Cu accumulation in leaf tissue, total reactive oxygen species (ROS) and the expression of genes involved in antioxidant activities and trace metal binding were determined after 1, 3 and 7 days of exposure. Z. muelleri accumulated Cu in the leaf tissue in a concentration-dependent manner and the bioaccumulation was saturated by day 3. Cu exposure resulted in an acute suppression of ϕPSII and Fv/Fm. These two parameters also showed a concentration- and time-dependent decline. NPQ increased sharply during the first few days before subsequently decreasing towards the end of the experiment. Cu accumulation induced oxidative stress in Z. muelleri as an elevated level of ROS was detected on day 7. Lower Cu concentration promoted an up-regulation of genes encoding Cu/Zn-superoxide dismutase (Cu/Zn-sod), ascorbate p...

Bui, HH, Ha, NH, Nguyen, TND, Nguyen, AT, Pham, TTH, Kandasamy, J & Nguyen, TV 2019, 'Integration of SWAT and QUAL2K for water quality modeling in a data scarce basin of Cau River basin in Vietnam', Ecohydrology & Hydrobiology, vol. 19, no. 2, pp. 210-223.
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© 2019 European Regional Centre for Ecohydrology of the Polish Academy of Sciences Water quality modeling in a river basin often faces the problem of having a large number of parameters yet limited available data. The important inputs to the water quality model are pollution concentrations and discharge from river tributaries, lateral inflows and related pollution load from different sources along the river. In general, such an extensive data set is rarely available, especially for data scarce basins. This makes water quality modeling more challenging. However, integration of models may be able to fill this data gap. Selection of models should be made based on the data that is available for the river basin. For the case of Cau River basin, the SWAT and QUAL2K models were selected. The outputs of SWAT model for lateral inflows and discharges of ungauged tributaries, and the observed pollutant concentrations data and estimated pollution loads of sub-watersheds were used as inputs to the water quality model QUAL2K. The resulting QUAL2K model was calibrated and validated using recent water quality data for two periods in 2014. Four model performance ratings PBIAS, NSE, RSR and R2 were used to evaluate the model results. PBIAS index was chosen for water quality model evaluation because it more adequately accounted for the large uncertainty inherent in water quality data. In term of PBIAS, the calibration and validation results for Cau River water quality model were in the “very good” performance range with ǀPBIASǀ < 15%. The obtained results could be used to support water quality management and control in the Cau River basin.

Castillo, EHC, Thomas, N, Al-Ketan, O, Rowshan, R, Abu Al-Rub, RK, Nghiem, LD, Vigneswaran, S, Arafat, HA & Naidu, G 2019, '3D printed spacers for organic fouling mitigation in membrane distillation', Journal of Membrane Science, vol. 581, pp. 331-343.
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Chan, QN, Fattah, IMR, Zhai, G, Yip, HL, Chen, TBY, Yuen, ACY, Yang, W, Wehrfritz, A, Dong, X, Kook, S & Yeoh, GH 2019, 'Color-ratio pyrometry methods for flame–wall impingement study', Journal of the Energy Institute, vol. 92, no. 6, pp. 1968-1976.
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© 2018 Energy Institute The use of color-ratio pyrometry (CRP) methods, with variable or prescribed soot content (KL) to image flame–wall interactions was examined, with results compared with that obtained using the more mature two-color pyrometry (TCP) technique. The CRP and TCP methods were applied to flame–wall impingement images recorded in a optically-accessible constant volume combustion chamber (CVCC) under compression-ignition (CI) engine conditions. Good correlation in the result trends were observed for the CRP method with fixed KL output and that generated using TCP. Slight discrepancies in the predicted absolute temperature values were observed, which were linked to the difference in the KL value prescribed to the CRP method, and the KL value predicted using TCP. No useful output was obtained with CRP method with variable soot output because of channel noise. A simplified flame transparency modeling was performed to assess the inherent errors associated with the pyrometry methods. The results indicated that the uncertainties arising from the fixing of the KL output appeared acceptable.

Chen, C, Guo, W & Ngo, HH 2019, 'Pesticides in stormwater runoff—A mini review', Frontiers of Environmental Science & Engineering, vol. 13, no. 5.
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© 2019, Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature. Recently, scientific interest has grown in harvesting and treating stormwater for potable water use, in order to combat the serious global water scarcity issue. In this context, pesticides have been identified as the key knowledge gap as far as reusing stormwater is concerned. This paper reviewed the presence of pesticides in stormwater runoff in both rural and urban areas. Specifically, the sources of pesticide contamination and possible pathways were investigated in this review. Influential factors affecting pesticides in stormwater runoff were critically identified as: 1) characteristics of precipitation, 2) properties of pesticide, 3) patterns of pesticides use, and 4) properties of application surface. The available pesticide mitigation strategies including best management practice (BMP), low impact development (LID), green infrastructure (GI) and sponge city (SC) were also included in this paper. In the future, large-scale multi-catchment studies that directly evaluate pesticide concentrations in both urban and rural stormwater runoff will be of great importance for the development of effective pesticides treatment approaches and stormwater harvesting strategies.[Figure not available: see fulltext.].

Chen, F, Lu, S, Hu, X, He, Q, Feng, C, Xu, Q, Chen, N, Ngo, HH & Guo, H 2019, 'Multi-dimensional habitat vegetation restoration mode for lake riparian zone, Taihu, China', Ecological Engineering, vol. 134, pp. 56-64.
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© 2019 Elsevier B.V. The riparian zones that were surround bodies of fresh water have been extensively degraded by human influence. Their restoration strength and management are an issue of urgent. Particularly, the knowledge based for the restoration of riparian zone has expanded in recent years. However, progress on a global scale has been limited, because little is known about its complex and diverse functions and structures. A national ecological restoration project of Taihu Lake (China)provided a case study for classifying and restoring the riparian zone. In this work, we quantified the classification of riparian zone, vegetation-zone in the ecotones and a recommended suite of introduced riparian vegetation communities. Taking the structures of the ecotones, soil conditions, vegetation configurations, and anthropogenic disturbances into account, six types of vegetation-zone were used to classify riparian zone, which are as follow: reefs, islands, dokdo–island, island–shore, dike–shore, and shoreland. Then a multi-dimensional habitat vegetation restoration mode for each type based on six vegetation-zones were also recommended. The water ecological quality was developed to a healthy state under this implement. Therefore, results suggest that profound division of habitat-vegetation is important in the modern ecological engineering theories for riparian zone. In order to provide a key parameter for Taihu Lake and other worldwide lakes with similar characteristics, an eco-restoration model and a reconstruction scheme for the vegetation community have been presented. In a conclusion, these recommendations could largely assist further development for lake management.

Chen, H, Li, A, Cui, C, Ma, F, Cui, D, Zhao, H, Wang, Q, Ni, B & Yang, J 2019, 'AHL-mediated quorum sensing regulates the variations of microbial community and sludge properties of aerobic granular sludge under low organic loading', Environment International, vol. 130, pp. 104946-104946.
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© 2019 The Authors Aerobic granular sludge (AGS) is promising in wastewater treatment. However, the formation and existence of AGS under low organic loading rate (OLR) is still not fully understood due to a knowledge gap in the variations and correlations of N-acyl-homoserine lactones (AHLs), the microbial community, extracellular polymeric substances (EPS) and other physiochemical granule properties. This study comprehensively investigated the AHL-mediated quorum sensing (QS) and microbial community characters in the AGS fed with ammonium-rich wastewater under a low OLR of 0.15 kg COD (m3 d)−1. The results showed that the AGS appeared within 90 days, and the size of mature granules was over 700 μm with strong settleability and ammonium removal performance. More tightly-bound extracellular polysaccharide and tightly-bound extracelluar protein were produced in the larger AGS. C10-HSL and C12-HSL gradually became dominant in sludge, and short-chain AHLs dominated in water. EPS producers and autotrophic nitrifiers were successfully retained in the AGS under low OLR. AHL-mediated QS utilized C10-HSL, C12-HSL and 3OC6-HSL as the critical AHLs to regulate the TB-EPS in aerobic granulation, and autotrophic nitrifiers may perform interspecific communication with C10-HSL. The correlations of bacterial genera with AGS properties and AHLs were complex due to the dynamic fluctuations of microbial composition and other variable factors in the mixed-culture system. These findings confirmed the participation of AHL-mediated QS in the regulation of microbial community characters and AGS properties under low OLR, which may provide guidance for the operation of AGS systems under low OLR from a microbiological viewpoint.

Chen, X, Lai, C-Y, Fang, F, Zhao, H-P, Dai, X & Ni, B-J 2019, 'Model-based evaluation of selenate and nitrate reduction in hydrogen-based membrane biofilm reactor', Chemical Engineering Science, vol. 195, pp. 262-270.
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© 2018 Elsevier Ltd A biofilm model was developed to describe the simultaneous NO3− and SeO42− reduction in a H2-based membrane biofilm reactor (MBfR). Model calibration and validation was conducted using the experimental data of a reported H2-based MBfR. With a good level of identifiability, the SeO42− affinity constant and the SeO32− affinity constant were estimated at 9.80 ± 0.51 g Se m−3 and 1.83 ± 0.38 g Se m−3, respectively. The model was then applied to evaluate the effects of key operating conditions on the single-stage H2-based MBfR and the role of reactor configuration through comparing two-stage to single-stage MBfR systems. The results showed that (i) high SeO42− or low NO3− concentration in the influent favored the growth of selenate-reducing bacteria (SeRB) and therefore benefited the Se removal, (ii) the influent dissolved oxygen slightly inhibited the Se removal through enhancing the aerobic microbial respiration on H2, (iii) the H2 supply should be controlled at a proper level to avoid SeRB suppression and H2 wastage, (iv) thin biofilm should be avoided to ensure a protected niche for SeRB and therefore a promising Se removal, and (v) the two-stage MBfR configuration offered relatively higher efficiency in removing Se and NO3− simultaneously under the same loading condition.

Chen, X, Ni, B & Sin, G 2019, 'Nitrous oxide production in autotrophic nitrogen removal granular sludge: A modeling study', Biotechnology and Bioengineering, vol. 116, no. 6, pp. 1280-1291.
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AbstractThe sustainability of autotrophic granular system performing partial nitritation and anaerobic ammonium oxidation (anammox) for complete nitrogen removal is impaired by the production of nitrous oxide (N2O). A systematic analysis of the pathways and affecting parameters is, therefore, required for developing N2O mitigation strategies. To this end, a mathematical model capable of describing different N2O production pathways was defined in this study by synthesizing relevant mechanisms of ammonium‐oxidizing bacteria (AOB), nitrite‐oxidizing bacteria, heterotrophic bacteria (HB), and anammox bacteria. With the model validity reliably tested and verified using two independent sets of experimental data from two different autotrophic nitrogen removal biofilm/granular systems, the defined model was applied to reveal the underlying mechanisms of N2O production in the granular structure as well as the impacts of operating conditions on N2O production. The results show that: (a) in the aerobic zone close to the granule surface where AOB contribute to N2O production through both the AOB denitrification pathway and the NH2OH pathway, the co‐occurring HB consume N2O produced by AOB but indirectly enhance the N2O production by providing NO from NO2− reduction for the NH2OH pathway, (b) the inner anoxic zone of granules with the dominance of anammox bacteria acts as a sink for NO2− diffusing from the outer aerobic zone and, therefore, reduces N2O production from the AOB denitrification pathway, (c) operating parameters including bulk DO, influent NH4+, and granu...

Chen, X, Sin, G & Ni, B-J 2019, 'Impact of granule size distribution on nitrous oxide production in autotrophic nitrogen removal granular reactor', Science of The Total Environment, vol. 689, pp. 700-708.
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© 2019 Elsevier B.V. This work applied an approach with reactor compartmentation and artificial diffusion to study the impact of granule size distribution on the autotrophic granular reactor performing partial nitritation and anaerobic ammonium oxidation with focus on the nitrous oxide (N2O) production. The results show that the microbial community and the associated N2O production rates in the granular structure are significantly influenced by the granule size distribution. Heterotrophic bacteria growing on microbial decay products tend to be retained and contribute to N2O consumption in relatively small granules. Ammonium-oxidizing bacteria are mainly responsible for N2O production via two pathways in granules of different sizes. Under the conditions studied, such heterogeneity in the granular structure disappears when the number of granule size classes considered reaches >4, where heterotrophic bacteria are completely outcompeted in the granules. In general, larger granules account for a higher portion of the net N2O production, while the trend regarding the volumetric contribution of each granule size class changes with a varied number of granule size classes, due to the different contributions of relevant N2O production pathways (with the heterotrophic denitrification pathway being the most decisive). Overall, with the increasing extent of granule size distribution, the nitrogen removal efficiency decreases slightly but consistently, whereas the N2O production factor increases until the number of granule size classes reaches 4 or above. Practical implications of this work include: i) granules should be controlled as well-distributed as possible in order to obtain high nitrogen removal while minimizing N2O production; ii) granule size distribution should be considered carefully and specifically when modelling N2O production/emission from the autotrophic nitrogen removal granular reactor.

Chen, X, Yang, L, Sun, J, Dai, X & Ni, B-J 2019, 'Modelling of simultaneous nitrogen and thiocyanate removal through coupling thiocyanate-based denitrification with anaerobic ammonium oxidation', Environmental Pollution, vol. 253, pp. 974-980.
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© 2019 Elsevier Ltd Thiocyanate (SCN−)-based autotrophic denitrification (AD) has recently been demonstrated as a promising technology that could be integrated with anaerobic ammonium oxidation (Anammox) to achieve simultaneous removal of nitrogen and SCN−. However, there is still a lack of a complete SCN−-based AD model, and the potential microbial competition/synergy between AD bacteria and Anammox bacteria under different operating conditions remains unknown, which significantly hinders the possible application of coupling SCN−-based AD with Anammox. To this end, a complete SCN−-based AD model was firstly developed and reliably calibrated/validated using experimental datasets. The obtained SCN−-based AD model was then integrated with the well-established Anammox model and satisfactorily verified with experimental data from a system coupling AD with Anammox. The integrated model was lastly applied to investigate the impacts of influent NH4+-N/NO2−-N ratio and SCN− concentration on the steady-state microbial composition as well as the removal of nitrogen and SCN−. The results showed that the NH4+-N/NO2−-N ratio in the presence of a certain SCN− level should be controlled at a proper value so that the maximum synergy between AD bacteria and Anammox bacteria could be achieved while their competition for NO2− would be minimized. For the simultaneous maximum removal (>95%) of nitrogen and SCN−, there existed a negative relationship between the influent SCN− concentration and the optimal NH4+-N/NO2−-N ratio needed. High-level (>95%) simultaneous removal of nitrogen and thiocyanate could be achieved through combining thiocyanate-based autotrophic denitrification and Anammox.

Chen, Y, Alanezi, AA, Zhou, J, Altaee, A & Shaheed, MH 2019, 'Optimization of module pressure retarded osmosis membrane for maximum energy extraction', Journal of Water Process Engineering, vol. 32, pp. 100935-100935.
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© 2019 Elsevier Ltd A full-scale Pressure Retarded Osmosis process (PRO) is optimized in non-ideal operating conditions using Grey Wolf Optimization (GWO) algorithms. Optimization process included the classical parameters that previous studies recommended such as operating pressure, and feed and draw fractions in the mixture solution. The study has revealed that the recommended operating pressure ΔP=Δπ/2 and the ratio of feed or draw solution to the total mixture solution, ̴ 0.5, in a laboratory scale unit or in an ideal PRO process are not valid in a non-ideal full-scale PRO module. The optimization suggested that the optimum operating pressure is less than the previously recommended value of ΔP=Δπ/2. The optimization of hydraulic pressure resulted in 4.4% increase of the energy output in the PRO process. Conversely, optimization of feed fraction in the mixture has resulted in 28%–70% higher energy yield in a single-module PRO process and 9%–54% higher energy yield in a four-modules PRO process. The net energy generated in the optimized PRO process is higher than that in the unoptimized (normal) PRO process. The findings of this study reveal the significance of incorporating machine-learning algorithms in the optimization of PRO process and identifying the preferable operating conditions.

Chen, Z, Duan, X, Wei, W, Wang, S & Ni, B-J 2019, 'Recent advances in transition metal-based electrocatalysts for alkaline hydrogen evolution', Journal of Materials Chemistry A, vol. 7, no. 25, pp. 14971-15005.
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Transition metal-based electrocatalysts for alkaline hydrogen evolution reaction.

Chen, Z, Liu, Y, Wei, W & Ni, B-J 2019, 'Recent advances in electrocatalysts for halogenated organic pollutant degradation', Environmental Science: Nano, vol. 6, no. 8, pp. 2332-2366.
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Advanced electrocatalysts for halogenated organic pollutant degradation.

Chenari, RJ, Fatahi, B, Ghoreishi, M & Taleb, A 2019, 'Physical and numerical modelling of the inherent variability of shear strength in soil mechanics', Geomechanics and Engineering, vol. 17, no. 1, pp. 31-45.
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In this study the spatial variability of soils is substantiated physically and numerically by using random field theory. Heterogeneous samples are fabricated by combining nine homogeneous soil clusters that are assumed to be elements of an adopted random field. Homogeneous soils are prepared by mixing different percentages of kaolin and bentonite at water contents equivalent to their respective liquid limits. Comprehensive characteristic laboratory tests were carried out before embarking on direct shear experiments to deduce the basic correlations and properties of nine homogeneous soil clusters that serve to reconstitute the heterogeneous samples. The tests consist of Atterberg limits, and Oedometric and unconfined compression tests. The undrained shear strength of nine soil clusters were measured by the unconfined compression test data, and then correlations were made between the water content and the strength and stiffness of soil samples with different consistency limits. The direct shear strength of heterogeneous samples of different stochastic properties was then evaluated by physical and numerical modelling using FISH code programming in finite difference software of FLAC 3D . The results of the experimental and stochastic numerical analyses were then compared. The deviation of numerical simulations from direct shear load-displacement profiles taken from different sources were discussed, potential sources of error was introduced and elaborated. This study was primarily to explain the mathematical and physical procedures of sample preparation in stochastic soil mechanics. It can be extended to different problems and applications in geotechnical engineering discipline to take in to account the variability of strength and deformation parameters.

Cheng, DL, Ngo, HH, Guo, WS, Chang, SW, Nguyen, DD & Kumar, SM 2019, 'Microalgae biomass from swine wastewater and its conversion to bioenergy', Bioresource Technology, vol. 275, pp. 109-122.
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© 2018 Elsevier Ltd Ever-increasing swine wastewater (SW) has become a serious environmental concern. High levels of nutrients and toxic contaminants in SW significantly impact on the ecosystem and public health. On the other hand, swine wastewater is considered as valuable water and nutrient source for microalgae cultivation. The potential for converting the nutrients from SW into valuable biomass and then generating bioenergy from it has drawn increasing attention. For this reason, this review comprehensively discussed the biomass production, SW treatment efficiencies, and bioenergy generation potentials through cultivating microalgae in SW. Microalgae species grow well in SW with large amounts of biomass being produced, despite the impact of various parameters (e.g., nutrients and toxicants levels, cultivation conditions, and bacteria in SW). Pollutants in SW can effectively be removed by harvesting microalgae from SW, and the harvested microalgae biomass elicits high potential for conversion to valuable bioenergy.

Cheng, L, Song, W, Rao, Q, Zhou, J & Zhao, Z 2019, 'Bioaccumulation and toxicity of methoxychlor on Chinese mitten crab (Eriocheir sinensis)', Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology, vol. 221, pp. 89-95.
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Chinese mitten crab, a featured macrobenthos, has been one of the most important economical aquatic species in China. This study assessed the accumulation of an organochlorine pesticide methoxychlor (MXC) in Chinese mitten crab during exposure to 1 mg/L of MXC. The results showed the residual concentration of MXC in the ovary and hepatopancreas reached 55.07 ± 2.64 ng/g and 34.51 ± 2.35 ng/g, respectively. After exposure, tubular vacuolization of epithelial tissues, condensed egg cells and obvious intervals between egg cell wall and stroma were observed in the hepatopancreas and ovary, respectively. Significant changes of three key metabolic enzymes in hepatopancreas were observed upon exposure to MXC. Compared to the control, acetylcholinesterase level was significantly higher at day 7 (0.15 ± 0.01 vs. 0.06 ± 0.00 U/mgprot); glutathione S-transferase level was elevated at both day 4 (12.01 ± 0.48 vs. 3.20 ± 0.44 U/mgprot) and day 7 (12.84 ± 1.01 vs. 8.22 ± 0.81 U/mgprot); superoxide dismutase was sharply increased at day 4 (21.20 ± 0.24 vs. 3.66 ± 0.60 U/mgprot) but decreased at day 7 (3.74 ± 0.12 vs. 9.44 ± 0.85 U/mgprot). Overall, dissolved MXC accumulated in lipid-rich tissues could cause damages on epithelial cells and egg cells and change metabolic activities of enzymes involved in antioxidative stress and detoxification processes.

Choi, J, Dorji, P, Shon, HK & Hong, S 2019, 'Applications of capacitive deionization: Desalination, softening, selective removal, and energy efficiency', Desalination, vol. 449, pp. 118-130.
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© 2018 Elsevier B.V. Capacitive deionization (CDI) has attracted a great attention as a promising desalination technology, and studies on CDI have increased significantly in the last ten years. However, there have been no guidelines for developing strategies involving CDI technology for specific applications. Therefore, our work presents a critical review of the recent advances in CDI to meet the technical requirements of various applicable areas, with an emphasis on hybrid systems. This paper first summarizes the major developments made on novel electrode materials for CDI for brackish water desalination. Then, CDI and reverse osmosis (RO) integrated systems are critically reviewed for both ultrapure water production and wastewater treatment. Additionally, the applicability of CDI on various industrial processes is discussed, covering two distinct topics: (1) water softening and (2) selective removal of valuable heavy metals and nutrients (nitrate/phosphate). Lastly, recent improvements on the energy efficiency of CDI processes are delineated, specifically focusing on energy recovery and hybridization with energy producing technology, such as reverse electrodialysis (RED) and microbial fuel cells (MFC). This review paper is expected to share the practical experience of CDI applications as well as to provide guidelines for electrode material development for each specific application.

Choi, Y, Naidu, G, Lee, S & Vigneswaran, S 2019, 'Effect of inorganic and organic compounds on the performance of fractional-submerged membrane distillation-crystallizer', Journal of Membrane Science, vol. 582, pp. 9-19.
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© 2019 Elsevier B.V. A novel approach - fractional-submerged membrane distillation crystallizer (F-SMDC) was evaluated for treating brine. F-SMDC is based on creating concentration gradient (CG) and temperature gradient (TG) in a reactor containing submerged hollow-fiber membrane. This enables water and salt recovery to occur simultaneously in a single reactor. The influence of inorganic and organic compounds present in brine solutions on the development and stability of CG/TG in F-SMDC was evaluated in detail in this study. The results of the study showed that properties of inorganic compounds - molecular weight and electronegativity played a significant role in influencing CG/TG in F-SMDC. A high CG ratio (between 1.51 and 1.83 after crystallization) was observed when using feed solutions with inorganic compounds such as KCl, MgSO4, and Na2SO4. However, only low CG ratio (between 0.94 and 1.46) was achieved in the case of feed solutions containing lower molecular weight compounds, NH4Cl and NaCl. The high CG ratio with KCl resulted in the occurrence of salt crystallization at a faster rate (from VCF 2.4 onwards) compared to the predicted theoretical salt saturation point of VCF 3.0. On the other hands, Na2SO4 showed lower flux decline (12.56% flux decline) compared to MgSO4 (55.93% flux decline) This was attributed to lower cation electronegativity of Na+. The presence of CG in F-SMDC by concentrated inorganic compounds also enhanced organic compounds to gravitate downwards to the bottom of the reactor, potentially mitigating organic deposition on the membrane.

Choi, Y, Naidu, G, Nghiem, LD, Lee, S & Vigneswaran, S 2019, 'Membrane distillation crystallization for brine mining and zero liquid discharge: opportunities, challenges, and recent progress', Environmental Science: Water Research & Technology, vol. 5, no. 7, pp. 1202-1221.
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This review outlines all the work done on the membrane distillation crystallization process.

Choi, Y, Ryu, S, Naidu, G, Lee, S & Vigneswaran, S 2019, 'Integrated submerged membrane distillation-adsorption system for rubidium recovery', Separation and Purification Technology, vol. 218, pp. 146-155.
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© 2019 Elsevier B.V. Seawater reverse osmosis (SWRO) brine management is essential for desalination. Improving brine recovery rate with resource recovery can enhance the overall desalination process. In this study, an integrated submerged membrane distillation (S-MD) with adsorption (granular potassium copper hexacyanoferrate (KCuFC)) was evaluated for improving water recovery from brine while extracting valuable Rb. The thermal S-MD process (55 °C) with a continuous supply of Rb-rich SWRO brine enabled Rb to be concentrated (99% rejection) while producing fresh water. Concentrated Rb in thermal condition enhanced Rb extraction by granular KCuFC. An optimum dose (0.24 g/L) KCuFC was identified based on 98% Rb mass adsorption (9.78 mg as Rb). The integrated submerged MD-adsorption system was able to achieve more than 85% water recovery and Rb extraction in continuous feed supply (in two cycles). Ca in SWRO brine resulted in CaSO4 deposition onto the membrane and surface of KCuFC, reducing recovery rate and Rb adsorption. MD water recovery significantly improved upon Ca removal while achieving a total of 6.65 mg of Rb extraction. In comparing the performance of different KCuFC forms (granular, particle and powder), the particle form of KCuFC exhibited 10–47% higher capacity in terms of total adsorbed Rb mass and adsorption rate.

Chu Van, T, Zare, A, Jafari, M, Bodisco, TA, Surawski, N, Verma, P, Suara, K, Ristovski, Z, Rainey, T, Stevanovic, S & Brown, RJ 2019, 'Effect of cold start on engine performance and emissions from diesel engines using IMO-Compliant distillate fuels', Environmental Pollution, vol. 255, no. Pt 2, pp. 113260-113260.
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© 2019 Elsevier Ltd Emissions from ships at berth are small compared to the total ship emissions; however, they are one of the main contributors to pollutants in the air of densely-populated areas, consequently heavily affecting public health. This is due to auxiliary marine engines being used to generate electric power and steam for heating and providing services. The present study has been conducted on an engine representative of a marine auxiliary, which was a heavy duty, six-cylinder, turbocharged and after-cooled engine with a high pressure common rail injection system. Engine performance and emission characterisations during cold start are the focus of this paper, since cold start is significantly influential. Three tested fuels were used, including the reference diesel and two IMO (International Maritime Organization) compliant spiked fuels. The research engine was operated at a constant speed and 25% load condition after 12 h cooled soak. Results show that during cold start, significant heat generated from combustion is used to heat the engine block, coolant and lubricant. During the first minute, compared to the second minute, emissions of particle number (PN), carbon monoxide (CO), particulate matter (PM), and nitrogen oxides (NOx) were approximately 10, 4, 2 and 1.5 times higher, respectively. The engine control unit (ECU) plays a vital role in reducing engine emissions by changing the engine injection strategy based on the engine coolant temperature. IMO-compliant fuels, which were higher viscosity fuels associated with high sulphur content, resulted in an engine emission increase during cold start. It should be taken into account that auxiliary marine diesel engines, working at partial load conditions during cold start, contribute considerably to emissions in coastal areas. It demonstrates a need to implement practical measures, such as engine pre-heating, to obtain both environmental and public health advantages in coastal areas.

Coleman, MA, Clark, JS, Doblin, MA, Bishop, MJ & Kelaher, BP 2019, 'Genetic differentiation between estuarine and open coast ecotypes of a dominant ecosystem engineer', Marine and Freshwater Research, vol. 70, no. 7, pp. 977-977.
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Temperate intertidal shores globally are often dominated by habitat-forming seaweeds, but our knowledge of these systems is heavily biased towards northern hemisphere species. Rocky intertidal shores throughout Australia and New Zealand are dominated by a single monotypic species, Hormosira banksii. This species plays a key role in facilitating biodiversity on both rocky shores and estuarine habitats, yet we know little about the processes that structure populations. Herein we characterise the genetic diversity and structure of Hormosira and demonstrate strong restrictions to gene flow over small spatial scales, as well as between estuarine and open coast populations. Estuarine ecotypes were often genetically unique from nearby open coast populations, possibly due to extant reduced gene flow between habitats, founder effects and coastal geomorphology. Deviations from random mating in many locations suggest complex demographic processes are at play within shores, including clonality in estuarine populations. Strong isolation by distance in Hormosira suggests that spatial management of intertidal habitats will necessitate a network of broad-scale protection. Understanding patterns of genetic diversity and gene flow in this important ecosystem engineer will enhance the ability to manage, conserve and restore this key species into the future.

Commault, AS, Fabris, M, Kuzhiumparambil, U, Adriaans, J, Pernice, M & Ralph, PJ 2019, 'Methyl jasmonate treatment affects the regulation of the 2-C-methyl-D-erythritol 4-phosphate pathway and early steps of the triterpenoid biosynthesis in Chlamydomonas reinhardtii', Algal Research, vol. 39, pp. 101462-101462.
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© 2019 Elsevier B.V. Terpenoids are a large and diverse class of naturally occurring metabolites serving many industrial applications and natural roles. Economically important terpenoids are often produced in low abundance from their natural sources, making their industrial-scale production challenging or uneconomical, therefore engineered microorganisms are frequently used as heterologous production platforms. Photosynthetic microorganisms, such as the green alga Chlamydomonas reinhardtii, represent promising systems to produce terpenoids in a cost-effective and sustainable manner, but knowledge about the regulation of their terpenoid metabolism remains limited. Here we report on the investigation of the phytohormone methyl jasmonate (MeJA) as elicitor of algal terpenoid synthesis. We treated C. reinhardtii cells in mid-exponential growth phase with three different concentrations of MeJA (0.05, 0.5 and 1 mM). The highest concentration of MeJA affected the photosynthetic activity of the cells, arrested the growth and up-regulated key genes of the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway, leading to a significant increase in intermediates of this pathway, squalene and (S)-2,3-epoxysqualene, while the abundance of cycloartenol, and two main sterols (ergosterol and 7-dehydroporiferasterol) decreased. These data suggest the redirection of the carbon flux towards the synthesis of yet uncharacterised triterpenoid secondary metabolites upon MeJA treatment. Our results offer important new insights into the regulation of the triterpenoid metabolism in C. reinhardtii and raise important questions on hormonal signalling in microalgae. Phytohormone treatment is tested for the first time in algae, where it holds great potential for identifying key transcriptional regulators of the MEP pathway as targets for future metabolic engineering studies for improve production of high-value triterpenoids.

Damanik, Ong, Mofijur, Tong, Silitonga, Shamsuddin, Sebayang, Mahlia, Wang & Jang 2019, 'The Performance and Exhaust Emissions of a Diesel Engine Fuelled with Calophyllum inophyllum—Palm Biodiesel', Processes, vol. 7, no. 9, pp. 597-597.
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Nowadays, increased interest among the scientific community to explore the Calophyllum inophyllum as alternative fuels for diesel engines is observed. This research is about using mixed Calophyllum inophyllum-palm oil biodiesel production and evaluation that biodiesel in a diesel engine. The Calophyllum inophyllum–palm oil methyl ester (CPME) is processed using the following procedure: (1) the crude Calophyllum inophyllum and palm oils are mixed at the same ratio of 50:50 volume %, (2) degumming, (3) acid-catalysed esterification, (4) purification, and (5) alkaline-catalysed transesterification. The results are indeed encouraging which satisfy the international standards, CPME shows the high heating value (37.9 MJ/kg) but lower kinematic viscosity (4.50 mm2/s) due to change the fatty acid methyl ester (FAME) composition compared to Calophyllum inophyllum methyl ester (CIME). The average results show that the blended fuels have higher Brake Specific Fuel Consumption (BSFC) and NOx emissions, lower Brake Thermal Efficiency (BTE), along with CO and HC emissions than diesel fuel over the entire range of speeds. Among the blends, CPME5 offered better performance compared to other fuels. It can be recommended that the CPME blend has great potential as an alternative fuel because of its excellent characteristics, better performance, and less harmful emission than CIME blends.

Damtie, MM, Woo, YC, Kim, B, Hailemariam, RH, Park, K-D, Shon, HK, Park, C & Choi, J-S 2019, 'Removal of fluoride in membrane-based water and wastewater treatment technologies: Performance review', Journal of Environmental Management, vol. 251, pp. 109524-109524.
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The presence of excess fluoride in aqueous media above local environmental standards (e.g., the U.S. Environmental Protection Agency (EPA) standard of 4 mg/L) affects the health of aquatic life. Excess fluoride in drinking water above the maximum contaminant level (e.g., the World Health Organization (WHO) standard of 1.5 mg/L) also affects the skeletal and nervous systems of humans. Fluoride removal from aqueous solutions is difficult using conventional electrochemical, precipitation, and adsorption methods owing to its ionic size and reactivity. Thus, new technologies have been introduced to reduce the fluoride concentration in industrial wastewater effluents and various drinking water sources. Membrane technology is one of the newer technologies found to be very effective in significantly reducing fluoride to desired standards levels; however, it has received less attention than other technologies because it is perceived as a costly process. This study critically reviewed the performance of various membrane process and compared it with effluent and zero liquid discharge (ZLD) standards. The performance review has been conducted with the consideration of the theoretical background, rejection mechanisms, technical viability, and parameters affecting flux and rejection performance. This review includes membrane systems investigated for the defluoridation process but operated under pressure (i.e., reverse osmosis [RO] and nanofiltration [NF]), temperature gradients (i.e., membrane distillation [MD]), electrical potential gradients (i.e., electrodialysis [ED] and Donnan dialysis [DD]), and concentration differences (i.e., forward osmosis [FO]). Moreover, the study also addressed the advantages, limitations, & applicable conditions of each membrane based defluoridation process.

De Carvalho Gomes, S, Zhou, JL, Li, W & Long, G 2019, 'Progress in manufacture and properties of construction materials incorporating water treatment sludge: A review', Resources, Conservation and Recycling, vol. 145, pp. 148-159.
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© 2019 Elsevier B.V. Water treatment sludge (WTS) management is a growing global problem for water treatment plants (WTPs) and governments. Considering the scarcity of raw materials in many parts of the planet and unique properties of WTS, extensive research has been conducted on the application of WTS in the production of construction materials such as roof tiles, bricks, lightweight aggregates, cement, concrete and geopolymers. This paper critically reviews the progress in the application of WTS in construction materials, by synthesizing results from recent studies. Research findings have revealed that incorporation of ≤10% alum-based sludge in ceramic bricks is satisfactory with a small reduction of mechanical performance. Using the iron-based sludge, the bricks presented better mechanical strength than the reference clay-bricks. Concerning WTS application in concrete, 5% replacement of cement or sand by WTS was considered as the ideal value for the application in a variety of structural and non-structural concrete without adverse effect on concrete mechanical performance. Furthermore, this paper discusses sludge-amended concrete in terms of durability, potential leaching of toxic elements and cost, and suggests topics for future research on the sustainable management of WTS.

Deng, L, Ngo, H-H, Guo, W & Zhang, H 2019, 'Pre-coagulation coupled with sponge-membrane filtration for organic matter removal and membrane fouling control during drinking water treatment', Water Research, vol. 157, pp. 155-166.
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© 2019 Elsevier Ltd A new hybrid system was developed in this study for the treatment of drinking water consisting of pre-coagulation using polyaluminium chloride (PACl) and membrane filtration (MF) with sponge cubes acting as biomass carriers (P-SMF). When compared to a conventional MF (CMF) and a MF after coagulation by utilizing PACl (P-MF), better removal of nutrients, UV254 and dissolved organic carbon (DOC) (>65%) was obtained from the P-SMF. The accumulation of biopolymers (including polysaccharides and proteins), humic substances, hydrophilic organics, and other small molecular weight (MW) organic matter in the CMF led to the most severe membrane fouling coupled with the highest pore blocking and cake resistance. Pre-coagulation was ineffective in eliminating small MW and hydrophilic organic matter. Conversely, the larger MW organics (i.e. biopolymers and humic substances), small MW organics and hydrophilic organic compounds could be removed in significantly larger quantities in the P-SMF by PACl coagulation. This was achieved via adsorption and the biodegradation by attached biomass on these sponges and by the suspended sludge. Further analyses of the microbial community indicated that the combined addition of PACl and sponges generated a high enrichment of Zoolgloea, Amaricoccus and Reyranella leading to the reduction of biopolymers, and Flexibacter and Sphingobium were linked to the degradation of humic substances. Moreover, some members of Alphaproteobacteria in the P-SMF may be responsible for the removal of low MW organics. These results suggest that the pre-coagulation process coupled with adding sponge in the MF system is a promising technology for mitigating membrane fouling.

Ding, A, Lin, D, Zhao, Y, Ngo, HH, Guo, W, Bai, L, Luo, X, Li, G, Ren, N & Liang, H 2019, 'Effect of metabolic uncoupler, 2,4‑dinitrophenol (DNP) on sludge properties and fouling potential in ultrafiltration membrane process', Science of The Total Environment, vol. 650, no. Pt 2, pp. 1882-1888.
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© 2018 Elsevier B.V. Energy uncoupling technology was applied to the membrane process to control the problem of bio-fouling. Different dosages of uncoupler (2,4‑dinitrophenol, DNP) were added to the activated sludge, and a short-term ultrafiltration test was systematically investigated for analyzing membrane fouling potential and underlying mechanisms. Ultrafiltration membrane was used and made of polyether-sulfone with a molecular weight cut off (MWCO) of 150 kDa. Results indicated that low DNP concentration (15–30 mg/g VSS) aggravated membrane fouling because more soluble microbial products were released and then rejected by the membrane, which significantly increased cake layer resistance compared with the control. Conversely, a high dosage of DNP (45 mg/g VSS) retarded membrane fouling owing to the high inhibition of extracellular polymeric substances (proteins and polysaccharides) of the sludge, which effectively prevented the formation of cake layer on the membrane surface. Furthermore, analyses of fouling model revealed that a high dosage of DNP delayed the fouling model from pore blocking transition to cake filtration, whereas this transition process was accelerated in the low dosage scenario.

Ding, W, Jin, W, Cao, S, Zhou, X, Wang, C, Jiang, Q, Huang, H, Tu, R, Han, S-F & Wang, Q 2019, 'Ozone disinfection of chlorine-resistant bacteria in drinking water', Water Research, vol. 160, pp. 339-349.
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© 2019 Elsevier Ltd The wide application of chlorine disinfectant for drinking water treatment has led to the appearance of chlorine-resistant bacteria, which pose a severe threat to public health. This study was performed to explore the physiological-biochemical characteristics and environmental influence (pH, temperature, and turbidity)of seven strains of chlorine-resistant bacteria isolated from drinking water. Ozone disinfection was used to investigate the inactivation effect of bacteria and spores. The DNA concentration and cell surface structure variations of typical chlorine-resistant spores (Bacillus cereus spores)were also analysed by real-time qPCR, flow cytometry, and scanning electron microscopy to determine their inactivation mechanisms. The ozone resistance of bacteria (Aeromonas jandaei < Vogesella perlucida < Pelomonas < Bacillus cereus < Aeromonas sobria)was lower than that of spores (Bacillus alvei < Lysinibacillus fusiformis < Bacillus cereus)at an ozone concentration of 1.5 mg/L. More than 99.9% of Bacillus cereus spores were inactivated by increasing ozone concentration and treatment duration. Moreover, the DNA content of Bacillus cereus spores decreased sharply, but approximately 1/4 of the target genes remained. The spore structure exhibited shrinkage and folding after ozone treatment. Both cell structures and gene fragments were damaged by ozone disinfection. These results showed that ozone disinfection is a promising method for inactivating chlorine-resistant bacteria and spores in drinking water.

Ding, X, Wei, D, Guo, W, Wang, B, Meng, Z, Feng, R, Du, B & Wei, Q 2019, 'Biological denitrification in an anoxic sequencing batch biofilm reactor: Performance evaluation, nitrous oxide emission and microbial community', Bioresource Technology, vol. 285, pp. 121359-121359.
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Dong, B, Xia, Z, Sun, J, Dai, X, Chen, X & Ni, B-J 2019, 'The inhibitory impacts of nano-graphene oxide on methane production from waste activated sludge in anaerobic digestion', Science of The Total Environment, vol. 646, pp. 1376-1384.
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© 2018 The wide application of graphene oxide nanoparticles inevitably leads to their discharge into wastewater treatment plants and combination with the activated sludge. However, to date, it is largely unknown if the nano-graphene oxide (NGO) has potential impacts on the anaerobic digestion of waste activated sludge (WAS). Therefore, this work aims to fill the knowledge gap through comprehensively investigating the effects of NGO on carbon transformation and methane production in the anaerobic digestion of WAS. Biochemical methane potential tests demonstrated the methane production dropped with increasing NGO additions, the cumulative methane production decreasing by 7.6% and 12.6% at the NGO dosing rates of 0.054 mg/mg-VS and 0.108 mg/mg-VS, respectively. Model-based analysis indicated NGO significantly reduced biochemical methane potential, with the highest biochemical methane potential decrease being approximately 10% at the highest NGO dosing rate. Further experimental analysis suggested that the decreased methane production was firstly related to a decrease in soluble organic substrates availability during the process of sludge disintegration, potentially attributing to the strong absorption of organic substrates by NGO. Secondly, NGO significantly inhibited the methanogenesis by negatively affecting the corresponding enzyme activity (i.e. coenzyme F420), which could also resulted in a decreased methane production.

Dorji, P, Kim, DI, Jiang, J, Choi, J, Phuntsho, S, Hong, S & Shon, HK 2019, 'Bromide and iodide selectivity in membrane capacitive deionisation, and its potential application to reduce the formation of disinfection by-products in water treatment', Chemosphere, vol. 234, pp. 536-544.
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© 2019 Elsevier Ltd The formation of toxic disinfection by-products during water disinfection due to the presence of bromide and iodide is a major concern. Current treatment technologies such as membrane, adsorption and electrochemical processes have been known to have limitations such as high energy demand and excessive chemical use. In this study, the selectivity between bromide and iodide, and their removal in membrane capacitive deionisation (MCDI) was evaluated. The results showed that iodide was more selectively removed over bromide from several binary feed waters containing bromide and iodide under various initial concentrations and applied voltages. Even in the presence of significant background concentration of sodium chloride, definite selectivity of iodide over bromide was observed. The high partial-charge transfer coefficient of iodide compared to bromide could be a feasible explanation for high iodide selectivity since both bromide and iodide have similar ionic charge and hydrated radius. The result also shows that MCDI can be a potential alternative for the removal of bromide and iodide during water treatment.

Dorji, U, Tenzin, UM, Dorji, P, Wangchuk, U, Tshering, G, Dorji, C, Shon, H, Nyarko, KB & Phuntsho, S 2019, 'Wastewater management in urban Bhutan: Assessing the current practices and challenges', Process Safety and Environmental Protection, vol. 132, pp. 82-93.
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© 2019 Institution of Chemical Engineers This study reviews the current wastewater management practices and their challenges in urban Bhutan. The study data was collected from the local authorities of 35 classified towns, and the field survey was conducted for the two representative towns of Thimphu City and Khuruthang town. The study observed that only eight of the 35 classified towns (22.8%) have public sewerage systems, with an average coverage of 19.7% of Bhutan's total urban population, or 7.4% of Bhutan's entire population. The imported modular wastewater treatment technology was significantly more expensive than alternative options; however, approximately six towns have already adopted this technology, due to a lack of space for a much cheaper waste stabilisation ponds. Currently, over 80% of Bhutan's urban population depends on the on-site sanitation system for their domestic wastewater disposal; however, over 40% of these properties lacked a soak-pit system for the safe disposal of septic tank effluent. Therefore, this study indicates that urban settlements in Bhutan are potentially subjected to overflow of significant amount of hazardous septic tank effluents directly into the environment posing significant risk to public and the environment. A critical urban plot space analysis indicates that the current system of on-site sanitation is inadequate and unsuitable for the current urban settings. Since it is impractical for the government to provide public sewerage system to all the towns, a low-cost public sewerage system, or an alternative and improved on-site treatment system, needs to be explored and promoted to achieve long-term environmental objectives.

Duan, H, Ye, L, Wang, Q, Zheng, M, Lu, X, Wang, Z & Yuan, Z 2019, 'Nitrite oxidizing bacteria (NOB) contained in influent deteriorate mainstream NOB suppression by sidestream inactivation', Water Research, vol. 162, pp. 331-338.
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© 2019 Sidestream sludge treatment approaches have been developed in recent years to achieve mainstream nitrite shunt or partial nitritation, where NOB are selectively inactivated by biocidal factors such as free nitrous acid (FNA) or free ammonium (FA) in a sidestream reactor. The existence of NOB in raw wastewater has been increasingly realized and could pose critical challenge to stable NOB suppressions in those systems. This study, for the first time, evaluated the impact of influent NOB on the NOB suppressions in a mainstream nitrite shunt system achieved through sidestream sludge treatment. An over 500-day sequential batch reactor operation with six experimental phases rigorously demonstrated the negative effects of influent NOB on mainstream NOB control. Continuously seeding of NOB contained in influent stimulated NOB community shifts, leading to different extents of ineffective NOB suppression. The role of primary wastewater treatment in NOB removal from raw wastewater was also investigated. Results suggest primary settling and High Rate Activated Sludge system could remove a large part of NOB contained in raw wastewater. Primary treatment for raw wastewater is necessary for ensuring stable mainstream NOB suppressions.

Duong, HC, Ansari, AJ, Nghiem, LD, Cao, HT, Vu, TD & Nguyen, TP 2019, 'Membrane Processes for the Regeneration of Liquid Desiccant Solution for Air Conditioning', Current Pollution Reports, vol. 5, no. 4, pp. 308-318.
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© 2019, Springer Nature Switzerland AG. Purpose of Review: Regeneration of liquid desiccant solutions is critical for the liquid desiccant air conditioning (LDAC) process. In most LDAC systems, the weak desiccant solution is regenerated using the energy-intensive thermal evaporation method which suffers from desiccant carry-over. Recently, membrane processes have gained increasing interest as a promising method for liquid desiccant solution regeneration. This paper provides a comprehensive review on the applications of membrane processes for regeneration of liquid desiccant solutions. Fundamental knowledge, working principles, and the applications of four key membrane processes (e.g., reverse osmosis (RO), forward osmosis (FO), electrodialysis (ED), and membrane distillation (MD)) are discussed to shed light on their feasibility for liquid desiccant solution regeneration and the associated challenges. Recent Findings: RO is effective at preventing desiccant carry-over; however, current RO membranes are not compatible with hypersaline liquid desiccant solutions. FO deploys a concentrated draw solution to overcome the high osmotic pressure of liquid desiccant solutions; hence, it is feasible for their regeneration despite the issues with internal/external concentration polarization and reverse salt flux. ED has proven its technical feasibility for liquid desiccant solution regeneration; nevertheless, more research into the process energy efficiency and the recycling of spent solution are recommended. Finally, as a thermally driven process, MD is capable of regenerating liquid desiccant solutions, but it is adversely affected by the polarization effects associated with the hypersalinity of the solutions. Summary: Extensive studies are required to realize the applications of membrane processes for the regeneration of liquid desiccant solutions used for LDAC systems.

Duong, HC, Pham, TM, Luong, ST, Nguyen, KV, Nguyen, DT, Ansari, AJ & Nghiem, LD 2019, 'A novel application of membrane distillation to facilitate nickel recovery from electroplating wastewater', Environmental Science and Pollution Research, vol. 26, no. 23, pp. 23407-23415.
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© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. In many years, the nickel electroplating technique has been applied to coat nickel on other materials for their increased properties. Nickel electroplating has played a vital role in our modern society but also caused considerable environmental concerns due to the mass discharge of its wastewater (i.e. containing nickel and other heavy metals) to the environment. Thus, there is a growing need for treating nickel electroplating wastewater to protect the environment and, in tandem, recover nickel for beneficial use. This study explores a novel application of membrane distillation (MD) for the treatment of nickel electroplating wastewater for a dual purpose: facilitating the nickel recovery and obtaining fresh water. The experimental results demonstrate the technical capability of MD to pre-concentrate nickel in the wastewater (i.e. hence pave the way for subsequent nickel recovery via chemical precipitation or electrodeposition) and extract fresh water. At a low operating feed temperature of 60 °C, the MD process increased the nickel content in the wastewater by more than 100-fold from 0.31 to 33 g/L with only a 20% reduction in the process water flux and obtained pure fresh water. At such high concentration factors, the membrane surface was slightly fouled by inorganic precipitates; however, membrane pore wetting was not evident, confirmed by the purity of the obtained fresh water. The fouled membrane was effectively cleaned using a 3% HCl solution to restore its surface morphology. Finally, the preliminary thermal energy analysis of the combined MD–chemical precipitation/electrodeposition process reveals a considerable reduction in energy consumption of the nickel recovery process.

Eeshwarasinghe, D, Loganathan, P & Vigneswaran, S 2019, 'Simultaneous removal of polycyclic aromatic hydrocarbons and heavy metals from water using granular activated carbon', Chemosphere, vol. 223, pp. 616-627.
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© 2019 Elsevier Ltd Polycyclic aromatic hydrocarbons (PAHs) and heavy metals are dangerous pollutants that commonly co-occur in water. An adsorption study conducted on the simultaneous removal of PAHs (acenaphthylene, phenanthrene) and heavy metals (Cd, Cu, Zn) by granular activated carbon (GAC) showed that, when these pollutants are present together, their adsorption was less than when they were present individually. The adsorptive removal percentage of PAHs (initial concentration 1 mg/L) was much higher than that of heavy metals (initial concentration (20 mg/L). The reduction in adsorption of PAHs by heavy metals followed the heavy metals' adsorption capacity and reduction in the negative zeta potential of GAC order (Cu > Zn > Cd). In contrast, PAHs had little effect on the zeta potential of GAC. The Langmuir adsorption capacities of acenaphthylene (0.31–2.63 mg/g) and phenanthrene (0.74–7.36 mg/g) on GAC decreased with increased metals' concentration with the reduction following the order of the metals’ adsorption capacity. The kinetic adsorption data fitted to Weber and Morris plots, indicating intra-particle diffusion of both PAHs and heavy metals into the mesopores and micropores in GAC with the diffusion rates. This depended on the type of PAH and metal and whether the pollutants were present alone or together.

Ekanayake, D, Aryal, R, Hasan Johir, MA, Loganathan, P, Bush, C, Kandasamy, J & Vigneswaran, S 2019, 'Interrelationship among the pollutants in stormwater in an urban catchment and first flush identification using UV spectroscopy', Chemosphere, vol. 233, pp. 245-251.
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© 2019 Elsevier Ltd Assessing urban stormwater quality by investigation and characterisation of pollutants is a prerequisite for its effective management, for reuse and safe discharge. The stochastic nature of rainfall, dry weather periods, topology, human activities and climatic conditions generate and wash-off pollutants differently from event to event. This study investigated the major physico-chemical pollutants in stormwater runoff collected from an urban catchment over a period of two years. The aim of this study was to explore the use of UV spectroscopy to identify the first flush. In this study, the variation of pollutants during the passage of a rain event and the relationships among the measured pollutants was analysed to help broaden the application of UV spectroscopy beyond the detection of organic matter. Correlation analysis and principal component analysis (PCA) were performed to identify the possible relationship among measured pollutants. Although correlation analysis revealed some relationships between pollutants, in general they were not strong enough and was not helpful. PCA biplots suggested a few groups and revealed that the two components model could explain nearly 72% of the variability between pollutants. Pollutants in the group that included dissolved organic carbon (DOC) behaved in a similar manner. UV spectroscopy was applied to identify the first flush by comparing the recorded spectrum of consecutive samples that were collected in an event. Analysis of the spectra was able to isolate the point when first flush ends for DOC and pollutants that behave similar to it.

Fahmi, Rahman, Ong, Jan, Kusumo, Sebayang, Husin, Silitonga, Mahlia & Rahman 2019, 'Production Process and Optimization of Solid Bioethanol from Empty Fruit Bunches of Palm Oil Using Response Surface Methodology', Processes, vol. 7, no. 10, pp. 715-715.
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This study aimed to observe the potential of solid bioethanol as an alternative fuel with high caloric value. The solid bioethanol was produced from liquid bioethanol, which was obtained from the synthesis of oil palm empty fruit bunches (PEFBs) through the delignification process by using organosolv pretreatment and enzymatic hydrolysis. Enzymatic hydrolysis was conducted using enzyme (60 FPUg−1 of cellulose) at a variety of temperatures (35 °C, 70 °C, and 90 °C) and reaction times (2, 6, 12, 18, and 24 h) in order to obtain a high sugar yield. The highest sugars were yielded at the temperature of 90 °C for 48 h (152.51 mg/L). Furthermore, fermentation was conducted using Saccharomyces cerevisiae. The bioethanol yield after fermentation was 62.29 mg/L. Bioethanol was extracted by distillation process to obtain solid bioethanol. The solid bioethanol was produced by using stearic acid as the additive. In order to get high-quality solid bioethanol, the calorific value was optimized using the response surface methodology (RSM) model. This model provided the factor variables of bioethanol concentration (vol %), stearic acid (g), and bioethanol (mL) with a minus result error. The highest calorific value was obtained with 7 g stearic acid and 5 mL bioethanol (43.17 MJ/kg). Burning time was tested to observe the quality of the solid bioethanol. The highest calorific value resulted in the longest burning time. The solid bioethanol has a potential as solid fuel due to the significantly higher calorific value compared to the liquid bioethanol.

Fatahi, B 2019, 'Editorial', Proceedings of the Institution of Civil Engineers - Ground Improvement, vol. 172, no. 1, pp. 1-2.
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Fatimah, I, Sahroni, I, Fadillah, G, Musawwa, MM, Mahlia, TMI & Muraza, O 2019, 'Glycerol to Solketal for Fuel Additive: Recent Progress in Heterogeneous Catalysts', Energies, vol. 12, no. 15, pp. 2872-2872.
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Biodiesel has been successfully commercialized in numerous countries. Glycerol, as a byproduct in biodiesel production plant, has been explored recently for fuel additive production. One of the most prospective fuel additives is solketal, which is produced from glycerol and acetone via an acetalization reaction. This manuscript reviewed recent progress on heterogeneous catalysts used in the exploratory stage of glycerol conversion to solketal. The effects of acidity strength, hydrophobicity, confinement effect, and others are discussed to find the most critical parameters to design better catalysts for solketal production. Among the heterogeneous catalysts, resins, hierarchical zeolites, mesoporous silica materials, and clays have been explored as effective catalysts for acetalization of glycerol. Challenges with each popular catalytic material are elaborated. Future works on glycerol to solketal will be improved by considering the stability of the catalysts in the presence of water as a byproduct. The presence of water and salt in the feed is certainly destructive to the activity and the stability of the catalysts.

Fattah, IMR, Yip, HL, Jiang, Z, Yuen, ACY, Yang, W, Medwell, PR, Kook, S, Yeoh, GH & Chan, QN 2019, 'Effects of flame-plane wall impingement on diesel combustion and soot processes', Fuel, vol. 255, pp. 115726-115726.
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© 2019 Elsevier Ltd This work aims to assess the effects of flame-wall impingement on the combustion and soot processes of diesel flames. For this work, experimental measurements were performed in a constant-volume combustion chamber (CVCC) at ambient conditions that are representative of compression-ignition engines. The characteristics of impinging and free flames were compared at two identical ambient and injector conditions (20.8 kg/m3 ambient density, 6 MPa ambient pressure, 1000 K bulk temperature, 15 and 10 vol% ambient O2 concentration, and 100 MPa injection pressure). To simulate flame-wall impingement, a flat plane steel wall, normal to the injector axis, was initially placed at 53 mm from nozzle, but was varied from 53 to 35 mm during the experiments. Under the test conditions of this work, it was found that wall impingement resulted in lower soot temperature and soot content, in addition to a loss of momentum for the wall jet. The results also revealed that decreasing impingement distance from the nozzle resulted in reduced soot temperature and soot level for the wall jet. The reduced soot content observed for the wall jet appeared to be mainly driven by enhanced mixing. Flame transparency modeling was also performed to assess the uncertainties of two-color measurements for flame-plane wall impingement. The analysis indicated that the derived soot temperature and concentration values would be affected by the actual temperature profiles, rendering the technique useful to reveal trends, but not reliable for absolute soot concentration measurements.

Feng, Y, Zhao, Y, Jiang, B, Zhao, H, Wang, Q & Liu, S 2019, 'Discrepant gene functional potential and cross-feedings of anammox bacteria Ca. Jettenia caeni and Ca. Brocadia sinica in response to acetate', Water Research, vol. 165, pp. 114974-114974.
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© 2019 Elsevier Ltd Although the enhancement of anammox performance for wastewater treatment due to the addition of small amount of acetate has been reported, discrepant metabolic responses of different anammox species have not been experimentally evaluated. Based on metagenomics and metatranscriptomic data, we investigated the competitiveness between two typical anammox species, Candidatus Jettenia caeni (J. caeni) and Candidatus Brocadia sinica (B. sinica), in anammox consortia under mixotrophic condition, where complex metabolic interactions among anammox bacteria and heterotrophs also changed with acetate addition. Contrary to J. caeni, the dissimilatory nitrate reduction to ammonium pathway of B. sinica was markedly stimulated for improving nitrogen removal. More acetate metabolic pathways and up-regulated AMP-acs expression for acetyl-CoA synthesis in B. sinica contributed to its superiority in acetate utilization. Interestingly, cross-feedings, including the nitrogen cycle, amino acid cross-feeding and B-vitamin metabolic exchange between B. sinica and other heterotrophs seemed to be enhanced with acetate addition, contributing to a reduction in metabolic energy cost to the whole community. Our work not only clarified the mechanism underlying discrepant responses of different anammox species to acetate, but also suggests a possible strategy for obtaining higher nitrogen removal rates in wastewater treatment under low C/N ratio.

Gao, P, Wang, X, Huang, Z & Yu, H 2019, '¹¹B NMR Chemical Shift Predictions via Density Functional Theory and Gauge-Including Atomic Orbital Approach: Applications to Structural Elucidations of Boron-Containing Molecules', ACS Omega, vol. 4, no. 7, pp. 12385-12392.
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© 2019 American Chemical Society. 11B nuclear magnetic resonance (NMR) spectroscopy is a useful tool for studies of boron-containing compounds in terms of structural analysis and reaction kinetics monitoring. A computational protocol, which is aimed at an accurate prediction of 11B NMR chemical shifts via linear regression, was proposed based on the density functional theory and the gauge-including atomic orbital approach. Similar to the procedure used for carbon, hydrogen, and nitrogen chemical shift predictions, a database of boron-containing molecules was first compiled. Scaling factors for the linear regression between calculated isotropic shielding constants and experimental chemical shifts were then fitted using eight different levels of theory with both the solvation model based on density and conductor-like polarizable continuum model solvent models. The best method with the two solvent models yields a root-mean-square deviation of about 3.40 and 3.37 ppm, respectively. To explore the capabilities and potential limitations of the developed protocols, classical boron-hydrogen compounds and molecules with representative boron bonding environments were chosen as test cases, and the consistency between experimental values and theoretical predictions was demonstrated.

Goh, BHH, Ong, HC, Cheah, MY, Chen, W-H, Yu, KL & Mahlia, TMI 2019, 'Sustainability of direct biodiesel synthesis from microalgae biomass: A critical review', Renewable and Sustainable Energy Reviews, vol. 107, pp. 59-74.
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© 2019 Elsevier Ltd Microalgae has been identified as a potential feedstock for biodiesel production since its cultivation requires less cropland compared to conventional oil crops and the high growth rate of microalgae. Research on microalgae oils often are focused on microalgae oil extraction and biomass harvesting techniques. However, energy intensive and costly lipid extraction methods are the major obstacles hampering microalgae biodiesel commercialisation. Direct biodiesel synthesis avoids such problems as it combines lipid extraction techniques and transesterification into a single step. In this review, the potential of direct biodiesel synthesis from microalgae biomass was comprehensively analysed. The various species of microalgae commonly used as biodiesel feedstock was critically assessed, particularly on high lipid content species. The production of microalgae biodiesel via direct conversion from biomass was systematically discussed, covering major enhancements such as heterogeneous catalysts, the use of ultrasonic and microwave- techniques and supercritical alcohols that focus on the overall improvement of biodiesel production. In addition, this review illustrates the cultivation conditions for biomass growth and lipid productivity improvement, the available harvesting and lipid extraction technologies, as well as the key challenges and future prospect of microalgae biodiesel production. This review serves as a basis for future research on direct biodiesel synthesis from modified microalgae biomass to improve profitability of microalgae biodiesel.

GOH, CJ, PARK, D, LEE, JS, DAVEY, PA, PERNICE, M, RALPH, PJ & HAHN, Y 2019, 'Zostera virus T – a novel virus of the genus Tepovirus identified in the eelgrass, Zostera muelleri', Acta virologica, vol. 63, no. 04, pp. 366-372.
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Analysis of a transcriptome dataset obtained from tissue samples of the eelgrass Zostera muelleri, an aquatic flowering plant species of the family Zosteraceae, yielded three genome sequence contigs of a novel RNA virus. Sequence comparison and phylogenetic analysis revealed that the novel RNA virus, named Zostera virus T (ZoVT), belongs to the genus Tepovirus of the family Betaflexiviridae. The three genome contigs of ZoVT showed 88.2‒97.2% nucleotide sequence identity to each other, indicating that they descended from a common ancestor. The ZoVT genome contains three open reading frames (ORFs): ORF1 encodes a 1816 amino acid (aa) replicase (REP) with RNA-dependent RNA polymerase (RdRp) activity; ORF2, a 398 aa movement protein (MP); and ORF3, a 240 aa coat protein (CP). The phylogenetic analysis using REP sequences of ZoVT and other Betaflexiviridae viruses showed that Prunus virus T is the closest known virus to ZoVT, whereas potato virus T, the type species of the genus Tepovirus, is the second closest virus. Genome sequences of ZoVT, which is the third tepovirus species identified to date, may be useful for investigating the evolution and molecular biology of tepoviruses. Keywords: Zostera virus T; Tepovirus; Betaflexiviridae; eelgrass; Zostera muelleri.

Gonzales, RR, Park, MJ, Bae, T-H, Yang, Y, Abdel-Wahab, A, Phuntsho, S & Shon, HK 2019, 'Melamine-based covalent organic framework-incorporated thin film nanocomposite membrane for enhanced osmotic power generation', Desalination, vol. 459, pp. 10-19.
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© 2019 A melamine-based covalent organic framework (COF) nanomaterial, Schiff base network-1 (SNW-1), was incorporated into the polyamide layer of a novel thin film nanocomposite (TFN) pressure retarded osmosis (PRO) membrane. The deposition of SNW-1 was made on an open mesh fabric-reinforced polyamide-imide (PAI) support substrate through interfacial polymerization (IP). SNW-1 loading influence on the water permeability and osmotic power density during PRO operation was investigated. The porous and highly hydrophilic SNW-1 nanomaterial facilitated the flow of water molecules across the membranes, while maintaining satisfactory salt rejection ability of the polyamide selective layer. The membranes exhibited significantly enhanced surface hydrophilicity, water permeability, and power density. The mode of incorporation of SNW-1 during IP was also investigated and it was observed that the secondary amine groups of SNW-1 react with the carbonyl groups of 1,3,5-benzenetricarbonyl trichloride, the acyl halide precursor in polyamide formation; thus, SNW-1 was incorporated through the amine precursor, 1,3-phenylenediamine. Testing with 1.0 M NaCl as the draw solution, the TFN membrane with a loading of 0.02 wt% SNW-1 exhibited the highest water flux of 42.5 Lm−2 h−1 and power density of 12.1 Wm−2, while withstanding hydraulic pressure over 24 bar. This study suggests that COF-incorporation can be a promising method in PRO membrane fabrication to improve both osmotic performance and energy harvesting capability for the PRO process.

Goyen, S, Camp, EF, Fujise, L, Lloyd, A, Nitschke, MR, LaJeunensse, T, Kahlke, T, Ralph, PJ & Suggett, D 2019, 'Mass coral bleaching of P. versipora in Sydney Harbour driven by the 2015–2016 heatwave', Coral Reefs, vol. 38, no. 4, pp. 815-830.
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© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. High-latitude coral communities are distinct from their tropical counterparts, and how they respond to recent heat wave events that have decimated tropical reefs remains unknown. In Australia, the 2016 El Niño resulted in the largest global mass coral bleaching event to date, reaching as far south as Sydney Harbour (~ 34°S). Coral bleaching was observed for the first time (affecting ca., 60% of all corals) as sea surface temperatures in Sydney Harbour remained > 2 °C above the long-term mean summer maxima, enabling us to examine whether high-latitude corals bleached in a manner described for tropical corals. Responses of the geographically cosmopolitan Plesiastrea versipora and southerly restricted Coscinaraea mcneilli were contrasted across two harbour sites, both in situ and among samples-maintained ex situ in aquaria continually supplied with Sydney Harbour seawater. While both coral taxa hosted the same species of microalgal endosymbiont (Breviolum spp; formerly clade B), only P. versipora bleached both in situ and ex situ via pronounced losses of endosymbiont cells. Both species displayed very different metabolic responses (growth, photosynthesis, respiration and calcification) and bleaching susceptibilities under elevated temperatures. Bacterial microbiome profiling, however, revealed a convergence of bacterial community composition across coral species throughout the bleaching. Corals species found in temperate regions, including the generalist P. versipora, will therefore likely be highly susceptible to future change as heat waves grow in frequency and severity unless their thermal thresholds increase. Our observations provide further evidence that high-latitude systems are susceptible to community reorganisation under climate change.

Goyen, S, Camp, EF, Fujise, L, Lloyd, A, Nitschke, MR, LaJeunesse, TC, Kahlke, T, Ralph, PJ & Suggett, D 2019, 'Correction to: Mass coral bleaching of P. versipora in Sydney Harbour driven by the 2015–2016 heatwave', Coral Reefs, vol. 38, no. 4, pp. 877-877.
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Guo, G, Sun, Y, Fu, Q, Ma, Y, Zhou, Y, Xiong, Z & Liu, Y 2019, 'Sol-gel synthesis of ternary conducting polymer hydrogel for application in all-solid-state flexible supercapacitor', International Journal of Hydrogen Energy, vol. 44, no. 12, pp. 6103-6115.
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© 2019 Hydrogen Energy Publications LLC In this contribution, we reported the preparation of a novel conducting polymer hydrogel (CPH) by a sol-gel method, which was subsequently employed to fabricate a flexible all-solid-state supercapacitor device. Taking advantage of the synergistic effects of the different components in the conducting polymer hydrogel and the merits of the proposed synthesis strategies, the prepared supercapacitor device with CPH as electrode exhibited high area-normalized capacitance (2.2 F cm −2 ), high gravimetric capacitance (1573.6 F g −1 ) as well as high energy density of 0.18 mWh cm −2 (or 128.7 Wh Kg −1 ) at 0.08 mW cm −2 (or 55.1 W kg −1 ). This study did not only represent a novel all-solid-state, high performance, flexible supercapacitor with potential applications in flexible energy-related devices, but also developed a new method for enhancing capacitances and mechanical stability of all-solid-state flexible supercapacitor.

Guo, H, Hu, J, Li, J, Gao, M-T, Wang, Q, Guo, W & Ngo, HH 2019, 'Systematic insight into the short-term and long-term effects of magnetic microparticles and nanoparticles on critical flux in membrane bioreactors', Journal of Membrane Science, vol. 582, pp. 284-288.
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© 2019 This study aims to systematically investigate the short-term and long-term effects of magnetic microparticles (MPs) and nanoparticles (NPs) on critical flux in membrane bioreactors (MBRs). Comparison among six MBRs was carried out with different activated sludge samples. Results showed that the short-term adsorption and flocculation contributed only minimally, however, the long-term magnetic induced bio-effect improved the critical flux by conditioning sludge properties. Additional molecular weight distribution of soluble microbial product (SMP) indicated that long-term magnetic induced bio-effect declined the content of macromolecules (>500 kDa and 300–500 kDa), but promoted the content of small molecules (<100 kDa), consequently reduced the free energy of SMP gelling foulants, and further promoted the higher critical flux. Moreover, the magnetic MPs presented the better performance than NPs. This study illustrated that sufficient pre-acclimatization of magnetic activated sludge is significantly necessary to improve the critical flux in MBRs.

Guo, W, Lei, Z, Wang, J & Wei, D 2019, 'Special issue on challenges in biological wastewater treatment and resource recovery', Bioresource Technology Reports, vol. 7, pp. 100243-100243.
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Hafiz, MA, Hawari, AH & Altaee, A 2019, 'A hybrid forward osmosis/reverse osmosis process for the supply of fertilizing solution from treated wastewater', Journal of Water Process Engineering, vol. 32, pp. 100975-100975.
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© 2019 Elsevier Ltd This work investigates the application of a hybrid system that combines forward osmosis (FO) and reverse osmosis (RO) processes for the supply of a fertilizing solution that could be used directly for irrigation purposes. In the FO process the feed solution is treated sewage effluent (TSE) and two different types of draw solutions were investigated. The impact of the feed solution and the draw solution flowrates and the membrane orientation on the membrane flux were investigated in the forward osmosis process. RO was used for the regeneration of the draw solution. In the forward osmosis process it was found that the highest membrane flux was 13.2 LMH. The FO process had high rejection rates for total phosphorus and ammonium which were 99% and 97%, respectively. RO achieved 99% total salts rejection rate. Seawater RO (SW30HR) and brackish water RO (BW30LE) membranes were used for the regeneration of the draw solution. The specific power consumption for the regeneration of the draw solution was 2.58 kW h/m3 and 2.18 kW h/m3 for SW30HR and BW30LE membranes, respectively. The final product water had high quality in terms of total dissolved solids concentration but the concentration of phosphorus was slightly higher than recommended due to adding 0.1 M of diammonium phosphate in the draw solution.

Han, R, Khan, MH, Angeloski, A, Casillas, G, Yoon, CW, Sun, X & Huang, Z 2019, 'Hexagonal Boron Nitride Nanosheets Grown via Chemical Vapor Deposition for Silver Protection', ACS Applied Nano Materials, vol. 2, no. 5, pp. 2830-2835.
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© 2019 American Chemical Society. In this study, hexagonal boron nitride nanosheets (h-BNNS) have been grown on polycrystalline silver substrates via chemical vapor deposition (CVD) using ammonia borane as a precursor. The h-BNNS are of few-atomic-layer thickness and form continuous coverage over the whole Ag substrate. The atomically thin coating poses negligible interference to the reflectivity in the UV-visible range. The nanosheet coating also proves very effective in protecting Ag foil chemically. In contrast to bare Ag foil, the coated foil displayed only minor decolorization under high concentration of H2S. The study indicates that h-BNNS can be a promising protective coating for Ag based items such as jewelry or mirrors used in astronomical telescopes.

Han, S-F, Jin, W, Abomohra, AE-F, Zhou, X, Tu, R, Chen, C, Chen, H, Gao, S-H & Wang, Q 2019, 'Enhancement of Lipid Production of Scenedesmus obliquus Cultivated in Municipal Wastewater by Plant Growth Regulator Treatment', Waste and Biomass Valorization, vol. 10, no. 9, pp. 2479-2485.
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© 2018, Springer Science+Business Media B.V., part of Springer Nature. Effects of four different plant growth regulators including indole-3-acetic acid (IAA), 1-triacontanol (TRIA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (6-BA) on biomass and lipid productivity of microalga Scenedesmus obliquus cultured in municipal wastewater were primarily studied. The results showed that the lipid productivity of S. obliquus was significantly increased by 30.5 and 23.6% after the treatment by IAA and TRIA, respectively. According to the GC analysis of the lipids, the addition of IAA and TRIA could increase the content of monounsaturated fatty acid in S. obliquus, and thus improving the grade of biodiesel. After the addition of IAA and TRIA, the nitrogen content of S. obliquus significantly decreased, while bacterial diversity in wastewater increased, which could enhance the stability of microbial system in the wastewater medium. Meanwhile, significant increase were also found in the abundances of β-Proteobacteria and α-Proteobacteria.

Han, S-F, Jin, W, Yang, Q, El-Fatah Abomohra, A, Zhou, X, Tu, R, Chen, C, Xie, G-J & Wang, Q 2019, 'Application of pulse electric field pretreatment for enhancing lipid extraction from Chlorella pyrenoidosa grown in wastewater', Renewable Energy, vol. 133, pp. 233-239.
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© 2018 Elsevier Ltd Lipid extraction is a key step of biodiesel production from microalgae, however, the application of traditional extraction methods was limited due to the difficulties of cell disruption as well as solvent toxicity. In this work, pretreatment method using pulsed electric field (PEF), was primarily applied to lipid extraction process from microalgae Chlorella pyrenoidosa grown in wastewater. After the pretreatment with PEF, the yields of fatty acid methyl esters from C.pyrenoidosa was 12.0% higher than traditional pretreatment with ultrasonic. The results indicated that PEF was an effective method for cell disruption. Fluorescence staining and scanning electron microscopy showed that the integrity of the cell membrane of microalgae was damaged under pulsed electric field, which enhanced the penetration of solvents and lipid extraction.

Hao, Q, Liu, Y, Chen, T, Guo, Q, Wei, W & Ni, B-J 2019, 'Bi₂O₃@Carbon Nanocomposites for Solar-Driven Photocatalytic Degradation of Chlorophenols', ACS Applied Nano Materials, vol. 2, no. 4, pp. 2308-2316.
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Copyright © 2019 American Chemical Society. Chlorophenols are corrosive and toxic in a water environment, which have caused increasing concerns and encourage the development of solar-driven techniques with highly efficient photocatalysts for green remediation. Coupling photocatalysis with the surface plasmon resonance (SPR) effect is a practical solution for boosting the utilization of solar light in the IR region while improving the overall performance of the photocatalysts. However, a facile and green strategy to synthesize metallic non-noble bismuth (Bi0)-based photocatalysts is still lacking. Herein, we report smart Bi/Bi2O3/C composites with high performance for the photocatalytic degradation of 2,4-dichlorophenol. Advanced characterizations such as X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy are applied to analyze the morphology and structure of the prepared materials. The photodegradation rate of the hybrid is significantly enhanced compared with the sole counterparts, which are 1.60-fold of Bi2O3 and 2.47-fold of g-C3N4. The synthesized Bi/C-2 exhibits excellent stability without a decline in activity after four cycles. The SPR effect of Bi is identified to account for the strengthened photoreactivity. Moreover, the relatively high utilization efficiency of solar energy and the rapid separation rate of photogenerated electron and hole pairs helped to enhance the photocatalytic performance synergistically. ©

Hassoun, M & Fatahi, B 2019, 'Novel integrated ground anchor technology for the seismic protection of isolated segmented cantilever bridges', Soil Dynamics and Earthquake Engineering, vol. 125, pp. 105709-105709.
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© 2019 Elsevier Ltd An external restraining system which is anchoring the bridge superstructure to the embankment backfill is proposed in this study for the seismic protection of isolated bridges. The restraining system is employed to reduce the seismic demands of the bridge deck by utilising the otherwise inactive ground behind the abutment back-walls. The system can be described as fastening the bridge end-diaphragms to the rocky strata that lie beneath the abutment backfill. The anchoring is achieved through a series of steel strands grouted to the rock to achieve a strong anchoring capacity. Indeed, the proposed anchor is flexible enough to allow the thermal, creep and shrinkage serviceability movements of the deck. A parametric study conducted in this paper shows that the ground anchor external restraining system is truly effective in reducing the seismic demands of the bridge deck.

Hossain, N & Mahlia, TMI 2019, 'Progress in physicochemical parameters of microalgae cultivation for biofuel production', Critical Reviews in Biotechnology, vol. 39, no. 6, pp. 835-859.
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© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. Microalgae have been exploited for biofuel generation in the current era due to its enormous energy content, fast cellular growth rate, inexpensive culture approaches, accumulation of inorganic compounds, and CO2 sequestration. Currently, research is ongoing towards the advancement of the microalgae cultivation parameters to enhance the biomass yield. The main objective of this study was to delineate the progress of physicochemical parameters for microalgae cultivation such as gaseous transfer, mixing, light demand, temperature, pH, nutrients and the culture period. This review demonstrates the latest research trends on mass transfer coefficient of different microalgae culturing reactors, gas velocity optimization, light intensity, retention time, and radiance effects on microalgae cellular growth, temperature impact on chlorophyll production, and nutrient dosage ratios for cellulosic metabolism to avoid nutrient deprivation. Besides that, cultivation approaches for microalgae associated with mathematical modeling for different parameters, mechanisms of microalgal growth rate and doubling time have been elaborately described. Along with that, this review also documents potential lipid-carbohydrate-protein enriched microalgae candidates for biofuel, biomass productivity, and different cultivation conditions including open-pond cultivation, closed-loop cultivation, and photobioreactors. Various photobioreactor types, the microalgae strain, productivity, advantages, and limitations were tabulated. In line with microalgae cultivation, this study also outlines in detail numerous biofuels from microalgae.

Hossain, N, Mahlia, TMI & Saidur, R 2019, 'Latest development in microalgae-biofuel production with nano-additives', Biotechnology for Biofuels, vol. 12, no. 1.
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© 2019 The Author(s). Background: Microalgae have been experimented as a potential feedstock for biofuel generation in current era owing to its' rich energy content, inflated growth rate, inexpensive culture approaches, the notable capacity of CO2 fixation, and O2 addition to the environment. Currently, research is ongoing towards the advancement of microalgal-biofuel technologies. The nano-additive application has been appeared as a prominent innovation to meet this phenomenon. Main text: The main objective of this study was to delineate the synergistic impact of microalgal biofuel integrated with nano-additive applications. Numerous nano-additives such as nano-fibres, nano-particles, nano-tubes, nano-sheets, nano-droplets, and other nano-structures' applications have been reviewed in this study to facilitate microalgae growth to biofuel utilization. The present paper was intended to comprehensively review the nano-particles preparing techniques for microalgae cultivation and harvesting, biofuel extraction, and application of microalgae-biofuel nano-particles blends. Prospects of solid nano-additives and nano-fluid applications in the future on microalgae production, microalgae biomass conversion to biofuels as well as enhancement of biofuel combustion for revolutionary advancement in biofuel technology have been demonstrated elaborately by this review. This study also highlighted the potential biofuels from microalgae, numerous technologies, and conversion processes. Along with that, the study recounted suitability of potential microalgae candidates with an integrated design generating value-added co-products besides biofuel production. Conclusions: Nano-additive applications at different stages from microalgae culture to end-product utilization presented strong possibility in mercantile approach as well as positive impact on the environment along with valuable co-products generation into the near future.

Hossain, N, Mahlia, TMI, Zaini, J & Saidur, R 2019, 'Techno‐economics and Sensitivity Analysis of Microalgae as Commercial Feedstock for Bioethanol Production', Environmental Progress & Sustainable Energy, vol. 38, no. 5, pp. 13157-13157.
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The foremost purpose of this techno‐economic analysis (TEA) modeling was to predict a harmonized figure of comprehensive cost analysis for commercial bioethanol generation from microalgae species in Brunei Darussalam based on the conventional market scenario. This model was simulated to set out economic feasibility and probabilistic assumption for large‐scale implementations of a tropical microalgae species, Chlorella vulgaris, for a bioethanol plant located in the coastal area of Brunei Darussalam. Two types of cultivation systems such as closed system (photobioreactor—PBR) and open pond approaches were anticipated for a total approximate biomass of 220 t year−1 on 6 ha coastal areas. The biomass productivity was 56 t ha−1 for PBR and 28 t ha−1 for pond annually. The plant output was 58.90 m3 ha−1 for PBR and 24.9 m3 ha−1 for pond annually. The total bioethanol output of the plant was 57,087.58 gal year−1 along with the value added by‐products (crude bio‐liquid and slurry cake). The total production cost of this project was US$2.22 million for bioethanol from microalgae and total bioethanol selling price was US$2.87 million along with the by‐product sale price of US$1.6 million. A sensitivity analysis was conducted to forecast the uncertainty of this conclusive modeling. Different data sets through sensitivity analysis also presented positive impacts of economical and environmental views. This TEA model is expected to be initialized to determine an alternative energy and also minimize environmental pollution. With this current modeling, microalgal‐bioethanol utilization mandated with gasoline as well as microalgae cultivation, biofuel production integrated with existing complementary industries, are strongly recommended for future applications. © 2019 A...

Hossain, N, Razali, AN, Mahlia, TMI, Chowdhury, T, Chowdhury, H, Ong, HC, Shamsuddin, AH & Silitonga, AS 2019, 'Experimental Investigation, Techno-Economic Analysis and Environmental Impact of Bioethanol Production from Banana Stem', Energies, vol. 12, no. 20, pp. 3947-3947.
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Banana stem is being considered as the second largest waste biomass in Malaysia. Therefore, the environmental challenge of managing this huge amount of biomass as well as converting the feedstock into value-added products has spurred the demand for diversified applications to be implemented as a realistic approach. In this study, banana stem waste was experimented for bioethanol generation via hydrolysis and fermentation methods with the presence of Saccharomyces cerevisiae (yeast) subsequently. Along with the experimental analysis, a realistic pilot scale application of electricity generation from the bioethanol has been designed by HOMER software to demonstrate techno-economic and environmental impact. During sulfuric acid and enzymatic hydrolysis, the highest glucose yield was 5.614 and 40.61 g/L, respectively. During fermentation, the maximum and minimum glucose yield was 62.23 g/L at 12 h and 0.69 g/L at 72 h, respectively. Subsequently, 99.8% pure bioethanol was recovered by a distillation process. Plant modeling simulated operating costs 65,980 US$/y, net production cost 869347 US$ and electricity cost 0.392 US$/kWh. The CO2 emission from bioethanol was 97,161 kg/y and SO2 emission was 513 kg/y which is much lower than diesel emission. The overall bioethanol production from banana stem and application of electricity generation presented the approach economically favorable and environmentally benign.

Hossain, N, Zaini, J & Indra Mahlia, TM 2019, 'Life cycle assessment, energy balance and sensitivity analysis of bioethanol production from microalgae in a tropical country', Renewable and Sustainable Energy Reviews, vol. 115, pp. 109371-109371.
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© 2019 Elsevier Ltd Overuse of petroleum and ongoing carbon-di-oxide (CO2) rise in the air of Brunei Darussalam has been emerged as a major environmental concern in this country. To resolve this issue, a comprehensive life cycle assessment (LCA) of alternative biofuel, bioethanol production from microalgae was demanded for realistic implementation. Therefore, LCA of bioethanol production from microalgae in terms of CO2 emission and energy balance was investigated based on the scenario of industrial-scale in Brunei Darussalam. This study demonstrated that 220 tons microalgae biomass was cultivated on 6 ha offshore lands for commercial bioethanol generation. The annual outcome of this commercial bioethanol plant has revealed net CO2 balance 218.86 ton. From the energy perspective, this study manifested itself as favourable with net energy ratio, 0.45 and net energy balance, −2749.6 GJ y−1. Apart from CO2 balance and energy generation aspect, the project demanded low water and land footprints. For photobioreactor cultivation, water and land footprints were 2 m3 GJ−1 and 2 m2 GJ−1, respectively as well as for open pond approach, they were 87 m3 GJ−1 and 13 m2 GJ−1, respectively. The project also presented microalgae growth supplements (phosphorus and nitrogen) accumulation possibilities from wastewater of manure and industries which is another positive aspect for benign environment. Overall, the commercial plant presented low CO2 emission, low land and water demand for microalgae cultivation, alternative eco-friendly and cheaper nutrients sources, quite high energy generation with main product and by-products. Thus, this study projected positive impact on energy and environmental aspects of microalgae-to-bioethanol conversion.

Hossain, N, Zaini, J & Mahlia, TMI 2019, 'Experimental investigation of energy properties forStigonematalessp. microalgae as potential biofuel feedstock', International Journal of Sustainable Engineering, vol. 12, no. 2, pp. 123-130.
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© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. Microalgae has been considered potential biofuel source from the last decade owing to its versatile perspectives such as excellent capability of CO 2 capture and sequestration, water treatment, prolific growth rate and enormous energy content. Thus, energy research on microalgae is being harnessed to mitigate CO 2 and meet future energy demands. This study investigated the bioenergy potential of native blue-green microalgae consortium as initial energy research on microalgae in Brunei Darussalam. The local species of microalgae were assembled from rainwater drains, the species were identified as Stigonematales sp. and physical properties were characterised. Sundried biomass with moisture content ranging from 6.5% to 7.37% was measured to be used to determine the net and gross calorific value and they were 7.98 MJ/kg-8.57 MJ/kg and 8.70 MJ/kg-9.45 MJ/kg, respectively. Besides that, the hydrogen content, ash content, volatile matter, and bulk density were also experimented and they were 2.56%-3.15%, 43.6%-36.71%, 57–38%-63.29% and 661.2 kg/m 3 -673.07 kg/m 3 , respectively. Apart from experimental values, other physical bioenergy parameters were simulated and they were biomass characteristic index 61,822.29 kg/m 3 -62,341.3 kg/m 3 , energy density 5.27 GJ/m 3 -5.76G J/m 3 and fuel value index 86.19–88.54. With these experimental results, microalgae manifested itself a potential source of biofuel feedstock for heat and electricity generation, a key tool to bring down the escalated atmospheric greenhouse gases and an alternation for fossil fuel.

Hossain, N, Zaini, J, Mahlia, TMI & Azad, AK 2019, 'Elemental, morphological and thermal analysis of mixed microalgae species from drain water', Renewable Energy, vol. 131, pp. 617-624.
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© 2018 Elsevier Ltd In this study, Stigonematales sp. microalgae were collected from drain water and characterized for its’ morphological edifice, elemental composition, thermal condition and energy generation capacity by using scanning electron microscopy, energy dispersive X-ray, thermogravimetric analyzer and bomb calorimeter, respectively. Scanning electron micrographs revealed the top view of microalgae and ash pellet with carbon coated specimens at low voltage (5.0 kV) through the secondary electron image detector. Elemental analysis revealed all the major and minor constituents of this microalgae species and its’ ash in terms of dry weight (%) and atomic weight (%). Thermogravimetric analysis was conducted at heating rate, 10 °C/min and this experimental results determined moisture content, volatile matter, ash content and fixed carbon of the sample with 4.5%, 35%, 39.5% and 21%, respectively. Microalgae powder blended with bituminous coal by 75%, 50% and 25% measured calorific value 14.07 MJ/kg, 19.88 MJ/kg and 26.42 MJ/kg, respectively. Microalgae (75%) -coal (25%) blend showed excellent amount of energy content, 24.59 MJ/kg. Microalgae blended with coal unveiled an outstanding outcome with elevation of the volatile matter and drop of the ash content. Optimization of microalgae-coal blend in large-scale application can initiate bright future in renewable energy exploration.

Hossain, SM, Park, MJ, Park, HJ, Tijing, L, Kim, J-H & Shon, HK 2019, 'Preparation and characterization of TiO2 generated from synthetic wastewater using TiCl4 based coagulation/flocculation aided with Ca(OH)2', Journal of Environmental Management, vol. 250, pp. 109521-109521.
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This study focused on the preparation of undoped and Ca-doped titania from flocculation generated sludge. Initially, TiCl4 was utilised to perform coagulation and flocculation in synthetic wastewater and an optimised dose of coagulant was determined by evaluating the turbidity, dissolved organic carbon (DOC) and zeta potential of the treated water. Later, using Ca(OH)2 as a coagulant aid, the effects on effluent pH, turbidity and DOC removal were investigated. Both Ca-doped and undoped anatase TiO2 were prepared from the flocculated sludge for morphological and photocatalytic evaluation. During the standalone use of TiCl4, maximum turbidity and DOC removal were found at 11.63 and 14.54 mg Ti/L, respectively. At the corresponding coagulant dose, rapid deprotonation of water caused the pH of the effluent to reach below 3.77 mg Ti/L. Whereas, when using Ca(OH)2 as a coagulant aid, a neutral pH (7.26) was attained at a simultaneous dosing of 32.40 mg Ca/L and 14.54 mg Ti/L. When aided with Ca(OH)2, the turbidity removal was further increased by 54.28% and the DOC removal was somewhat similar to the standalone use of TiCl4. TiO2 was prepared by incinerating the collected sludge at 600 °C for 2 h. Both XRD and SEM analysis were conducted to observe the morphology of the prepared titania. The XRD pattern of the TiO2 showed only an anatase phase along with the presence of a high atomic proportion of Ca (4.14%). Consequently, a high amount of Ca atoms inhibited the level of TiO2 phase and no obvious presence of CaO was observed. The prepared Ca-doped TiO2 at the optimised dose of Ca(OH)2 was found to be inferior to the undoped TiO2 during the photodegradation of acetaldehyde. However, a reduced dose of Ca(OH)2 (<15 mg Ca/L) exhibited a substantial increase in photoactivity under UV irradiance.

How, HG, Teoh, YH, Masjuki, HH, Nguyen, H-T, Kalam, MA, Chuah, HG & Alabdulkarem, A 2019, 'Impact of two-stage injection fuel quantity on engine-out responses of a common-rail diesel engine fueled with coconut oil methyl esters-diesel fuel blends', Renewable Energy, vol. 139, pp. 515-529.
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Howard, D, Macsween, K, Edwards, GC, Desservettaz, M, Guérette, E-A, Paton-Walsh, C, Surawski, NC, Sullivan, AL, Weston, C, Volkova, L, Powell, J, Keywood, MD, Reisen, F & (Mick) Meyer, CP 2019, 'Investigation of mercury emissions from burning of Australian eucalypt forest surface fuels using a combustion wind tunnel and field observations', Atmospheric Environment, vol. 202, pp. 17-27.
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© 2018 Environmental cycling of the toxic metal mercury (Hg) is ubiquitous, and still not completely understood. Volatilisation and emission of mercury from vegetation, litter and soil during burning represents a significant return pathway for previously-deposited atmospheric mercury. Rates of such emission vary widely across ecosystems as they are dependent on species-specific uptake of atmospheric mercury as well as fire return frequencies. Wildfire burning in Australia is currently thought to contribute between 1 and 5% of the global total of mercury emissions, yet no modelling efforts to date have utilised local mercury emission factors (mass of emitted mercury per mass of dry fuel) or local mercury emission ratios (ratio of emitted mercury to another emitted species, typically carbon monoxide). Here we present laboratory and field investigations into mercury emission from burning of surface fuels in dry sclerophyll forests, native to the temperate south-eastern region of Australia. From laboratory data we found that fire behaviour — in particular combustion phase — has a large influence on mercury emission and hence emission ratios. Further, emission of mercury was predominantly in gaseous form with particulate-bound mercury representing <1% of total mercury emission. Importantly, emission factors and emission ratios with respect to carbon monoxide and carbon dioxide, from both laboratory and field data all show that gaseous mercury emission from biomass burning in Australian dry sclerophyll forests is currently overestimated by around 60%. Based on these results, we recommend a mercury emission factor of 28.7 ± 8.1 μg Hg kg−1 dry fuel, and emission ratio of gaseous elemental mercury relative to carbon monoxide of 0.58 ± 0.01 × 10−7, for estimation of mercury release from the combustion of Australian dry sclerophyll litter.

Huang, Q-S, Wei, W, Sun, J, Mao, S & Ni, B-J 2019, 'Hexagonal K₂W₄O₁₃ Nanowires for the Adsorption of Methylene Blue', ACS Applied Nano Materials, vol. 2, no. 6, pp. 3802-3812.
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© 2019 American Chemical Society. In this study, novel hexagonal K2W4O13 (h-K2W4O13) nanowires were strategically synthesized via a facial hydrothermal method, which exhibited excellent adsorption capacities for wastewater treatment. The inorganic agent K2SO4 was used as a structure-directing agent to scaffold the tunnel structure of h-K2W4O13 and form the one-dimensional structure. Through increasing the relative molar ratio of K2SO4 to Na2WO4 precursor, the pure-phase h-WO3 nanorods and h-K2W4O13 nanowires were obtained, attributing to the competitive electrostatic adsorption between K+ ions and Na+ ions on h-WO3 nuclei. With a smaller hydrated radius in the solution (dK+ = 3.31 Å, dNa+= 3.58 Å), K+ exhibited superior affinity compared to Na+ with the negatively charged h-WO3 nuclei because of a larger charge density, resulting in the formation of h-K2W4O13. Adsorption experimental results showed that 89.4% of methylene blue was removed by h-K2W4O13 in the first 5 min (99% in 1 h) and the maximum uptake capacity reached 204.08 mg g-1. In addition, the novel h-K2W4O13 exhibited acid or alkali resistance and good reusability, revealed by the stable adsorption capacity in a wide pH range of 3.0-11.0 and five-run recycle tests. The large specific area, high proportion of effective pore volume, and abundant hydroxyl groups of the synthesized h-K2W4O13 resulted in excellent adsorption performance for methylene blue.

Huang, Q-S, Wu, W, Wei, W & Ni, B-J 2019, 'Polyethylenimine modified potassium tungsten oxide adsorbent for highly efficient Ag+ removal and valuable Ag0 recovery', Science of The Total Environment, vol. 692, pp. 1048-1056.
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Elemental Ag0 is well known for its remarkable catalytic and antibacterial properties, thus the regeneration of valuable Ag0 metal from Ag+ wastewater is of great significance. In this study, a novel polyethylenimine (PEI) modified potassium tungsten oxide (N-K2W4O13) adsorbent was prepared for Ag+ removal and reduction to Ag0 using glutaraldehyde as crosslinking agent. XPS and FT-IR spectra verified PEI successfully anchored on the surface O and W atoms of K2W4O13 through aldehyde bridges. The content of PEI in N-K2W4O13 was calculated as 8.74wt% by TG curve. A heterogeneous PEI coating was observed in the SEM and TEM images. The N-K2W4O13 exhibited larger Ag+ uptake (48.25mg/g) than the raw K2W4O13 (42.50mg/g) though required a longer equilibrium time. This was due to the combined results of strong chelation and weak electrostatic repulsion that meanwhile occurring on the positive-charged surface of N-K2W4O13. The maximum Ag+ uptake on N-K2W4O13 was 72.5mg/g, which was larger than many of the reported adsorbents. Furthermore, the prepared N-K2W4O13 displayed good anti-interference toward background ions (Na+, K+) and hold a stable Ag+ removal (>95%) after five runs of recycling tests. The mechanism studies elucidated that NH/N groups from the PEI modified N-K2W4O13 mainly accounted for the Ag+ adsorption and Ag0 recovery in the adsorption-reduction process. Ion-exchange between Ag+ and K+ from the N-K2W4O13 lattice also occurred. This work provided a facile method to synthesize a promising adsorbent for Ag+ wastewater remediation and valuable Ag0 recovery.

Huang, W-Y, Ngo, H-H, Lin, C, Vu, C-T, Kaewlaoyoong, A, Boonsong, T, Tran, H-T, Bui, X-T, Vo, T-D-H & Chen, J-R 2019, 'Aerobic co-composting degradation of highly PCDD/F-contaminated field soil. A study of bacterial community', Science of The Total Environment, vol. 660, pp. 595-602.
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This study investigated bacterial communities during aerobic food waste co-composting degradation of highly PCDD/F-contaminated field soil. The total initial toxic equivalent quantity (TEQ) of the soil was 16,004 ng-TEQ kg-1 dry weight. After 42-day composting and bioactivity-enhanced monitored natural attenuation (MNA), the final compost product's TEQ reduced to 1916 ng-TEQ kg-1 dry weight (approximately 75% degradation) with a degradation rate of 136.33 ng-TEQ kg-1 day-1. Variations in bacterial communities and PCDD/F degraders were identified by next-generation sequencing (NGS). Thermophilic conditions of the co-composting process resulted in fewer observed bacteria and PCDD/F concentrations. Numerous organic compound degraders were identified by NGS, supporting the conclusion that PCDD/Fs were degraded during food waste co-composting. Bacterial communities of the composting process were defined by four phyla (Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes). At the genus level, Bacillus (Firmicutes) emerged as the most dominant phylotype. Further studies on specific roles of these bacterial strains are needed, especially for the thermophiles which contributed to the high degradation rate of the co-co-composting treatment's first 14 days.

Huang, Y, Ng, ECY, Yam, Y-S, Lee, CKC, Surawski, NC, Mok, W-C, Organ, B, Zhou, JL & Chan, EFC 2019, 'Impact of potential engine malfunctions on fuel consumption and gaseous emissions of a Euro VI diesel truck', Energy Conversion and Management, vol. 184, pp. 521-529.
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© 2019 Elsevier Ltd Although new vehicles are designed to comply with specific emission regulations, their in-service performance would not necessarily achieve them due to wear-and-tear and improper maintenance, as well as tampering or failure of engine control and exhaust after-treatment systems. In addition, there is a lack of knowledge on how significantly these potential malfunctions affect vehicle performance. This study was therefore conducted to simulate the effect of various engine malfunctions on the fuel consumption and gaseous emissions of a 16-tonne Euro VI diesel truck using transient chassis dynamometer testing. The simulated malfunctions included those that would commonly occur in the intake, fuel injection, exhaust after-treatment and other systems. The results showed that all malfunctions increased fuel consumption except for the malfunction of EGR fully closed which reduced fuel consumption by 31%. The biggest increases in fuel consumption were caused by malfunctions in the intake system (16%–43%), followed by the exhaust after-treatment (6%–30%), fuel injection (4%–24%) and other systems (6%–11%). Regarding pollutant emissions, the effect of engine malfunctions on HC and CO emissions was insignificant, which remained unchanged or even reduced for most cases. An exception was EGR fully open which increased HC and CO emissions by 343% and 1124%, respectively. Contrary to HC and CO emissions, NO emissions were significantly increased by malfunctions. The largest increases in NO emissions were caused by malfunctions in the after-treatment system, ranging from 38% (SCR) to 1606% (DPF pressure sensor). Malfunctions in the fuel injection system (24%–1259%) and intercooler (438%–604%) could also increase NO emissions markedly. This study demonstrated clearly the importance of having properly functioning engine control and exhaust after-treatment systems to achieve the required performance of fuel consumption and pollutant emissions.

Huang, Y, Organ, B, Zhou, JL, Surawski, NC, Yam, Y-S & Chan, EFC 2019, 'Characterisation of diesel vehicle emissions and determination of remote sensing cutpoints for diesel high-emitters', Environmental Pollution, vol. 252, no. Part A, pp. 31-38.
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© 2019 Elsevier Ltd Diesel vehicles are a major source of air pollutants in cities and have caused significant health risks to the public globally. This study used both on-road remote sensing and transient chassis dynamometer to characterise emissions of diesel light goods vehicles. A large sample size of 183 diesel vans were tested on a transient chassis dynamometer to evaluate the emission levels of in-service diesel vehicles and to determine a set of remote sensing cutpoints for diesel high-emitters. The results showed that 79% and 19% of the Euro 4 and Euro 5 diesel vehicles failed the transient cycle test, respectively. Most of the high-emitters failed the NO limits, while no vehicle failed the HC limits and only a few vehicles failed the CO limits. Vehicles that failed NO limits occurred in both old and new vehicles. NO/CO2 ratios of 57.30 and 22.85 ppm/% were chosen as the remote sensing cutpoints for Euro 4 and Euro 5 high-emitters, respectively. The cutpoints could capture a Euro 4 and Euro 5 high-emitter at a probability of 27% and 57% with one snapshot remote sensing measurement, while only producing 1% of false high-emitter detections. The probability of high-emitting events was generally evenly distributed over the test cycle, indicating that no particular driving condition produced a higher probability of high-emitting events. Analysis on the effect of cutpoints on real-driving diesel fleet was carried out using a three-year remote sensing program. Results showed that 36% of Euro 4 and 47% of Euro 5 remote sensing measurements would be detected as high-emitting using the proposed cutpoints. In-service diesel vehicles emit low CO and HC but high NO.

Huang, Y, Surawski, NC, Organ, B, Zhou, JL, Tang, OHH & Chan, EFC 2019, 'Fuel consumption and emissions performance under real driving: Comparison between hybrid and conventional vehicles', Science of The Total Environment, vol. 659, pp. 275-282.
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© 2018 Elsevier B.V. Hybrid electric vehicles (HEVs) are perceived to be more energy efficient and less polluting than conventional internal combustion engine (ICE) vehicles. However, increasing evidence has shown that real-driving emissions (RDE) could be much higher than laboratory type approval limits and the advantages of HEVs over their conventional ICE counterparts under real-driving conditions have not been studied extensively. Therefore, this study was conducted to evaluate the real-driving fuel consumption and pollutant emissions performance of HEVs against their conventional ICE counterparts. Two pairs of hybrid and conventional gasoline vehicles of the same model were tested simultaneously in a novel convoy mode using two portable emission measurement systems (PEMSs), thus eliminating the effect of vehicle configurations, driving behaviour, road conditions and ambient environment on the performance comparison. The results showed that although real-driving fuel consumption for both hybrid and conventional vehicles were 44%–100% and 30%–82% higher than their laboratory results respectively, HEVs saved 23%–49% fuel relative to their conventional ICE counterparts. Pollutant emissions of all the tested vehicles were lower than the regulation limits. However, HEVs showed no reduction in HC emissions and consistently higher CO emissions compared to the conventional ICE vehicles. This could be caused by the frequent stops and restarts of the HEV engines, as well as the lowered exhaust gas temperature and reduced effectiveness of the oxidation catalyst. The findings therefore show that while achieving the fuel reduction target, hybridisation did not bring the expected benefits to urban air quality.

Hurtado-McCormick, V, Kahlke, T, Petrou, K, Jeffries, T, Ralph, PJ & Seymour, JR 2019, 'Regional and Microenvironmental Scale Characterization of the Zostera muelleri Seagrass Microbiome', Frontiers in Microbiology, vol. 10, no. MAY.
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Seagrasses are globally distributed marine plants that represent an extremely valuable component of coastal ecosystems. Like terrestrial plants, seagrass productivity and health are likely to be strongly governed by the structure and function of the seagrass microbiome, which will be distributed across a number of discrete microenvironments within the plant, including the phyllosphere, the endosphere and the rhizosphere, all different in physical and chemical conditions. Here we examined patterns in the composition of the microbiome of the seagrass Zostera muelleri, within six plant-associated microenvironments sampled across four different coastal locations in New South Wales, Australia. Amplicon sequencing approaches were used to characterize the diversity and composition of bacterial, microalgal, and fungal microbiomes and ultimately identify “core microbiome” members that were conserved across sampling microenvironments. Discrete populations of bacteria, microalgae and fungi were observed within specific seagrass microenvironments, including the leaves and roots and rhizomes, with “core” taxa found to persist within these microenvironments across geographically disparate sampling sites. Bacterial, microalgal and fungal community profiles were most strongly governed by intrinsic features of the different seagrass microenvironments, whereby microscale differences in community composition were greater than the differences observed between sampling regions. However, our results showed differing strengths of microbial preferences at the plant scale, since this microenvironmental variability was more pronounced for bacteria than it was for microalgae and fungi, suggesting more specific interactions between the bacterial consortia and the seagrass host, and potentially implying a highly specialized coupling between seagrass and bacterial metabolism and ecology. Due to their persistence within a given seagrass microenviron...

Ibrar, I, Naji, O, Sharif, A, Malekizadeh, A, Alhawari, A, Alanezi, AA & Altaee, A 2019, 'A Review of Fouling Mechanisms, Control Strategies and Real-Time Fouling Monitoring Techniques in Forward Osmosis', Water, vol. 11, no. 4, pp. 695-695.
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Forward osmosis has gained tremendous attention in the field of desalination and wastewater treatment. However, membrane fouling is an inevitable issue. Membrane fouling leads to flux decline, can cause operational problems and can result in negative consequences that can damage the membrane. Hereby, we attempt to review the different types of fouling in forward osmosis, cleaning and control strategies for fouling mitigation, and the impact of membrane hydrophilicity, charge and morphology on fouling. The fundamentals of biofouling, organic, colloidal and inorganic fouling are discussed with a focus on recent studies. We also review some of the in-situ real-time online fouling monitoring technologies for real-time fouling monitoring that can be applicable to future research on forward osmosis fouling studies. A brief discussion on critical flux and the coupled effects of fouling and concentration polarization is also provided.

Idroes, R, Yusuf, M, Saiful, S, Alatas, M, Subhan, S, Lala, A, Muslem, M, Suhendra, R, Idroes, GM, Marwan, M & Mahlia, TMI 2019, 'Geochemistry Exploration and Geothermometry Application in the North Zone of Seulawah Agam, Aceh Besar District, Indonesia', Energies, vol. 12, no. 23, pp. 4442-4442.
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A geochemistry study has been done in four geothermal manifestations—Ie-Seu’um, Ie-Brôuk, Ie-Jue and the Van-Heutz crater—located in the north zone of Seulawah Agam mountain (Aceh Besar District, Indonesia). The study was performed through water and gas analysis. Water analysis were done for all geothermal manifestations, but gas analysis was only done for the Ie-Jue manifestation that has fumaroles. Cation and anion contents were analyzed by ion chromatography, ICP-OES, alkalimetry titrations, and spectrophotometry, meanwhile isotopes were measured by a Liquid Water Isotope Analyzer. The resulting data were used for fluid and gas geothermometry calculations, and plotted in a FT-CO2 Cross-Plot and a CH4-CO2-H2S triangle diagram to obtain reservoir temperatures. The data were also plotted by a Cl-HCO3-SO4 triangle and Piper diagram to obtain the water type and dominant chemical composition, a Na-K-Mg triangle diagram to obtain fluid equilibria, the isotope ratio in the stable isotope plot to obtain the origin of water, and a N2-He-Ar triangle diagram to establish the origin of fumaroles. The water analysis results showed that (1) Ie-Seu’um has an average reservoir temperature of 241.9 ± 0.3 °C, a chloride water type, a dominant Na-K-Cl chemical composition, a mature water fluid equilibrium, and water of meteoric origin; (2) Ie-Brôuk has an average reservoir temperature of 321.95 ± 13.4 °C, a bicarbonate water type, a dominant Na-Ca-HCO3chemical composition, an immature water fluid equilibrium, and water of meteoric origin; (3) Ie-Jue has an average reservoir temperature of 472.4 ± 91.4 °C, a sulphate water type, a dominant Ca-SO4 chemical composition, an immature water fluid equilibrium and water of meteoric origin; and (4) the Van-Heutz crater has an average reservoir temperature of 439.3 ± 95.3 °C, a sulphate water type, a dominant Ca-SO4 chemical composition, an immature water fluid equilibrium and water of magmatic origin. The results of our ...

Jafari, M, Verma, P, Bodisco, TA, Zare, A, Surawski, NC, Borghesani, P, Stevanovic, S, Guo, Y, Alroe, J, Osuagwu, C, Milic, A, Miljevic, B, Ristovski, ZD & Brown, RJ 2019, 'Multivariate analysis of performance and emission parameters in a diesel engine using biodiesel and oxygenated additive', Energy Conversion and Management, vol. 201, pp. 112183-112183.
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© 2019 Elsevier Ltd Rising concerns over environmental and health issues of internal combustion engines, along with growing energy demands, have motivated investigation into alternative fuels derived from biomasses, such as biodiesel. Investigating engine and exhaust emission behaviour of such alternative fuels is vital in order to assess suitability for further utilisation. Since many parameters are relevant, an effective multivariate analysis tool is required to identify the underlying factors that affect the engine performance and exhaust emissions. This study utilises principal component analysis (PCA) to present a comprehensive correlation of various engine performance and emission parameters in a compression ignition engine using diesel, biodiesel and triacetin. The results show that structure-borne acoustic emission is strongly correlated with engine parameters. Brake specific NOx, primary particle diameter and fringe length increases by increasing the rate of pressure rise. Longer ignition delay and higher engine speeds can increase the nucleation particle emissions. Higher air-fuel equivalence ratio can increase the oxidative potential of the soot by increasing fringe distance and tortuosity. The availability of oxygen in the cylinder, from the intake air or fuel, can increase soot aggregate compactness. Fuel oxygen content reduces particle mass and particle number in the accumulation mode; however, they increase the proportion of oxygenated organic species. PCA results for particle chemical and physical characteristics show that soot particles reactivity increases with fuel oxygen content.

Jamaluddin, NAM, Riayatsyah, TMI, Silitonga, AS, Mofijur, M, Shamsuddin, AH, Ong, HC, Mahlia, TMI & Rahman, SMA 2019, 'Techno-Economic Analysis and Physicochemical Properties of Ceiba pentandra as Second-Generation Biodiesel Based on ASTM D6751 and EN 14214', Processes, vol. 7, no. 9, pp. 636-636.
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Processing biodiesel from non-edible sources of feedstock seems to be thriving in recent years. It also has also gathered more attention than in the past, mainly because the biodiesel product is renewable and emits lower pollution compared to fossil fuels. Researchers have started their work on various kinds of biodiesel product, especially from a non-edible feedstock. Non-edible feedstocks such as Ceiba pentandra show great potential in the production of biodiesel, especially in the Southeast Asia region because the plants seem to be abundant in that region. Ceiba pentandra, also known as the Kapok tree, produces hundreds of pods with a length of 15 cm (5.9 in) and diameter 2–5 cm (1–2 in). The pods consist of seeds and fluff in the surrounding areas inside the pod, which itself contains yellowish fibre, a mixture of cellulose and lignin. The seeds of Ceiba pentandra can be used as feedstock for biodiesel production. The study for Ceiba pentandra will involve techno-economic, as well as a sensitivity analysis. Moreover, the study also shows that the techno-economic analysis of a biodiesel processing plant for 50 ktons Ceiba pentandra with a life span of 20 years is around $701 million with 3.7 years of the payback period. Besides that, this study also shows the differences in operating cost and oil conversion yield, which has the least impact on running cost. By improving the conversion processes continuously and by increasing the operational efficiency, the cost of production will decrease. In addition, the study also explains the differences of final price biodiesel and diesel fossil fuel, both showing dissimilar scenarios subsidy and taxation. Biodiesel has a subsidy of $0.10/L and $0.18/L with a total tax exemption of 15%. The value was obtained from the latest subsidy cost and diesel in Malaysia. Finally, further research is needed in order to fully utilize the use of Ceiba pentandra as one of the non-edible sources of biodiesel.

Jamil, S, Loganathan, P, Kandasamy, J, Listowski, A, Khourshed, C, Naidu, R & Vigneswaran, S 2019, 'Removal of dissolved organic matter fractions from reverse osmosis concentrate: Comparing granular activated carbon and ion exchange resin adsorbents', Journal of Environmental Chemical Engineering, vol. 7, no. 3, pp. 103126-103126.
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© 2019 Elsevier Ltd. All rights reserved. Reverse osmosis (RO) generates a concentrate (ROC) containing dangerous levels of pollutants including dissolved organic carbon (DOC). Adsorption experiments were conducted to study the effectiveness of removing DOC and its fractions from ROCs produced in a water reclamation plant using three adsorbents tested individually and in sequential combination. The ROCs had 23-42 mg/L DOC which contained 83-90% hydrophilics. These hydrophilics comprised 72-76% humics, 2-3% biopolymers, 5-7% building blocks, and 16-18% low molecular weight neutrals. Granular activated carbon (GAC) removed a larger amount of DOC than two strong base anion exchange resins (Purolite A502PS, Purolite A860S). In both batch and column experiments, the adsorptive removal of the hydrophobic fraction was greater for GAC than for the Purolites. Humics present in hydrophilic fraction was completely removed by Purolites but only partially by GAC. In the sequential adsorption batch experiment, GAC followed by Purolite treatment removed more hydrophobics, however, Purolite followed by GAC removed more humics. Almost 100% of humics was removed for all doses of adsorbents when Purolite served as the first treatment. It is concluded that the order of adsorbent use for effectively treating ROC depends on the target DOC fraction intended to be removed.

Jamil, S, Loganathan, P, Listowski, A, Kandasamy, J, Khourshed, C & Vigneswaran, S 2019, 'Simultaneous removal of natural organic matter and micro-organic pollutants from reverse osmosis concentrate using granular activated carbon', Water Research, vol. 155, pp. 106-114.
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© 2019 Elsevier Ltd Although reverse osmosis produces high quality reusable water from wastewater the rejected concentrate (ROC) poses potentially serious health hazards to non-target species. This is especially the case when it is disposed into aquatic environments due to the presence of high concentrations of dissolved natural organics, micro-organic pollutants (MOPs) and other pollutants. In batch and column studies we found that granular activated carbon (GAC) was very effective in simultaneously removing dissolved organic carbon (DOC) and 18 MOPs from ROC. The amounts of all DOC fractions adsorbed (0.01–3 mg/g) were much higher than those of the MOPs (0.01–2.5 μg/g) mainly because ROC contained larger concentrations of DOC fractions than MOPs. However, the partition coefficient which is a measure of the adsorbability was higher for most of the MOPs (0.21–21.6 L/g) than for the DOC fractions (0.01–0.45 L/g). The amount of DOC fraction adsorbed was in the order: humics > low molecular weights > building blocks > biopolymers (following mostly their concentrations in ROC). The partition coefficient was in the order: low molecular weigth nuetrals > humics > building blocks > biopolymers. The MOPs were classified into four groups based on their hydrophobicity (log Kow) and charge. The four positively charged MOPs with high hydrophobicity had the highest amounts adsorbed and partition coefficient, with 95–100% removal in the GAC column. The MOPs that are negatively charged, regardless of their hydrophobicity, had the lowest amounts adsorbed and partition coefficient with 73–94% removal.

Jamshaid, M, Masjuki, HH, Kalam, MA, Zulkifli, NWM, Arslan, A, Alwi, A, Khuong, LS, Alabdulkarem, A & Syahir, AZ 2019, 'Production optimization and tribological characteristics of cottonseed oil methyl ester', Journal of Cleaner Production, vol. 209, pp. 62-73.
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Jamshidi Chenari, R, Alaie, R & Fatahi, B 2019, 'Constrained Compression Models for Tire-Derived Aggregate-Sand Mixtures Using Enhanced Large Scale Oedometer Testing Apparatus', Geotechnical and Geological Engineering, vol. 37, no. 4, pp. 2591-2610.
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© 2018, Springer Nature Switzerland AG. Tire derived aggregates have recently been in wide use both in industry and engineering applications depending on the size and the application sought. Five different contents of tire derived aggregates (TDA) were mixed with sand thoroughly to ensure homogeneity. A series of large scale oedometer experiments were conducted to investigate the compressibility properties of the mixtures. Tire shreds content, TDA aspect ratio, skeletal relative density and overburden pressure are studied parameters. Constrained deformation modulus and coefficient of earth pressure at rest are measured parameters. All tests were conducted at seven overburden pressure levels. It was concluded that deformability of TDA-sand mixture increases with soft inclusion. Overburden pressure and skeletal relative density are also important parameters which render more rigidity and less lateral earth pressure coefficient accordingly. TDA size or aspect ratio was shown to have minor effect at least for the constrained strain conditions encountered in current study. An EPR-based parametric study and also sensitivity analyses based on cosine amplitude method revealed quantitative evaluation of the relative importance of each input parameter in varying deformation and lateral earth pressure coefficient as the outputs.

Jaramillo-Madrid, AC, Ashworth, J, Fabris, M & Ralph, PJ 2019, 'Phytosterol biosynthesis and production by diatoms (Bacillariophyceae)', Phytochemistry, vol. 163, pp. 46-57.
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© 2019 Elsevier Ltd Diatoms are abundant unicellular marine photosynthetic algae that have genetically diversified their physiology and metabolism while adapting to numerous environments. The metabolic repertoire of diatoms presents opportunities to characterise the biosynthesis and production of new and potentially valuable microalgal compounds, including sterols. Sterols of plant origin, known as phytosterols, have been studied for health benefits including demonstrated cholesterol-lowering properties. In this review we summarise sterol diversity, the unique metabolic features of sterol biosynthesis in diatoms, and prospects for the extraction of diatom phytosterols in comparison to existing sources. We also review biotechnological efforts to manipulate diatom biosynthesis, including culture conditions and avenues for the rational engineering of metabolism and cellular regulation.

Javaheri, F, Kheshti, Z, Ghasemi, S & Altaee, A 2019, 'Enhancement of Cd2+ removal from aqueous solution by multifunctional mesoporous silica: Equilibrium isotherms and kinetics study', Separation and Purification Technology, vol. 224, pp. 199-208.
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© 2019 In this work, a novel amino-functionalized mesoporous microsphere was synthesized to remove cadmium ions from water. The Fe3O4@SiO2@m-SiO2–NH2 micro-spheres were successfully prepared via a facile two-stage process by coating of the as-synthesized magnetic cores with a silica shell followed by increasing the porosity of the structure using a cationic surfactant as structure-directing agents. The template removal from the structure has been performed following the method of solvent extraction and methanol-enhanced supercritical fluid CO2 (SCF-CO2)extraction. This novel approach provides the multifunctional microspheres with a high surface area, which improves the adsorption capacity of adsorbent. Characterization of the as-synthesized adsorbent were analytically determined showing that as-prepared adsorbent has a significant surface area of 637.38 m2 g−1. The kinetic data agreed with pseudo-second-order model and Langmuir isotherm. The maximum adsorption capacity of the synthesized adsorbent was about 884.9 mg g−1, and can be easily separated from solution under an external magnetic field. The synthesized microspheres were recycled using HCl and cadmium removal was over 92% after 6 cycles, which confirms the chemical stability and reusability of the manufactured particles.

Jeong, SY, Chang, SW, Ngo, HH, Guo, W, Nghiem, LD, Banu, JR, Jeon, B-H & Nguyen, DD 2019, 'Influence of thermal hydrolysis pretreatment on physicochemical properties and anaerobic biodegradability of waste activated sludge with different solids content', Waste Management, vol. 85, pp. 214-221.
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© 2018 Elsevier Ltd The influence of thermal hydrolysis pretreatment (THP) on physicochemical properties (pH, total solids, volatile solids, chemical oxygen demand, total nitrogen, ammonium nitrogen, volatile fatty acids, viscosity, and cell morphology) and anaerobic biodegradability of highly concentrated waste activated sludge (WAS) with TS content ranging from 1 to 7% was evaluated at different temperatures ranging from 100 to 220 °C. The biomethane potential (BMP) of the WAS was systematically analyzed and evaluated. Images of its cellular structure were also analyzed. The results indicated that THP is a useful method for solubilizing volatile solids and enhancing CH 4 production regardless of the TS content of the WAS feed. The ultimate CH 4 production determined from the BMP analysis was 313–348 L CH 4 /kg VS (72.6–74.1% CH 4 ) at the optimum THP temperature of 180 °C. The results showed that THP could improve both the capacity and efficiency of anaerobic digestion, even at a high TS content, and could achieve the dual purpose of sludge reduction and higher energy recovery.

Jia, H, Feng, F, Wang, J, Ngo, H-H, Guo, W & Zhang, H 2019, 'On line monitoring local fouling behavior of membrane filtration process by in situ hydrodynamic and electrical measurements', Journal of Membrane Science, vol. 589, pp. 117245-117245.
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© 2019 The hollow fiber ultrafiltration (UF) membrane has been widely applied in the water treatment industry, however, the membrane fouling is the core reason and limiting factor in terms of its industrial application. In the constant flux process, hollow fiber membranes (HFM) non-uniform fouling varies along the axis direction, which is the basic mechanism of HFM fouling. In this paper, the local membrane fouling behaviors and verities are investigated using electrical impedance (EI) and zeta potential (ZP) to capture the feedback signals of membrane fouling behaviors. The results are then, integrated with Hermia's model and an equivalent circuit model. As the fitting results show, both the EI and ZP can be employed as indicators of different membrane fouling states. This work defines the different stages of membrane fouling depending on the alternating relationship between EI and ZP in the membrane filtration process. Furthermore, the behavior of cake layer compaction is defined from the perspective of the membrane fouling mechanism. Therefore, this study provides an effective means for accurate identification of membrane fouling behavior. In addition, the EI and ZP exhibit great potential to identify the fouling distributions and proceedings in HFM fouling. Doing so successfully confirms that the characteristics of non-uniform fouling of HFM are reflected in the spatiotemporal difference of the fouling process.

Jiang, J, Kim, DI, Dorji, P, Phuntsho, S, Hong, S & Shon, HK 2019, 'Phosphorus removal mechanisms from domestic wastewater by membrane capacitive deionization and system optimization for enhanced phosphate removal', Process Safety and Environmental Protection, vol. 126, pp. 44-52.
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© 2019 Institution of Chemical Engineers Membrane capacitive deionization (MCDI) is an emerging technology for effective removal of charged pollutants from the water sources including domestic wastewater. In this work, a lab-scale MCDI system was employed to investigate its feasibility for effective phosphorus removal from domestic wastewater. The effect of phosphate equilibrium reactions on the ion sorption behaviour was studied in sodium phosphate buffer solution at typical pH range maintained in a real domestic raw wastewater effluent (between 6.5 and 8.5). The results demonstrated that phosphate equilibrium system has positive impact on the degree of inorganic phosphorus (P) adsorption capacity in aqueous solution. In addition, the ion selectivity of P over other co-existing anions (Cl-, SO42-) were experimentally studied using a synthetic wastewater solution. And it was found that the preferential electrosorption sequence of the competitive anions is: Cl-> SO42- > P, while the initial ion concentration order in the synthetic feed solution is: Cl- 1.90 mM> P (0.40 mM) > SO42- (0.32 mM). The experiments with diverse operating conditions revealed that the optimal adsorption of inorganic phosphorus over chloride and sulphate can be achieved in some extent with slower flow rates and higher applied potentials (less than 1.23 V).

Jo, Y, Johir, MAH, Cho, Y, Naidu, G, Rice, SA, McDougald, D, Kandasamy, J, Vigneswaran, S & Sun, S 2019, 'A comparative study on nitric oxide and hypochlorite as a membrane cleaning agent to minimise biofilm growth in a membrane bioreactor (MBR) process', Biochemical Engineering Journal, vol. 148, pp. 9-15.
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© 2019 Elsevier B.V. Reverse osmosis concentrates (ROC) produced from water reclamation plants can threaten the environment if it is not appropriately treated before discharge. A membrane bioreactor (MBR) process to treat ROC was used in this project. In an MBR, fouling is an essential and inevitable phenomenon which leads to higher operational and capital costs. A comparative study on chemical cleaning, such as sodium hypochlorite (NaOCl) and nitric oxide (NO), was experimentally evaluated together with the influence of filtration flux. Exposure to a low concentration of NO reduced biofilms in an MBR system. NO treatment delayed the formation of new biofilm biomass on the membrane. NO also showed good performance in reducing membrane fouling and had no adverse effect on activated sludge and the environment. In MBR, the bacterial community was dominated by Proteobacteria (61%), with Alpha and Beta-proteobacteria representing approximately 54% of the community. After NO treatment, the relative abundance of the Proteobacteria decreased to 44%, and this was also reflected in a reduction in Alpha and Beta-proteobacteria, to 30% and 5% respectively. Thus, NO treatment resulted in the decrease of the relative biofilms associated with reduced MBR performance.

Kahlke, T & Ralph, PJ 2019, 'BASTA – Taxonomic classification of sequences and sequence bins using last common ancestor estimations', Methods in Ecology and Evolution, vol. 10, no. 1, pp. 100-103.
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AbstractIdentification of the taxonomic origin of a DNA sequence is crucial for many sequencing projects, e.g. metagenomics studies, identification of contaminations in whole genome sequencing projects and filtering of organisms of interest in marker‐gene based community analyses.Last common ancestor algorithms are powerful approaches to estimate the taxonomy of a given sequence and have been widely used for classification of next‐generation sequencing (NGS) reads, also known as 2nd generation sequencing reads.Here, we present BASTA (https://github.com/timkahlke/BASTA), a basic sequence taxonomy annotator, which extends last common ancestor estimations from sequencing reads to any kind of nucleotide or amino acid sequence utilizing NCBI taxonomies of user‐defined best hits.BASTA can be configured to use the output of many common sequence comparison tools, e.g. BLAST and Diamond, in conjunction with either provided or user‐defined target sequence databases.

Kalaruban, M, Loganathan, P, Nguyen, TV, Nur, T, Hasan Johir, MA, Nguyen, TH, Trinh, MV & Vigneswaran, S 2019, 'Iron-impregnated granular activated carbon for arsenic removal: Application to practical column filters', Journal of Environmental Management, vol. 239, pp. 235-243.
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© 2019 Elsevier Ltd Arsenic is a major drinking water contaminant in many countries causing serious health hazards, and therefore, attempts are being made to remove it so that people have safe drinking water supplies. The effectiveness of arsenic removal from As(V) solutions using granular activated carbon (GAC) (zero point of charge (ZPC) pH 3.2) and iron incorporated GAC (GAC-Fe) (ZPC pH 8.0) was studied at 25 ± 1 °C. The batch study confirmed that GAC-Fe had higher Langmuir adsorption capacity at pH 6 (1.43 mg As/g) than GAC (1.01 mg As/g). Adsorption data of GAC-Fe fitted the Freundlich model better than the Langmuir model, thus indicating the presence of heterogeneous adsorption sites. Weber and Morris plots of the kinetic adsorption data suggested intra-particle diffusion into meso and micro pores in GAC. The column adsorption study revealed that 2–4 times larger water volumes can be treated by GAC-Fe than GAC, reducing the arsenic concentration from 100 μg/L to the WHO guideline of 10 μg/L. The volume of water treated increased with a decrease in flow velocity and influent arsenic concentration. The study indicates the high potential of GAC-Fe to remove arsenic from contaminated drinking waters in practical column filters.

Kang, Y, Xie, H, Li, B, Zhang, J, Hao Ngo, H, Guo, W, Guo, Z, Kong, Q, Liang, S, Liu, J, Cheng, T & Zhang, L 2019, 'Performance of constructed wetlands and associated mechanisms of PAHs removal with mussels', Chemical Engineering Journal, vol. 357, pp. 280-287.
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Khabbaz, H, Gibson, R & Fatahi, B 2019, 'Effect of constructing twin tunnels under a building supported by pile foundations in the Sydney central business district', Underground Space, vol. 4, no. 4, pp. 261-276.
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© 2019 Tongji University and Tongji University Press In congested cities such as Sydney, competition for underground space escalates within the built environment because various assets require finite geotechnical strength and support. Specific problems such as damage to buildings may develop when high-rise buildings on piled foundations are subject to ground movements as tunnels are constructed. This paper focuses on the risks of tunneling beneath Sydney's Martin Place and how buildings are subject to additional loads caused by tunneling. The key objective of this study is to improve the understanding of tunnel–rock–pile interactions and to encourage sustainable development. A finite element model is developed to predict the interaction between tunnel construction and piled foundations. The tunnel, rock, and pile components are studied separately and are then combined into a single model. The ground model is based on the characteristics of Hawkesbury Sandstone and is developed through a desktop study. The piles are designed using Australian Standards and observations of high-rise buildings. The tunnel construction is modeled based on the construction sequence of a tunnel boring machine. After combining the components, a parametric study on the relationship between tunnel location, basements, and piles is conducted. Our findings, thus far, show that tunneling can increase the axial and flexural loads of piles, where the additional loading exceeds the structural capacity of some piles, especially those that are close to basement walls. The parametric study reveals a strong relationship between tunnel depth and lining stresses, while the relationship between tunnel depth and induced pile loads is less convincing. Furthermore, the horizontal tunnel position relative to piles shows a stronger relationship with pile loads. Further research into tunnel–rock–pile interactions is recommended, especially beneath basements, to substantiate the results of this study.

Khan, JA, Shon, HK & Nghiem, LD 2019, 'From the Laboratory to Full-Scale Applications of Forward Osmosis: Research Challenges and Opportunities', Current Pollution Reports, vol. 5, no. 4, pp. 337-352.
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© 2019, Springer Nature Switzerland AG. Forward osmosis (FO) has recently emerged as a new separation platform for a range of applications that are currently not possible for other membrane processes. This review paper covers key aspects of FO development with a specific emphasis on current technical challenges for practical applications. Main hurdles in the transition of FO from a lab-scale process to large scale applications include low-performance membranes, development of suitable draw solute, inherent transport phenomena (e.g. concentration polarization and reverse solute flux), membrane fouling and subsequent membrane cleaning. Several new FO membranes have been developed with some improved performances but no membrane has yet been found convincing in all of the key performance indicators. Draw solutes have been broadly investigated but mainly at the lab-scale. There have only been very few pilot-scale studies, most of them using inorganic salts as draw solutes. Development of thermo-responsive draw solutes and TFC membranes have been reported to be most effective in reducing reverse solute flux while altering the hydrodynamic conditions and the use of ultrasonication along with exploring other viable options have been suggested to tackle external and internal concentration polarization respectively. Although membrane fouling types and mitigation strategies have been extensively explored, this review also highlights the need for further research in biofouling for long-term FO operation.

Khan, MA, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Varjani, S, Liu, Y, Deng, L & Cheng, C 2019, 'Selective production of volatile fatty acids at different pH in an anaerobic membrane bioreactor', Bioresource Technology, vol. 283, pp. 120-128.
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© 2019 Elsevier Ltd This study investigated the production of major volatile fatty acid (VFA) components in an anaerobic membrane bioreactor (AnMBR) to treat low-strength synthetic wastewater. No selective inhibition was applied for methane production and solvent-extraction method was used for VFA extraction. The results showed acetic and propionic acid were the predominant VFA components at pH 7.0 and 6.0 with concentrations of 1.444 ± 0.051 and 0.516 ± 0.032 mili-mol/l respectively. At pH 12.0 isobutyric acid was the major VFA component with a highest concentration of 0.712 ± 0.008 mili-mol/l. The highest VFA yield was 48.74 ± 1.5 mg VFA/100 mg CODfeed at pH 7.0. At different pH, AnMBR performance was evaluated in terms of COD, nutrient removal and membrane fouling rate. It was observed that the membrane fouled at a faster rate in both acidic and alkaline pH conditions, the slowest rate in membrane fouling was observed at pH 7.0.

Khan, MA, Ngo, HH, Guo, W, Liu, Y, Nghiem, LD, Chang, SW, Nguyen, DD, Zhang, S, Luo, G & Jia, H 2019, 'Optimization of hydraulic retention time and organic loading rate for volatile fatty acid production from low strength wastewater in an anaerobic membrane bioreactor', Bioresource Technology, vol. 271, pp. 100-108.
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This study aims to investigate the production of volatile fatty acids (VFAs) from low strength wastewater at various hydraulic retention time (HRT) and organic loading rate (OLR) in a continuous anaerobic membrane bioreactor (AnMBR) using glucose as carbon source. This experiment was performed without any selective inhibition of methanogens and the reactor pH was maintained at 7.0 ± 0.1. 48, 24, 18, 12, 8 and 6 h-HRTs were applied and the highest VFA concentration was recorded at 8 h with an overall VFA yield of 48.20 ± 1.21 mg VFA/100 mg CODfeed. Three different ORLs were applied (350, 550 and 715 mg CODfeed) at the optimum 8 h-HRT. The acetic and propanoic acid concentration maximums were (1.1845 ± 0.0165 and 0.5160 ± 0.0141 mili-mole/l respectively) at 550 mg CODfeed. The isobutyric acid concentration was highest (0.3580 ± 0.0407 mili-mole/l) at 715 mg CODfeed indicating butyric-type fermentation at higher organic loading rate.

Kheshti, Z, Azodi Ghajar, K, Altaee, A & Kheshti, MR 2019, 'High-Gradient Magnetic Separator (HGMS) combined with adsorption for nitrate removal from aqueous solution', Separation and Purification Technology, vol. 212, pp. 650-659.
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© 2018 Elsevier B.V. This paper investigates the adsorption of nitrate anions from aqueous solutions on ammonium-functionalized magnetic mesoporous silica. The adsorbent was prepared via two-step coating process of silica on magnetic core (Fe3O4). The resultant structure was modified by 3-aminopropyl triethoxysilane (APTES), and finally acidified in HCl solution to convert the grafted amino groups to ammonium ones. Field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), vibration sample magnetometer (VSM), Energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), and N2 adsorption/desorption were used to characterize the obtained samples. Experimental results showed that several factors affected the uptake behavior such as pH, contact time, and initial concentration of nitrate. The amount of sorbent loading were examined and the adsorbent shows great adsorption capacity for NO3¯ (ca.51.28 mg g−1 at 25 °C). The nitrate loaded multifunctional microsphere can be easily regenerated with NaOH solution. The separation of multifunctional magnetic microspheres from solution by novel high gradient magnetic separation (HGMS), using the collection of rods, was also investigated in details. Contrast to other methods based on filter and batch conditions, large volumes of water can be easily handled by the new designed HGMS due to the decreasing pressure drop and retention times. The effect of a set of two different experimental variables, i.e. flowrate and magnetic field strength, were investigated to identify the best working conditions for the separation of adsorbent from treated water. The most efficient backwash system was offered to reuse the magnetic particles, too. The removal efficiency of NO3¯ from solution was around 86.24% by the constructed HGMS under the optimal experimental conditions of 7.5 mL s −1 flowrate and: 3.49 mT magnitude of the magnetic field.

Kim, B-J, Piao, G, Kim, S, Yang, SY, Park, Y, Han, DS, Shon, HK, Hoffmann, MR & Park, H 2019, 'High-Efficiency Solar Desalination Accompanying Electrocatalytic Conversions of Desalted Chloride and Captured Carbon Dioxide', ACS Sustainable Chemistry & Engineering, vol. 7, no. 18, pp. 15320-15328.
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Kim, DI, Dorji, P, Gwak, G, Phuntsho, S, Hong, S & Shon, H 2019, 'Effect of Brine Water on Discharge of Cations in Membrane Capacitive Deionization and Its Implications on Nitrogen Recovery from Wastewater', ACS Sustainable Chemistry & Engineering, vol. 7, no. 13, pp. 11474-11484.
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© 2019 American Chemical Society. We examined the desorption behavior of cations in membrane capacitive deionization (MCDI) from the cathode into high-concentration brine through a cation-exchange membrane (CEM) brine, during mineral recovery. Several major issues were explored to demonstrate the suitability of the mineral recovery process: discharge behavior using different solution chemistries, desorption efficiencies of various regeneration methods for the enrichment of ions, and desorption selectivity among selected cations. The desorption efficiency was hampered when the adsorbed cations migrated toward the brine solution against a higher ionic-strength gradient and was further lowered by the enhanced membrane resistance under the low concentration of the adsorbed ions on the cathode. Furthermore, the electrochemically adsorbed ions were limitedly discharged by the cost-effective regeneration method (short-circuiting). The cations were preferentially released in the order of K+ > Na+ > Mg2+, as mainly determined by their physiochemical properties such as diffusion rate and charge valence, whereas the influence of permselectivity through the CEM was insignificant. Furthermore, through the ammonium recovery tests, a high concentration of ammonium brine was obtained from wastewater through a successive five-cycle-operation due to its selective desorption over the sodium ions present. However, the incomplete discharge of ions from the electrode was a challenging issue to overcome for the use of MCDI for ammonium recovery.

Kim, DI, Dorji, P, Gwak, G, Phuntsho, S, Hong, S & Shon, H 2019, 'Reuse of municipal wastewater via membrane capacitive deionization using ion-selective polymer-coated carbon electrodes in pilot-scale', Chemical Engineering Journal, vol. 372, pp. 241-250.
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© 2019 Elsevier B.V. This study investigated membrane capacitive deionization (MCDI) at a pilot-scale using ion-selective polymer-coated carbon electrodes for wastewater reuse. Several issues have been addressed to verify the suitability of MCDI for wastewater reclamation: electrosorption performance, removal efficiency and selectivity of ions present in wastewater, optimization of operating conditions, and performance degradation in long-term caused by the accumulation of organic contaminants. The coated electrodes had better adsorption capacities and charge efficiencies than the conventional MCDI system, which was attributed to their low electrical resistance induced by the thin coated layer. The pilot-scale MCDI test cell involved 50 pairs of anion- and cation-selective electrodes and achieved good removal efficiency of ions from the wastewater effluent, particularly for problematic charged impurities, such as nitrate (NO3−) (up to 91.08% of NO3− was removed). Increasing the flow rate and reducing the applied potential were shown to be efficient for achieving better water quality by enhancing the NO3− selectivity. Last, the 15 d operation showed good reproducibility in electrosorption and regeneration for the coated electrodes, despite the fact that high concentrations of organics were contained in the wastewater feed solution (12.4 mg/L of dissolved organic carbon).

Kim, JE, Kuntz, J, Jang, A, Kim, IS, Choi, JY, Phuntsho, S & Shon, HK 2019, 'Techno-economic assessment of fertiliser drawn forward osmosis process for greenwall plants from urban wastewater', Process Safety and Environmental Protection, vol. 127, pp. 180-188.
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© 2019 Institution of Chemical Engineers Pressure-assisted osmosis (PAO) has been suggested to integrate with fertiliser driven forward osmosis (FDFO) to improve the overall efficiency of simultaneous wastewater reuse and fertiliser osmotic dilution. This study aims to demonstrate the techno-economic feasibility of pressure-assisted fertiliser driven forward osmosis (PAFDO) hybrid system compared to the existing ultraviolet and reverse osmosis (UV–RO) process. The results showed that coupling FDFO with PAO (i.e. PAFDO) could help fulfill the water quality required for greenwall fertigation. An economic analysis on capital and operational costs for the PAFDO showed that the PAO mode application at a lower FDFO dilution stage could significantly reduce the costs. However, when considering the different applied pressures in PAO (i.e. 2, 4, and 6 bar), the increase in the total water cost was not significant. This indicates that the dilution stage for applying PAO is more sensitive to the total water cost of the PAFDO than the applied pressure. A coupling of higher average water flux (>10 L/m2h) and lower draw solution (DS) dilution factor (DF < 60) is recommended. Therefore, this could make the PAFDO system economically viable compared to the benchmark for the UV-RO disinfection system.

Kim, M, Pernice, M, Watson-Lazowski, A, Guagliardo, P, Kilburn, MR, Larkum, AWD, Raven, JA & Ralph, PJ 2019, 'Effect of reduced irradiance on 13C uptake, gene expression and protein activity of the seagrass Zostera muelleri', Marine Environmental Research, vol. 149, pp. 80-89.
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Photosynthesis in the seagrass Zostera muelleri remains poorly understood. We investigated the effect of reduced irradiance on the incorporation of 13C, gene expression of photosynthetic, photorespiratory and intermediates recycling genes as well as the enzymatic content and activity of Rubisco and PEPC within Z. muelleri. Following 48 h of reduced irradiance, we found that i) there was a ∼7 fold reduction in 13C incorporation in above ground tissue, ii) a significant down regulation of photosynthetic, photorespiratory and intermediates recycling genes and iii) no significant difference in enzyme activity and content. We propose that Z. muelleri is able to alter its physiology in order to reduce the amount of C lost through photorespiration to compensate for the reduced carbon assimilation as a result of reduced irradiance. In addition, the first estimated rate constant (Kcat) and maximum rates of carboxylation (Vcmax) of Rubisco is reported for the first time for Z. muelleri.

Kim, Y, Li, S, Phuntsho, S, Xie, M, Shon, HK & Ghaffour, N 2019, 'Understanding the organic micropollutants transport mechanisms in the fertilizer-drawn forward osmosis process', Journal of Environmental Management, vol. 248, pp. 109240-109240.
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© 2019 Elsevier Ltd We systematically investigated the transport mechanisms of organic micropollutants (OMPs) in a fertilizer-drawn forward osmosis (FDFO) membrane process. Four representative OMPs, i.e., atenolol, atrazine, primidone, and caffeine, were chosen for their different molecular weights and structural characteristics. All the FDFO experiments were conducted with the membrane active layer on the feed solution (FS) side using three different fertilizer draw solutions (DS): potassium chloride (KCl), monoammonium phosphate (MAP), and diammonium phosphate (DAP) due to their different properties (i.e., osmotic pressure, diffusivity, viscosity and solution pH). Using KCl as the DS resulted in both the highest water flux and the highest reverse solute flux (RSF), while MAP and DAP resulted in similar water fluxes with varying RSF. The pH of the FS increased with DAP as the DS due to the reverse diffusion of NH4+ ions from the DS toward the FS, while for MAP and DAP DS, the pH of the FS was not impacted. The OMPs transport behavior (OMPs flux) was evaluated and compared with a simulated OMPs flux obtained via the pore-hindrance transport model to identify the effects of the OMPs structural properties. When MAP was used as DS, the OMPs flux was dominantly influenced by the physicochemical properties (i.e., hydrophobicity and surface charge). Those OMPs with positive charge and more hydrophobic, exhibited higher forward OMP fluxes. With DAP as the DS, the more hydrated FO membrane (caused by increased pH) as well as the enhanced RSF hindered OMPs transport through the FO membrane. With KCl as DS, the structural properties of the OMPs were dominant factors in the OMPs flux, however the higher RSF of the KCl draw solute may likely hamper the OMPs transport through the membrane especially those with higher MW (e.g., atenolol). The pore-hindrance model can be instrumental in understanding the effects of the hydrodynamic properties and the surface propertie...

Kretzschmar, AL, Larsson, ME, Hoppenrath, M, Doblin, MA & Murray, SA 2019, 'Characterisation of Two Toxic Gambierdiscus spp. (Gonyaulacales, Dinophyceae) from the Great Barrier Reef (Australia): G. lewisii sp. nov. and G. holmesii sp. nov.', Protist, vol. 170, no. 6, pp. 125699-125699.
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© 2019 Elsevier GmbH Ciguatera fish poisoning (CFP) is a human illness caused via consumption of seafood contaminated with neurotoxins produced by some species from the epiphytic dinoflagellate genus Gambierdiscus. In this study, we describe two new species of Gambierdiscus isolated from Heron Island in the Southern Great Barrier Reef, Queensland, Australia. These new species were analysed using light microscopy, scanning electron microscopy, and phylogenetic analyses of nuclear encoded ribosomal ITS, SSU as well as D1-D3 and D8-D10 of the LSU gene regions. Gambierdiscus lewisii sp. nov. (Po, 3′, 0a, 7″, 6c,? s, 5‴, 0p, 2′‴) is distinguished by its strong reticulate-foveate ornamentation and is genetically distinct from its sister species, G. pacificus. Gambierdiscus holmesii sp. nov. (Po, 3′, 0a, 7″, 6c, 6s?, 5‴, 0p, 2′‴) is morphologically distinct from the genetically similar species G. silvae because of a strongly ventrally displaced apical pore complex and a characteristic fold at the anterior edge of the sulcus. Both G. lewisii and G. holmesii produce putative Maitotoxin-(44-Methylgambierone) and compounds which show ciguatoxin and maitotoxin-like activities. Identification of two new Gambierdiscus species will enable us to more accurately assess the risk of CFP in Australia and internationally.

Kusuma, MH, Putra, N, Rosidi, A, Ismarwanti, S, Antariksawan, AR, Ardiyati, T, Juarsa, M & Mahlia, TMI 2019, 'Investigation on the Performance of a Wickless-Heat Pipe Using Graphene Nanofluid for Passive Cooling System', Atom Indonesia, vol. 45, no. 3, pp. 173-173.
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To enhance the thermal safety in case of station blackout, a wickless-heat pipe is proposed as an alternative passive cooling system technology to remove decay heat generation in the nuclear spent fuel storage pool. The objectives of this research are to investigate the heat transfer phenomena in vertical straight wickless-heat pipe using Graphene nanofluid working fluid and to study the effect of Graphene nanofluid on the vertical straight wickless-heat pipe thermal performance. The investigation was conducted in 6 meters height and 0.1016 m inside diameter of vertical straight wickless-heat pipe. In this research, the Graphene nanofluid with 1 % of weight concentration was used as working fluid. The effect of working fluid filling ratio, evaporator heat load, and coolant volumetric flow rate on the water jacket were studied. The results showed that the heat transfer phenomena, which were indicated by an overshoot, zigzag, and stable state, were observed. Based on thermal resistance obtained, it was shown that the vertical straight wickless-heat pipe charged with the Graphene nanofluid has a lower thermal resistance compared to one with demineralized water. The thermal resistance of vertical straight wickless-heat pipe using Graphene nanofluid and demineralized water were 0.015 °C/W and 0.016 °C/W, respectively. While the best thermal performance was achieved at a filing ratio of 80 %, higher heat load, and higher coolant volumetric flow rate. It can be concluded that Graphene nanofluid could enhance the thermal performance of vertical straight wickless-heat pipe.

Kusumo, F, Mahlia, TMI, Shamsuddin, AH, Ong, HC, Ahmad, AR, Ismail, Z, Ong, ZC & Silitonga, AS 2019, 'The Effect of Multi-Walled Carbon Nanotubes-Additive in Physicochemical Property of Rice Brand Methyl Ester: Optimization Analysis', Energies, vol. 12, no. 17, pp. 3291-3291.
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Biodiesel as an alternative to diesel fuel produced from vegetable oils or animal fats has attracted more and more attention because it is renewable and environmentally friendly. Compared to conventional diesel fuel, biodiesel has slightly lower performance in engine combustion due to the lower calorific value that leads to lower power generated. This study investigates the effect of multi-walled carbon nanotubes (MWCNTs) as an additive to the rice bran methyl ester (RBME). Artificial neural network (ANN) and response surface methodology (RSM) was used for predicting the calorific value. The interaction effects of parameters such as dosage of MWCNTs, size of MWCNTs and reaction time on the calorific value of RBME were studied. Comparison of RSM and ANN performance was evaluated based on the correlation coefficient (R2), the root mean square error (RMSE), the mean absolute percentage error (MAPE), and the average absolute deviation (AAD) showed that the ANN model had better performance (R2 = 0.9808, RMSE = 0.0164, MAPE = 0.0017, AAD = 0.173) compare to RSM (R2 = 0.9746, RMSE = 0.0170, MAPE = 0.0028, AAD = 0.279). The optimum predicted of RBME calorific value that is generated using the cuckoo search (CS) via lévy flight optimization algorithm is 41.78 (MJ/kg). The optimum value was obtained using 64 ppm of < 7 nm MWCNTs blending for 60 min. The predicted calorific value was validated experimentally as 41.05 MJ/kg. Furthermore, the experimental results have shown that the addition of MWCNTs was significantly increased the calorific value from 36.87 MJ/kg to 41.05 MJ/kg (11.6%). Also, the addition of MWCNTs decreased flashpoint (−18.3%) and acid value (−0.52%). As a conclusion, adding MWCNTs as an additive had improved the physicochemical properties characteristics of RBME. To our best knowledge, no research has yet been performed on the effect of multi-walled carbon nanotubes-additive in physicochemical property of rice brand methyl ester appli...

Larsson, ME, Harwood, TD, Lewis, RJ, S. W. A., H & Doblin, MA 2019, 'Toxicological characterization of Fukuyoa paulensis (Dinophyceae) from temperate Australia', Phycological Research, vol. 67, no. 1, pp. 65-71.
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SUMMARYDinoflagellates of the genus Gambierdiscus are known to produce neurotoxins that cause the human illness ciguatera, a tropical and sub‐tropical fish poisoning. Some species from the Gambierdiscus genus were recently re‐classified into a new genus, Fukuyoa based on their phylogenetic and morphological divergence, however, little is known about their distribution, ecology and toxicology. Here we report the first occurrence of F. paulensis in the temperate coastal waters of eastern Australia and characterize its toxicology. Liquid chromatography–tandem mass spectrometry (LC–MS/MS) did not detect the presence of ciguatoxins, however, a putative maitotoxin congener (MTX‐3) was present. Similarly, high maitotoxin‐like activity was detected in High Performance Liquid Chromatography (HPLC) fractionated cell extracts using a Ca2+ influx bioassay on a Fluorescent Imaging Plate Reader (FLIPR), but no ciguatoxin‐like activity was detected.

Larsson, ME, Smith, KF & Doblin, MA 2019, 'First description of the environmental niche of the epibenthic dinoflagellate species Coolia palmyrensis, C. malayensis, and C. tropicalis (Dinophyceae) from Eastern Australia', Journal of Phycology, vol. 55, no. 3, pp. 565-577.
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Environmental variables such as temperature, salinity, and irradiance are significant drivers of microalgal growth and distribution. Therefore, understanding how these variables influence fitness of potentially toxic microalgal species is particularly important. In this study, strains of the potentially harmful epibenthic dinoflagellate species Coolia palmyrensis, C. malayensis, and C. tropicalis were isolated from coastal shallow water habitats on the east coast of Australia and identified using the D1‐D3 region of the large subunit (LSU) ribosomal DNA (rDNA). To determine the environmental niche of each taxon, growth was measured across a gradient of temperature (15–30°C), salinity (20–38), and irradiance (10–200 μmol photons · m−2 · s−1). Specific growth rates of Coolia tropicalis were highest under warm temperatures (27°C), low salinities (ca. 23), and intermediate irradiance levels (150 μmol photons · m−2 · s−1), while C. malayensis showed the highest growth at moderate temperatures (24°C) and irradiance levels (150 μmol photons · m−2 · s−1) and growth rates were consistent across the range of salinity levels tested (20–38). Coolia palmyrensis had the highest growth rate of all species tested and favored moderate temperatures (24°C), oceanic salinity (35), and high irradiance (>200 μmol photons · m−2 · s−1). This is the first study to characterize the environmental niche of species from the benthic harmful algal bloom genus

Law, Y, Matysik, A, Chen, X, Swa Thi, S, Ngoc Nguyen, TQ, Qiu, G, Natarajan, G, Williams, RBH, Ni, B-J, Seviour, TW & Wuertz, S 2019, 'High Dissolved Oxygen Selection against Nitrospira Sublineage I in Full-Scale Activated Sludge', Environmental Science & Technology, vol. 53, no. 14, pp. 8157-8166.
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© 2019 American Chemical Society. A single Nitrospira sublineage I OTU was found to perform nitrite oxidation in full-scale domestic wastewater treatment plants (WWTPs) in the tropics. This taxon had an apparent oxygen affinity constant lower than that of the full-scale domestic activated sludge cohabitating ammonium oxidizing bacteria (AOB) (0.09 ± 0.02 g O2 m-3 versus 0.3 ± 0.03 g O2 m-3). Thus, nitrite oxidizing bacteria (NOB) may in fact thrive under conditions of low oxygen supply. Low dissolved oxygen (DO) conditions selected for and high aeration inhibited the NOB in a long-term lab-scale reactor. The relative abundance of Nitrospira sublineage I gradually decreased with increasing DO until it was washed out. Nitritation was sustained even after the DO was lowered subsequently. The morphologies of AOB and NOB microcolonies responded to DO levels in accordance with their oxygen affinities. NOB formed densely packed spherical clusters with a low surface area-to-volume ratio compared to the Nitrosomonas-like AOB clusters, which maintained a porous and nonspherical morphology. In conclusion, the effect of oxygen on AOB/NOB population dynamics depends on which OTU predominates given that oxygen affinities are species-specific, and this should be elucidated when devising operating strategies to achieve mainstream partial nitritation.

Lee, S, Choi, J, Park, Y-G, Shon, H, Ahn, CH & Kim, S-H 2019, 'Hybrid desalination processes for beneficial use of reverse osmosis brine: Current status and future prospects', Desalination, vol. 454, pp. 104-111.
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© 2018 Elsevier B.V. As water shortage has increasingly become a serious global problem, desalination using seawater reverse osmosis (SWRO) is considered as a sustainable source of potable water sources. However, a major issue on the SWRO desalination plant is the generation of brine that has potential adverse impact due to its high salt concentration. Accordingly, it is necessary to develop technologies that allow environmentally friendly and economically viable management of SWRO brines. This paper gives an overview of recent research works and technologies to treat SWRO brines for its beneficial use. The treatment processes have been classified into two different groups according to their final purpose: 1) technologies for producing fresh water and 2) technologies for recovering energy. Topics in this paper includes membrane distillation (MD), forward osmosis (FO), pressure-retarded osmosis (PRO), reverse electrodialysis (RED) as emerging tools for beneficial use of SWRO brine. In addition, a new approach to simultaneously recover water and energy from SWRO brine is introduced as a case study to provide insight into improving the sustainability of seawater desalination.

Li, L, Geng, S, Wu, C, Song, K, Sun, F, Visvanathan, C, Xie, F & Wang, Q 2019, 'Microplastics contamination in different trophic state lakes along the middle and lower reaches of Yangtze River Basin', Environmental Pollution, vol. 254, no. Pt A, pp. 112951-112951.
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© 2019 Elsevier Ltd Microplastics can enter freshwater lakes through many sources. They can act as carriers to adsorb bacteria, virus, or pollutants (e.g., heavy metal and toxic organic compounds) that threaten human health through food chain. Microplastics can exist in surface water and sediments in freshwater lakes after they enter the lakes through discharge points. Wastewater discharge is the main cause of lake eutrophication and is the main emission source of microplastics. The correlation between lake trophic state and microplastic abundance has been rarely reported. This study investigated the microplastic contamination in surface water and sediments of 18 lakes along the middle and lower reaches of the Yangtze River Basin in the period of August–September 2018. The correlation between lake trophic state and microplastic abundance in surface water and sediments was investigated and discussed. The microplastic abundance in surface water was approximately two orders of magnitude lower than that in sediments in all 18 lakes. Hong Lake had the highest microplastic abundance in surface water sample, and Nantaizi Lake had the highest microplastic abundance in sediment sample. The dominant microplastic shape was fiber of 93.81% in surface water sample and 94.77% in sediment sample. Blue-colored microplastics were dominant in nearly all lakes in surface water sample (around 40%–60%) and sediment sample (around 60%–80%), followed by purple- and green-colored ones. The microplastics size <1 mm was dominant in surface water sample (around 40%–60%) and sediment sample (around 50%–80%). The dominant material was polypropylene in surface water sample (around 60%–80%) and sediment sample (around 40%–60%).

Li, W, Li, J, Liu, Y, Qu, J, Liu, B, Zhu, M, Li, Y, Huang, Z & Zheng, R 2019, 'Artificial 2D Flux Pinning Centers in MgB₂ Induced by Graphitic-Carbon Nitride Coated on Boron for Superconductor Applications', ACS Applied Nano Materials, vol. 2, no. 9, pp. 5399-5408.
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© 2019 American Chemical Society. Systemic investigation was carried out on the microstructure, superconducting properties, and flux pinning mechanism of MgB2 in situ fabricated with magnesium and g-C3N4 coated boron as precursors. The encapsulation of the boron powders with g-C3N4 was achieved by polycondensation of urea on boron powders. The g-C3N4 decomposes during the MgB2 fabrication to induce two-dimensional few-carbon layer, dispersed nanoparticles, and carbon-rich phases in the matrix to enhance the flux pinning force and Hirr of MgB2, which accounts for the in-field critical current density (Jc(H)) increase compared to the pure MgB2. The carbon layers acting as artificial two-dimensional flux pinning centers, have demonstrated high flux pinning efficiency to increase the Jc(H) of MgB2 superconductors.

Li, X, Liu, Y, Xu, Q, Liu, X, Huang, X, Yang, J, Wang, D, Wang, Q, Liu, Y & Yang, Q 2019, 'Enhanced methane production from waste activated sludge by combining calcium peroxide with ultrasonic: Performance, mechanism, and implication', Bioresource Technology, vol. 279, pp. 108-116.
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© 2019 Elsevier Ltd This study reported a novel and high-efficient pretreatment method for anaerobic digestion, i.e., combining calcium peroxide (CaO2) with ultrasonic (US), by which not only the methane production was remarkably improved but also the removal of refractory organic contaminants was enhanced. Experimental results showed the optimum condition for methane production was achieved at 0.1 g CaO2/g VSS combined with US (1 W/ml, 10 min). Under this condition, the maximal methane yield of 211.90 ± 2.6 L CH4/kg VSS was obtained after 36 d of anaerobic digestion, which was respectively 1.36-fold, 1.19-fold and 1.26-fold of that from the control, solo US (1 W/ml, 10 min) and solo CaO2 (0.1 g/g VSS). Mechanism investigations revealed that CaO2 + US not only improved the disintegration of waste activated sludge (WAS) but also increased the proportion of biodegradable organic matters. Moreover, the total frequency of recalcitrant contaminants contained in WAS decreased significantly when CaO2 + US was applied.

Li, X, Mei, Q, Chen, L, Zhang, H, Dong, B, Dai, X, He, C & Zhou, J 2019, 'Enhancement in adsorption potential of microplastics in sewage sludge for metal pollutants after the wastewater treatment process', Water Research, vol. 157, pp. 228-237.
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© 2019 Elsevier Ltd Microplastics (MPs) as new pollutants of environmental concern have been widely detected in sewage sludge, and may act as significant vectors for metal pollutants due to their adsorption property. Our findings show that Cd, Pb, and Co, but not Ni, contents in sewage sludge are lower than that of corresponding metal irons adsorbed on sludge-based MPs, indicating that the MPs accumulate such metal pollutants as Cd in the sludge samples. In contrast to virgin MPs, sludge-based MPs are one order of magnitude higher adsorption capacity for Cd, which reaches up to 2.523 mg g−1, implying that there is a considerable enhancement in adsorption potential of the MPs for metals after the wastewater treatment process. SEM analysis shows that sludge-based MPs have rougher and more porous surface than virgin MPs, and FTIR spectra reveal that functional groups such as C–O and O–H are found on sludge-based MPs. Further, two-dimensional FTIR correlation spectroscopy indicates that C–O and N–H functional groups play a vital role in the process that sludge-based MPs adsorb Cd, which are not found in virgin MPs. The results imply that increased adsorption potentials of the sludge-based MPs to Cd are attributed to changes in the MP physicochemical properties during wastewater treatment process. In addition, such factors as pH value, and sludge inorganic and organic components also have an effect on the MP adsorption to Cd. Principal component analysis shows that the MPs could be divided into three categories, i.e. polyamide, rubbery MPs (polyethylene and polypropylene) and glassy MPs (polyvinyl chloride and polystyrene). Their adsorption potentials to Cd follow the decreasing order: polyamide > rubbery MPs > glassy MPs. In summary, these findings indicate that MPs may exert an important influence on fate and transport of metal pollutants during sewage sludge treatment process, which deserves to be further concerned.

Li, Y, Huang, C, Ngo, HH, Pang, J, Zha, X, Liu, T & Guo, W 2019, 'In situ reconstruction of long-term extreme flooding magnitudes and frequencies based on geological archives', Science of The Total Environment, vol. 670, pp. 8-17.
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© 2019 Extreme flooding magnitudes and frequencies are essentially related to assessment of risk and reliability in hydrological design. Extreme flooding and its discharge are highly sensitive to regional climate change. Presently, its discharge can be reconstructed by a geological archive or record along the river valley. Two units of typical extreme flooding deposits (EFDs) carrying long-term information preserved in the Holocene loess–palaeosol sequence were found at Xipocun (XPC), which is located in Chengcheng County, China. It is situated in the downstream section of the Beiluohe (hereafter BLH) River. Based on multiple sedimentary proxy indices (grain-size distribution (GSD), magnetic susceptibility (MS), and loss-on-ignition (LOI), etc.), EFDs were interpreted as well-sorted clayey silt in suspension. They were then deposited as a result of riverbank flooding in a stagnant environment during high water level. Through the Optically Stimulated Luminescence (OSL) dating technique and stratigraphic correlations, chronologies of two identified extreme flooding periods were 7600–7400 a B.P. and 3200–3000 a B.P. Two phases of extreme flooding occurrence under climate abnormality scenarios were characterized as having high frequencies of hydrological extremes in river systems. According to simulation and verification using the Slope–Area Method and Hydrologic Engineering Center's River Analysis System (HEC-RAS) model, the extreme flooding discharges at the XPC site were reconstructed between 9625 m 3 /s and 16,635 m 3 /s. A new long-term flooding frequency and peak discharge curve, involved gauged flooding, historical flooding at Zhuangtou station and in situ reconstructed extreme flooding events, was established for the downstream BLH River. The results improve the accuracy of low-frequency flooding risk assessment and provide evidence for predicting the response of fluvial systems to climate instability. Thus, this improves the analysis of the BLH River watershed.

Lim, S, Tran, VH, Akther, N, Phuntsho, S & Shon, HK 2019, 'Defect-free outer-selective hollow fiber thin-film composite membranes for forward osmosis applications', Journal of Membrane Science, vol. 586, pp. 281-291.
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© 2019 Elsevier B.V. This study presents the successful fabrication of a novel defect-free outer-selective hollow fiber (OSHF) thin-film composite (TFC) membrane for forward osmosis (FO) applications. Thin and porous FO membrane substrates made of polyether sulfone (PES) with a dense and smooth outer surface were initially fabricated at different air-gap distances. A modified vacuum-assisted interfacial polymerization (VAIP) technique was then successfully utilised for coating polyamide (PA) layer on the hollow fiber (HF) membrane substrate to prepare OSHF TFC membranes. Experimental results showed that the molecular weight cut-off (MWCO) of the surface of the membrane substrate should be less than 88 kDa with smooth surface roughness to obtain a defect-free PA layer via VAIP. The FO test results showed that the newly developed OSHF TFC membranes achieved water flux of 30.2 L m−2 h−1 and a specific reverse solute flux of 0.13 g L−1 using 1 M NaCl and DI water as draw and feed solution, respectively. This is a significant improvement on commercial FO membranes. Moreover, this OSHF TFC FO membrane demonstrated higher fouling resistance and better cleaning efficiency against alginate-silica fouling. This membrane also has a strong potential for scale-up for use in larger applications. It also has strong promise for various FO applications such as osmotic membrane bioreactor (OMBR) and fertilizer-drawn OMBR processes.

Liu, F, Nattestad, A, Naficy, S, Han, R, Casillas, G, Angeloski, A, Sun, X & Huang, Z 2019, 'Fluorescent Carbon‐ and Oxygen‐Doped Hexagonal Boron Nitride Powders as Printing Ink for Anticounterfeit Applications', Advanced Optical Materials, vol. 7, no. 24, pp. 1901380-1901380.
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AbstractIncreasing demands for optical anticounterfeiting technology require the development of versatile luminescent materials with tunable photoluminescence properties. Herein, a number of fluorescent carbon‐ and oxygen‐doped hexagonal boron nitride (denoted as BCNO) phosphors are found to offer a such high‐tech anticounterfeiting solution. These multicolor BCNO powders, developed in a two‐step process with controlled annealing and oxidation, feature rod‐like particle shape, with varied luminescence properties. Studies of the optical properties of BCNO, along with other characterization, provide insight into this underexplored material. Anticounterfeiting applications are demonstrated with printed patterns which are indistinguishable to the naked eye under visible light but become highly discernible under UV irradiation. The fabricated patterns are demonstrated to be both chemically stable in corrosive environments and physically robust in mechanical bending testing. These properties render BCNO as promising and versatile anticounterfeiting material a wide variety of environments.

Liu, H, Zhou, X, Ding, W, Zhang, Z, Nghiem, LD, Sun, J & Wang, Q 2019, 'Do Microplastics Affect Biological Wastewater Treatment Performance? Implications from Bacterial Activity Experiments', ACS Sustainable Chemistry & Engineering, vol. 7, no. 24, pp. 20097-20101.
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© 2019 American Chemical Society. Microplastics have been ubiquitously detected in the wastewater treatment plants, while their effects on the activities of wastewater treatment bacteria have never been evaluated. This study investigated the effects of polyester (PES), polyethylene (PE), and polyvinyl chloride (PVC) microplastics (100-1200 μm; 50-10000 particles/L) on the activities of ammonium-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), denitrifiers, and polyphosphate-accumulating organisms (PAOs). The activities of AOB and NOB without microplastics addition are 6.3 ± 0.3 and 4.0 ± 0.4 mg N/g MLVSS/h (MLVSS: mixed liquor volatile suspended solids), which are similar (p > 0.05) to their activities (5.2 ± 0.7 to 6.8 ± 0.8 and 3.7 ± 0.9 to 5.1 ± 0.8 mg N/g MLVSS/h) with microplastics addition. Similarly, the activities of denitrifiers and PAOs without microplastics addition (14.1 ± 1.1 mg N/g MLVSS/h and 29.2 ± 0.9 mg P/g MLVSS/h) are comparable (p > 0.05) to those with microplastics addition (12.8 ± 1.2 to 15.1 ± 0.5 mg N/g MLVSS/h and 28.0 ± 1.1 to 29.7 ± 2.4 mg P/g MLVSS/h). The results demonstrated that microplastics do not significantly affect the activities of AOB, NOB, denitrifiers, and PAOs, and therefore the effect of microplastics on the wastewater treatment performance should not be overemphasized.

Liu, M, Nothling, MD, Webley, PA, Fu, Q & Qiao, GG 2019, 'Postcombustion Carbon Capture Using Thin-Film Composite Membranes', Accounts of Chemical Research, vol. 52, no. 7, pp. 1905-1914.
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Climate change due to anthropogenic carbon dioxide emissions (e.g., combustion of fossil fuels) represents one of the most profound environmental disasters of this century. Equipping power plants with carbon capture and storage (CCS) technology has the potential to reduce current worldwide CO2 emissions. However, existing CCS schemes (i.e., amine scrubbing) are highly energy-intensive. The urgent abatement of CO2 emissions relies on the development of new, efficient technologies to capture CO2 from existing power plants. Membrane-based CO2 separation is an attractive technology that meets many of the requirements for energy-efficient industrial carbon capture. Within this domain, thin-film composite (TFC) membranes are particularly attractive, providing high gas permeance in comparison with conventional thicker (∼50 μm) dense membranes. TFC membranes are usually composed of three layers: (1) a bottom porous support layer; (2) a highly permeable intermediate gutter layer; and (3) a thin (<1 μm) species-selective top layer. A key challenge in the development of TFC membranes has been to simultaneously maximize the transmembrane gas permeance of the assembled membrane (by minimizing the gas resistance of each layer) while maintaining high gas-specific selectivity. In this Account, we provide an overview of our recent development of high-performance TFC membrane materials as well as insights into the unique fabrication strategies employed for the selective layer and gutter layer. Optimization of each layer of the membrane assembly individually results in significant improvements in overall membrane performance. First, incorporating nanosized fillers into the selective layer (poly(ethylene glycol)-based polymers) and reducing its thickness (to ca. 50 nm) through continuous assembly of polymers technology yields major improvements in CO2 permeance without loss of selectivity. Second, we focus on optimization of the middle gutter layer of TFC membranes. The de...

Liu, R, Zhao, Y, Li, W, Wang, Q, Shen, C, Awe, OW & Hao, X 2019, 'Dynamics of the activated sludge in a newly-defined green bio-sorption reactor (GBR)', Chemical Engineering Journal, vol. 374, pp. 1046-1054.
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© 2019 Elsevier B.V. When upgrading an aging wastewater treatment plant (WWTP), the sludge management line is always out of consideration in terms of cost and easy-operation. This study presented the dynamics of the sludge when upgrading a conventional sequencing batch reactor (SBR) to green bio-sorption reactor (GBR) by embedding alum sludge-based constructed wetland (AlCW). The aluminum (Al(III)) content in the effluent and the resultant impact on organisms were also evaluated. The results showed that the Al(III) residues was at an acceptable level (<0.2 mg/L). The AlCW and its leachate Al(III) did not pose any detrimental impact on the activity of heterotrophic organisms and the nitrifiers whereas the activity of the polyphosphate accumulating organisms was completely suppressed and eliminated out of the reactor. In addition, the Al(III) hydroxides and natural organic matter promoted the flocculation of activated sludge flocs by complexation with the extracellular polymeric substances. As a result, the larger and compact activated sludge led to an increase of the settling velocity and the dewatering efficiency while deteriorating the sludge compressibility (sludge volume index of 150 mL/g). Interestingly, this laboratory-scale GBR was verified to be a promising alternative to upgrade the ageing WWTPs simultaneously with an improvement of the dewatering properties of the activated sludge.

Liu, X, Duan, X, Wei, W, Wang, S & Ni, B-J 2019, 'Photocatalytic conversion of lignocellulosic biomass to valuable products', Green Chemistry, vol. 21, no. 16, pp. 4266-4289.
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This review summarizes the state-of-the-art accomplishments in photocatalytic conversion of lignocellulosic biomass and its derivatives.

Liu, X, Xu, Q, Wang, D, Wu, Y, Fu, Q, Li, Y, Yang, Q, Liu, Y, Ni, B-J, Wang, Q, Yang, G, Li, H & Li, X 2019, 'Microwave pretreatment of polyacrylamide flocculated waste activated sludge: Effect on anaerobic digestion and polyacrylamide degradation', Bioresource Technology, vol. 290, pp. 121776-121776.
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© 2019 Elsevier Ltd Deterioration of anaerobic digestion can occur with the presence of polyacrylamide (PAM) in waste activated sludge, but the information on alleviating this deterioration is still limited. In this study, the simultaneous alleviation of negative effect of PAM and improvement of methane production during anaerobic digestion was accomplished by microwave pretreatment. Experimental results showed that with the microwave pretreatment times increased from 0 to 12 min, the biochemical methane potential of PAM-flocculated sludge (12 g PAM/kg total solids) asymptotically increased from 123.1 to 242.5 mL/g volatile solids, hydrolysis rate increased from 0.06 to 0.13 d−1. Mechanism analysis indicated that the microwave pretreatment accelerated the release and hydrolysis of organic substrates from PAM-flocculated sludge, facilitated the breaking of large firm “PAM-sludge” floccules, and benefited the degradation of PAM, which alleviated the PAM inhibitory impacts on digestion and meanwhile provided better contact between the released organic substrates and anaerobic bacteria for methane production.

Liu, X, Xu, Q, Wang, D, Wu, Y, Yang, Q, Liu, Y, Wang, Q, Li, X, Li, H, Zeng, G & Yang, G 2019, 'Unveiling the mechanisms of how cationic polyacrylamide affects short-chain fatty acids accumulation during long-term anaerobic fermentation of waste activated sludge', Water Research, vol. 155, pp. 142-151.
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© 2019 Elsevier Ltd Cationic polyacrylamide, a flocculation powder widely used in wastewater pretreatment and sludge dewatering, was highly accumulated in waste activated sludge. However, its effect on short-chain fatty acids (SCFAs) accumulation from anaerobic fermentation of waste activated sludge has not been investigated. This work therefore aims to deeply unveil how cationic polyacrylamide affects SCFAs production, through both long-term and batch tests using either real waste activated sludge or synthetic wastewaters as fermentation substrates. Experimental results showed that the presence of cationic polyacrylamide not only significantly decreased the accumulation of SCFAs but also affected the composition of individual SCFA. The concentration of SCFAs decreased from 3374.7 to 2391.7 mg COD/L with cationic polyacrylamide level increasing from 0 to 12 g/kg of total suspended solids, whereas the corresponding percentage of acetic acid increased from 45.2% to 55.5%. The mechanism studies revealed that although cationic polyacrylamide could be partially degraded to produce SCFAs during anaerobic fermentation, cationic polyacrylamide and its major degradation metabolite, polyacrylic acid, inhibited all the sludge solubilization, hydrolysis, acidogenesis, acetogenesis and homoacetogenesis processes to some extents. As a result, the accumulation of SCFAs in the cationic polyacrylamide added systems decreased rather than increased. However, the inhibition to acetogenesis and homoacetogenesis was slighter than that to acidogenesis, leading to an increase of acetic acid to total SCFAs. It was further found that cationic polyacrylamide had stronger ability to adhere to protein molecules surface, which inhibited the bioconversion of proteins more severely. Illumina MiSeq sequencing analyses showed that cationic polyacrylamide decreased microbial community diversity, altered community structure and changed activities of key enzymes responsible for SCFAs accumulation.

Liu, X, Xu, Q, Wang, D, Yang, Q, Wu, Y, Li, Y, Fu, Q, Yang, F, Liu, Y, Ni, B-J, Wang, Q & Li, X 2019, 'Thermal-alkaline pretreatment of polyacrylamide flocculated waste activated sludge: Process optimization and effects on anaerobic digestion and polyacrylamide degradation', Bioresource Technology, vol. 281, pp. 158-167.
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© 2019 Elsevier Ltd Deterioration of anaerobic digestion can occur with the presence of polyacrylamide (PAM) in waste activated sludge, and little information on mitigating this deterioration is currently available. In this study, simultaneous mitigation of PAM negative effects and improvement of methane production was accomplished by thermal-alkaline pretreatment. Under the optimized pretreatment conditions (i.e., 75 °C, pH 11.0 for 17.5 h), the biochemical methane potential of PAM-flocculated sludge increased from 100.5 to 210.8 mL/g VS and the hydrolysis rate increased from 0.122 to 0.187 d−1. Mechanism investigations revealed that the pretreatment not only broke the large firm floccules, improved the degradation of PAM, but also facilitated the release of biodegradable organics from sludge, which thereby provided better growth environment and enough nutrients to anaerobic microbes for methane production. The activities of key enzymes responsible for methane production and PAM degradation were greatly improved in pretreated reactor, with the accumulation of acrylamide being avoided.

Liu, X, Xu, Q, Wang, D, Yang, Q, Wu, Y, Yang, J, Liu, Y, Wang, Q, Ni, B-J, Li, X, Li, H & Yang, G 2019, 'Enhanced Short-Chain Fatty Acids from Waste Activated Sludge by Heat–CaO₂ Advanced Thermal Hydrolysis Pretreatment: Parameter Optimization, Mechanisms, and Implications', ACS Sustainable Chemistry & Engineering, vol. 7, no. 3, pp. 3544-3555.
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© 2019 American Chemical Society. In the present work,heat-CaO2 advanced thermal hydrolysis pretreatment was applied for enhancing fermentative short-chain fatty acids (SCFAs) production from waste activated sludge (WAS). Various pretreatment conditions including heating temperatures, CaO2 doses, and times were optimized. Simulation and experimental results showed that the optimal pretreatment conditions were a temperature of 67.4 °C, CaO2 of 0.12 g/g VSS, and time of 19 h, under which the maximum SCFAs yield reached to 336.5 mg COD/g VSS after 5 days of fermentation, with the percentage of acetic acid accounted for 70.1%. Mechanism investigations exhibited that CaO2 and heat pretreatment caused positive synergy on sludge solubilization and SCFAs production. Compared with the control, heat pretreatment, and CaO2 addition alone, the heat-CaO2 pretreatment not only facilitated the organic released from WAS but also increased the proportion of biodegradable organic matters, which thereby providing more organics for subsequent SCFA production. It was found that the heat-CaO2 pretreatment improved the activities of both hydrolytic and acid-forming enzymes while it inhibited the coenzymes of methanogens during the fermentation process. In addition, heat-CaO2 pretreatment and subsequent fermentation worked well in removal of refractory organic pollutants and pathogens contained in WAS. Further analysis indicated that the heat-CaO2 pretreatment can be used as an effective method for both valuable carbon source recovery and refractory pollutant removal in the WAS treatment process.

Liu, Y, Jin, W, Zhou, X, Han, S-F, Tu, R, Feng, X, Jensen, PD & Wang, Q 2019, 'Efficient harvesting of Chlorella pyrenoidosa and Scenedesmus obliquus cultivated in urban sewage by magnetic flocculation using nano-Fe3O4 coated with polyethyleneimine', Bioresource Technology, vol. 290, pp. 121771-121771.
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© 2019 Elsevier Ltd In this work, a novel flocculation process by using nano-Fe3O4 coated with polyethyleneimine (Fe3O4@PEI) as magnetic seeds was developed to harvest the microalgae cultivated in urban sewage. Experiment results indicated that the harvest efficiency of Chlorella pyrenoidosa (0.5 g/L) was 98.92 ± 0.41% under the optimal conditions of Fe3O4@PEI dose of 20 mL/L, flocculation time of 20 min, and stirring speed of 800 rpm (3 min), while that of Scenedesmus obliquus (0.4 g/L) was 98.45 ± 0.35% under a Fe3O4@PEI dose of 16 mL/L, flocculation time of 15 min, and stirring speed of 730 rpm (3 min). Moreover, the process did not reduce the lipid content of microalgae and quality of biodiesel. After microalgae harvest, Fe3O4@PEI could be recovered by ultrasonication, re-wrapped with polyethyleneimine and reused to reduce operational cost.

Liu, Y, Ngo, HH, Guo, W, Peng, L, Wang, D & Ni, B 2019, 'The roles of free ammonia (FA) in biological wastewater treatment processes: A review', Environment International, vol. 123, pp. 10-19.
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© 2018 Free ammonia (FA) can pose inhibitory and/or biocidal effects on a variety of microorganisms involved in different biological wastewater treatment process, which is widely presented in wastewater treatment plants (WWTPs) due to the high levels of ammonium in the systems. This review article gives the up-to-date status on several essential roles of FA in biological wastewater treatment processes: the impacts of FA, mechanisms of FA roles, modeling of FA impacts, and implications of FA for wastewater treatment. Specifically, the impacts of FA on both wastewater and sludge treatment lines were firstly summarized, including nitrification, denitrification, anaerobic ammonium oxidation (Anammox), enhanced biological phosphorus removal and anaerobic processes. The involved mechanisms were then analyzed, which indicated FA inhibition can slow specific microbial activities or even reconfigure the microbial community structure, likely due to negative impacts of FA on intracellular pH, specific enzymes and extracellular polymeric substances (EPS), thus causing cell inactivation/lysis. Mathematical models describing the impact of FA on both wastewater and sludge treatment processes were also explored to facilitate process optimization. Finally, the key implications of FA were identified, that is FA can be leveraged to substantially enhance the biodegradability of secondary sludge, which would further improve biological nutrient removal and enhance renewable energy production.

Long, G, Li, L, Li, W, Ma, K, Dong, W, Bai, C & Zhou, JL 2019, 'Enhanced mechanical properties and durability of coal gangue reinforced cement-soil mixture for foundation treatments', Journal of Cleaner Production, vol. 231, pp. 468-482.
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© 2019 Elsevier Ltd High-speed railways with high load capacity and long-term performance have been developed by the aid of high-performance construction materials for foundation treatments. The mechanical properties and durability of new cement-soil mixture reinforced by local sourced waste coal gangue aggregate were investigated in this study. Extensive experiments were carried out to analyse the effects of coal gangue on compressive strength, elastic modulus, stress-strain curve and anti-corrosion of cement-soil mixture. The results show that incorporation of coal gangue significantly improve the strength, stiffness and anti-corrosion ability of cement-soil mixture. Strength improvements up to 81.8% was achieved, but the ductile failure model shited to brittle failure with more than 42% coal gangue reinforcements. Except for the declining segment of the stress-strain curve, the ascending segment of the stress-strain curve can be fitted by the existing models. From the microstructural characterization, coal gangue can reduce acid solution permeation compared to the soil. For the cemented soil with coal gangue, the mass-loss rates only reach 4–7% after 140 days acid solution immersion. Therefore, this new clean production of high-performance cement-soil mixture through waste coal gangue reinforcement has great potential for railway foundation treatments.

Lu, P, Liu, T, Ni, B-J, Guo, J, Yuan, Z & Hu, S 2019, 'Growth kinetics of Candidatus ‘Methanoperedens nitroreducens’ enriched in a laboratory reactor', Science of The Total Environment, vol. 659, pp. 442-450.
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© 2018 Recently it has been shown that Candidatus ‘Methanoperedens nitroreducens’, an anaerobic methanotrophic archaea (ANME), can reduce nitrate to nitrite using electrons derived from anaerobic oxidation of methane. In this study, the growth kinetics of ‘M. nitroreducens’ enriched in a laboratory reactor were studied. In the experimental concentration range (up to 16 mg CH 4 L −1 ), anaerobic oxidation of methane by ‘M. nitroreducens’ was found to comply with first order kinetic model with a rate constant of 0.019 ± 0.006 h −1 and a biomass-specific rate constant of 0.04–0.14 L h −1 g −1 VSS. Meanwhile, the nitrate reduction to nitrite was well described by the Monod-type kinetic model with an affinity constant for nitrate of 2.1 ± 0.4 mg N L −1 , which is slightly higher than, but comparable to, that of most known denitrifying bacteria. This is the first time that the growth kinetics of ‘M. nitroreducens’ have been experimentally studied. The applicability of the kinetic model reported herein to this organism or similar organisms in natural or engineering systems requires further investigation.

Lyu, H, Dong, Z, Roobavannan, M, Kandasamy, J & Pande, S 2019, 'Rural unemployment pushes migrants to urban areas in Jiangsu Province, China', Palgrave Communications, vol. 5, no. 1.
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AbstractMigration is often seen as an adaptive human response to adverse socio-environmental conditions, such as water scarcity. A rigorous assessment of the causes of migration, however, requires reliable information on the migration in question and related variables, such as, unemployment, which is often missing. This study explores the causes of one such type of migration, from rural to urban areas, in the Jiangsu province of China. A migration model is developed to fill a gap in the understanding of how rural to urban migration responds to variations in inputs to agricultural production including water availability and labor and how rural population forms expectations of better livelihood in urban areas. Rural to urban migration is estimated at provincial scale for period 1985–2013 and is found to be significantly linked with rural unemployment. Further, migration reacts to a change in rural unemployment after 2–4 years with 1% increase in rural unemployment, on average, leading to migration of 16,000 additional people. This implies that rural population takes a couple of years to internalize a shock in employment opportunities before migrating to cities. The analysis finds neither any evidence of migrants being pulled by better income prospects to urban areas nor being pushed out of rural areas by water scarcity. Corroborated by rural–urban migration in China migration survey data for 2008 and 2009, this means that local governments have 2–4 years of lead time after an unemployment shock, not necessarily linked to water scarcity, in rural areas to prepare for the migration wave in urban areas. This original analysis of migration over a 30-year period and finding its clear link with unemployment, and not with better income in urban areas or poor rainfall, thus provides conclusive evidence in support of policy interventions that focus on generating employment opportunities in rural areas to reduce migration flow to ur...

Ma, XY, Wang, Y, Dong, K, Wang, XC, Zheng, K, Hao, L & Ngo, HH 2019, 'The treatability of trace organic pollutants in WWTP effluent and associated biotoxicity reduction by advanced treatment processes for effluent quality improvement', Water Research, vol. 159, pp. 423-433.
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© 2019 Elsevier Ltd As increasing attention is paid to surface water protection, there has been demand for improvements of domestic wastewater treatment plant (WWTP) effluent. This has led to the application of many different advanced treatment processes (ATPs). In this study, the treatability of trace organic pollutants in secondary effluent (SE) and associated biotoxicity reduction by four types of ATPs, including coagulation, granular activated carbon (GAC) adsorption, ultraviolet (UV) photolysis and photocatalysis, and ozonation, were investigated at the bench-scale. The ATPs showed different removal capacity for the 48 chemicals, which were classified into seven categories. EDCs, herbicides, bactericides and pharmaceuticals were readily degraded, and insecticides, flame retardants, and UV filters were relatively resistant to removal. During these processes, the efficiency of the ATPs in reducing four biological effects were investigated. Of the four biological effects, the estrogenic activity from SE was not detected using the yeast estrogen screen. In contrast with genotoxicity and photosynthesis inhibition, bacterial cytotoxicity posed by SE was the most difficult biological effect to reduce with these ATPs. GAC adsorption and ozonation were the most robust treatment processes for reducing the three detected biotoxicities. UV photolysis and photocatalysis showed comparable efficiencies for the reduction of genotoxicity and photosynthesis inhibition. However, coagulation only performed well in genotoxicity reduction. The effect-based trigger values for the four bioassays, that were derived from the existing environmental quality standards and from HC5 (hazardous concentration for 5% of aquatic organisms), were all used to select and optimize these ATPs for ecological safety. Conducting ATPs in more appropriate ways could eliminate the negative effects of WWTP effluent on receiving water bodies.

Mahdavi, H, Fatahi, B & Khabbaz, H 2019, 'A comparison of frictional and socketed concrete injected columns in a transition zone', Geosynthetics International, vol. 26, no. 5, pp. 497-514.
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This paper sets out to investigate the options available for the transition from Concrete Injected Columns (CICs) to other ground improvement methods, used away from the bridge abutment. Two possible alternatives, widely spaced CICs socketed into stiff material and shorter, closely spaced, frictional CICs, were numerically simulated using FLAC3D software considering the dissipation of porewater pressure and variation of soil permeability with time. The total length of the CICs and the total volume of concrete used for their construction were the same for both alternatives. A geosynthetic layer was introduced into the load transfer platform, and interface elements were incorporated to simulate CIC-soil interaction. The numerical results were also compared with an established analytical solution and a good agreement was achieved. A comparison was then made between the two scenarios; indeed, the embankment on frictional CICs experienced less settlement on the surface, less loads in the geosynthetic, and the bending moments and shear forces generated in the columns were less than the corresponding values for socketed CICs. This study offers an enhanced understanding of the available options to practising engineers when designing road embankments on soft soil.

Mahlia, TMI, Ismail, N, Hossain, N, Silitonga, AS & Shamsuddin, AH 2019, 'Palm oil and its wastes as bioenergy sources: a comprehensive review', Environmental Science and Pollution Research, vol. 26, no. 15, pp. 14849-14866.
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Due to global warming and increasing price of fossil fuel, scientists all over the world have been trying to find reliable alternative fuels. One of the most potential candidates is renewable energy from biomass. The race for renewable energy from biomass has long begun and focused on to combat the deteriorating condition of the environment. Palm oil has been in the spotlight as an alternative of bioenergy sources to resolve fossil fuel problem due to its environment-friendly nature. This review will look deep into the origins of palm oil and how it is processed, bioproducts from this biomass, and oil palm biomass-based power plant in Malaysia. Palm oil is usually processed from oil palm fruits and other parts of the oil palm plant are candidates for raw material of bioproduct generation. Oil palm biomass can be turned into three subcategories: bioproduct, biofuels, and biopower. Focusing on biofuel, the biodiesel from palm oil will be explored in detail and its implication in Malaysia as one of the biggest producers of oil palm in the world will also be emphasized comprehensively. The paper presents the detail of a schematic flow diagram of a palm oil mill process of transforming oil palm into crude palm oil and it wastes. This paper will also discuss the current oil palm biomass power plants in Malaysia. Palm oil has been proven itself as a potential alternative to reduce negative environmental impact of global warming.

Mahlia, TMI, Syaheed, H, Abas, AEP, Kusumo, F, Shamsuddin, AH, Ong, HC & Bilad, MR 2019, 'Organic Rankine Cycle (ORC) System Applications for Solar Energy: Recent Technological Advances', Energies, vol. 12, no. 15, pp. 2930-2930.
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Organic Rankine Cycle (ORC) power generation systems may be used to utilize heat source with low pressure and low temperature such as solar energy. Many researchers have focused on different aspects of ORC power generation systems, but none so far has focused on the patent landscape of ORC system applications. As such, the objective of this study is to identify published patents on ORC system applications, particularly for solar energy. Four (4) technologies were identified in ORC application for solar energy: parabolic dish, parabolic trough, solar tower, and linear Fresnel reflector. A methodical search and analysis of the patent landscape in ORC system applications for solar energy published between 2007–2018 was conducted using the Derwent Innovation patent database. From the approximately 51 million patents in the database from various countries and patent agencies, 3859 patents were initially identified to be related to ORC applications for solar energy. After further stringent selection processes, only 1100 patents were included in this review. From these 1100 patents, approximately 12% (130 patents) are associated with parabolic dishes, about 39% (428 patents) are associated with parabolic troughs, approximately 21% (237 patents) are associated with solar towers, and about 28% (305 patents) are associated with linear Fresnel reflectors. Published patents on solar tower technology are currently on an increasing trend, led by China. All of these patents were published in the past 11 years. From this study, further researches on ORC application are still ongoing, but ORC application for solar energy has the potential to advance; allowing the world to ease issues related to over-reliance on fossil fuel.

Mahmudul, HM, Rasul, MG, Akbar, D & Mofijur, M 2019, 'Opportunities for solar assisted biogas plant in subtropical climate in Australia: A review', Energy Procedia, vol. 160, pp. 683-690.
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© 2019 The Authors. Published by Elsevier Ltd. Household waste generation has become a serious environmental issue in recent years. However, some technologies are available to convert household domestic waste into energy. One of such techniques is the biogas generation using household waste. The biogas generation technique is not a new method of energy generation, but its production efficiency is questionable. Biogas yield from domestic waste are influenced by pH level, temperature, HRT and C/N ratio. Moisture and the temperature levels in the biogas generation systems are very critical to its production efficiency, especially this is highly affected in the colder weather condition. Solar assisted biogas plant may provide better production efficiency compared to the traditionally designed biogas plant. In this paper, the scopes and opportunities of solar assisted biogas generation are reviewed. Possible benefits and challenges associated with the solar assisted biogas generation are highlighted.

Majeed, K, Ahmed, A, Abu Bakar, MS, Indra Mahlia, TM, Saba, N, Hassan, A, Jawaid, M, Hussain, M, Iqbal, J & Ali, Z 2019, 'Mechanical and Thermal Properties of Montmorillonite-Reinforced Polypropylene/Rice Husk Hybrid Nanocomposites', Polymers, vol. 11, no. 10, pp. 1557-1557.
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In recent years, there has been considerable interest in the use of natural fibers as potential reinforcing fillers in polymer composites despite their hydrophilicity, which limits their widespread commercial application. The present study explored the fabrication of nanocomposites by melt mixing, using an internal mixer followed by a compression molding technique, and incorporating rice husk (RH) as a renewable natural filler, montmorillonite (MMT) nanoclay as water-resistant reinforcing nanoparticles, and polypropylene-grafted maleic anhydride (PP-g-MAH) as a compatibilizing agent. To correlate the effect of MMT delamination and MMT/RH dispersion in the composites, the mechanical and thermal properties of the composites were studied. XRD analysis revealed delamination of MMT platelets due to an increase in their interlayer spacing, and SEM micrographs indicated improved dispersion of the filler(s) from the use of compatibilizers. The mechanical properties were improved by the incorporation of MMT into the PP/RH system and the reinforcing effect was remarkable as a result of the use of compatibilizing agent. Prolonged water exposure of the prepared samples decreased their tensile and flexural properties. Interestingly, the maximum decrease was observed for PP/RH composites and the minimum was for MMT-reinforced and PP-g-MAH-compatibilized PP/RH composites. DSC results revealed an increase in crystallinity with the addition of filler(s), while the melting and crystallization temperatures remained unaltered. TGA revealed that MMT addition and its delamination in the composite systems improved the thermal stability of the developed nanocomposites. Overall, we conclude that MMT nanoclay is an effective water-resistant reinforcing nanoparticle that enhances the durability, mechanical properties, and thermal stability of composites.

MANNAN, A, SABRI, MFM, KALAM, MA & MASJUKI, HH 2019, 'Tribological Properties of Steel/Steel, Steel/DLC and DLC/DLC Contacts in the Presence of Biodegradable Oil', Journal of the Japan Petroleum Institute, vol. 62, no. 1, pp. 11-18.
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Mat Nawi, NI, Bilad, MR, Zolkhiflee, N, Nordin, NAH, Lau, WJ, Narkkun, T, Faungnawakij, K, Arahman, N & Mahlia, TMI 2019, 'Development of A Novel Corrugated Polyvinylidene difluoride Membrane via Improved Imprinting Technique for Membrane Distillation', Polymers, vol. 11, no. 5, pp. 865-865.
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Membrane distillation (MD) is an attractive technology for desalination, mainly because its performance that is almost independent of feed solute concentration as opposed to the reverse osmosis process. However, its widespread application is still limited by the low water flux, low wetting resistance and high scaling vulnerability. This study focuses on addressing those limitations by developing a novel corrugated polyvinylidene difluoride (PVDF) membrane via an improved imprinting technique for MD. Corrugations on the membrane surface are designed to offer an effective surface area and at the same time act as a turbulence promoter to induce hydrodynamic by reducing temperature polarization. Results show that imprinting of spacer could help to induce surface corrugation. Pore defect could be minimized by employing a dual layer membrane. In short term run experiment, the corrugated membrane shows a flux of 23.1 Lm−2h−1 and a salt rejection of >99%, higher than the referenced flat membrane (flux of 18.0 Lm−2h−1 and similar rejection). The flux advantage can be ascribed by the larger effective surface area of the membrane coupled with larger pore size. The flux advantage could be maintained in the long-term operation of 50 h at a value of 8.6 Lm−2h−1. However, the flux performance slightly deteriorates over time mainly due to wetting and scaling. An attempt to overcome this limitation should be a focus of the future study, especially by exploring the role of cross-flow velocity in combination with the corrugated surface in inducing local mixing and enhancing system performance.

McInnes, AS, Laczka, OF, Baker, KG, Larsson, ME, Robinson, CM, Clark, JS, Laiolo, L, Alvarez, M, Laverock, B, Kremer, CT, van Sebille, E & Doblin, MA 2019, 'Live cell analysis at sea reveals divergent thermal performance between photosynthetic ocean microbial eukaryote populations', The ISME Journal, vol. 13, no. 5, pp. 1374-1378.
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Abstract Experimentation at sea provides insight into which traits of ocean microbes are linked to performance in situ. Here we show distinct patterns in thermal tolerance of microbial phototrophs from adjacent water masses sampled in the south-west Pacific Ocean, determined using a fluorescent marker for reactive oxygen species (ROS). ROS content of pico-eukaryotes was assessed after 1, 5 and 25 h of incubation along a temperature gradient (15.6–32.1 °C). Pico-eukaryotes from the East Australian Current (EAC) had relatively constant ROS and showed greatest mortality after 25 h at 7 °C below ambient, whereas those from the Tasman Sea had elevated ROS in both warm and cool temperature extremes and greatest mortality at temperatures 6–10 °C above ambient, interpreted as the outcome of thermal stress. Tracking of water masses within an oceanographic circulation model showed populations had distinct thermal histories, with EAC pico-eukaryotes experiencing higher average temperatures for at least 1 week prior to sampling. While acclimatization and community assembly could both influence biological responses, this study clearly demonstrates that phenotypic divergence occurs along planktonic drift trajectories.

Mishra, B, Varjani, S, Iragavarapu, GP, Ngo, HH, Guo, W & Vishal, B 2019, 'Microbial Fingerprinting of Potential Biodegrading Organisms', Current Pollution Reports, vol. 5, no. 4, pp. 181-197.
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© 2019, Springer Nature Switzerland AG. The world is witnessing various pollutants in the environment since the last few decades that threaten human life. The biological responses to various pollutants show variations as the living system behaves differently in their sensitivities to the same types of pollutants. The relative response and activity depend upon the duration of exposure to the specific pollutant. It is impossible to stop various activities leading to environmental pollution; however, pollutants can be eliminated from the environment using the microorganisms. Application of biological processes can be executed in order to get rid of toxic pollutants through their biodegradation. The pollutants like hydrocarbons, heavy metals, chlorinated hydrocarbons, nitro-aromatic compounds, non-chlorinated herbicides and pesticides, organophosphates, radionuclides can lead to serious health and environmental problems. The main objective of this paper is to evaluate the effects of pollutants on the living beings and environment, microbial responses to pollution, and distribution of various biodegrading microorganisms in the environment. Profiling of biodegrading microorganisms, microbial biosensor to detect environmental pollution, and strain improvement through genetic manipulation to enhance the biodegradation process have been discussed in detail.

Mofijur, M, Hasan, MM, Mahlia, TMI, Rahman, SMA, Silitonga, AS & Ong, HC 2019, 'Performance and Emission Parameters of Homogeneous Charge Compression Ignition (HCCI) Engine: A Review', Energies, vol. 12, no. 18, pp. 3557-3557.
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Strict emission regulations and demand for better fuel economy are driving forces for finding advanced engines that will be able to replace the conventional internal combustion engines in the near future. Homogeneous charge compression ignition (HCCI) engines use a different combustion technique; there are no spark plugs or injectors to assist the combustion. Instead, when the mixtures reach chemical activation energy, combustion auto-ignites in multiple spots. The main objective of this review paper is to study the engine performance and emission characteristics of HCCI engines operating in various conditions. Additionally, the impact of different fuels and additives on HCCI engine performance is also evaluated. The study also introduces a potential guideline to improve engine performance and emission characteristics. Compared to conventional compression ignition and spark ignition combustion methods, the HCCI combustion mode is noticeably faster and also provides better thermal efficiency. Although a wide range of fuels including alternative and renewable fuels can be used in the HCCI mode, there are some limitation/challenges, such as combustion limited operating range, phase control, high level of noise, cold start, preparation of homogeneous charge, etc. In conclusion, the HCCI combustion mode can be achieved in existing spark ignition (SI) engines with minor adjustments, and it results in lower oxides of nitrogen (NOx) and soot emissions, with practically a similar performance as that of SI combustion. Further improvements are required to permit extensive use of the HCCI mode in future.

Mofijur, M, Mahlia, T, Silitonga, A, Ong, H, Silakhori, M, Hasan, M, Putra, N & Rahman, SM 2019, 'Phase Change Materials (PCM) for Solar Energy Usages and Storage: An Overview', Energies, vol. 12, no. 16, pp. 3167-3167.
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Solar energy is a renewable energy source that can be utilized for different applications in today’s world. The effective use of solar energy requires a storage medium that can facilitate the storage of excess energy, and then supply this stored energy when it is needed. An effective method of storing thermal energy from solar is through the use of phase change materials (PCMs). PCMs are isothermal in nature, and thus offer higher density energy storage and the ability to operate in a variable range of temperature conditions. This article provides a comprehensive review of the application of PCMs for solar energy use and storage such as for solar power generation, water heating systems, solar cookers, and solar dryers. This paper will benefit the researcher in conducting further research on solar power generation, water heating system, solar cookers, and solar dryers using PCMs for commercial development.

Mofijur, M, Rasul, M, Hassan, NMS & Uddin, MN 2019, 'Investigation of exhaust emissions from a stationary diesel engine fuelled with biodiesel', Energy Procedia, vol. 160, pp. 791-797.
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© 2019 The Authors. Published by Elsevier Ltd. This paper studied the production of waste cooking biodiesel as an alternative fuel for diesel engine. The biodiesel was produced through conventional transesterification process using the base catalyst (KOH). A multi-cylinder diesel engine was used to evaluate the emission of 20% (B20) waste cooking biodiesel fuel at different engine speeds and full load condition. It was found that the characteristics of biodiesel are within the limit of specified standards (American Society for Testing and Materials, ASTM D6751) and comparable to diesel fuel. Engine emission results indicated that waste cooking biodiesel fuel sample reduces the average carbon monoxide (CO) and particulate matter (PM) emissions except nitrogen oxides (NOx) than diesel fuel. Finally, it can be concluded that 20% of waste cooking biodiesel can significantly contribute to lower the harmful emission of an unmodified stationary diesel engine to the environment.

Mofijur, M, Rasul, MG, Hassan, NMS & Nabi, MN 2019, 'Recent Development in the Production of Third Generation Biodiesel from Microalgae', Energy Procedia, vol. 156, pp. 53-58.
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© 2019 The Authors. Published by Elsevier Ltd. Increasing global energy demand at a rate faster than the population growth has led the researcher to look for alternative fuel. Amongst the options, biodiesel is an environmentally sustainable substitute of diesel fuel being renewable, biodegradable and have similar properties of fossil diesel. Among the biodiesel sources, microalgae is a potential third generation biodiesel feedstock which can be produced throughout the year and its oil yield is higher than any other crops. This paper reviews recent development in microalgae biodiesel in terms of its oil extraction technics, challenges of oil extraction, production of biodiesel from microalgae oil and its fuel properties. Finally, the paper discusses the performance and combustion analysis of diesel engine fuelled with microalgae biodiesel. This paper provides a clear understanding of the potential use of microalgae biodiesel as an alternative source to fossil diesel for diesel engines.

Mofijur, Mahlia, Logeswaran, Anwar, Silitonga, Rahman & Shamsuddin 2019, 'Potential of Rice Industry Biomass as a Renewable Energy Source', Energies, vol. 12, no. 21, pp. 4116-4116.
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Fossil fuel depletion, along with its ever-increasing price and detrimental impact on the environment, has urged researchers to look for alternative renewable energy. Of all the options available, biomass presents a very reliable source due to its never-ending supply. As research on various biomasses has grown in recent years, waste from these biomasses has also increased, and it is now time to shift the focus to utilizing these wastes for energy. The current waste management system mainly focuses on open burning and soil incorporation as it is cost-effective; however, these affect the environment. There must be an alternative way, such as to use it for power generation. Rice straw and rice husk are examples of such potential biomass waste. Rice is the main food source for the world, mostly in Asian regions, as most people consume rice daily. This paper reviews factors that impact the implementation of rice-straw-based power plants. Ash content and moisture content are important properties that govern combustion, and these vary with location. Logistical improvements are required to reduce the transport cost of rice husk and rice straw, which is higher than the transportation cost of coal.

Mojiri, A, Zhou, JL, Ohashi, A, Ozaki, N & Kindaichi, T 2019, 'Comprehensive review of polycyclic aromatic hydrocarbons in water sources, their effects and treatments', Science of The Total Environment, vol. 696, pp. 133971-133971.
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© 2019 Elsevier B.V. Polycyclic aromatic hydrocarbons (PAHs) are principally derived from the incomplete combustion of fossil fuels. This study investigated the occurrence of PAHs in aquatic environments around the world, their effects on the environment and humans, and methods for their removal. Polycyclic aromatic hydrocarbons have a great negative impact on the humans and environment, and can even cause cancer in humans. Use of good methods and equipment are essential to monitoring PAHs, and GC/MS and HPLC are usually used for their analysis in aqueous solutions. In aquatic environments, the PAHs concentrations range widely from 0.03 ng/L (seawater; Southeastern Japan Sea, Japan) to 8,310,000 ng/L (Domestic Wastewater Treatment Plant, Siloam, South Africa). Moreover, bioaccumulation of ∑16PAHs in fish has been reported to range from 11.2 ng/L (Cynoscion guatucupa, South Africa) to 4207.5 ng/L (Saurida undosquamis, Egypt). Several biological, physical and chemical and biological techniques have been reported to treat water contaminated by PAHs, but adsorption and combined treatment methods have shown better removal performance, with some methods removing up to 99.99% of PAHs.

Naidu, G, Ryu, S, Thiruvenkatachari, R, Choi, Y, Jeong, S & Vigneswaran, S 2019, 'A critical review on remediation, reuse, and resource recovery from acid mine drainage', Environmental Pollution, vol. 247, pp. 1110-1124.
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© 2019 Elsevier Ltd Acid mine drainage (AMD) is a global environmental issue. Conventionally, a number of active and passive remediation approaches are applied to treat and manage AMD. Case studies on remediation approaches applied in actual mining sites such as lime neutralization, bioremediation, wetlands and permeable reactive barriers provide an outlook on actual long-term implications of AMD remediation. Hence, in spite of available remediation approaches, AMD treatment remains a challenge. The need for sustainable AMD treatment approaches has led to much focus on water reuse and resource recovery. This review underscores (i) characteristics and implication of AMD, (ii) remediation approaches in mining sites, (iii) alternative treatment technologies for water reuse, and (iv) resource recovery. Specifically, the role of membrane processes and alternative treatment technologies to produce water for reuse from AMD is highlighted. Although membrane processes are favorable for water reuse, they cannot achieve resource recovery, specifically selective valuable metal recovery. The approach of integrated membrane and conventional treatment processes are especially promising for attaining both water reuse and recovery of resources such as sulfuric acid, metals and rare earth elements. Overall, this review provides insights in establishing reuse and resource recovery as the holistic approach towards sustainable AMD treatment. Finally, integrated technologies that deserve in depth future exploration is highlighted. Challenges associated with AMD can be sustainability addressed through integrated treatment approaches that attain both water reuse and valuable resource recovery.

Nasruddin, Sholahudin, Satrio, P, Mahlia, TMI, Giannetti, N & Saito, K 2019, 'Optimization of HVAC system energy consumption in a building using artificial neural network and multi-objective genetic algorithm', Sustainable Energy Technologies and Assessments, vol. 35, pp. 48-57.
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© 2019 Elsevier Ltd The optimization of heating, ventilating and air conditioning (HVAC) system operations and other building parameters intended to minimize annual energy consumption and maximize the thermal comfort is presented in this paper. The combination of artificial neural network (ANN) and multi-objective genetic algorithm (MOGA) is applied to optimize the two-chiller system operation in a building. The HVAC system installed in the building integrates radiant cooling system, variable air volume (VAV) chiller system, and dedicated outdoor air system (DOAS). Several parameters including thermostat setting, passive solar design, and chiller operation control are considered as decision variables. Subsequently, the percentage of people dissatisfied (PPD) and annual building energy consumption is chosen as objective functions. Multi-objective optimization is employed to optimize the system with two objective functions. As the result, ANN performed a good correlation between decision variables and the objective function. Moreover, MOGA successfully provides several alternative possible design variables to achieve optimum system in terms of thermal comfort and annual energy consumption. In conclusion, the optimization that considers two objectives shows the best result regarding thermal comfort and energy consumption compared to base case design.

Ngo, HH, Guo, W & Boopathy, R 2019, 'Editorial overview: Green technologies for environmental remediation', Current Opinion in Environmental Science & Health, vol. 12, pp. A1-A3.
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Ngoc, TP, Fatahi, B & Khabbaz, H 2019, 'Impacts of Drying-Wetting and Loading-Unloading Cycles on Small Strain Shear Modulus of Unsaturated Soils', International Journal of Geomechanics, vol. 19, no. 8, pp. 04019090-04019090.
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© 2019 American Society of Civil Engineers. The small strain shear modulus (Gmax) is an important parameter in geodynamic problems. To predict the Gmax of unsaturated soils that are normally subjected to complex drying and wetting processes, the effect of hydraulic hysteresis needs to be evaluated. Although several equations have been proposed in recent years, limitations still exist, requiring more research studies in this field. In this study, Gmax was investigated in a multistage test during several drying-wetting cycles and a loading-unloading cycle of net stress. The results revealed four key factors that directly influence the magnitude of Gmax: the void ratio, net stress, matric suction, and degree of saturation. Although variations of the void ratio, net stress, and matric suction cause persistent responses of Gmax (i.e., if all other factors remain unchanged, Gmax would then be reversely proportional to the void ratio and directly proportional to the net stress and matric suction), variations in the degree of saturation result in different responses. A decrease in the degree of saturation may induce a reduction or growth of Gmax because, on the one hand, it reduces the effect of matric suction, whereas on the other hand, it increases the total effect of van der Waals attractions and electric double-layer repulsions. At the same stress state, a reverse trend, induced by an increase in the degree of saturation, will occur with a growth in the effect of matric suction and a reduction in the combined effect of van der Waals attractions and electric double-layer repulsions. An analysis of the results showed that hydraulic hysteresis occurred in all the stress loops, and it directly influenced the response of Gmax. The effect of hydraulic hysteresis can only be captured if the van der Waals attractions and electric double-layer repulsions are considered. A model to estimate Gmax while incorporating the van der Waals attractions and electric double-la...

Nguyen, AQ, Nguyen, LN, Phan, HV, Galway, B, Bustamante, H & Nghiem, LD 2019, 'Effects of operational disturbance and subsequent recovery process on microbial community during a pilot-scale anaerobic co-digestion', International Biodeterioration & Biodegradation, vol. 138, pp. 70-77.
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© 2019 This study investigated changes in microbial community structure and composition in response to operational disturbance and subsequent process recovery by inoculum addition. Amplicon sequencing of 16S rRNA and mcrA marker genes on the Illumina Miseq platform was used for microbial community analysis. The results show that imbalance among core microbial groups caused volatile fatty acid accumulation and subsequent deteriorated biogas production (decreased by 45% of daily volume) and methane content (<49%). Operational disturbance led to the enrichment of hydrolytic and fermentative bacteria (accounted for >57% of the total abundance) and reduction of acetogenic and methanogenic microbes (they accounted for <9% and <3% of the total abundance, respectively). Acetogens and methanogens were replenished by inoculum addition to recover digester performance. Although digester performances were similar in stable (prior to disturbance) and post recovery phases, the microbial community did not return to the original state, suggesting the existence of functional redundancy in the community.

Nguyen, DD, Jeon, B-H, Jeung, JH, Rene, ER, Banu, JR, Ravindran, B, Vu, CM, Ngo, HH, Guo, W & Chang, SW 2019, 'Thermophilic anaerobic digestion of model organic wastes: Evaluation of biomethane production and multiple kinetic models analysis', Bioresource Technology, vol. 280, pp. 269-276.
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© 2019 Elsevier Ltd The main aim of this work was to test various organic wastes, i.e. from a livestock farm, a cattle slaughterhouse and agricultural waste streams, for its ability to produce methane under thermophilic anaerobic digestion (AD) conditions. The stability of the digestion, potential biomethane production and biomethane production rate for each waste were assessed. The highest methane yield (110.83 mL CH4/g VSadded day) was found in the AD of crushed animal carcasses on day 4. The experimental results were analyzed using four kinetic models and it was observed that the Cone model described the biomethane yield as well as the methane production rate of each substrate. The results from this study showed the good potential of model organic wastes to produce biomethane.

Nguyen, HH, Khabbaz, H & Fatahi, B 2019, 'A numerical comparison of installation sequences of plain concrete rigid inclusions', Computers and Geotechnics, vol. 105, pp. 1-26.
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© 2018 Elsevier Ltd Soil displacement induced when installing controlled modulus columns (CMC) as ground reinforcement could affect the columns installed close by. Realising numerical analyses may provide useful insights, this paper describes a numerical approach to investigate how groups of CMC installed in different sequences could affect columns installed previously. Coupled consolidation analyses in large strain mode and incorporating soil-CMC interaction were carried out using the three-dimensional finite difference software package FLAC3D. The CMCs were modelled using advanced non-linear Hoek-Brown material with a tensile yield criterion while soils with a typical profile were characterised using the modified Cam Clay and the elastic-perfectly plastic material with a Mohr-Coulomb yield criterion. Where possible, the predicted responses of ground surrounding the CMCs were compared to a number of existing analytical methods. Predictions revealed that lateral soil movement and soil heave near existing CMCs induced by installing new CMCs towards the existing CMCs were approximately 15% and 25% greater than corresponding predictions when a reverse installation sequence was adopted. The maximum excess pore water pressures, induced near existing columns due to installing new columns towards the existing ones, were almost twice more than those caused by the reverse sequence of installation. Moreover, the predicted bending moments generated in the existing columns induced by installing new columns towards the existing CMCs were almost 22% greater than the corresponding values when the reverse installation sequence was adopted. This shows the importance of selecting an appropriate installation sequence in the CMC construction process as well as considering the initial stress field and bending moments in the surrounding soil and CMCs, respectively when designing embankments on improved soft soils.

Nguyen, HTH, Sakakibara, M, Nguyen, MN, Mai, NT & Nguyen, VT 2019, 'Effect of Dissolved Silicon on the Removal of Heavy Metals from Aqueous Solution by Aquatic Macrophyte Eleocharis acicularis', Water, vol. 11, no. 5, pp. 940-940.
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Silicon (Si) has been recently reconsidered as a beneficial element due to its direct roles in stimulating the growth of many plant species and alleviating metal toxicity. This study aimed at validating the potential of an aquatic macrophyte Eleocharis acicularis for simultaneous removal of heavy metals from aqueous solutions under different dissolved Si. The laboratory experiments designed for determining the removal efficiencies of heavy metals were conducted in the absence or presence of Si on a time scale up to 21 days. Eleocharis acicularis was transplanted into the solutions containing 0.5 mg L−1 of indium (In), gallium (Ga), silver (Ag), thallium (Tl), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) with various Si concentrations from 0 to 4.0 mg L−1. The results revealed that the increase of dissolved Si concentrations enhanced removal efficiencies of E. acicularis for Ga, Cu, Zn, Cd, and Pb, while this increase did not show a clear effect for In, Tl, and Ag. Our study presented a notable example of combining E. acicularis with dissolved Si for more efficient removals of Cu, Zn, Cd, Pb, and Ga from aqueous solutions. The findings are applicable to develop phytoremediation or phytomining strategy for contaminated environment.

Nguyen, KT, Nguyen, HM, Truong, CK, Ahmed, MB, Huang, Y & Zhou, JL 2019, 'Chemical and microbiological risk assessment of urban river water quality in Vietnam', Environmental Geochemistry and Health, vol. 41, no. 6, pp. 2559-2575.
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© 2019, Springer Nature B.V. Abstract: The contamination and risk by nutrients (NH4+, NO2−, NO3− and PO43−), COD, BOD5, coliform and potentially toxic elements (PTEs) of As, Cd, Ni, Hg, Cu, Pb, Zn and Cr were investigated in urban river (Nhue River), Vietnam during 2010–2017. The extensive results demonstrated that concentrations of these contaminants showed significant spatial and temporal variations. The Nhue River was seriously polluted by NH4+ (0.025–11.28 mg/L), PO43− (0.17–1.72 mg/L), BOD5 (5.8–179.6 mg/L), COD (1.4–239.8 mg/L) and coliform (1540–326,470 CFU/100 mL); moderately polluted by As (0.2–131.15 μg/L) and Hg (0.11–4.1 μg/L); and slightly polluted by NO2− (0.003–0.33 mg/L) and Cd (2.1–18.2 μg/L). The concentrations of NH4+, PO43−, COD, BOD5 and coliform frequently exceeded both drinking water guidelines and irrigation water standards. Regarding PTEs, As, Cd and Hg concentrations were frequently higher than the regulatory limits. Human health risks of PTEs were evaluated by estimating hazard index (HI) and cancer risk through ingestion and dermal contacts for adults and children. The findings indicated that As was the most important pollutant causing both non-carcinogenic and carcinogenic concerns. The non-carcinogenic risks of As were higher than 1.0 at all sites for both adults (HI = 1.83–7.4) and children (HI = 2.6–10.5), while As posed significant carcinogenic risks for adults (1 × 10−4−4.96 × 10−4). A management strategy for controlling wastewater discharge and protecting human health is urgently needed. Graphical abstract: [Figure not available: see fulltext.]

Nguyen, LN, Commault, AS, Johir, MAH, Bustamante, H, Aurisch, R, Lowrie, R & Nghiem, LD 2019, 'Application of a novel molecular technique to characterise the effect of settling on microbial community composition of activated sludge', Journal of Environmental Management, vol. 251, pp. 109594-109594.
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Activated sludge (AS) and return activated sludge (RAS) microbial communities from three full-scale municipal wastewater treatment plants (denoted plant A, B and C) were compared to assess the impact of sludge settling (i.e. gravity thickening in the clarifier) and profile microorganisms responsible for nutrient removal and reactor foaming. The results show that all three plants were dominated with microbes in the phyla of Proteobacteria, Bacteroidetes, Verrucomicrobia, Actinobacteria, Chloroflexi, Firmicutes, Nitrospirae, Spirochaetae, Acidobacteria and Saccharibacteria. AS and RAS shared above 80% similarity in the microbial community composition, indicating that sludge thickening does not significantly alter the microbial composition. Autotrophic and heterotrophic nitrifiers were present in the AS. However, the abundance of autotrophic nitrifiers was significantly lower than that of the heterotrophic nitrifiers. Thus, ammonium removal at these plants was achieved mostly by heterotrophic nitrification. Microbes that can cause foaming were at 3.2% abundance, and this result is well corroborated with occasional aerobic biological reactor foaming. By contrast, these microbes were not abundant (<2.1%) at plant A and C, where aerobic biological reactor foaming has not been reported.

Nguyen, LN, Johir, MAH, Commault, A, Bustamante, H, Aurisch, R, Lowrie, R & Nghiem, LD 2019, 'Impacts of mixing on foaming, methane production, stratification and microbial community in full-scale anaerobic co-digestion process', Bioresource Technology, vol. 281, pp. 226-233.
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© 2019 Elsevier Ltd This study investigated the impact of mixing on key factors including foaming, substrate stratification, methane production and microbial community in three full scale anaerobic digesters. Digester foaming was observed at one plant that co-digested sewage sludge and food waste, and was operated without mixing. The lack of mixing led to uneven distribution of total chemical oxygen demand (tCOD) and volatile solid (VS) as well as methane production within the digester. 16S rRNA gene-based community analysis clearly differentiated the microbial community from the top and bottom. By contrast, foaming and substrate stratification were not observed at the other two plants with internal circulation mixing. The abundance of methanogens (Methanomicrobia) at the top was about four times higher than at the bottom, correlating to much higher methane production from the top verified by ex-situ biomethane assay, causing foaming. This result is consistent with foaming potential assessment of digestate samples from the digester.

Nguyen, LN, Labeeuw, L, Commault, AS, Emmerton, B, Ralph, PJ, Johir, MAH, Guo, W, Ngo, HH & Nghiem, LD 2019, 'Validation of a cationic polyacrylamide flocculant for the harvesting fresh and seawater microalgal biomass', Environmental Technology & Innovation, vol. 16, pp. 100466-100466.
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© 2019 Elsevier B.V. A simple, efficient, and fast settling flocculation technique to harvest microalgal biomass was demonstrated using a proprietary cationic polyacrylamide flocculant for a freshwater (Chlorella vulgaris) and a marine (Phaeodactylum tricornutum) microalgal culture at their mid-stationary growth phase. The optimal flocculant doses were 18.9 and 13.7 mg/g of dry algal biomass for C. vulgaris and P. tricornutum, respectively (equivalent to 7 g per m3 of algal culture for both species). The obtained optimal dose was well corroborated with changes in cell surface charge, and culture solution optical density and turbidity. At the optimal dose, charge neutralization of 64 and 86% was observed for C. vulgaris and P. tricornutum algal cells, respectively. Algae recovery was independent of the culture solution pH in the range of pH 6 to 9. Algal biomass recovery was achieved of 100 and 90% for C vulgaris and P. tricornutum respectively, and over 98% medium recovery was achievable by simple decanting.

Nguyen, LN, Nguyen, AQ, Johir, MAH, Guo, W, Ngo, HH, Chaves, AV & Nghiem, LD 2019, 'Application of rumen and anaerobic sludge microbes for bio harvesting from lignocellulosic biomass', Chemosphere, vol. 228, pp. 702-708.
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This study investigated the production of biogas, volatile fatty acids (VFAs), and other soluble organic from lignocellulosic biomass by two microbial communities (i.e. rumen fluid and anaerobic sludge). Four types of abundant lignocellulosic biomass (i.e. wheat straw, oaten hay, lurence hay and corn silage) found in Australia were used. The results show that rumen microbes produced four-time higher VFAs level than that of anaerobic sludge reactors, indicating the possible application of rumen microorganism for VFAs generation from lignocellulosic biomass. VFA production in the rumen fluid reactors was probably due to the presence of specific hydrolytic and acidogenic bacteria (e.g. Fibrobacter and Prevotella). VFA production corroborated from the observation of pH drop in the rumen fluid reactors indicated hydrolytic and acidogenic inhibition, suggesting the continuous extraction of VFAs from the reactor. Anaerobic sludge reactors on the other hand, produced more biogas than that of rumen fluid reactors. This observation was consistent with the abundance of methanogens in anaerobic sludge inoculum (3.98% of total microbes) compared to rumen fluid (0.11%). VFA production from lignocellulosic biomass is the building block chemical for bioplastic, biohydrogen and biofuel. The results from this study provide important foundation for the development of engineered systems to generate VFAs from lignocellulosic biomass.

Nguyen, TKL, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Nghiem, LD, Liu, Y, Ni, B & Hai, FI 2019, 'Insight into greenhouse gases emissions from the two popular treatment technologies in municipal wastewater treatment processes', Science of The Total Environment, vol. 671, pp. 1302-1313.
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© 2019 Elsevier B.V. Due to the impact of methane, carbon dioxide and nitrous oxide on global warming, the quantity of these greenhouse gases (GHG) emissions from municipal wastewater treatment plants (WWTPs) has attracted more and more attention. Consequently, GHG emissions from the two popular treatment technologies: anaerobic/anoxic/oxic (AAO) process and sequencing batch reactor (SBR) should be properly identified and discussed toward the current situation in developing countries. Direct and indirect carbon dioxide (with and/or without including in Intergovernmental Panel on Climate Change (IPCC) report) are all discussed in this article. This literature study observed that a quantity of total carbon dioxide emissions from SBR (374 g/m3 of wastewater) was double that of AAO whilst 10% of these was direct carbon dioxide. Methane emitted from an SBR was 0.50 g/m3 wastewater while 0.18 g CH4/m3 wastewater was released from an AAO. The level of nitrous oxide from AAO and SBR accounted for 0.97 g/m3 wastewater and 4.20 g/m3 wastewater, respectively. Although these results were collected from different WWTPs and where influent was in various states, GHGs emitted from both biological units and other treatment units in various processes are significant. The results also revealed that aerated zone is the major contributing factor in a wastewater treatment plant to the large amount of GHG emissions.

Nguyen, T-T, Bui, X-T, Dang, B-T, Ngo, H-H, Jahng, D, Fujioka, T, Chen, S-S, Dinh, Q-T, Nguyen, C-N & Nguyen, P-T-V 2019, 'Effect of ciprofloxacin dosages on the performance of sponge membrane bioreactor treating hospital wastewater', Bioresource Technology, vol. 273, pp. 573-580.
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© 2018 Elsevier Ltd This study aimed to evaluate treatment performance and membrane fouling of a lab-scale Sponge-MBR under the added ciprofloxacin (CIP) dosages (20; 50; 100 and 200 µg L−1) treating hospital wastewater. The results showed that Sponge-MBR exhibited effective removal of COD (94–98%) during the operation period despite increment of CIP concentrations from 20 to 200 µg L−1. The applied CIP dosage of 200 µg L−1 caused an inhibition of microorganisms in sponges, i.e. significant reduction of the attached biomass and a decrease in the size of suspended flocs. Moreover, this led to deteriorating the denitrification rate to 3–12% compared to 35% at the other lower CIP dosages. Importantly, Sponge-MBR reinforced the stability of CIP removal at various added CIP dosages (permeate of below 13 µg L−1). Additionally, the fouling rate at CIP dosage of 200 µg L−1 was 30.6 times lower compared to the control condition (no added CIP dosage).

Nguyen, TT, Ngo, HH, Guo, W, Wang, XC, Ren, N, Li, G, Ding, J & Liang, H 2019, 'Implementation of a specific urban water management - Sponge City', Science of The Total Environment, vol. 652, pp. 147-162.
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© 2018 Elsevier B.V. Climate change, rapid urbanization and inappropriate urban planning policies in many countries have resulted in urban water-related problems, such as flooding disasters, water pollution and water shortages. To tackle these issues, the specific urban water management strategy known as Sponge City has been implemented in China since 2013. This is a complex method and one involving many challenges. This paper critically assesses the approaches associated with conventional urban water management. The Sponge City concept and its adoption are then scrutinized to comprehensively assess the limitations and opportunities. It emerges that Sponge City has four main principles, these being: urban water resourcing, ecological water management, green infrastructures, and urban permeable pavement. The uncertainties in Sponge City design and planning, and financial insufficiencies are the most serious problems that can risk the failure of the Sponge City concept. While significant barriers exist, the opportunities for implementing a Sponge City are evident. To obtain multi-ecosystem services of Sponge City, it should be implemented at the watershed scales and be flexible, depending on different decision levels or catchment characteristics. It is essential to apply an intelligent decision-making mechanism and consider the need for close cooperation between various agencies with which the central government can work. A suitable sized and harmonious Sponge City, ensuring a good balance between socio-economic development and environmental conservation, is the ideal.

Nguyen, XC, Chang, SW, Tran, TCP, Nguyen, TTN, Hoang, TQ, Banu, JR, Al-Muhtaseb, AH, La, DD, Guo, W, Ngo, HH & Nguyen, DD 2019, 'Comparative study about the performance of three types of modified natural treatment systems for rice noodle wastewater', Bioresource Technology, vol. 282, pp. 163-170.
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© 2019 Elsevier Ltd In this study, three semi-pilot scale systems (vertical flow constructed wetland, multi-soil layering, and integrated hybrid systems) for treating real rice noodle wastewater were operated parallelly for the first time in a tropical climate at a loading rate of 50 L/(m2·d) for more than 7 months to determine the optimal conditions and to compare their treatment performance. The results demonstrated that these systems were appropriate for the removal of organics, suspended solids, and total coliform (Tcol). The highest reductions in chemical oxygen demand (CODCr, 73.2%), phosphorus (PO4-P, 54%), and Tcol (4.78 log MPN/100 mL inactivation) were obtained by the integrated hybrid system, while the highest removal efficiencies of ammonium (NH4-N, 60.64%) and suspended solids (80.49%) were achieved in the vertical-flow-constructed wetland and multi-soil layering systems respectively.

Ni, B-J, Huang, Q-S, Wang, C, Ni, T-Y, Sun, J & Wei, W 2019, 'Competitive adsorption of heavy metals in aqueous solution onto biochar derived from anaerobically digested sludge', Chemosphere, vol. 219, pp. 351-357.
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© 2018 Elsevier Ltd Heavy metals often coexist in contaminated wastewater systems and their competitive behavior could affect the adsorption capacity of biochar. Till now, the competitive adsorption of heavy metals by biochar derived from anaerobically digested sludge has never been reported. In this work, biochar from anaerobically digested sludge was synthesized and characterized to explore the competitive behavior of widely co-existed Pb(II) and Cd(II). The mutual effects and inner mechanisms of their adsorption on studied biochar were systematically investigated via single-metal and binary-metals systems. In single-metal system, the biochar exhibited much higher adsorption capacity for Pb(II) compared to that for Cd(II). The maximum adsorption capacities of Pb(II) and Cd(II) based on single-component adsorption isotherm were 0.75 and 0.55 mmoL/g, respectively, which were much higher than those reported biochars from different materials. In binary-metals system, the Cd(II) adsorption on biochar was severely inhibited, while the uptake of Pb(II) was not affected significantly. The results of binary-components adsorption isotherm clearly demonstrated the competitive adsorption between two metals occurred as well as the preference of biochar for Pb(II) compared to Cd(II). FTIR and metal characteristics analysis results revealed that Pb(II) had exactly the same adsorption sites with Cd(II), but Pb(II) has a greater affinity than Cd(II), thereby exhibiting a competitive advantage in the coexisting system.

Ni, B-J, Yan, X, Sun, J, Chen, X, Peng, L, Wei, W, Wang, D, Mao, S, Dai, X & Wang, Q 2019, 'Persulfate and zero valent iron combined conditioning as a sustainable technique for enhancing dewaterability of aerobically digested sludge', Chemosphere, vol. 232, pp. 45-53.
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© 2019 Elsevier Ltd Aerobic digestion followed by dewatering is a widely applied method for sludge stabilization and reduction in decentralized wastewater treatment plants. It is important to enhance the sludge dewaterability of the aerobically digested sludge due to its considerable impact on cost of sludge disposal and management. In this study, an innovative technique is developed for improving the dewaterability of aerobically digested sludge by combined conditioning with persulfate (PS) and zero valent iron (ZVI). The results demonstrated that the dewaterability of aerobically digested sludge could be significantly enhanced with the PS and ZVI dosage in the range of 0–0.5 g/gTS and 0–0.4 g/gTS, respectively. The highest improvement was achieved at 0.05 g ZVI/g TS with 0.1 g PS/g TS, and the capillary suction time was reduced by ∼80%. The extracellular polymeric substances (EPS) characterization revealed that the combined PS-ZVI treatment could largely reduce proteins, polysaccharides and humic acids-like compounds in the tightly bounded EPS of the aerobically digested sludge, leading to bound water releasing from sludge flocs. The recovery of the ZVI particles could reach around 45%–80% after the treatment, further proved the sustainability of the approach. The proposed PS-ZVI conditioning would not have significant impact on the final choice of sludge disposal and the mainstream wastewater treatment. However, plant-scale test are still required for better assessing the proposed technique.

Nie, W-B, Xie, G-J, Ding, J, Lu, Y, Liu, B-F, Xing, D-F, Wang, Q, Han, H-J, Yuan, Z & Ren, N-Q 2019, 'High performance nitrogen removal through integrating denitrifying anaerobic methane oxidation and Anammox: from enrichment to application', Environment International, vol. 132, pp. 105107-105107.
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© 2019 The Authors Integrating denitrifying anaerobic methane oxidation (DAMO) with Anammox provides alternative solutions to simultaneously remove nitrogen and mitigate methane emission from wastewater treatment. However, the practical application of DAMO has been greatly limited by slow-growing DAMO microorganisms living on low-solubility gaseous methane. In this work, DAMO and Anammox co-cultures were fast enriched using high concentration of mixed sludges from various environments, and achieved nitrogen removal rate of 76.7 mg NH4+-N L−1 d−1 and 87.9 mg NO3−-N L−1 d−1 on Day 178. Subsequently, nitrogen removal rate significantly decreased but recovered quickly through increasing methane flushing frequency, indicating methane availability could be the limiting factor of DAMO activity. Thus, this work developed a novel Membrane Aerated Membrane Bioreactor (MAMBR), which equipped with gas permeable membrane for efficient methane delivery and ultrafiltration membrane for complete biomass retention. After inoculated with enriched sludge, nitrogen removal rates of MAMBR were significantly enhanced to 126.9 mg NH4+-N L−1 d−1 and 158.8 mg NO3−-N L−1 d−1 by membrane aeration in batch test. Finally, the MAMBR was continuously fed with synthetic wastewater containing ammonium and nitrite to mimic the effluent from partial nitritation. When steady state with nitrogen loading rate of 2500 mg N L−1 d−1 was reached, the MAMBR achieved total nitrogen removal of 2496.7 mg N L−1 d−1, with negligible nitrate in effluent (~6.5 mg NO3−-N L−1). 16S rRNA amplicon sequencing and fluorescence in situ hybridization revealed the microbial community dynamics during enrichment and application. The high performance of nitrogen removal (2.5 kg N m−3 d−1) within 200 days operation and excellent biomass retention capacity (8.67 kg VSS m−3) makes the MAMBR promising for practical application of DAMO and Anammox in wastewater treatment.

Niu, Q, Xu, Q, Wang, Y, Wang, D, Liu, X, Liu, Y, Wang, Q, Ni, B-J, Yang, Q, Li, X & Li, H 2019, 'Enhanced hydrogen accumulation from waste activated sludge by combining ultrasonic and free nitrous acid pretreatment: Performance, mechanism, and implication', Bioresource Technology, vol. 285, pp. 121363-121363.
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© 2019 Elsevier Ltd This study presents a novel and effective method, i.e., adding nitrite into acidic fermentations after ultrasonic (US) pretreatment to form free nitrous acid (FNA), to further enhance hydrogen yield. Experimental results showed that when 180 mg/L nitrite was added into the US (2 W/mL, 15 min) pretreated waste activated sludge (WAS), the maximal hydrogen yield of 24.81 ± 1.24 mL/g VSS (volatile suspended solids) was obtained under acidic fermentation (1.0 mg/L FNA was initially formed under this condition), which was 2.21-folds (or 1.36-folds) of that from US pretreatment (or FNA treatment) alone. This combination approach caused a positive synergy on sludge disintegration and enhanced the transformation of the released organics from non-biodegradable to biodegradable. Further study showed that the inhibiting effect of this combination method on hydrogen consuming microorganism was severer. Considering its pollution free, this combination strategy is an attractive technology for hydrogen recovery from WAS.

Nur, T, Loganathan, P, Ahmed, MB, Johir, MAH, Nguyen, TV & Vigneswaran, S 2019, 'Removing arsenic from water by coprecipitation with iron: Effect of arsenic and iron concentrations and adsorbent incorporation', Chemosphere, vol. 226, pp. 431-438.
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© 2019 Elsevier Ltd Arsenic (As) contamination of drinking water is a major cause of As toxicity in many parts of the world. A study was conducted to evaluate As removal from water containing 100–700 μg/L of As and As to Fe concentration ratios of 1:5–1:1000 using the coprecipitation process with and without As/Fe adsorption onto granular activated carbon (GAC). Fe concentration required to reduce As concentrations in order to achieve the WHO standard level of 10 μg/L increased exponentially with the increase in initial As concentration. When small amounts of GAC were added to the As/Fe solutions the Fe required to remove these As concentrations reduced drastically. This decline was due to the GAC adsorption of Fe and As, enhancing the removal of these metals through coprecipitation. Predictive regression equations were developed relating the GAC dose requirement to the initial As and Fe concentrations. Zeta potential data revealed that As was adsorbed on the GAC by outer-sphere complexation whereas Fe was adsorbed by inner-sphere complexation reversing the negative charge on GAC to positive values. X-ray diffraction of the GAC samples in the presence of Fe had an additional peak characteristic of ferrihydrite (Fe oxide) compared to that of the GAC sample without Fe. The study showed that incorporating an adsorbent into the coprecipitation process has the advantage of removing As from waters at all concentrations of Fe and As compared to coprecipitation alone which does not remove As to the required levels if Fe concentration is low.

Ong, HC, Milano, J, Silitonga, AS, Hassan, MH, Shamsuddin, AH, Wang, C-T, Indra Mahlia, TM, Siswantoro, J, Kusumo, F & Sutrisno, J 2019, 'Biodiesel production from Calophyllum inophyllum-Ceiba pentandra oil mixture: Optimization and characterization', Journal of Cleaner Production, vol. 219, pp. 183-198.
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© 2019 Elsevier Ltd In this study, a novel modeling approach (artificial neural networks (ANN) and ant colony optimization (ACO)) was used to optimize the process variables for alkaline-catalyzed transesterification of CI40CP60 oil mixture (40 wt% of Calophyllum inophyllum oil mixed with 60 wt% of Ceiba pentandra oil) in order to maximize the biodiesel yield. The optimum values of the methanol-to-oil molar ratio, potassium hydroxide catalyst concentration, and reaction time predicted by the ANN-ACO model are 37%, 0.78 wt%, and 153 min, respectively, at a constant reaction temperature and stirring speed of 60 °C and 1000 rpm, respectively. The ANN-ACO model was validated by performing independent experiments to produce the CI40CP60 methyl ester (CICPME) using the optimum transesterification process variables predicted by the ANN-ACO model. There is very good agreement between the average CICPME yield determined from experiments (95.18%) and the maximum CICPME yield predicted by the ANN-ACO model (95.87%) for the same optimum values of process variables, which corresponds to a difference of 0.69%. Even though the ANN-ACO model is only implemented to optimize the transesterification of process variables in this study. It is believed that the model can be used to optimize other biodiesel production processes such as seed oil extraction and acid-catalyzed esterification for various types of biodiesels and biodiesel blends.

Organ, B, Huang, Y, Zhou, JL, Surawski, NC, Yam, Y-S, Mok, W-C & Hong, G 2019, 'A remote sensing emissions monitoring programme reduces emissions of gasoline and LPG vehicles', Environmental Research, vol. 177, pp. 108614-108614.
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© 2019 Elsevier Inc. Vehicle emissions are a major source of air pollution in Hong Kong affecting human health. A ‘strengthened emissions control of gasoline and liquefied petroleum gas (LPG) vehicles’ programme has been operating in Hong Kong since September 2014 utilising remote sensing (RS) technology. RS has provided measurement data to successfully identify high emitting gasoline and LPG vehicles which then need to be repaired or removed from the on-road vehicle fleet. This paper aims to evaluate the effectiveness of this globally unique RS monitoring programme. A large RS dataset of 2,144,422 records was obtained covering the period from 6th January 2012 to 30th December 2016, of which 1,206,762 records were valid and suitable for further investigation. The results show that there have been significant reductions of emissions factors (EF) for 40.5% HC, 45.3% CO and 29.6% NO for gasoline vehicles. Additionally, EF reductions of 48.4% HC, 41.1% CO and 58.7% NO were achieved for LPG vehicles. For the combined vehicle fleet, the reductions for HC, CO and NO were 55.9%, 50.5% and 60.9% respectively during this survey period. The findings demonstrate that the strengthened emissions control programme utilising RS has been very effective in identifying high emitting vehicles for repair so as to reduce the emissions from gasoline and LPG vehicles under real driving.

Pan, Y, Liu, Y, Peng, L, Ngo, HH, Guo, W, Wei, W, Wang, D & Ni, B-J 2019, 'Substrate Diffusion within Biofilms Significantly Influencing the Electron Competition during Denitrification', Environmental Science & Technology, vol. 53, no. 1, pp. 261-269.
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© 2018 American Chemical Society. A common and long-existing operational issue of wastewater denitrification is the unexpected accumulation of nitrite (NO 2- ) that could suppress the activity of various microorganisms involved in biological wastewater treatment process and nitrous oxide (N 2 O) that could emit as a potent greenhouse gas. Recently, it has been confirmed that the accumulation of these denitrification intermediates in biological wastewater treatment process is greatly influenced by the electron competition between the four denitrification steps. However, little is known about this in biofilm systems. In this work, we applied a mathematical model that links carbon oxidation and nitrogen reduction processes through a pool of electron carriers, to assess electron competition in denitrifying biofilms. Simulations were performed comprehensively at seven combinations of electron acceptor addition scheme (i.e., simultaneous addition of one, two or three among nitrate (NO 3- ), NO 2- , and N 2 O) to compare the effect of electron competition on NO 3- , NO 2- and N 2 O reduction. Overall, the effects of substrate loading, biofilm thickness and effective diffusion coefficients on electron competition are not always intuitive. Model simulations show that electron competition was intensified due to the substrate load limitation (from 120 to 20 mg COD/L) and increasing biofilm thicknesses (from 0.1 to 1.6 mm) in most cases, where electrons were prioritized to nitrite reductase because of the insufficient electron donor availability in the biofilm. In contrast, increasing effective diffusion coefficients did not pose a significant effect on electron competition and only increased electrons distributed to nitrite reductase when both NO 2- and N 2 O are added.

Pan, Y, Liu, Y, Wang, D & Ni, B-J 2019, 'Modeling effects of H₂S on electron competition among nitrogen oxide reduction and N₂O accumulation during denitrification', Environmental Science: Water Research & Technology, vol. 5, no. 3, pp. 533-542.
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A novel model was developed to describe electron competition during three-step denitrification through linking nitrogen reduction and carbon oxidation with electron carriers.

Park, MJ, Lim, S, Gonzales, RR, Phuntsho, S, Han, DS, Abdel-Wahab, A, Adham, S & Shon, HK 2019, 'Thin-film composite hollow fiber membranes incorporated with graphene oxide in polyethersulfone support layers for enhanced osmotic power density', Desalination, vol. 464, pp. 63-75.
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© 2019 Elsevier B.V. This study focused on the development of pressure retarded osmosis (PRO) thin film composite (TFC) membranes for enhanced osmotic power using hollow fiber polyethersulfone (PES) support structure modified by incorporating hydrophilic graphene oxide (GO) nanosheets. The GO loadings in the hollow fiber substrates were varied to improve water flux performances without compromising the mechanical strength. GO embedded (≤0.2 wt%) PES hollow fiber supports revealed noticeable improvements in pure water permeability, improved structural morphologies, as well as the hydrophilicity within the support layer, without deteriorating the mechanical properties. The GO (0.2 wt%)-incorporated TFC-PRO membrane appeared to have an initial PRO flux (without any applied pressure) of 43.74 L m−2 h−1, lower specific reverse salt flux of 0.04 g L−1 and structural parameter (S) of 522 μm, significantly better than the control membrane. The maximum power density of 14.6 W m−2 was achieved at an operating pressure of 16.5 bar under the condition of DI water and 1 M NaCl as feed and draw solutions, respectively. The results obtained in this study indicate that modification of PRO hollow fiber support layer by incorporating nanoparticles such as GO nanosheet can be a useful tool to improve the PRO performance.

Peng, L, Ngo, HH, Song, S, Xu, Y, Guo, W, Liu, Y, Wei, W, Chen, X, Wang, D & Ni, B-J 2019, 'Heterotrophic denitrifiers growing on soluble microbial products contribute to nitrous oxide production in anammox biofilm: Model evaluation', Journal of Environmental Management, vol. 242, pp. 309-314.
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© 2019 Elsevier Ltd In this work, a model framework was constructed to assess and predict nitrous oxide (N 2 O) production, substrate and microbe interactions in an anammox biofilm bioreactor. The anammox kinetics were extended by including kinetics of autotrophic soluble microbial products (SMP) formation, which consisted of utilization-associated products (UAP) and biomass-associated products (BAP). Heterotrophic bacteria growing on UAP, BAP and decay released substance (SS) were modelled to perform four-step sequential reductions from nitrate to dinitrogen gas. N 2 O was modelled as an intermidiate of heterotrophic denitrification via three pathways with UAP, BAP and SS as the electron donors. The developed model framework was evaluated using long-term operational data from an anammox biofilm reactor and satisfactorily reproduced effluent nitrogen and SMP as well as N 2 O emission factors under different operational conditions. The modeling results revealed that N 2 O was mainly produced with UAP as the electron donor while BAP and SS play minor roles. Heterotrophic denitrifiers growing on UAP would significantly contribute to N 2 O emission from anammox biofilm reactor even though heterotrophs only account for a relatively small fraction of active biomass in the anammox biofilm. Comprehensive simulations were conducted to investigate the effects of N loading rate and biofilm thickness, which indicated that maintaining a low N loading rate and a thick biofilm thickness were essential for high total nitrogen removal efficiency and low N 2 O emission.

Pettit, T, Irga, PJ, Surawski, NC & Torpy, FR 2019, 'An Assessment of the Suitability of Active Green Walls for NO2 Reduction in Green Buildings Using a Closed-Loop Flow Reactor', Atmosphere, vol. 10, no. 12, pp. 801-801.
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Nitrogen dioxide (NO2) is a common urban air pollutant that is associated with several adverse human health effects from both short and long term exposure. Additionally, NO2 is highly reactive and can influence the mixing ratios of nitrogen oxide (NO) and ozone (O3). Active green walls can filter numerous air pollutants whilst using little energy, and are thus a candidate for inclusion in green buildings, however, the remediation of NO2 by active green walls remains untested. This work assessed the capacity of replicate active green walls to filter NO2 at both ambient and elevated concentrations within a closed-loop flow reactor, while the concentrations of NO and O3 were simultaneously monitored. Comparisons of each pollutant’s decay rate were made for green walls containing two plant species (Spathiphyllum wallisii and Syngonium podophyllum) and two lighting conditions (indoor and ultraviolet). Biofilter treatments for both plant species exhibited exponential decay for the biofiltration of all three pollutants at ambient concentrations. Furthermore, both treatments removed elevated concentrations of NO and NO2, (average NO2 clean air delivery rate of 661.32 and 550.8 m3∙h−1∙m−3 of biofilter substrate for the respective plant species), although plant species and lighting conditions influenced the degree of NOx removal. Elevated concentrations of NOx compromised the removal efficiency of O3. Whilst the current work provided evidence that effective filtration of NOx is possible with green wall technology, long-term experiments under in situ conditions are needed to establish practical removal rates and plant health effects from prolonged exposure to air pollution.

Pu, Y, Tang, J, Wang, XC, Hu, Y, Huang, J, Zeng, Y, Ngo, HH & Li, Y 2019, 'Hydrogen production from acidogenic food waste fermentation using untreated inoculum: Effect of substrate concentrations', International Journal of Hydrogen Energy, vol. 44, no. 50, pp. 27272-27284.
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© 2019 Hydrogen Energy Publications LLC The effect of substrate concentrations (0, 7.5, 15, 22.5, 30, and 37.5 g-VS/L) on hydrogen production from heat-treated and fresh food waste (FW) using untreated inoculums was investigated in this work. The highest hydrogen yield (75.3 mL/g-VS) was obtained with heat-treated FW at 15 g-VS/L. Lower substrate content could not provide enough organic matter for hydrogen fermentation, while higher substrate concentrations shifted the metabolic pathways from hydrogen fermentation to lactic acid fermentation by enriching the lactic acid bacteria (LAB), which lowered the slurry pH and decreased enzyme activity, resulting in a lower chemical oxygen demand (COD), volatile solid (VS), carbohydrate removal rate, and hydrogen yield. Compared with fresh FW, heat-treated FW is preferred for biohydrogen process with acetate as the main organic product. Additionally, at the optimal concentration (15 g-VS/L) using fresh FW, lactic acid is first accumulated and then degraded to produce hydrogen with butyrate as the main metabolite.

Putra, N, Hakim, II, Erwin, FP, Abdullah, NA, Ariantara, B, Amin, M, Mahlia, TMI & Kusrini, E 2019, 'Development of a novel thermoelectric module based device for thermal stability measurement of phase change materials', Journal of Energy Storage, vol. 22, pp. 331-335.
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© 2019 Elsevier Ltd A recently developed method for the thermal stability measurement of phase-change materials (PCMs) involves thermal cycling using a thermoelectric module as a heating and cooling element. However, the utility of this approach was found to have some limitations, mainly because the thermoelectric polarity is changed according to time rather than the actual sample temperature. A method for thermal cycling test, where the thermoelectric polarity is automatically changed according to the sample temperature was developed in this study. In addition, a new cartridge design in this device requires a small sample volume (1.53 cm 3 ) and can be easily assembled and disassembled. This proposed device was tested on beeswax as a PCM sample. This is very important for savings PCMs material which usually expensive. The results showed that the apparatus had automatically cycled between the melting and cooling temperatures of beeswax. The thermal data showed that beeswax retains consistent melting and freezing temperatures after 1000 cycles, however, its heat of fusion degrades over repeated thermal cycling. This apparatus can be readily applied to study a wide range of PCMs for such as thermal energy storage materials for energy conservation. To our best knowledge, yet no study has been performed on this kind of equipment so far.

Putra, N, Rawi, S, Amin, M, Kusrini, E, Kosasih, EA & Indra Mahlia, TM 2019, 'Preparation of beeswax/multi-walled carbon nanotubes as novel shape-stable nanocomposite phase-change material for thermal energy storage', Journal of Energy Storage, vol. 21, pp. 32-39.
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© 2018 Elsevier Ltd Development of phase-change material (PCM) as thermal energy storage for building envelopes is promising for energy utilization. However, there are two major drawbacks of PCM application, which are low thermal conductivity and high-volume reduction due to phase-change transition. One solution is to develop a shape-stabilized phase-change material (SSPCM) as a composite that is able to prevent leakage during the transition from solid to liquid. Therefore, the objective of this study is to prepare beeswax/multi-walled carbon nanotubes as form-stable nanocomposite phase-change material for thermal energy storage, based on previously unattempted methods. Beeswax was being used as PCM because of its high latent heat and multi-walled carbon nanotubes (MWCNTs) as supporting material with high thermal conductivity. There are three types of MWCNTs applied in this research: pristine MWCNTs, ball-milled MWCNTs and acid-treated MWCNTs. Beeswax/CNT composite samples were prepared with ratios of 5 and 20 wt%. Composite samples were tested from structure modification and thermal performance, including latent heat, sensible heat, melting point, solidifying point, thermal conductivity, and thermal-cycle testing for up to 300 cycles. Experimental results showed that thermal conductivity of novel shape-stable nanocomposite PCM increased by a factor of 2 and there was no significant phase transition in the melting or solidifying temperature. The high heat storage capability and thermal conductivity of nanocomposite PCM enable it to be a potential material for thermal energy storage in practical applications.

Rahman, SMA, Mahila, TMI, Ahmad, A, Nabi, MN, Jafari, M, Dowell, A, Islam, MA, Marchese, AJ, Tryner, J, Brooks, PR, Bodisco, TA, Stevanovic, S, Rainey, T, Ristovski, ZD & Brown, RJ 2019, 'Effect of Oxygenated Functional Groups in Essential Oils on Diesel Engine Performance, Emissions, and Combustion Characteristics', Energy & Fuels, vol. 33, no. 10, pp. 9828-9834.
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Waste management cost for Australia is increasing every year, and thus, it is important to find alternative ways to use the waste. For example, essential oil has a significant waste stream that can be utilized in vehicles of their producers. However, some of the essential oils contain oxygen which considerably affects engine performance, emission, and combustion characteristics of diesel engines. Thus, this research paper will try to evaluate the essential oils as a replacement of diesel fuel to operate a multicylider diesel engine. For this study, two essential oils are selected which contain different oxygenated functional groups, tea tree oil (5.4% oxygen) and eucalyptus oil (8.4% oxygen), with an aim to evaluate the effect of these functional groups on engine performance and emission parameters. These oils were blended with neat diesel (0% oxygen) to obtain a blend cotaining 2.2% oxygen by weight. The blends produced similar brake power; however, brake-specific fuel consumption (BSFC) increased for eucalyptus oil blends (2.4-3.7%) and tea tree oil blends (3.9-5.3%). Essential oil-diesel blends resulted in less CO and increased NOX emission, produced similar peak pressure, and indicated mean effective pressure. The results then lead to the conclusion that oxygenated essential oils can have a role to reduce dependency of agricultural sector on diesel in the near future.

Rahmawati, R, Bilad, MR, Laziz, AM, Nordin, NAHM, Jusoh, N, Putra, ZA, Mahlia, TMI & Jaafar, J 2019, 'Finned spacer for efficient membrane fouling control in produced water filtration', Journal of Environmental Management, vol. 249, pp. 109359-109359.
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© 2019 Elsevier Ltd Membrane based technologies are highly reliable for water and wastewater treatment, including for removal of total oil and grease from produced water. However, performances of the pressure driven processes are highly restricted by membrane fouling and the application of traditional air bubbling system is limited by their low shear stress due to poor contacts with the membrane surface. This study develops and assesses a novel finned spacer, placed in between vertical panel, for membrane fouling control in submerged plate-and-frame module system for real produced water filtration. Results show that permeability of the panel is enhanced by 87% from 201 to 381 L/(m2 h bar). The spacer system can be operated in switching mode to accommodate two-sided panel aeration. This leads to panel permeability increment by 22% higher than the conventional vertical system. The mechanisms of finned spacer in encouraging the flow trajectory was proven by visual observation and flow simulation. The fins alter the air bubbles flow trajectory toward the membrane surface to effectively scour-off the foulant. Overall results demonstrate the efficacy of the developed spacer in projecting the air bubble trajectory toward the membrane surface and thus significantly enhances membrane panel productivity.

Ramarajan, M, Fabris, M, Abbriano, RM, Pernice, M & Ralph, PJ 2019, 'Novel endogenous promoters for genetic engineering of the marine microalga Nannochloropsis gaditana CCMP526', Algal Research, vol. 44, pp. 101708-101708.
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© 2019 Elsevier B.V. Nannochloropsis is a marine microalga from the Eustigmatophyceae stramenopile lineage that has been studied extensively due to a broad range of industrial applications, mostly related to their oil and pigment production. However, tools to genetically engineer members of this group, and therefore further understand and maximise their industrial potential are still limited. In order to expand the potential industrial uses of this organism, several molecular tools, including gene promoters of different strength, are needed. A comprehensive and diverse set of well-characterized promoters is key to a number of genetic engineering and synthetic biology applications, such as the assembly of complex biological functions or entire metabolic pathways. In this study, we measured the promoter activity of three endogenous constitutive promoters from N. gaditana genes EPPSII (Nga02101); HSP90 (Nga00934); ATPase (Nga06354.1) in driving the expression of a Sh ble- mVenus fluorescent reporter fusion protein. Through a combined approach that includes flow cytometry, RT-qPCR and immunoblotting, we profiled the activity of these promoters at both the transcript and protein level. Two promoters HSP90 (Nga00934) and EPPSII (Nga02101) outperformed the widely used β-tubulin promoter, exhibiting 4.5 and 3.1-fold higher mVenus fluorescence, respectively. A third promoter ATPase (Nga06354.1) was also able to drive the expression of transgenes, albeit at lower levels. We show that the new promoters identified in this study are valuable tools, which can be used for genetic engineering and functional genetics studies in N. gaditana.

Rasouli, H & Fatahi, B 2019, 'A novel cushioned piled raft foundation to protect buildings subjected to normal fault rupture', Computers and Geotechnics, vol. 106, pp. 228-248.
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© 2018 Elsevier Ltd Recent earthquake events have shown that besides the earthquake forces, interaction between the fault rupture and structure could cause a lot of damage to the surface and underground structures. Field observations have revealed a need to design structures for fault induced loading in regions with active faults. In this present study, three-dimensional numerical modelling using ABAQUS finite element software is used to study the interactive mechanism of normal fault rupture with a 20-story moment-resisting building frame sitting on a raft, connected piled raft, and cushioned piled raft foundations. The performance of a foundation-structure system is examined by considering geotechnical and structural performance objectives such as structural inter-story drift, raft displacement, and the bending moment and shear forces within the raft and piles. In order to improve the geotechnical and structural performance of foundations and buildings, a new foundation system with cushioned piles below the raft is proposed because of its superior performance with regards to raft rocking and permanent structural inter-story drifts under normal fault rupture. This proposed foundation system also curtailed the bending moments induced in the piles.

Ren, J, Woo, YC, Yao, M, Lim, S, Tijing, LD & Shon, HK 2019, 'Nanoscale zero-valent iron (nZVI) immobilization onto graphene oxide (GO)-incorporated electrospun polyvinylidene fluoride (PVDF) nanofiber membrane for groundwater remediation via gravity-driven membrane filtration', Science of The Total Environment, vol. 688, pp. 787-796.
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Nanoscale zero-valent iron (nZVI), with its high reactivity towards a broad range of contaminants, has been a promising material for groundwater remediation. Membrane-supported nZVI can both avoid nZVI agglomeration for better reactivity and recycle nZVI to lower the risk of secondary pollution. In this study, we successfully fabricated a PVDF-GO membrane via electrospinning technology and employed the functionalized nanofiber membrane to immobilize nZVI particles. The addition of GO into PVDF nanofibers can both increase the hydrophilicity to improve membrane flux and offer -COOH as a binder to immobilize nZVI particles. PVDF-GO-nZVI membranes with different GO loadings (0%, 0.5%, 1%, 3% of PVDF) were tested with two typical nZVI-targeted contaminants (Cd(II) and trichloroethylene (TCE)) via gravity-driven membrane filtration. The results show that membrane with 1% GO had the best nZVI distribution against the aggregation and a better performance in both Cd removal (100%) and TCE removal (82%). The nZVI membrane had a high flux in gravity-driven filtration at 255 LMH for Cd(II) and 265 LMH for TCE respectively. Generally, the developed PVDF-GO-nZVI electrospun nanofiber membrane had an excellent performance in the gravity-driven membrane filtration system for groundwater remediation.

Ren, J, Yao, M, Woo, YC, Tijing, LD, Kim, J-H & Shon, HK 2019, 'Recyclable nanoscale zerovalent iron (nZVI)-immobilized electrospun nanofiber composites with improved mechanical strength for groundwater remediation', Composites Part B: Engineering, vol. 171, pp. 339-346.
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© 2019 Elsevier Ltd Nanoscale zero-valent iron (nZVI), as a promising material, has been widely used in groundwater remediation. Membrane-supported nZVI can both avoid nZVI agglomeration for better reactivity and recycle nZVI/contaminants to lower the risk of secondary pollution. However, membrane mechanical strength is a critical property for long-term operation and the regeneration of nZVI membranes. This study tried to use a high molecular weight dual-crosslinking method to improve the mechanical strength of polymeric electrospun nanofiber membranes. Specifically, high molecular weight polyacrylic acid (PAA, Mw = 450,000) was dual-crosslinked by adding polyvinyl alcohol (PVA) as covalent cross-linker (named as M450k) and Fe(II) or Fe(III) as the ionic cross-linker (named as M450k-II and M450k-III). The results indicated that the M450k had better thermal resistance against membrane shrinkage, thus having larger surface areas and more –COOH groups to immobilize more nZVI particles. Besides, M450k-III had the highest tensile strength at 8.5 MPa, 5 times the figure for the mono-crosslinked low molecular weight membrane (M2k). In terms of nZVI immobilization and filtration performance, the Fe(II)-crosslinked membrane had better nZVI immobilization with the highest removal capacity at 463 mg/g while Fe(III)-crosslinked membrane had overwhelming mechanical strength with decent and stable removal capacity under multiple nZVI regenerations over 15 filtration cycles. Generally, the high molecular weight Fe(III)-crosslinked PAA-PVA electrospun nZVI showed better potential for long-term filtration process.

Ren, Y, Ngo, HH, Guo, W, Ni, B-J & Liu, Y 2019, 'Linking the nitrous oxide production and mitigation with the microbial community in wastewater treatment: A review', Bioresource Technology Reports, vol. 7, pp. 100191-100191.
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© 2019 Elsevier Ltd Nitrous oxide (N2O) is largely produced during wastewater treatment. However, there is a lack of review on linking N2O production and mitigation with microbial communities in wastewater treatment. In this study, various microbial communities contributing to N2O turnovers are reviewed according to their functions in nitrogen cycle, including ammonia oxidizing bacteria and archaea, comammox bacteria, autotrophic denitrifying bacteria, heterotrophic denitrifying bacteria and non-denitrifying N2O reducers. Their metabolic pathways and enzymatic reactions of N2O production are demonstrated, including nitrifier denitrification, nitritation, archaeal N2O production and denitrification pathways. The N2O emission factor of the nitrifier denitrification pathway is generally higher than nitritation pathway, and that of denitrifying bacteria depends on species and electron acceptors. The mitigation strategies are developed according to the dominating microbial communities. Overall, this review illustrates a comprehensive characteristic of N2O production by microbial communities in wastewater treatment, which could contribute to the development of effective N2O mitigation strategies.

Reyhani, A, McKenzie, TG, Fu, Q & Qiao, GG 2019, 'Fenton‐Chemistry‐Mediated Radical Polymerization', Macromolecular Rapid Communications, vol. 40, no. 18, pp. e1900220-1900220.
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AbstractIn this review, the power of a classical chemical reaction, the Fenton reaction for initiating radical polymerizations, is demonstrated. The reaction between the Fenton reagents (i.e., Fe2+ and H2O2) generates highly reactive hydroxyl radicals, which can act as radical initiators for the polymerization of vinyl monomers. Since the Fenton reaction is fast, easy to set up, cheap, and biocompatible, this unique chemistry is widely employed in various polymer synthesis studies via free radical polymerization or reversible addition–fragmentation chain transfer polymerization, and is utilized in a wide range of applications, such as the fabrication of biomaterials, hydrogels, and core‐shell particles. Biologically activated Fenton‐mediated radical polymerization, which can be performed in aerobic environments, are particularly useful for applications in biomedical systems.

Reyhani, A, McKenzie, TG, Fu, Q & Qiao, GG 2019, 'Redox-Initiated Reversible Addition–Fragmentation Chain Transfer (RAFT) Polymerization', Australian Journal of Chemistry, vol. 72, no. 7, pp. 479-479.
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Reversible addition–fragmentation chain transfer (RAFT) polymerization initiated by a radical-forming redox reaction between a reducing and an oxidizing agent (i.e. ‘redox RAFT’) represents a simple, versatile, and highly useful platform for controlled polymer synthesis. Herein, the potency of a wide range of redox initiation systems including enzyme-mediated redox reactions, the Fenton reaction, peroxide-based reactions, and metal-catalyzed redox reactions, and their application in initiating RAFT polymerization, are reviewed. These redox-RAFT polymerization methods have been widely studied for synthesizing a broad range of homo- and co-polymers with tailored molecular weights, compositions, and (macro)molecular structures. It has been demonstrated that redox-RAFT polymerization holds particular promise due to its excellent performance under mild conditions, typically operating at room temperature. Redox-RAFT polymerization is therefore an important and core part of the RAFT methodology handbook and may be of particular importance going forward for the fabrication of polymeric biomaterials under biologically relevant conditions or in biological systems, in which naturally occurring redox reactions are prevalent.

Reyhani, A, Ranji-Burachaloo, H, McKenzie, TG, Fu, Q & Qiao, GG 2019, 'Heterogeneously Catalyzed Fenton-Reversible Addition–Fragmentation Chain Transfer Polymerization in the Presence of Air', Macromolecules, vol. 52, no. 9, pp. 3278-3287.
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© 2019 American Chemical Society. Aqueous Fenton-reversible addition-fragmentation chain transfer (RAFT) polymerization catalyzed by heterogeneous catalysts, that is, Fe(II) metal-organic framework (MOF) particles, coupled with hydrogen peroxide (H2O2) with the reaction mixture exposed to air in open vessels is reported. Reactive hydroxyl radicals are generated via a heterogeneous redox reaction between Fe(II) of the MOF particles and H2O2, which then chemically deoxygenate the reaction mixture in situ, initiating RAFT polymerization. Well-controlled polymers (Ä < 1.1) with experimental molecular weights close to theoretical values at high monomer conversions (ca. 85%) were achieved within 15 min. High 'livingness' of the synthesized polymer chains was demonstrated by chain extension experiments and matrix-assisted laser desorption/ionization time-of-flight analysis. This study contributes to the growing interest in nonenzymatic deoxygenation techniques via heterogeneous catalysis for conducting radical polymerization reactions.

Ryu, S, Naidu, G, Hasan Johir, MA, Choi, Y, Jeong, S & Vigneswaran, S 2019, 'Acid mine drainage treatment by integrated submerged membrane distillation–sorption system', Chemosphere, vol. 218, pp. 955-965.
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Acid mine drainage (AMD), an acidic effluent characterized by high concentrations of sulfate and heavy metals, is an environmental and economic concern. The performance of an integrated submerged direct contact membrane distillation (DCMD) - zeolite sorption system for AMD treatment was evaluated. The results showed that modified (heat treated) zeolite achieved 26-30% higher removal of heavy metals compared to natural untreated zeolite. Heavy metal sorption by heat treated zeolite followed the order of Fe > Al > Zn > Cu > Ni and the data fitted well to Langmuir and pseudo second order kinetics model. Slight pH adjustment from 2 to 4 significantly increased Fe and Al removal rate (close to 100%) due to a combination of sorption and partial precipitation. An integrated system of submerged DCMD with zeolite for AMD treatment enabled to achieve 50% water recovery in 30 h. The integrated system provided a favourable condition for zeolite to be used in powder form with full contact time. Likewise, heavy metal removal from AMD by zeolite, specifically Fe and Al, mitigated membrane fouling on the surface of the hollow fiber submerged membrane. The integrated system produced high quality fresh water while concentrating sulfuric acid and valuable heavy metals (Cu, Zn and Ni).

Ryu, S, Naidu, G, Moon, H & Vigneswaran, S 2019, 'Selective copper extraction by multi-modified mesoporous silica material, SBA-15', Science of The Total Environment, vol. 697, pp. 134070-134070.
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© 2018 Selective copper (Cu) recovery from wastewater mitigates environmental pollution and is economically valuable. Mesoporous silica adsorbents, SBA-15, with amine-grafting (SBA-15-NH2) and manganese loading along with amine-grafting (Mn-SBA-15-NH2) were fabricated using KMnO4 and 3-aminopropyltriethoxysilane. The characteristics of the synthesized adsorbents were evaluated in detail in terms of its crystal structure peaks, surface area and pore size distribution, transmission electron microscope and X-ray photoelectron spectroscopy. The results established the 2.08 mmol/g of Cu adsorption capacity on Mn-SBA-15-NH2. Furthermore, in a mixed heavy metal solution, high selective Cu adsorption capacity on Mn-SBA-15-NH2 (2.01 mmol/g) was achieved while maintaining 96% adsorption amount as that of a single Cu solution. Comparatively, Cu adsorption on SBA-15-NH2 decreased by half due to high competition with other heavy metals. Optimal Cu adsorption occurred at pH 5. This pH condition enabled grafted amine group in Mn-SBA-15-NH2 to form strong chelating bonds with Cu, avoiding protonation of amine group (below pH 5) as well as precipitation (above pH 5). The adsorption equilibrium well fitted to Langmuir and Freundlich isotherm models, while kinetic results were represented by models of linear driving force approximation (LDFA) and pore diffusion model (PDM). High regeneration and reuse capacity of Mn-SBA-15-NH2 were well established by its capacity to maintain 90% adsorption capacity in a multiple adsorption-desorption cycle. Cu was selectively extracted from Mn-SBA-15-NH2 with an acid solution.

Samadi-Boroujeni, H, Altaee, A, Khabbaz, H & Zhou, J 2019, 'Application of buoyancy-power generator for compressed air energy storage using a fluid–air displacement system', Journal of Energy Storage, vol. 26, pp. 100926-100926.
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© 2019 Elsevier Ltd This study proposes a gravity power generator based on the fluid–air displacement system using Compressed Air Energy Storage from renewable energy sources to increase the solar and wind power system penetration in the power network. A computer model was applied to estimate the performance of the fluid–air displacement system, taking into account the effects of key design and operating parameters. Analysis of the system was performed to calculate the net energy generation as the difference between the energy input and the energy output. Simulation results indicated that the round-trip efficiency of the fluid–air displacement system was between 47% and 60%, assuming 80% compressor efficiency. Results also showed that a system generating the maximum energy density should have a speed of cylinders movement of 0.65 m/s, a cylinder-wall distance of 0.25 × diameter of the cylinder and a gap distance between centers of two tandem cylinders is equal to 1.25. Furthermore, a sensitivity analysis conducted on the main parameters of the system identified that the gap ratio and the buckets moving speed were the highly sensitive parameters to the design and operation of the proposed system. This study also demonstrates the feasibility of using the fluid-displacement system in energy storage from renewable energy technologies.

Sandu, S, Yang, M, Mahlia, TMI, Wongsapai, W, Ong, HC, Putra, N & Rahman, SMA 2019, 'Energy-Related CO2 Emissions Growth in ASEAN Countries: Trends, Drivers and Policy Implications', Energies, vol. 12, no. 24, pp. 4650-4650.
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The primary objective of this paper is to analyse the growth of energy-related CO2 emissions in ASEAN (Association of Southeast Asian Nations), with specific emphasis on identifying its trends and underlying drivers. This objective is premised on the arguments that: (1) there is a general lack of analysis of energy-related CO2 emissions growth across ASEAN countries; and (2) such an analysis is critical, because it could enable an assessment to be made of the efficacy of existing energy policies for reducing emissions. Decomposition analysis is the main approach adopted in this paper. The findings of this paper suggest that the growth of energy-related CO2 emissions has slowed in some major emitters in the region, due to energy efficiency improvement, and, to a lesser extent, a gradual switch in energy fuel mix towards lower emission sources (gas and renewables). However, this improvement is unlikely to drive a major transformation in the energy sectors of the region to the extent considered adequate for redressing the challenge of rising emissions, as indicated by a steady emissions growth in most ASEAN countries over the entire study period (1971–2016). By implication, this suggests that a significant scale-up of existing policy effort is needed to rectify the situations.

Scott, M, Millar, GJ & Altaee, A 2019, 'Process design of a treatment system to reduce conductivity and ammoniacal nitrogen content of landfill leachate', Journal of Water Process Engineering, vol. 31, pp. 100806-100806.
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© 2019 Elsevier Ltd An innovative combination of computational modelling and laboratory testing was applied to address the challenge of reducing conductivity and ammoniacal nitrogen in landfill leachate. The hypothesis was that accelerated selection of an appropriate treatment process could be achieved by application of new water process engineering software termed AqMB. Several scenarios were investigated incorporating settling ponds, clarifiers, lime softening, ion exchange, pH adjustment and degassing unit operations. Settling ponds reduced the lime demand if a lime softening process was tested, albeit ponds involved greater expense and needed space. Alternately, a clarifier using aluminium chlorohydrate removed suspended solids. Use of a single cation resin bed in series with a strong base anion (SBA) resin column was not able to meet regulatory targets. However, employment of a weak acid cation (WAC) and strong acid cation (SAC) resin combination achieved very low ammoniacal nitrogen levels. To satisfy conductivity limits both a degassing unit and a strong base anion (SBA) resin were also necessary. Bench top testing of actual leachate confirmed that the software predicted the trends in water quality. Final solution conductivity of ca. 250 μS/cm and ammoniacal nitrogen content of <1 mg/l were recorded which were compliant with target values of <1600 μS/cm and <100 mg/l ammoniacal nitrogen. Process economics encompassing power, chemicals, and resin costs were calculated to be A$10.50 per kL leachate.

Serrano, O, Lovelock, CE, B. Atwood, T, Macreadie, PI, Canto, R, Phinn, S, Arias-Ortiz, A, Bai, L, Baldock, J, Bedulli, C, Carnell, P, Connolly, RM, Donaldson, P, Esteban, A, Ewers Lewis, CJ, Eyre, BD, Hayes, MA, Horwitz, P, Hutley, LB, Kavazos, CRJ, Kelleway, JJ, Kendrick, GA, Kilminster, K, Lafratta, A, Lee, S, Lavery, PS, Maher, DT, Marbà, N, Masque, P, Mateo, MA, Mount, R, Ralph, PJ, Roelfsema, C, Rozaimi, M, Ruhon, R, Salinas, C, Samper-Villarreal, J, Sanderman, J, J. Sanders, C, Santos, I, Sharples, C, Steven, ADL, Cannard, T, Trevathan-Tackett, SM & Duarte, CM 2019, 'Australian vegetated coastal ecosystems as global hotspots for climate change mitigation', Nature Communications, vol. 10, no. 1, p. 4313.
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AbstractPolicies aiming to preserve vegetated coastal ecosystems (VCE; tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO2 emission benefits of VCE conservation and restoration. Australia contributes 5–11% of the C stored in VCE globally (70–185 Tg C in aboveground biomass, and 1,055–1,540 Tg C in the upper 1 m of soils). Potential CO2 emissions from current VCE losses are estimated at 2.1–3.1 Tg CO2-e yr-1, increasing annual CO2 emissions from land use change in Australia by 12–21%. This assessment, the most comprehensive for any nation to-date, demonstrates the potential of conservation and restoration of VCE to underpin national policy development for reducing greenhouse gas emissions.

Shah Mohammadi, N, Buapet, P, Pernice, M, Signal, B, Kahlke, T, Hardke, L & Ralph, PJ 2019, 'Transcriptome profiling analysis of the seagrass, Zostera muelleri under copper stress', Marine Pollution Bulletin, vol. 149, pp. 110556-110556.
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Copper (Cu) in an essential trace metal but it can also contaminate coastal waters at high concentrations mainly from agricultural run-off and mining activities which are detrimental to marine organisms including seagrasses. The molecular mechanisms driving Cu toxicity in seagrasses are not clearly understood yet. Here, we investigated the molecular responses of the Australian seagrass, Z. muelleri at the whole transcriptomic level after 7 days of exposure to 250 μg Cu L-1 and 500 μg Cu L-1. The leaf-specific whole transcriptome results showed a concentration-dependent disturbance in chloroplast function, regulatory stress responses and defense mechanisms. This study provided new insights into the responses of seagrasses to trace metal stress and reports possible candidate genes which can be considered as biomarkers to improve conservation and management of seagrass meadows.

Silitonga, A, Mahlia, T, Shamsuddin, A, Ong, H, Milano, J, Kusumo, F, Sebayang, A, Dharma, S, Ibrahim, H, Husin, H, Mofijur, M & Rahman, S 2019, 'Optimization of Cerbera manghas Biodiesel Production Using Artificial Neural Networks Integrated with Ant Colony Optimization', Energies, vol. 12, no. 20, pp. 3811-3811.
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Optimizing the process parameters of biodiesel production is the key to maximizing biodiesel yields. In this study, artificial neural network models integrated with ant colony optimization were developed to optimize the parameters of the two-step Cerbera manghas biodiesel production process: (1) esterification and (2) transesterification. The parameters of esterification and transesterification processes were optimized to minimize the acid value and maximize the C. manghas biodiesel yield, respectively. There was excellent agreement between the average experimental values and those predicted by the artificial neural network models, indicating their reliability. These models will be useful to predict the optimum process parameters, reducing the trial and error of conventional experimentation. The kinetic study was conducted to understand the mechanism of the transesterification process and, lastly, the model could measure the physicochemical properties of the C. manghas biodiesel.

Silitonga, AS, Mahlia, TMI, Kusumo, F, Dharma, S, Sebayang, AH, Sembiring, RW & Shamsuddin, AH 2019, 'Intensification of Reutealis trisperma biodiesel production using infrared radiation: Simulation, optimisation and validation', Renewable Energy, vol. 133, pp. 520-527.
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© 2018 Elsevier Ltd Biodiesel production using intensification of methyl ester is becoming very important due to its considerably lower energy requirement and shorter reaction time in obtaining feedstock oil. The present study investigated utilisation of Reutealis trisperma oil to produce biodiesel. A Box-Behnken experimental design was used to optimise the transesterification process. The process variables were explored and the optimum methanol to oil molar ratio, catalyst concentration, reaction temperature, and reaction time were 8:1, 1.2 wt%, 64 °C and 68 min respectively and the corresponding methyl ester yield was 98.39%. The experiment was conducted in triplicate to validate the quadratic model. Results showed average methyl ester yield was 97.78%, which is close to the predicted value, indicating reliability of the model. Results also indicated that using infrared radiation method has many advantageous, such as less energy consumption as a result of deeper penetration of reactant mass which can improve mass transfer between the immiscible reactants in order to improve quality of biodiesel. The physicochemical properties of Reutealis trisperma methyl ester produced under optimum transesterification process variables were also measured and the properties fulfilled the fuel specifications as per ASTM D6751 and EN 14214 standards.

Song, J-H, Shon, HK, Wang, P, Jang, A & Kim, IS 2019, 'Tuning the nanostructure of nitrogen-doped graphene laminates for forward osmosis desalination', Nanoscale, vol. 11, no. 45, pp. 22025-22032.
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Studies have concentrated on the physicochemical properties of graphene-based membranes that can replace polymeric membranes for use in forward osmosis (FO) systems.

Song, K, Yeerken, S, Li, L, Sun, J & Wang, Q 2019, 'Improving Post-Anaerobic Digestion of Full-Scale Anaerobic Digestate Using Free Ammonia Treatment', ACS Sustainable Chemistry & Engineering, vol. 7, no. 7, pp. 7171-7176.
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© 2019 American Chemical Society. Post-anaerobic digestion of full-scale anaerobic digestate (AD) is used in enhancing sludge reduction in some sewage treatment plants (STPs). However, the AD degradation is usually inhibited due to its slow hydrolysis rate and low degradability. This study presents an innovative pretreatment method by using free ammonia (FA, i.e., NH 3 ) to improve post-anaerobic digestion full-scale AD degradation. The FA treatment at over 360 mg NH 3 -N/L for 24 h has improved AD degradation with the highest solubilization (0.1 mg chemical oxygen demand (COD)/mg volatile solids (VS), at 850 mg NH 3 -N/L), being 5.3 times that without pretreatment (0.019 mg COD/mg VS). After 8 days of post-anaerobic digestion, non-pretreated AD has degraded 8.5%, while the FA pretreated AD at 360-850 mg NH 3 -N/L has degraded 9.9-10.9%, representing a relative increase of 14-22%. The mathematical model captured the tested data well with R 2 > 0.994 in all cases, and the model revealed that AD degradation improvement was attributed to an increase in AD degradation percentage. Economic analysis shows that the FA pretreatment method could be economically favorable in enhancing full-scale AD post-anaerobic digestion.

Song, Z, Zhang, X, Ngo, HH, Guo, W, Song, P, Zhang, Y, Wen, H & Guo, J 2019, 'Zeolite powder based polyurethane sponges as biocarriers in moving bed biofilm reactor for improving nitrogen removal of municipal wastewater', Science of The Total Environment, vol. 651, no. Pt 1, pp. 1078-1086.
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This study aims to enhance nitrogen removal efficiency of a moving bed biofilm reactor (MBBR) by developing a new MBBR with zeolite powder-based polyurethane sponges as biocarriers (Z-MBBR). Results indicated the total nitrogen (TN) removal efficiency and simultaneous nitrification and denitrification (SND) performance in Z-MBBR were nearly 10% higher than those in the conventional MBBR with sponges as biocarriers (S-MBBR). About 84.2 ± 4.8% of TN was removed in Z-MBBR compared to 75.1 ± 6.8% in S-MBBR. Correspondingly, the SND performance in Z-MBBR and S-MBBR was 90.7 ± 4.1% and 81.7 ± 6.5%, respectively. The amount of biofilm attached to new biocarriers (0.470 ± 0.131 g/g carrier) was 1.3 times more than that of sponge carriers (0.355 ± 0.099 g/g carrier). Based on the microelectrode measurements and microbial community analysis, more denitrifying bacteria existed in the Z-MBBR system, and this can improve the SND performance. Consequently, this new Z-MBBR can be a promising option for a hybrid treatment system to better nitrogen removal from wastewater.

Song, Z, Zhang, X, Ngo, HH, Guo, W, Wen, H & Li, C 2019, 'Occurrence, fate and health risk assessment of 10 common antibiotics in two drinking water plants with different treatment processes', Science of The Total Environment, vol. 674, pp. 316-326.
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© 2019 Elsevier B.V. The occurrence of antibiotics in drinking water has become a serious problem worldwide as they are a potential and real threat to human health. In this study, the variability of 10 typical antibiotics in two drinking water plants was investigated in two seasons (n = 12). The total concentrations of target antibiotics in raw water were significantly higher in winter than in summer, which may be attributed to the more frequent occurrence of colds and respiratory diseases as well as less rainfall in winter. The efficiency in removing the antibiotics varied from −46.5% to 45.1% in water plant A (WP-A) using a conventional process and 40.3% to 70.3% in water plant B (WP-B) with an advanced treatment process. Results indicated that the antibiotics in WP-A were mainly removed via the coagulation process. However in WP-B, the ultraviolet + chlorination process played a key role in antibiotics removal, followed by the pre-ozone + coagulation process. According to the human health risk assessment, it was suggested that the risk of drinking water was significantly higher than that of skin contact. However, the risk of carcinogenesis and non-carcinogenesis caused by antibiotics was at an acceptable level.

Soudagar, MEM, Nik-Ghazali, N-N, Kalam, MA, Badruddin, IA, Banapurmath, NR, Yunus Khan, TM, Bashir, MN, Akram, N, Farade, R & Afzal, A 2019, 'The effects of graphene oxide nanoparticle additive stably dispersed in dairy scum oil biodiesel-diesel fuel blend on CI engine: performance, emission and combustion characteristics', Fuel, vol. 257, pp. 116015-116015.
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In the present investigation, the effects of graphene oxide nanoparticles on performance and emissions of a CI engine fueled with dairy scum oil biodiesel was studied. Nanofuel blend was prepared by dispersing graphene oxide in varying quantities in dairy scum oil methyl ester (DSOME)-diesel blend. Sodium dodecyl sulfate (SDS) was used as a surfactant for a steady dispersion of graphene oxide nanoparticles in the fuel blends. The dispersion and homogeneity were characterized by ultraviolet–visible spectrometry. An ideal graphene-to-surfactant ratio was defined, highest absolute value UV-absorbency was seen for a mass fraction of 1:4. The concentration of surfactant above or below this ratio resulted in reduction in the stability of dispersion. Graphene oxide nanoparticles were amalgamated with dairy scum oil biodiesel at proportions of 20, 40 and 60 parts per million using ultrasonication technique. Experiments were performed at a constant speed and varying the brake power and load condtions. The results were notable enhancements in the performance and emissions characteristics, the brake thermal efficiency improved by 11.56%, a reduction in brake specific fuel consumption by 8.34%, unburnt hydrocarbon by 21.68%, smoke by 24.88%, carbon monoxide by 38.662% for the nanofuel blend DSOME2040 and oxides of nitrogen emission by 5.62% for fuel DSOME(B20). Similarly, the addition of graphene nanoparticles in DSOME fuel blends resulted in significant reduction in the combustion duration, ignition delay period, improvement in the peak pressure and heat release rate at maximum load condition. Finally, it is concluded that nano-graphene oxide nanoparticles can be introduced as a suitable substitute fuel additive for dairy scum oil biodiesel blends to enhance the overall engine performance and emissions characteristics.

Su, D, Zhang, QH, Ngo, HH, Dzakpasu, M, Guo, WS & Wang, XC 2019, 'Development of a water cycle management approach to Sponge City construction in Xi'an, China', Science of The Total Environment, vol. 685, pp. 490-496.
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In recent years, climate change, population growth, and inefficient use of water have exacerbated the water resources scarcity problems around the world. Hence, this paper establishes a new approach of Sponge City construction (SCC) based on water cycle management (WCM) for the sustainable exploitation of groundwater, recycled wastewater and rainwater in the Xi'an Siyuan University. The University is located in an isolated area that is far away from the city center so that no centralized water supply system could be utilized. To mitigate water scarcity problems in the University, 39% of the annual rainfall is harvested and stored from impervious surfaces and grasslands by using the Curve Number (CN) method. This stored water is reused for non-potable purposes: 40% for toilet flushing and 60% as miscellaneous water. According to findings, the available rainwater of500-700 m3/d accounts for 16-23% of the non-potable water from April to December. Moreover, the utilization rate of water resources increases from 204% to 227%. With the minimum volume of large-scale rainwater harvesting cistern of 52,760 m3, the environment could be adequately watered while improving the expansion and development conditions on the campus. Furthermore, water scarcity problems could be mitigated through optimization of the water resources utilization system. This study demonstrates that this new approach of SCC based on WCM could alleviate water resources scarcity problems in Xi'an Siyuan University effectively. It is hoped that this study will provide a model and example of the new approach for future applications.

Sun, J, Dai, X, Wang, Q, van Loosdrecht, MCM & Ni, B-J 2019, 'Microplastics in wastewater treatment plants: Detection, occurrence and removal', Water Research, vol. 152, pp. 21-37.
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© 2018 Elsevier Ltd Microplastics have aroused increasing concern as they pose threats to aquatic species as well as human beings. They do not only contribute to accumulation of plastics in the environment, but due to absorption they can also contribute to spreading of micropollutants in the environment. Studies indicated that wastewater treatment plants (WWTPs) play an important role in releasing microplastics to the environment. Therefore, effective detection of the microplastics and understanding their occurrence and fate in WWTPs are of great importance towards microplastics control. In this review, the up-to-date status on the detection, occurrence and removal of microplastics in WWTPs are comprehensively reviewed. Specifically, the different techniques used for collecting microplastics from both wastewater and sewage sludge, and their pretreatment and characterization methods are reviewed and analyzed. The key aspects regarding microplastics occurrence in WWTPs, such as concentrations, total discharges, materials, shapes and sizes are summarized and compared. Microplastics removal in different treatment stages and their retention in sewage sludge are explored. The development of potential microplastics-targeted treatment technologies is also presented. Although previous researches in microplastics have undoubtedly improved our level of understanding, it is clear that much remains to be learned about microplastics in WWTPs, as many unanswered questions and thereby concerns still remain; some of these important future research areas are outlined. The key challenges appear to be to harmonize detection methods as well as microplastics mitigation from wastewater and sewage sludge.

Sun, L, Fang, H, Cai, Q, Yang, X, He, J, Zhou, JL & Wang, X 2019, 'Sediment load change with erosion processes under simulated rainfall events', Journal of Geographical Sciences, vol. 29, no. 6, pp. 1001-1020.
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© 2019, Science Press Springer-Verlag. It is of great significance to quantify sediment load changing with erosion processes for improving the precision of soil loss prediction. Indoor rainfall experiments were conducted in 2 rainfall intensities (90 mm·h−1 and 120 mm·h−1), four slope gradients (17.60%, 26.80%, 36.40%, 46.60%) and 2 slope lengths (5 m, 10 m). Erosion processes are divided into five stages. Results show that sediment yield is mainly sourced from rill erosion, contributing from 54.60% to 95.70% and the duration of which is extended by slope gradients. Sediment load and sediment concentration are significantly different along erosion stages, with the highest values in rill development stage (SIV). Surface flow velocities (interrill and rill) demonstrate less significant differences along erosion stages. Rainfall intensity increases sediment load in all stages, with up to 12.0 times higher when changing from 90 to 120 mm·h−1. There is an increasing trend for sediment load and sediment concentration with the rising slope gradient, however, fluctuations existed with the lowest values on 26.80% and 36.40%, respectively, among different treatments. The slope gradient effects are enhanced by rainfall intensity and slope length. Results from this study are important for validating and improving hillslope erosion modelling at each erosion stage.

Sun, Y, Wang, C, Guo, G, Fu, Q, Xiong, Z, Li, D & Liu, Y 2019, 'Facile synthesis of highly efficient photocatalysts based on organic small molecular co-catalyst', Applied Surface Science, vol. 469, pp. 553-563.
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© 2018 Elsevier B.V. A new metal-free organic molecular as co-catalyst was developed, which could drastically enhance the photocatalytic performance of photocatalyst (eg. g-C 3 N 4 , MoS 2 and TiO 2 ). The enhancing photocatalytic activity was evaluated for photocatalytic degradation of organic dyes. It showed ultra-high photocatalytic rate (4.17 mg/g·min) and ultra-short time (about 6.0 min) for photocatalytic degradation of organic dyes (25 mg/ml). The enhanced photocatalytic performance was attributed to suppress recombination of photogenerated charges and provide a new photoredox reaction pathway under molecular co-catalyst assistance. The study represents a facile method to develop ultra-effectively photocatalyst for applications in production of green and renew-able energy carrier, H 2 from water, reduction of CO 2 , synthesis of fine chemicals and remediation of environmental pollutants.

Surindra, M, Caesarendra, W, Prasetyo, T, Mahlia, T & Taufik 2019, 'Comparison of the Utilization of 110 °C and 120 °C Heat Sources in a Geothermal Energy System Using Organic Rankine Cycle (ORC) with R245fa, R123, and Mixed-Ratio Fluids as Working Fluids', Processes, vol. 7, no. 2, pp. 113-113.
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Binary cycle experiment as one of the Organic Rankine Cycle (ORC) technologies has been known to provide an improved alternate scenario to utilize waste energy with low temperatures. As such, a binary geothermal power plant simulator was developed to demonstrate the geothermal energy potential in Dieng, Indonesia. To better understand the geothermal potential, the laboratory experiment to study the ORC heat source mechanism that can be set to operate at fixed temperatures of 110 °C and 120 °C is conducted. For further performance analysis, R245fa, R123, and mixed ratio working fluids with mass flow rate varied from 0.1 kg/s to 0.2 kg/s were introduced as key parameters in the study. Data from the simulator were measured and analyzed under steady-state condition with a 20 min interval per given mass flow rate. Results indicate that the ORC system has better thermodynamic performance when operating the heat source at 120 °C than those obtained from 110 °C. Moreover, the R123 fluid produces the highest ORC efficiency with values between 9.4% and 13.5%.

Sutherland, DL & Ralph, PJ 2019, 'Microalgal bioremediation of emerging contaminants - Opportunities and challenges', Water Research, vol. 164, pp. 114921-114921.
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© 2019 Emerging contaminants (ECs) are primarily synthetic organic chemicals that have a focus of increasing attention due to either increased awareness of their potential risks to humans and aquatic biota, or only recently been detected in the aquatic environment or drinking water supplies, through improved analytical techniques. Many ECs have no regulatory standards due to the lack of information on the effects of chronic exposure. Pharmaceuticals, personal care products, pesticides and flame retardants are some of the most frequently detected ECs in aquatic environments, with over 200 individual compounds identified, to date. Current wastewater treatment is ineffective at removing ECs and there is a vital need for the development of efficient, cost-effective EC treatment systems that can be applied to a range of scales and wastewater types. Microalgae have demonstrated potential for detoxifying organic and inorganic pollutants, with a number of large-scale wastewater treatment microalgal technologies already developed. There are three main pathways that microalgae can bioremediate ECs; bioadsorption, bio-uptake and biodegradation. Microalgal bioadsorption occurs when ECs are either adsorbed to cell wall components, or onto organic substances excreted by the cells, while bio-uptake involves the active transport of the contaminant into the cell, where it binds to intracellular proteins and other compounds. Microalgal biodegradation of ECs involves the transformation of complex compounds into simpler breakdown molecules through catalytic metabolic degradation. Biodegradation provides one of the most promising technologies for the remediation of contaminants of concern as it can transform the contaminant to less toxic compounds rather than act as a biofilter. Further research is needed to exploit microalgal species for EC bioremediation properties, such as increased bioadsorption, enhanced biodegrading enzymes and optimised growth conditions. When couple...

Tang, J, Pu, Y, Wang, XC, Hu, Y, Huang, J, Ngo, HH, Pan, S, Li, Y & Zhu, N 2019, 'Effect of additional food waste slurry generated by mesophilic acidogenic fermentation on nutrient removal and sludge properties during wastewater treatment', Bioresource Technology, vol. 294, pp. 122218-122218.
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Fermentation slurry from food waste (FSFW) generated by acidogenic fermentation at mesophilic temperature was utilized to improve the nutrients removal from wastewater. Organic acids (such as lactate and volatile fatty acids) in the FSFW behaved as readily biodegradable carbon sources, while the particulate and macromolecular organics acted as slowly biodegradable carbon sources during denitrification processes. The FSFW dosage significantly influenced the nitrogen removal performance, and a C/N ratio (in terms of chemical oxygen demand to nitrogen ratio) of 8 could achieve complete denitrification in the batch tests. In a sequencing batch reactor (SBR) using FSFW for long-term wastewater treatment, extracellular polymeric substances (EPS) gradually accumulated, sludge particle size significantly increased, and microbial communities were selectively enriched, which contributed to promoting the nitrogen (>80%) and phosphate (90.1%) removal efficiencies. Overall, the FSFW produced by acidogenic fermentation under mesophilic temperature served as an excellent intermediary between FW valorization and wastewater treatment.

Tang, J, Wang, XC, Hu, Y, Pu, Y, Huang, J, Ngo, HH, Zeng, Y & Li, Y 2019, 'Nutrients removal performance and sludge properties using anaerobic fermentation slurry from food waste as an external carbon source for wastewater treatment', Bioresource Technology, vol. 271, pp. 125-135.
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Enhancement of nitrogen and phosphate removal using thermophilic fermentation slurry from food waste (FSFW) as external carbon source was investigated. Based on the batch tests, the soluble and particulate fractions of the FSFW acted as easily and slowly biodegradable carbon sources, respectively, and the fermented slurry showed the combined nutrients removal properties of soluble and solid organics. During the long-term operation of a sequencing batch reactor (SBR) with FSFW for wastewater treatment, the sludge particle size increased obviously, the bacterial metabolic capacity improved significantly, and some functional microorganisms were enriched selectively, which significantly promoted the nitrogen removal efficiency (approximately 90%) by enhancing the anoxic denitrification and simultaneous nitrification and denitrification (SND) processes. Moreover, high phosphate removal efficiency (above 98%) was achieved through the aerobic and anoxic phosphate accumulation processes. Thus, using the FSFW as supplementary carbon source is a suitable solution for both food waste disposal and wastewater treatment.

Tang, Z, Li, W, Hu, Y, Zhou, JL & Tam, VWY 2019, 'Review on designs and properties of multifunctional alkali-activated materials (AAMs)', Construction and Building Materials, vol. 200, pp. 474-489.
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© 2018 Elsevier Ltd The stream of research on alkali-activated materials (AAMs) has expanded rapidly during the last decades owing to the potential as a viable alternative to cement-based materials. In addition to the load-carrying function, AAMs have been integrated with other functions to develop advanced construction materials, namely multifunctional AAMs. Multifunctional AAMs are intelligent systems not only serve a basic structural function but also exhibit other functional properties or have the abilities to react upon external stimuli or disturbances. Materials of this kind have tremendous potential to enhance the mechanical performance and durability of structure, improve the reliability and longevity of infrastructure, as well as reduce life-cycle service and maintenance cost. These multifunctional properties are mainly achieved through materials composition design, incorporation of functional elements, or microstructure modification. This paper presents an overview on designs and properties of multifunctional AAMs covering the smart functions, mechanical functions, and electrical functions, and with special attention to their definition, principles, and current progress. Furthermore, the challenges in the research of multifunctional AAMs have been discussed, as well as the future directions to increase the innovation and engineering application of these materials and structures.

Tang, Z, Li, W, Ke, G, Zhou, JL & Tam, VWY 2019, 'Sulfate attack resistance of sustainable concrete incorporating various industrial solid wastes', Journal of Cleaner Production, vol. 218, pp. 810-822.
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© 2019 Elsevier Ltd Industrial solid wastes are inducing severe environmental problems, but the problem can be overcame by reusing them as construction materials. The sulfate resistances of sustainable concrete incorporating various solid waste materials, including waste glass powder (WGP), coal gangue powder (CGP) and fly ash (FA) were investigated in this study. Concrete mixes with different water to binder (w/b) ratios and containing various solid waste materials as partial replacement of Portland cement by ratios of 10%, 20%, and 30% were prepared. These mixes were immersed in the 5% Na 2 SO 4 solution for a total period of 22 months. The sulfate attack resistances were evaluated extensively based on visual appearance, mass change, compressive strength, splitting tensile strength, ultrasonic pulse velocity, mineralogy, and microstructure. The results indicate that regardless of the type and content of solid waste materials, the replacement of cement by solid waste materials exhibit a positive impact on the sulfate attack resistance. Under the same substitution level, WGP appear to be the most effective in offsetting the destructive effect of sulfate attack, followed by CGP and FA. Therefore, sustainable concrete incorporating solid waste materials can not only promote the recycling of solid waste, but also provide high sulfate attack resistance.

Teoh, YH, How, HG, Masjuki, HH, Nguyen, H-T, Kalam, MA & Alabdulkarem, A 2019, 'Investigation on particulate emissions and combustion characteristics of a common-rail diesel engine fueled with Moringa oleifera biodiesel-diesel blends', Renewable Energy, vol. 136, pp. 521-534.
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Terechovs, AKE, Ansari, AJ, McDonald, JA, Khan, SJ, Hai, FI, Knott, NA, Zhou, J & Nghiem, LD 2019, 'Occurrence and bioconcentration of micropollutants in Silver Perch (Bidyanus bidyanus) in a reclaimed water reservoir', Science of The Total Environment, vol. 650, no. Pt 1, pp. 585-593.
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© 2018 This study examined the occurrence of 49 micropollutants in reclaimed water and Silver Perch (Bidyanus bidyanus) living in a reclaimed water reservoir. The numbers of micropollutants detected in reclaimed water, Silver Perch liver, and Silver Perch flesh were 20, 23, and 19, respectively. Concentrations of all micropollutants in reclaimed water, except benzotriazole, were well below the Australian Guideline for Recycled Water (AGRW) values for potable purposes. The concentration of benzotriazole in reclaimed water was 675 ± 130 ng/L while the AGRW value for this compound was 7 ng/L. Not all micropollutants detected in the water phase were identified in the Silver Perch flesh and liver tissues. Likewise, not all micropollutants detected in the Silver Perch flesh and liver were identified in the reclaimed water. In general, micropollutant concentrations in the liver were higher than in the flesh. Perfluorooctane sulfonate (PFOS) was detected at a trace level in reclaimed water well below the AGRW guideline value for potable purposes, but showed a high and medium bioconcentration factor in Silver Perch liver and flesh, respectively. In addition, the risk quotient for PFOS was medium and high when considering its concentration in Silver Perch liver and flesh, respectively. Results reported here highlight the need to evaluate multiple parameters for a comprehensive risk assessment. The results also single out PFOS as a notable contaminant of concern for further investigation.

Thabit, MS, Hawari, AH, Ammar, MH, Zaidi, S, Zaragoza, G & Altaee, A 2019, 'Evaluation of forward osmosis as a pretreatment process for multi stage flash seawater desalination', Desalination, vol. 461, pp. 22-29.
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© 2019 The present study evaluates the feasibility of applying forward osmosis (FO) process for the pretreatment of feed solution to a Multi Stage Flash (MSF) desalination plant. For the first time, real brine reject and real seawater were used as the draw solution and the feed solution, respectively in the FO process. The FO pretreatment is expected to dilute the brine reject and reduce the concentration of divalent ions, which are responsible for scale formation on the surface of heat exchanger in the MSF evaporator unit. The FO experiments were performed at different draw solution temperatures ranging between 25 and 40 °C, different draw and feed solutions flowrates and different membrane orientations. A maximum average membrane flux of 22.3 L/m2·h was reported at a draw solution temperature of 40 °C and 0.8 and 2.0 LPM flow rate of draw and feed solutions, respectively. The experimental results also revealed the process sensitivity to the feed solution temperature. It was found that the average membrane flux in the FO process operating at 0.8 and 2 LPM draw and feed solution flow rates, respectively was 16.9 L/m2·h at 25 °C brine temperature but increased to 22.3 L/m2·h at 40 °C brine temperature. These membrane fluxes resulted in 3% and 8.5% dilution of the draw solution at 25 °C and 40 °C temperatures, respectively. The average membrane flux in the FO mode was equal to that in the PRO mode at low flow rates but it was lower than that in the PRO mode at high flow rates of the feed and draw solutions. The outcomes of the study are very promising with regard to membrane flux and dilution of draw solution.

Thomson, ACG, Trevathan‐Tackett, SM, Maher, DT, Ralph, PJ & Macreadie, PI 2019, 'Bioturbator‐stimulated loss of seagrass sediment carbon stocks', Limnology and Oceanography, vol. 64, no. 1, pp. 342-356.
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AbstractSeagrass ecosystems are highly productive, and are sites of significant carbon sequestration. Sediment‐held carbon stocks can be many thousands of years old, and persist largely due to sediment anoxia and because microbial activity is decreasing with depth. However, the carbon sequestered in seagrass ecosystems may be susceptible to remineralization via the activity of bioturbating fauna. Microbial priming is a process whereby remineralization of sediment carbon (recalcitrant organic matter) is stimulated by disturbance, i.e., burial of a labile source of organic matter (seagrass). We investigated the hypothesis that bioturbation could mediate remineralization of sediment carbon stocks through burial of seagrass leaf detritus. We carried out a 2‐month laboratory study to compare the remineralization (measured as CO2 release) of buried seagrass leaves (Zostera muelleri) to the total rate of sediment organic matter remineralization in sediment with and without the common Australian bioturbating shrimp Trypaea australiensis (Decapoda: Axiidea). In control sediment containing seagrass but no bioturbators, we observed a negative microbial priming effect, whereby seagrass remineralization was favored over sediment remineralization (and thus preserving sediment stocks). Bioturbation treatments led to a two‐ to five‐fold increase in total CO2 release compared to controls. The estimated bioturbator‐stimulated microbial priming effect was equivalent to 15% of the total daily sediment‐derived CO2 releases. We propose that these results indicate that bioturbation is a potential mechanism that converts these sediments from carbon sinks to sources through stimulation of priming‐enhanced sediment carbon remineralization. We further hypothesized that significant changes to seagrass faunal communities may influence...

To, VHP, Nguyen, TV, Bustamante, H & Vigneswaran, S 2019, 'Deleterious effects of soluble extracellular polymeric substances on polyacrylamide demand for conditioning of anaerobically digested sludge', Journal of Environmental Chemical Engineering, vol. 7, no. 2, pp. 102941-102941.
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© 2019 Elsevier Ltd. All rights reserved. High polyacrylamide (polymer) demand for conditioning of sludge, especially anaerobically digested sludge (ADS), is a major issue for the water industry. Currently, this problem is being investigated and the reasons for doing so are varied. It has been demonstrated that excess amounts of soluble extracellular polymeric substances (EPS) can lead to high polymer demand for conditioning. This study developed a simple and unique yet effective method for quantifying the contribution of soluble EPS to conditioning polymer demand. It did this by measuring absorbance at 191.5 nm wavelength of the supernatant derived from conditioned ADS. Experimental results confirmed that approximately 87 wt% of soluble EPS interacted with polyacrylamides during the conditioning process. Furthermore, they revealed that a specified amount of soluble EPS could not be removed by polymer flocculation despite high polymer dosage. This study concluded that about 86 wt% of the polyacrylamide used for conditioning was consumed solely by soluble EPS. These results confirm the important role of reducing this EPS fraction in ADS in order to curtail significant chemical costs for sludge conditioning and dewatering.

Tran, HN, Nguyen, DT, Le, GT, Tomul, F, Lima, EC, Woo, SH, Sarmah, AK, Nguyen, HQ, Nguyen, PT, Nguyen, DD, Nguyen, TV, Vigneswaran, S, Vo, D-VN & Chao, H-P 2019, 'Adsorption mechanism of hexavalent chromium onto layered double hydroxides-based adsorbents: A systematic in-depth review', Journal of Hazardous Materials, vol. 373, pp. 258-270.
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© 2019 Elsevier B.V. An attempt has been made in this review to provide some insights into the possible adsorption mechanisms of hexavalent chromium onto layered double hydroxides-based adsorbents by critically examining the past and present literature. Layered double hydroxides (LDH) nanomaterials are typical dual-electronic adsorbents because they exhibit positively charged external surfaces and abundant interlayer anions. A high positive zeta potential value indicates that LDH has a high affinity to Cr(VI) anions in solution through electrostatic attraction. The host interlayer anions (i.e., Cl−, NO3−, SO42−, and CO32−) provide a high anion exchange capacity (53–520 meq/100 g) which is expected to have an excellent exchangeable capacity to Cr(VI) oxyanions in water. Regarding the adsorption-coupled reduction mechanism, when Cr(VI) anions make contact with the electron-donor groups in the LDH, they are partly reduced to Cr(III) cations. The reduced Cr(III) cations are then adsorbed by LDH via numerous interactions, such as isomorphic substitution and complexation. Nonetheless, the adsorption-coupled reduction mechanism is greatly dependent on: (1) the nature of divalent and trivalent salts utilized in LDH preparation, and the types of interlayer anions (i.e., guest intercalated organic anions), and (3) the adsorption experiment conditions. The low Brunauer–Emmett–Teller specific surface area of LDH (1.80–179 m2/g) suggests that pore filling played an insignificant role in Cr(VI) adsorption. The Langmuir maximum adsorption capacity of LDH (Qomax) toward Cr(VI) was significantly affected by the natures of used inorganic salts and synthetic methods of LDH. The Qomax values range from 16.3 mg/g to 726 mg/g. Almost all adsorption processes of Cr(VI) by LDH-based adsorbent occur spontaneously (ΔG° <0) and endothermically (ΔH° >0) and increase the randomness (ΔS° >0) in the system. Thus, LDH has much potential as a promising material that can effectively rem...

Tran, HN, Nguyen, HC, Woo, SH, Nguyen, TV, Vigneswaran, S, Hosseini-Bandegharaei, A, Rinklebe, J, Kumar Sarmah, A, Ivanets, A, Dotto, GL, Bui, TT, Juang, R-S & Chao, H-P 2019, 'Removal of various contaminants from water by renewable lignocellulose-derived biosorbents: a comprehensive and critical review', Critical Reviews in Environmental Science and Technology, vol. 49, no. 23, pp. 2155-2219.
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© 2019, © 2019 Taylor & Francis Group, LLC. Contaminants in water bodies cause potential health risks for humans and great environmental threats. Therefore, the development and exploration of low-cost, promising adsorbents to remove contaminants from water resources as a sustainable option is one focus of the scientific community. Here, we conducted a critical review regarding the application of pristine and modified/treated biosorbents derived from leaves for the removal of various contaminants. These include potentially toxic cationic and oxyanionic metal ions, radioactive metal ions, rare earth elements, organic cationic and anionic dyes, phosphate, ammonium, and fluoride from water media. Similar to lignocellulose-based biosorbents, leaf-based biosorbents exhibit a low specific surface area and total pore volume but have abundant surface functional groups, high concentrations of light metals, and a high net surface charge density. The maximum adsorption capacity of biosorbents strongly depends on the operation conditions, experiment types, and adsorbate nature. The absorption mechanism of contaminants onto biosorbents is complex; therefore, typical experiments used to identify the primary mechanism of the adsorption of contaminants onto biosorbents were thoroughly discussed. It was concluded that byproduct leaves are renewable, biodegradable, and promising biosorbents which have the potential to be used as a low-cost green alternative to commercial activated carbon for effective removal of various contaminants from the water environment in the real-scale plants.

Tran, NH, Hoang, L, Nghiem, LD, Nguyen, NMH, Ngo, HH, Guo, W, Trinh, QT, Mai, NH, Chen, H, Nguyen, DD, Ta, TT & Gin, KY-H 2019, 'Occurrence and risk assessment of multiple classes of antibiotics in urban canals and lakes in Hanoi, Vietnam', Science of The Total Environment, vol. 692, pp. 157-174.
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Tran, VH, Lim, S, Han, DS, Pathak, N, Akther, N, Phuntsho, S, Park, H & Shon, HK 2019, 'Efficient fouling control using outer-selective hollow fiber thin-film composite membranes for osmotic membrane bioreactor applications', Bioresource Technology, vol. 282, pp. 9-17.
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© 2019 Elsevier Ltd This paper investigates the efficiency of fouling mitigation methods using a novel outer selective hollow fiber thin-film composite forward osmosis (OSHF TFC FO) membrane for osmosis membrane bioreactor (OMBR) system treating municipal wastewater. Two home-made membrane modules having similar transport properties were used. Two operation regimes with three different fouling mitigation strategies were utilized to test the easiness of membrane for fouling cleaning. These two membrane modules demonstrated high performance with high initial water flux of 14.4 LMH and 14.1 LMH and slow increase rate of mixed liquor's salinity in the bioreactor using 30 g/L NaCl as draw solution. OMBR system showed high removals of total organic carbon and NH4 + -N (>98%). High fouling cleaning efficiency was achieved using OSHF TFC FO membrane with different fouling control methods. These results showed that this membrane is suitable for OMBR applications due to its high performance and its simplicity for fouling mitigation.

Tu, R, Jin, W, Han, S-F, Zhou, X, Wang, T, Gao, S-H, Wang, Q, Chen, C, Xie, G-J & Wang, Q 2019, 'Rapid enrichment and ammonia oxidation performance of ammonia-oxidizing archaea from an urban polluted river of China', Environmental Pollution, vol. 255, no. Pt 2, pp. 113258-113258.
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© 2019 Elsevier Ltd In this study, the optimum growth conditions of AOA in a polluted river were investigated. AOB also play an important role in ammonia oxidation in the river water.

Turner, BD, Sloan, SW & Currell, GR 2019, 'Novel remediation of per- and polyfluoroalkyl substances (PFASs) from contaminated groundwater using Cannabis Sativa L. (hemp) protein powder', Chemosphere, vol. 229, pp. 22-31.
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Uddin, MN, Rahman, MA, Mofijur, M, Taweekun, J, Techato, K & Rasul, MG 2019, 'Renewable energy in Bangladesh: Status and prospects', Energy Procedia, vol. 160, pp. 655-661.
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© 2019 The Authors. Published by Elsevier Ltd. Global energy demand has risen sharply over the years with developing countries recording the greatest share in this trend. Biomass as an energy resource is mostly available locally and can easily be converted into secondary energy without huge capital investments. Nowadays, Bangladesh shares a percentage of renewable energy only 3% of total energy ratio, Bangladesh has already taken a master plan in the renewable energy sector. Whereas installed electricity generation installed capacity of Bangladesh rapidly increased to 13265 MW with captive generation capacity which is insufficient for fulfilling the demand of electricity of the nations. One-third of the power production of Bangladesh depends on expensive imported fossil fuel energy resources and 65% of power generation depends on a natural gas reserve of the country, though one day the reserve of current gas will be diminished. Moreover, inadequate electricity production leads the country in a un-industrialization. The present and future crucial energy crisis situation adapted by installing renewable power into electricity production. The current renewable energy agenda of Bangladeshi government force the specialization of renewable energy generation budget by decreasing global pollution with saving movement of biomass, solar, hydro, wind, and tidal power sector. This paper presents the currents national energy scenario of Bangladesh. According to this, the greater potentiality of renewable energy resources is also reviewed and presented in this paper.

Van, HT, Nguyen, LH, Nguyen, VD, Nguyen, XH, Nguyen, TH, Nguyen, TV, Vigneswaran, S, Rinklebe, J & Tran, HN 2019, 'Characteristics and mechanisms of cadmium adsorption onto biogenic aragonite shells-derived biosorbent: Batch and column studies', Journal of Environmental Management, vol. 241, pp. 535-548.
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© 2018 Elsevier Ltd Calcium carbonate (CaCO3)-enriched biomaterial derived from freshwater mussel shells (FMS) was used as a non-porous biosorbent to explore the characteristics and mechanisms of cadmium adsorption in aqueous solution. The adsorption mechanism was proposed by comparing the FMS properties before and after adsorption alongside various adsorption studies. The FMS biosorbent was characterized using nitrogen adsorption/desorption isotherm, X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy, Fourier-transform infrared spectroscopy, and point of zero charge. The results of batch experiments indicated that FMS possessed an excellent affinity to Cd(II) ions within solutions pH higher than 4.0. An increase in ionic strength resulted in a significant decrease in the amount of Cd(II) adsorbed onto FMS. Kinetic study demonstrated that the adsorption process quickly reached equilibrium at approximately 60 min. The FMS biosorbent exhibited the Langmuir maximum adsorption capacity as follows: 18.2 mg/g at 10 °C < 26.0 mg/g at 30 °C < 28.6 mg/g at 50 °C. The Cd(II) adsorption process was irreversible, spontaneous (−ΔG°), endothermic (+ΔH°), and more random (+ΔS°). Selective order (mmol/g) of metal cations followed as Pb2+ > Cd2+ > Cu2+ > Cr3+ > Zn2+. For column experiments, the highest Thomas adsorption capacity (7.86 mg/g) was achieved at a flow rate (9 mL/min), initial Cd(II) concentration (10 mg/L), and bed height (5 cm). The Cd(II) removal by FMS was regarded as non-activated chemisorption that occurred very rapidly (even at a low temperature) with a low magnitude of activation energy. Primary adsorption mechanism was surface precipitation. Cadmium precipitated in the primary (Cd,Ca)CO3 form with a calcite-type structure on the FMS surface. A crust of rhombohedral crystals on the substrate was observed by SEM. Freshwater mussel shells have the potential as a renewable adsorbent to remove cadmium from water.

Verma, A, Kohli, GS, Harwood, DT, Ralph, PJ & Murray, SA 2019, 'Transcriptomic investigation into polyketide toxin synthesis in Ostreopsis (Dinophyceae) species', Environmental Microbiology, vol. 21, no. 11, pp. 4196-4211.
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SummaryIn marine ecosystems, dinoflagellates can become highly abundant and even dominant at times, despite their comparatively slow growth. Their ecological success may be related to their production of complex toxic polyketide compounds. Ostreopsis species produce potent palytoxin‐like compounds (PLTX), which are associated with human skin and eye irritations, and illnesses through the consumption of contaminated seafood. To investigate the genetic basis of PLTX‐like compounds, we sequenced and annotated transcriptomes from two PLTX‐producing Ostreopsis species; O. cf. ovata, O. cf. siamensis, one non‐PLTX producing species, O. rhodesae and compared them to a close phylogenetic relative and non‐PLTX producer, Coolia malayensis. We found no clear differences in the presence or diversity of ketosynthase and ketoreductase transcripts between PLTX producing and non‐producing Ostreopsis and Coolia species, as both groups contained >90 and > 10 phylogenetically diverse ketosynthase and ketoreductase transcripts, respectively. We report for the first‐time type I single‐, multi‐domain polyketide synthases (PKSs) and hybrid non‐ribosomal peptide synthase/PKS transcripts from all species. The long multi‐modular PKSs were insufficient by themselves to synthesize the large complex polyether backbone of PLTX‐like compounds. This implies that numerous PKS domains, including both single and multi‐, work together on the biosynthesis of PLTX‐like and other related polyketide compounds.

Vo, HNP, Ngo, HH, Guo, W, Liu, Y, Chang, SW, Nguyen, DD, Nguyen, PD, Bui, XT & Ren, J 2019, 'Identification of the pollutants’ removal and mechanism by microalgae in saline wastewater', Bioresource Technology, vol. 275, pp. 44-52.
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© 2018 Elsevier Ltd This study investigated the growth dynamics of a freshwater and marine microalgae with supported biochemical performance in saline wastewater, the pollutants assimilation by a developed method, and the mechanism of salinity's effect to pollutants assimilation. Maximal biomass yield was 400–500 mg/L at 0.1–1% salinity while the TOC, NO3−-N, PO43−-P were eliminated 39.5–92.1%, 23–97.4% and 7–30.6%, respectively. The biomass yield and pollutants removal efficiencies reduced significantly when salinity rose from 0.1 to 5%. The freshwater Chlorella vulgaris performed its best with a focus on TOC removal at 0.1% salinity. The marine Chlorella sp. was prominent for removing NO3−-N at 0.1–1% salinity. Through the developed method, the freshwater C. vulgaris competed to the marine microalgae referring to pollutants assimilation up to 5% salinity. This study unveiled the mechanism of salinity's effect with evidence of salt layer formation and salt accumulation in microalgae.

Vo, HNP, Ngo, HH, Guo, W, Nguyen, TMH, Liu, Y, Liu, Y, Nguyen, DD & Chang, SW 2019, 'A critical review on designs and applications of microalgae-based photobioreactors for pollutants treatment', Science of The Total Environment, vol. 651, no. Pt 1, pp. 1549-1568.
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© 2018 Elsevier B.V. The development of the photobioreactors (PBs) is recently noticeable as cutting-edge technology while the correlation of PBs' engineered elements such as modellings, configurations, biomass yields, operating conditions and pollutants removal efficiency still remains complex and unclear. A systematic understanding of PBs is therefore essential. This critical review study is to: (1) describe the modelling approaches and differentiate the outcomes; (2) review and update the novel technical issues of PBs' types; (3) study microalgae growth and control determined by PBs types with comparison made; (4) progress and compare the efficiencies of contaminants removal given by PBs' types and (5) identify the future perspectives of PBs. It is found that Monod model's shortcoming in internal substrate utilization is well fixed by modified Droop model. The corroborated data also remarks an array of PBs' types consisting of flat plate, column, tubular, soft-frame and hybrid configuration in which soft-frame and hybrid are the latest versions with higher flexibility, performance and smaller foot-print. Flat plate PBs is observed with biomass yield being 5 to 20 times higher than other PBs types while soft-frame and membrane PBs can also remove pharmaceutical and personal care products (PPCPs) up to 100%. Looking at an opportunity for PBs in sustainable development, the flat plate PBs are applicable in PB-based architectures and infrastructures indicating an encouraging revenue-raising potential.

Vo, T-D-H, Bui, X-T, Lin, C, Nguyen, V-T, Hoang, T-K-D, Nguyen, H-H, Nguyen, P-D, Ngo, HH & Guo, W 2019, 'A mini-review on shallow-bed constructed wetlands: a promising innovative green roof', Current Opinion in Environmental Science & Health, vol. 12, pp. 38-47.
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© 2019 Elsevier B.V. Shallow-bed constructed wetland (SCW) has been used as a secondary wastewater treatment technology with low cost, less maintaining, and operational requirements and environmental friendliness. Green roof has been considered an effective solution in saving energy, enhancing green space, providing landscape aesthetics, limiting stormwater runoff causing flooding, and purifying air pollutants. Recently, a wetland roof (WR) has been interested as a good integration of these two technologies. To gain an insight understanding of this combination, this review aimed to provide the potential applications of SCW on the roof as a WR. Factors affecting performance, benefits, and challenges of SCW were also discussed. The literature data showed WR was a promising green technology that is needed to be investigated and scaled up in the future.

Volkova, L, Roxburgh, SH, Surawski, NC, Meyer, CPM & Weston, CJ 2019, 'Improving reporting of national greenhouse gas emissions from forest fires for emission reduction benefits: An example from Australia', Environmental Science & Policy, vol. 94, pp. 49-62.
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© 2018 Elsevier Ltd Forest fires are a significant contributor to global greenhouse gas (GHG) emissions. Accurate reporting of GHG emissions from forest fires requires development of detailed methodologies and country specific data for estimating emissions. In recent years, Australia has updated its national methodology for reporting GHG emissions from fires on temperate forested lands, using a Tier 2 approach of the 2006 Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories. This involved refinement of the equation for estimating GHG emissions from fires provided in the Guidance, and the revision of country specific data which was derived from a comprehensive literature review. The refinements were key to transparent reporting and evaluation of the climatic impacts of mitigation actions such as forest fire management. In this paper we describe the steps required to develop a Tier 2 method in reporting fire emissions using this Australian example, the lessons learnt, and the steps required to reduce uncertainties in estimates. This paper may assist other countries seeking to estimate and report GHG emissions from forest fires by moving from the default Tier 1 method to Tier 2 using country-specific information.

Volpin, F, Chekli, L, Phuntsho, S, Ghaffour, N, Vrouwenvelder, JS & Shon, HK 2019, 'Optimisation of a forward osmosis and membrane distillation hybrid system for the treatment of source-separated urine', Separation and Purification Technology, vol. 212, pp. 368-375.
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© 2018 Elsevier B.V. The high concentration of nitrogen, phosphorous and potassium in human urine makes it a suitable raw material for fertiliser production. However, urine is often diluted with a significant amount of flushing water which increases the costs for the downstream nutrients recovery process. Re-using the water and the nutrients in the urine is paramount for enhancing the sustainability of our waste management system. In this work, a combination of forward osmosis (FO) and membrane distillation (MD) was used to extract distilled water from human urine. FO was chosen as MD pre-treatment to increase the overall nitrogen rejection and to prevent wetting of the MD membrane. The goal of this investigation was to tune the FO and MD operating parameters to reduce the nitrogen transport to the MD permeate. Urine pH, draw solution (DS) salt concentration and operating pressure were varied as a means to enhance the FO performances. On the other hand, feed temperature, nitrogen concentration and membrane characteristics were investigated to optimise the MD process. With 2.5 M NaCl as DS commercial FO membranes achieved a water flux between 31.5 and 28.7 L m−2 h−1 and a minimum nitrogen flux of 1.4 g L−1. An additional 33% reduction in the nitrogen transport was observed by applying minimal hydraulic pressure on the DS. However, this was also found to significantly reduce the net transmembrane water flux. Acidification of the feed was also beneficial for both FO and MD nitrogen rejection. Finally, we demonstrated that, by tuning the MD membrane porosity and thickness, higher MD permeate quality could be achieved. To conclude, the hybrid FO-MD process is expected to be an effective solution for the production of clean water and concentrated fertiliser from human urine. This double barrier separation process could be suitable for both water reclamation in space application and resource recovery in urban application.

Volpin, F, Heo, H, Hasan Johir, MA, Cho, J, Phuntsho, S & Shon, HK 2019, 'Techno-economic feasibility of recovering phosphorus, nitrogen and water from dilute human urine via forward osmosis', Water Research, vol. 150, pp. 47-55.
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© 2018 Elsevier Ltd Due to high phosphorus (P) and nitrogen (N) content, human urine has often proven to suitable raw material for fertiliser production. However, most of the urine diverting toilets or male urinals dilute the urine 2 to 10 times. This decreases the efficiency in the precipitation of P and stripping of N. In this work, a commercial fertiliser blend was used as forward osmosis (FO) draw solution (DS) to concentrate real diluted urine. During the concentration, the urea in the urine is recovered as it diffuses to the fertiliser. Additionally, the combination of concentrate PO43-, reverse Mg2+ flux from the DS and the Mg2+ presents in the flushing water, was able to recover the PO43- as struvite. With 50% concentrated urine, 93% P recovery was achieved without the addition of an external Mg2+. Concurrently, 50% of the N was recovered in the diluted fertiliser DS. An economic analysis was performed to understand the feasibility of this process. It was found that the revenue from the produced fertilisers could potentially offset the operational and capital costs of the system. Additionally, if the reduction in the downstream nutrients load is accounted for, the total revenue of the process would be over 5.3 times of the associated costs.

Volpin, F, Yu, H, Cho, J, Lee, C, Phuntsho, S, Ghaffour, N, Vrouwenvelder, JS & Shon, HK 2019, 'Human urine as a forward osmosis draw solution for the application of microalgae dewatering', Journal of Hazardous Materials, vol. 378, pp. 120724-120724.
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© 2019 Elsevier B.V. Human urine is a unique solution that has the right composition to constitute both a severe environmental threat and a rich source of nitrogen and phosphorous. In fact, between 4–9% of urine mass consists of ions, such as K+, Cl−, Na+ or NH4+. Because of its high ionic strength, urine osmotic pressure can reach values of up to 2000 kPa. With this in mind, this work aimed to study the effectiveness of real urine as a novel draw solution for forward osmosis. Water flux, reverse nitrogen flux and membrane fouling were investigated using fresh or hydrolysed urine. Water flux as high as 16.7 ± 1.1 L m−2 h−1 was recorded using real hydrolysed urine. Additionally, no support layer membrane fouling was noticed in over 20 h of experimentation. Urine was also employed to dewater a Chlorella vulgaris culture. A fourfold increase in algal concentration was achieved while having an average flux of 14.1 L m−2 h−1. During the algae dewatering, a flux decrease of about 19% was noticed; this was mainly due to a thin layer of algal deposition on the active side of the membrane. Overall, human urine was found to be an effective draw solution for forward osmosis.

Wang, B, Ni, B-J, Yuan, Z & Guo, J 2019, 'Cometabolic biodegradation of cephalexin by enriched nitrifying sludge: Process characteristics, gene expression and product biotoxicity', Science of The Total Environment, vol. 672, pp. 275-282.
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© 2019 Elsevier B.V. The nitrifying systems have been reported to be able to biodegrade micropollutants, yet it is still unclear about the cometabolism of ammonia-oxidizing bacteria (AOB) towards micropollutants, in particular their enzyme and transcriptional responses under exposure of micropollutants. This study investigated cometabolic biodegradation of a selected antibiotic, cephalexin (CFX), by an enriched nitrifying culture through a series of batch experiments, together with the assessments of enzymatic activity, key gene expression, and biotoxicity of the degradation products. More than 99% CFX with an initial concentration of 50 μg/L could be removed with the presence of ammonium, while <44% of CFX removal was observed in the absence of ammonium, suggesting the cometabolic degradation of CFX by ammonia-oxidizing bacteria (AOB). After the addition of 50 μg/L CFX, the ammonia oxidizing rate (AOR) decreased from 36.6 to 11.0 mg N/(L·h·g VSS), followed by a slight recovery when CFX concentration decreased to below 8 μg/L. Ammonia monooxygenase (AMO) activity showed a similar trend with that of AOR. The quantitative reverse transcription PCR assay indicated that the expression level of amoA gene was significantly upregulated (up to 3-fold, p < 0.05) due to the addition of CFX, while decreased to the normal level once CFX was degraded, suggesting a mechanism of AOB to neutralize the toxicity of CFX by metabolizing ammonia more effectively. Meanwhile, the biotoxicity test showed the degradation products of CFX did not exhibit any antibacterial impacts in terms of cell viability, compared to the parent compounds. Our finding shed a light on AMO-mediated cometabolic biodegradation of antibiotics in nitrifying cultures.

Wang, B, Ni, B-J, Yuan, Z & Guo, J 2019, 'Insight into the nitrification kinetics and microbial response of an enriched nitrifying sludge in the biodegradation of sulfadiazine', Environmental Pollution, vol. 255, no. Pt 1, pp. 113160-113160.
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© 2019 Elsevier Ltd SDZ could be cometabolically degraded by enriched nitrifying culture, and the expression level of amoA gene was down-regulated during the process, but didn't decrease proportionally with AOR.

Wang, D, He, D, Liu, X, Xu, Q, Yang, Q, Li, X, Liu, Y, Wang, Q, Ni, B-J & Li, H 2019, 'The underlying mechanism of calcium peroxide pretreatment enhancing methane production from anaerobic digestion of waste activated sludge', Water Research, vol. 164, pp. 114934-114934.
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© 2019 Elsevier Ltd Recent investigations verified that calcium peroxide (CaO2) could be used to pretreat waste activated sludge to promote methane yield from anaerobic digestion. However, the underlying mechanism of how CaO2 pretreatment promotes methane production is unclear. This work therefore aims to provide insights into such systems. Experimental results showed that with an increase of CaO2 dosage from 0 to 0.14 g/g VSS (volatile suspended solids) the methane yield increased linearly from 146.3 to 215.9 mL/g VSS. Further increases of CaO2 resulted in decreases in methane yield. CaO2 pretreatment promoted the disintegration of sludge and the degradation of sludge recalcitrant organics (especially humus and lignocellulose), thereby providing more substrates for subsequent methane production. Ultraviolet absorption spectroscopy indicated that CaO2 enhanced the cleavage of unsaturated conjugated bonds and reduced the aromaticity of humus and lignocellulose. Fourier transform infrared spectroscopy showed that CaO2 changed the structures and functional groups of humus and lignocellulose, making them transform to be biodegradable. GC/MS analyses exhibited that the degradation products of humus and lignocellulose included several types of small molecular organics such as ester-like, acid-like, and alcohol-like substances. Further investigation demonstrated that substantial methane could be produced from these degradation products. It was also found that the presence of recalcitrant organics was detrimental to anaerobes relevant to anaerobic digestion, and the degradation of such recalcitrant organics mitigated their inhibitions to the anaerobes. Model-based analysis suggested that CaO2 pretreatment increased the maximum methane yield and methane production rate, which were consistent with the analysis above.

Wang, D, Wang, Y, Liu, X, Xu, Q, Yang, Q, Li, X, Zhang, Y, Liu, Y, Wang, Q, Ni, B-J & Li, H 2019, 'Heat pretreatment assists free ammonia to enhance hydrogen production from waste activated sludge', Bioresource Technology, vol. 283, pp. 316-325.
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© 2019 Elsevier Ltd Controlling free ammonia in an anaerobic fermenter at pertinent levels is reported recently to be an economically attractive and practically feasible approach to enhance hydrogen yield from waste activated sludge (WAS). This paper reports a new technology for WAS dark fermentation, i.e., using heat pretreatment (70 °C for 60 min) to assist free ammonia for further improving hydrogen yield. The experimental results showed that the accumulative hydrogen production from combined reactors was promoted from 12.3 to 19.2 mL/g VSS (volatile suspended solids), the maximum of which was 1.8, 2.7, and 7.1 times of that from sole free ammonia (131.9 mg NH3-N/L), sole heat, and blank reactors, respectively. Mechanism explorations showed that the combination strategy significantly enhanced WAS disintegration, providing more substrates for hydrogen production. Moreover, the combination suppressed activities of all microbes associated with anaerobic fermentation, but its inhibition to hydrogen consumers was much severer than that to other microbes.

Wang, D, Zhang, D, Xu, Q, Liu, Y, Wang, Q, Ni, B-J, Yang, Q, Li, X & Yang, F 2019, 'Calcium peroxide promotes hydrogen production from dark fermentation of waste activated sludge', Chemical Engineering Journal, vol. 355, pp. 22-32.
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© 2018 Elsevier B.V. Calcium peroxide (CaO2), one of versatile and harmless inorganic peroxy compounds, has been recently used as a highly effective oxidant to degrade pollutants in sludge and a method to achieve sludge resource utilization. However, its impact on hydrogen production has never been studied before. This investigation therefore aims to fill this knowledge gap. Results indicated that with CaO2 increased from 0.05 to 0.25 g/g VSS (volatile suspended solids), the maximum hydrogen yield increased from 0.77 to 10.55 mL/g VSS. The mechanism studies revealed that CaO2 accelerated the breakage and death of sludge cells. Excitation emission matrix (EEM) analyses further indicated that CaO2 increased the biodegradability of the released substances, which could provide more biodegradable organics for the following reactions. Although CaO2 caused inhibitions to some extents to all the tested microbes, its inhibition to hydrogen consumers was much severer than that to hydrolytic microbes and hydrogen producers. The enzyme analyses also demonstrated that the suppression of calcium peroxide to the activities of enzymes related to hydrogen consumption process was much severer than that to the activities of the activities of enzymes related to hydrogen production process. Further investigations exhibited that alkali, [rad]O2− and [rad]OH radicals, were the major intermediate products of CaO2 decomposition. All of them were verified to contribute the increased hydrogen production, and their contributions were in the order of alkali > [rad]O2− > [rad]OH. This is the first work demonstrating that CaO2 can enhance hydrogen production from WAS. The findings reported in our paper not only expand the application field of CaO2 but also deepen the understanding of the CaO2-involved sludge fermentation process.

Wang, Q, Gong, Y, Liu, S, Wang, D, Liu, R, Zhou, X, Nghiem, LD & Zhao, Y 2019, 'Free Ammonia Pretreatment To Improve Bio-hydrogen Production from Anaerobic Dark Fermentation of Microalgae', ACS Sustainable Chemistry & Engineering, vol. 7, no. 1, pp. 1642-1647.
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© 2018 American Chemical Society. Microalgae are third generation feedstocks for bio-hydrogen production to achieve a low carbon economy. Nevertheless, the bio-hydrogen production from microalgae is generally low. In this study, an innovative free ammonia (FA, i.e., NH 3 ) pretreatment technology was first demonstrated to improve bio-hydrogen production from the secondary effluent cultivated microalgae during the anaerobic dark fermentation experiments. Scanning electron microscopy revealed that FA pretreatment disrupted microalgae surface morphology. The soluble chemical oxygen demand (SCOD) release increased from 0.01 g SCOD/g VS microalgae (VS = volatile solids) to 0.05-0.07 g SCOD/g VS microalgae after FA pretreatment of 240-530 mg NH 3 -N/L for 1 day, indicating the enhanced microalgae solubilization. Dark fermentation bio-hydrogen potential experiments showed that bio-hydrogen production from microalgae was substantially improved following FA pretreatment of 240-530 mg NH 3 -N/L. The bio-hydrogen production potential and maximum bio-hydrogen production rate increased from 18.2 L H 2 /kg VS microalgae and 2.5 L H 2 /kg VS microalgae/d to 19.9-22.1 L H 2 /kg VS microalgae and 3.1-3.8 L H 2 /kg VS microalgae/d, respectively, after FA pretreatment of 240-530 mg NH 3 -N/L was implemented on the microalgae for 1 day. This FA technology follows a circular economic model because the required FA is from the FA rich dark fermentation liquid, which is a wastewater treatment waste.

Wang, Q, Sun, J, Liu, S, Gao, L, Zhou, X, Wang, D, Song, K & Nghiem, LD 2019, 'Free ammonia pretreatment improves anaerobic methane generation from algae', Water Research, vol. 162, pp. 269-275.
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© 2019 Elsevier Ltd Anaerobic methane generation from algae is hindered by the slow and poor algae biodegradability. A novel free ammonia (NH3 i.e. FA) pretreatment technology was proposed in this work to enhance anaerobic methane generation from algae cultivated using a real secondary effluent. The algae solubilisation was 0.05–0.06 g SCOD/g TCOD (SCOD: soluble chemical oxygen demand; TCOD: total chemical oxygen demand) following FA pretreatment of 240–530 mg NH3–N/L for 24 h, whereas the solubilisation was only 0.01 g SCOD/g TCOD for the untreated algae. This indicates that FA pretreatment at 240–530 mg NH3–N/L could substantially enhance algae solubilisation. Biochemical methane potential tests revealed that FA pretreatment on algae at 240–530 mg NH3–N/L is able to significantly enhance anaerobic methane generation. The hydrolysis rate (k) and biochemical methane potential (P0) of algae increased from 0.21 d−1 and 132 L CH4/kg TCOD to 0.33–0.50 d−1 and 140–154 L CH4/kg TCOD, respectively, after the algae was pretreated by FA at 240–530 mg NH3–N/L. Further analysis indicated that FA pretreatment improved k of both quickly and slowly biodegradable substrates, and also increased P0 of the slowly biodegradable substrate although it negatively affected P0 of the quickly biodegradable substrate. This FA technology is a closed-loop technology.

Wang, R, Hao, Q, Feng, J, Wang, G-C, Ding, H, Chen, D & Ni, B 2019, 'Enhanced separation of photogenerated charge carriers and catalytic properties of ZnO-MnO2 composites by microwave and photothermal effect', Journal of Alloys and Compounds, vol. 786, pp. 418-427.
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© 2019 Elsevier B.V. To improve the solar energy utilization and photodegradation efficiency of ZnO and α-MnO2, ZnO/MnO2 composite materials were prepared by a facile method. The materials are characterized by XRD, Raman spectra, X-ray photoelectron spectroscopy, scanning electronic microscopy, transmission electron microscopy, and UV–vis diffuse reflection spectroscopy. The photocatalytic activity and microwave-assisted photocatalytic activity of the composite are much higher than that of ZnO or α-MnO2. The main active species in the reaction progress were confirmed by electron paramagnetic resonance spectra and trapping experiments. According to the DFT calculation result and photothermal images, the enhanced catalytic activity is attributed to the photothermal and microwave-assisted effect. The addition of α-MnO2 improves the absorption of light and microwave by the composite, which can further heat up the catalysts. As a result, the separation of photogenerated charge carriers is accelerated. Finally, a mechanism for the enhanced catalytic performance of the composite materials was proposed.

Wang, Y, Fan, S, Liao, F, Zheng, X, Huang, Z, Wang, Y & Han, X 2019, 'In situ formation and superior lithium storage properties of tentacle-like ZnO@NC@CNTs composites', Nanoscale Advances, vol. 1, no. 3, pp. 1200-1206.
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A novel structure of double carbon coated tentacle-like ZnO composite has been synthesized, which delivers remarkable Li⁺ storage properties.

Wang, Y, Wang, D, Chen, F, Yang, Q, Ni, B-J, Wang, Q, Sun, J, Li, X & Liu, Y 2019, 'Nitrate addition improves hydrogen production from acidic fermentation of waste activated sludge', Chemosphere, vol. 235, pp. 814-824.
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© 2019 Elsevier Ltd In this work, a low-cost alternative method (i.e., adding nitrate into WAS) to significantly enhance hydrogen production was reported. Experimental results showed that with an increase of nitrate addition from 0 to 362 mg/L, the maximal hydrogen production from acidic (pH 5.5) fermentation of WAS obviously increased from 12.6 ± 0.5 to 19.3 ± 0.9 mL per gram volatile suspended solids (VSS). The mechanism investigations illustrated more substrates were provided for subsequent hydrogen production. Although the nitrate added inhibited all the biological processes, its inhibition to the hydrogen consumption processes was much severer than that to the hydrogen production processes. The enzyme analyses on the long-term semi-continuous fermenters showed that the nitrate addition slightly inhibited the relative activities of protease, butyrate kinase, acetate kinase, CoA-transferase, and [FeFe] hydrogenase but largely suppressed the relative activities of coenzyme F420, carbon monoxide dehydrogenase, and adenylyl sulfate reductase.

Wang, Z, Chen, X-M, Ni, B-J, Tang, Y-N & Zhao, H-P 2019, 'Model-based assessment of chromate reduction and nitrate effect in a methane-based membrane biofilm reactor', Water Research X, vol. 5, pp. 100037-100037.
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© 2019 Zhejiang University Chromate contamination can pose a high risk to both the environment and public health. Previous studies have shown that CH4-based membrane biofilm reactor (MBfR) is a promising method for chromate removal. In this study, we developed a multispecies biofilm model to study chromate reduction and its interaction with nitrate reduction in a CH4-based MBfR. The model-simulated results were consistent with the experimental data reported in the literature. The model showed that the presence of nitrate in the influent promoted the growth of heterotrophs, while suppressing methanotrophs and chromate reducers. Moreover, it indicated that a biofilm thickness of 150 μm and an influent dissolved oxygen concentration of 0.5 mg O2/L could improve the reactor performance by increasing the chromate removal efficiency under the simulated conditions.

Wei, W, Huang, Q-S, Sun, J, Dai, X & Ni, B-J 2019, 'Revealing the Mechanisms of Polyethylene Microplastics Affecting Anaerobic Digestion of Waste Activated Sludge', Environmental Science & Technology, vol. 53, no. 16, pp. 9604-9613.
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Copyright © 2019 American Chemical Society. Polyethylene (PE) microplastics retained in sewage sludge inevitably enter the anaerobic digestion system. To date, no information has been reported on the mechanisms of PE microplastics affecting anaerobic digestion of waste activated sludge (WAS). This study evaluated the mechanisms using batch and continuous tests. Short exposure to PE microplastics at lower levels (i.e., 10, 30, and 60 particles/g-TS) did not significantly affect the methane production, but higher levels of PE microplastics (i.e., 100 and 200 particles/g TS) significantly (P = 0.006 and 0.0003) decreased methane production by 12.4-27.5%, with a lower methane potential and hydrolysis coefficient. In continuous test over 130 days, feeding WAS with 200 particles PE microplastics/g TS decreased vs destruction by up to 27.3% (P = 2.18 × 10-18) and resulted in a 9.1% (P = 0.002) increase in the volume of digested sludge for disposal. Correspondingly, the microbial community was shifted in the direction against anaerobic digestion. A mechanisms study revealed that the negative effect of PE microplastics was likely attributed to the induction of reactive oxygen species (ROS) rather than the released acetyl tri-n-butyl citrate. The generation of ROS caused a 7.6-15.4% reduction of cell viability, thereby restraining sludge hydrolysis, acidification, and methanogenesis.

Wei, W, Huang, Q-S, Sun, J, Wang, J-Y, Wu, S-L & Ni, B-J 2019, 'Polyvinyl Chloride Microplastics Affect Methane Production from the Anaerobic Digestion of Waste Activated Sludge through Leaching Toxic Bisphenol-A', Environmental Science & Technology, vol. 53, no. 5, pp. 2509-2517.
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© 2019 American Chemical Society. The retention of polyvinyl chloride (PVC) microplastics in sewage sludge during wastewater treatment raises concerns. However, the effects of PVC microplastics on methane production from anaerobic digestion of waste activated sludge (WAS) have never been documented. In this work, the effects of PVC microplastics (1 mm, 10-60 particles/g TS) on anaerobic methane production from WAS were investigated. The presence of 10 particles/g TS of PVC microplastics significantly (P = 0.041) increased methane production by 5.9 ± 0.1%, but higher levels of PVC microplastics (i.e., 20, 40, and 60 particles/g TS) inhibited methane production to 90.6 ± 0.3%, 80.5 ± 0.1%, and 75.8 ± 0.2% of the control, respectively. Model-based analysis indicated that PVC microplastics at >20 particles/g TS decreased both methane potential (B0) and hydrolysis coefficient (k) of WAS. The mechanistic studies showed that bisphenol A (BPA) leaching from PVC microplastics was the primary reason for the decreased methane production, causing significant (P = 0.037, 0.01, 0.004) inhibitory effects on the hydrolysis-acidification process. The long-term effects of PVC microplastics revealed that the microbial community was shifted in the direction against hydrolysis-acidification and methanation. In conclusion, PVC microplastic caused negative effects on WAS anaerobic digestion through leaching the toxic BPA.

Wei, W, Zhang, Y-T, Huang, Q-S & Ni, B-J 2019, 'Polyethylene terephthalate microplastics affect hydrogen production from alkaline anaerobic fermentation of waste activated sludge through altering viability and activity of anaerobic microorganisms', Water Research, vol. 163, pp. 114881-114881.
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© 2019 Alkaline (especially pH 10) anaerobic fermentation of waste activated sludge (WAS) has been reported to be an effective approach for hydrogen production through inhibiting the homoacetogenesis and methanogenesis. However, the potential effect of the widespread microplastics in sludge on the performance of hydrogen production has never been reported. To fill this knowledge gap, the dominant polyethylene terephthalate (PET) microplastics in WAS were selected as the model microplastics to evaluate their influences on hydrogen production during alkaline anaerobic fermentation of WAS as well as the key mechanisms involved. Experimental results demonstrated that hydrogen production from WAS decreased in the presence of PET microplastics (i.e., 10, 30 and 60 particles/g-TS) compared to the control, with the hydrogen yield at 60 particles/g-TS being only 70.7 ± 0.9% of the control. Although the hydrogen consumption (i.e., homoacetogenesis and methanogenesis) was restrained under alkaline (pH 10) condition, PET microplastics inhibited hydrolysis, acidogenesis and acetogenesis in alkaline WAS anaerobic fermentation, leading to the inhibitory effect on hydrogen production. This was further confirmed by the microbial analysis, which clearly showed PET microplastics caused the shift of the microbial community toward the direction against hydrolysis-acidification. Mechanism studies revealed that PET microplastics carried on their negative influence mainly through leaching the toxic di-n-butyl phthalate (DBP). The reactive oxygen species (ROS) and live/dead staining tests indicated that the increased ROS was induced by PET microplastics, causing more cells dead, which further resulted in the decreased production of hydrogen.

Wicks, M, Millar, GJ & Altaee, A 2019, 'Process simulation of ion exchange desalination treatment of coal seam gas associated water', Journal of Water Process Engineering, vol. 27, pp. 89-98.
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© 2018 Elsevier Ltd The aim of this investigation was to develop an ion exchange process for the remediation of coal seam gas (CSG) associated water to make it suitable for beneficial reuse. The hypothesis was that computational modelling could accelerate the selection of appropriate ion exchange desalination strategies. Hence, we applied AqMB water process engineering software to predict which combination of weak acid cation (WAC), strong acid cation (SAC), weak base anion (WBA) and strong base anion (SBA) resins were most appropriate. Simulation results revealed that both SAC/WBA and SAC/SBA resin combinations were unable to meet water beneficial reuse standards for conductivity (< 950 μS/cm) due to the presence of bicarbonate species (4973 and 1918 μS/cm, respectively). Thus, a degasser unit was necessary to remove the large concentrations (ca. 1328 mg/L) of dissolved carbon dioxide formed due to decomposition of bicarbonate/carbonate species under acidic conditions in the cation resin stages. pH adjustment of effluent from the preferred SBA resin with acid not only did not meet solution conductivity guidelines but also raised the concentration of chloride or sulphate ions to levels, which may be detrimental for crop growth. Addition of a WAC resin allowed production of high quality water (either SAC/SBA/WAC or WAC/SAC/SBA combinations). To comply with sodium adsorption ratio requirements for irrigating soil it was suggested to apply micronized gypsum to the treated water. Economic evaluation suggested the treated water cost was A$1003 (WAC/SAC/SBA) to A$1276 (SAC/SBA/WAC) per ML treated which was comparable to estimated costs for a reverse osmosis desalination system.

Wu, Y, Song, K, Sun, X, Li, L, Wang, W, Wang, Q & Wang, D 2019, 'Effects of free nitrous acid and freezing co-pretreatment on sludge short-chain fatty acids production and dewaterability', Science of The Total Environment, vol. 669, pp. 600-607.
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© 2019 Elsevier B.V. Short-chain fatty acids (SCFAs) as recoverable carbon source from waste activated sludge anaerobic fermentation process have aroused wide concern. In this study, free nitrous acid (FNA) and freezing pretreatments were combined to enhance SCFAs yield and fermented sludge dewaterability in the anaerobic fermentation system. The effects of different FNA concentrations and different freezing conditions (with or without curing stages) were analysed and compared. The results indicated that combining 1.07 mg N/L FNA with 48 h continuous freezing at −5 °C, raised SCFAs production from 6.7 mg COD/g volatile suspended solids (VSS) for the blank (no pretreatment) up to 124.0 mg COD/g VSS. In addition, the minimal water content of the treated fermented sludge cake was 78.11%, which was less than that of the blank (81.22%). SCFAs production and dewaterability enhancement could be attributed to sludge disintegration induced by the co-pretreatment, which led to sludge solubilisation, organics release, methanogenesis inhibition and particle size variation. This study implied that FNA and freezing co-pretreatment has the potential to enhance SCFAs production and sludge dewaterability in wastewater treatment plants.

Wu, Y, Song, K, Sun, X, Ngo, H, Guo, W, Nghiem, LD & Wang, Q 2019, 'Mechanisms of free nitrous acid and freezing co-pretreatment enhancing short-chain fatty acids production from waste activated sludge anaerobic fermentation', Chemosphere, vol. 230, pp. 536-543.
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© 2019 Elsevier Ltd Free nitrous acid (FNA) or freezing has been recently utilized as an efficient pretreatment method to increase short-chain fatty acids (SCFAs) yield from waste activated sludge (WAS) anaerobic fermentation (AF). But until now, the performances and mechanisms of the co-pretreatment for SCFAs production are unknown. This research aimed to investigate the AF mechanisms through studying its influence on sludge solubilization and related bioprocesses. WAS was pretreated for 48 h with FNA (1.07 mg N/L), freezing (−5 °C) and combination of FNA and freezing (0.53–2.13 mg N/L FNA at −5 °C), respectively, then conducted batch AF. Experimental results indicated that the optimal total SCFAs yield of 391.19 ± 5.54 mg COD/g VSS was achieved after 1.07 mg N/L FNA + freezing pretreatment at 9 days of AF, which was 2.2, 1.6 and 1.3-fold of the blank, freezing and FNA pretreated samples, respectively. The mechanisms analysis showed that co-pretreatment showed synergetic effects on sludge disintegration and solubilization, which could release more soluble substrates for SCFAs production. The co-pretreatment resulted in slight inhibition to hydrolysis and negligible inhibition to acidogenesis but severe inhibition to methanogenesis, maybe due to less endurance of methanogens.

Wu, Y, Wang, D, Liu, X, Xu, Q, Chen, Y, Yang, Q, Li, H & Ni, B 2019, 'Effect of poly aluminum chloride on dark fermentative hydrogen accumulation from waste activated sludge', Water Research, vol. 153, pp. 217-228.
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© 2019 Elsevier Ltd Poly aluminum chloride (PAC), an inorganic coagulant being accumulated in waste activated sludge (WAS) at substantial levels, are generally thought to inhibit WAS anaerobic fermentation. However, its effect on dark fermentative hydrogen accumulation has not been documented. This work therefore aimed to explore its effect on hydrogen accumulation and to elucidate the mechanism of how PAC affects hydrogen accumulation. Experimental results showed that with an increase of PAC addition from 0 to 20 mg Al per gram of total suspended solids (TSS), the maximal hydrogen yield from alkaline fermentation (pH 9.5) increased from 20.9 mL to 27.4 mL per gram volatile suspended solids (VSS) under the standard condition. Further increase of PAC to 30 mg Al/g TSS didn't cause a significant increase of hydrogen yield (p > 0.05). The mechanism explorations revealed that although PAC reduced the total short-chain fatty acid (SCFA) production, this reduction was mainly enforced to propionic acid fermentation type, which did not contribute hydrogen production. PAC suppressed all the microbial processes relevant to anaerobic fermentation to some extents, but its inhibition to hydrogen consumption was much severer than that to hydrogen production. Illumina Miseq sequencing analysis revealed that PAC did not affect the populations of SCFA and hydrogen producers, but the two hydrogen consumers, Acetoanaerobium and Desulfobulbus, were almost washed out by PAC. Among the three types of Al species present in the anaerobic fermentation systems, Ala (monomeric species) significantly affected the maximal hydrogen production potential while Alb (medium polymer species) and Alc (species of sol or gel) posed impacts on hydrogen production rate and the lag time.

Wu, Y, Wu, Z, Chu, H, Li, J, Ngo, HH, Guo, W, Zhang, N & Zhang, H 2019, 'Comparison study on the performance of two different gas-permeable membranes used in a membrane-aerated biofilm reactor', Science of The Total Environment, vol. 658, pp. 1219-1227.
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Wu, Z, Ambrožová, N, Eftekhari, E, Aravindakshan, N, Wang, W, Wang, Q, Zhang, S, Kočí, K & Li, Q 2019, 'Photocatalytic H2 generation from aqueous ammonia solution using TiO2 nanowires-intercalated reduced graphene oxide composite membrane under low power UV light', Emergent Materials, vol. 2, no. 3, pp. 303-311.
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We report for the first time the nitrogen doping of reduced graphene oxide (rGO) and TiO2 nanowires (NWs) when TiO2 NWs intercalated rGO membranes were immersed in ammonia aqueous solution under 8 W 254 nm UV irradiation. Such nitrogen-doped rGO/TiO2 NWs photocatalytic membrane produced H2 at a rate of 208 μmol h−1 g−1 under 8 W 254 nm UV irradiation, which is more than 14 times higher than the yield of the TiO2-P25 and 30-fold higher than TiO2 NWs alone under the same condition. Our study demonstrates a new synthesis route for doping nitrogen in rGO and TiO2, as well as the preliminary feasibility of hydrogen extraction from ammonia-containing wastewater with such a low-cost recyclable photocatalyst. In addition, the study illustrates the complexity of photocatalysis of ammonia aqueous solution, which involves multiple reactions in concurrence.

Xiao, Z, Li, Z, Guo, H, Liu, Y, Wang, Y, Yin, H, Li, X, Song, J, Nghiem, LD & He, T 2019, 'Scaling mitigation in membrane distillation: From superhydrophobic to slippery', Desalination, vol. 466, pp. 36-43.
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© 2019 Elsevier B.V. Scaling is a major obstacle to commercial application of membrane distillation (MD) for desalination. Contemporary understanding of scaling formation onto hydrophobic membrane was built on thermodynamic assumption of a non-slip condition. This research provides an alternative theory and a novel insight from a hydrodynamic view of slip boundary. We purposely selected three polyvinylidene difluoride (PVDF) membranes with different surface characteristics - namely a tailor made superhydrophobic micro-pillared (CF4-MP-PVDF), a micro-pillared (MP-PVDF) and a commercial (C-PVDF) membranes, for direct contact membrane distillation (DCMD) using a supersaturated CaSO4 feed. MD flux analysis showed that CF4-MP-PVDF was highly scaling resistant whereas the other two membranes were not. Nucleation energy barrier, wetting state factor and slip length were used to explain for the observed difference in scaling behavior. Results showed that hydrodynamic properties, such as the wetting state and slip length, play a critical role in determining the anti-scaling behavior of a hydrophobic membrane rather than the contact angle nor the thermodynamic nucleation energy barrier. New findings from this study serve as a new guideline for the fabrication of antiscaling membranes by creating a slippery surface.

Xie, K, Fu, Q, Qiao, GG & Webley, PA 2019, 'Recent progress on fabrication methods of polymeric thin film gas separation membranes for CO2 capture', Journal of Membrane Science, vol. 572, pp. 38-60.
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© 2018 Elsevier B.V. Membrane technology has been recognized as an attractive and environment-friendly technology for carbon capture due to its low expense (capital and operating), ease of operation as well as low energy consumption. Traditionally, the membrane materials are cast into dense membranes with a thickness of 50–150 µm and their gas separation properties are evaluated by the trade-off between permeability and selectivity. However, permeance (gas flux), rather than permeability, is more emphasized recently because the increase of the real gas flux through a membrane without the loss of selectivity has been recognized to be more important in industrial scenarios. The permeance is inversely proportional to the membrane thickness, and thus the thin film membranes with sub-micro scale selective layers as part of a composite membrane has drawn particular interests. In thin film membranes, the membrane fabrication technique as well as the membrane configuration design are more important than the membrane materials. However, the recent progress on membrane fabrication techniques, especially the bottom-up approaches for composite membranes, have not been fully reviewed and compared. This review focuses on the recent progress in fabrication techniques and approaches of the thin film (sub-micron) polymeric membranes for CO2 capture, the state-of-art performance of those membranes will be summarized, and future direction of thin film composite membrane will be discussed.

Xu, J, Cao, Z, Wang, Y, Zhang, Y, Gao, X, Ahmed, MB, Zhang, J, Yang, Y, Zhou, JL & Lowry, GV 2019, 'Distributing sulfidized nanoscale zerovalent iron onto phosphorus-functionalized biochar for enhanced removal of antibiotic florfenicol', Chemical Engineering Journal, vol. 359, pp. 713-722.
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© 2018 Aggregation of nZVI and sulfur-modified nZVI (S-nZVI) can lower its reactivity with contaminants in water. To overcome this limitation, we synthesized biochar-supported nZVI and S-nZVI using a phosphate pretreatment of the biochar (pBC) to uniformly distribute the nZVI and S-nZVI onto the biochar support. The participation of phosphorus groups in the synthesis, and the good distribution of S-nZVI on the pBC were confirmed by FTIR, SEM, XRD, and XPS. Pretreatment of the biochar led to smaller well-dispersed S-nZVI compared to S-nZVI supported on untreated biochar. This increased the surface area of the S-nZVI and the reaction rate with the antibiotic florfenicol (FF). The removal rate of FF by pBC-S-nZVI was 4.3 times higher than that by unsupported S-nZVI. Even though FF strongly adsorbed to the pBC support, FF was fully degraded based on the mass balance results. Surface area normalized reaction rate constants (kSA) for FF removal by S-nZVI, BC-S-nZVI, and pBC-S-nZVI were similar, suggesting that the enhanced reactivity is due to the greater dispersion of S-nZVI on the treated biochar. These results provide a simple pretreatment method for dispersing nZVI or S-nZVI onto biochar supports.

Xu, Q, Liu, X, Wang, D, Liu, Y, Wang, Q, Ni, B-J, Li, X, Yang, Q & Li, H 2019, 'Enhanced short-chain fatty acids production from waste activated sludge by sophorolipid: Performance, mechanism, and implication', Bioresource Technology, vol. 284, pp. 456-465.
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© 2019 Elsevier Ltd It was found in this study that the presence of sophorolipid (SL) enhanced the production of short-chain fatty acid (SCFA) from anaerobic fermentation of waste activated sludge (WAS). Experimental results showed that with an increase of SL addition from 0 to 0.1 g/g TSS, the maximal SCFA yield increased from 50.5 ± 4.9 to 246.2 ± 7.5 mg COD/g VSS. The presence of SL reduced the surface tension between hydrophobic organics and fermentation liquid, which thereby accelerated the disintegration of WAS and improved the biodegradability of the released organics. SL promoted the carbon/nitrogen ratio of the fermentation system, enhancing the conversion of proteins in WAS. Moreover, SL suppressed severely the activities of methanogens, probably due to the drop of pH caused by SL addition. Amplicon sequencing analyses revealed that SL increased the abundance of hydrolytic microbes such as Bacteroides sp. and Macellibacteroides sp., and SCFA producers (e.g., Acinetobacter sp.).

Xu, Q, Liu, X, Yang, G, Wang, D, Wang, Q, Liu, Y, Li, X & Yang, Q 2019, 'Free nitrous acid-based nitrifying sludge treatment in a two-sludge system obtains high polyhydroxyalkanoates accumulation and satisfied biological nutrients removal', Bioresource Technology, vol. 284, pp. 16-24.
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© 2019 Elsevier Ltd A novel strategy to achieve substantial polyhydroxyalkanoates (PHA) accumulation in waste activated sludge (WAS) was developed, which was conducted in a two-sludge system consisted of an anaerobic/anoxic/oxic reactor (AAO-SBR) and a nitrifying reactor (N-SBR), where the nitrifying-sludge was treated by free nitrous acid (FNA). Initially, 0.98 ± 0.09 and 1.46 ± 0.10 mmol-c/g VSS of PHA were respectively determined in the control-SBR and AAO-SBR. When 1/16 of nitrifying sludge was daily treated with 1.49 mg N/L FNA for 24 h, ∼46.5% of nitrite was accumulated in the N-SBR, ∼2.43 ± 0.12 mmol-c/g VSS of PHA was accumulated in WAS in AAO-SBR without deteriorating nutrient removal. However, nutrient removal of control-SBR was completely collapsed after implementing the same FNA treatment. Further investigations revealed that the activity and abundance of nitrite oxidizing bacteria (NOB) was decreased significantly after FNA treatment. Finally, sludge with high PHA level to generate more methane was confirmed.

Xu, R & Fatahi, B 2019, 'Impact of In Situ Soil Shear-Wave Velocity Profile on the Seismic Design of Tall Buildings on End-Bearing Piles', Journal of Performance of Constructed Facilities, vol. 33, no. 5, pp. 04019053-04019053.
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© 2019 American Society of Civil Engineers. In this study, a numerical investigation into how the shear wave velocity profile affects the seismic performance of tall buildings and foundations was carried out using FLAC3D software. The in situ soil profile and equivalent average soil profile, which reflect the actual soil shear wave velocity profile and the corresponding uniform time-averaged soil shear wave profile based on the actual profile, respectively, were studied. Overconsolidated soil near the ground surface was considered in the in situ soil profile. A 20-story building supported by an end-bearing pile foundation was designed and simulated. A fully coupled nonlinear dynamic analysis was carried out in the time domain to evaluate the seismic response of the structure and foundation system under strong earthquakes. The variations of the interface parameters with depth around the piles were considered according to the variations in the stiffness of surrounding soil with depth in the numerical model when the in situ soil profile was used. The predicted shear forces, maximum lateral deformation, and maximum interstory drifts of the building are presented and discussed, as are the maximum shear forces, maximum bending moments, and the maximum lateral deformation of the piles. The results indicate that the use of an actual shear wave velocity profile instead of an equivalent average profile gives design engineers the opportunity to optimize their design and achieve cost-effective solutions.

Xu, R & Fatahi, B 2019, 'Novel application of geosynthetics to reduce residual drifts of mid-rise buildings after earthquakes', Soil Dynamics and Earthquake Engineering, vol. 116, pp. 331-344.
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© 2018 Elsevier Ltd Geosynthetics have been used in variety of geotechnical engineering projects, such as ground improvement, erosion control, slope stabilisation and foundation strength improvement and they have been proved to be cost and time effective in many cases. In this study, a geosynthetic reinforced composite soil (GRCS) foundation system is proposed for seismic protection of mid-rise buildings supported by a shallow foundation potentially suffering from residual structural drift or permanent foundation settlement. To evaluate the proposed GRCS, a conventional reinforced concrete moment resisting building sitting on this composite ground under the earthquake excitations of 1978 Tabas, 1994 Northridge and 1995 Kobe was numerically simulated using FLAC3D software. The effect of soil-structure interaction (SSI) was captured using direct method of analysis adopting a three-dimensional numerical model. By adopting direct calculation method, the soil deposit, the geosynthetic reinforcement, the foundation and the structure were simulated simultaneously. Inelastic behaviour of the structure was considered, while hysteretic damping algorithm was adopted representing the variation of the shear modulus and corresponding damping ratio of the soil with cyclic shear strain capturing the energy dissipation characteristics of the soil. Both material and geometry nonlinearities were taken into account at the interface between the foundation and ground surface. The results are then presented in terms of mobilised tensile force in geosynthetic layers, the response spectra at bedrock and ground surface level, the shear force developed in the superstructure, the maximum foundation rocking angle, the maximum lateral deflection, the maximum inter-storey drift, and most importantly the residual inter-storey drift and permanent foundation settlement. The results showed that the proposed GRCS could offer design engineers a rational and cost-effective alternative solution to con...

Xu, X, Zhou, Y, Han, R, Song, K, Zhou, X, Wang, G & Wang, Q 2019, 'Eutrophication triggers the shift of nutrient absorption pathway of submerged macrophytes: Implications for the phytoremediation of eutrophic waters', Journal of Environmental Management, vol. 239, pp. 376-384.
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© 2019 Elsevier Ltd Ecologically restoring eutrophic water bodies by using submerged macrophytes is an economical, effective and sustainable technology worldwide. However, current understanding on the nutrient absorption pathway of submerged macrophytes in freshwater ecosystems, especially under different trophic states, is still limited. In this study, two strategically designed systems were established to form isolated units for preventing nutrient exchange amongst Potamogeton crispus, water column and sediments. Results showed that, in oligotrophic state, P. crispus mainly relied on their roots to absorb nutrients from sediments for maintaining stable growth, with the maximum average height, fresh weight and relative growth rate of 12.85 cm, 4.86 g ind −1 and 0.062, respectively. However, the eutrophic conditions (TN of 4 mg L −1 and TP of 0.3 mg L −1 ) triggered the shift of the nutrient absorption pathway from the roots to the shoots to some extent, that is, the shoots of P. crispus gradually became a remarkable pathway to directly absorb nutrients from the water column. Approximately 49.85% and 18.35% of total nitrogen (TN) and total phosphorus (TP) from overlying water were allocated to the shoots of P. crispus, but had no effects on the growth, photosynthesis and ecological stoichiometric differences (p > 0.05). Sediments acting as a nitrogen (N) source supported nearly 11.56% of TN for shoot uptake and simultaneously received around 13.33% of TP subsidy from the overlying water. The no longer sole dependence of submerged macrophytes on their root system to absorb N and phosphorus nutrients indicated that the ability of shoots to absorb nutrients increased with the gradual increase in nutrients in water column. These findings imply that the large specific surface area of shoots is beneficial for restoring eutrophic waters.

Xue, S, Zhang, X, Ngo, HH, Guo, W, Wen, H, Li, C, Zhang, Y & Ma, C 2019, 'Food waste based biochars for ammonia nitrogen removal from aqueous solutions', Bioresource Technology, vol. 292, pp. 121927-121927.
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© 2019 Elsevier Ltd Biochar derived from waste has been increasingly considered as a potential green adsorbent due to its significant ability and affordable production costs. This study prepared and evaluated 7 types of food waste-based biochars (FWBBs) (including meat and bone, starchy staples, leafy stemmed vegetables, nut husks, fruit pericarp, bean dreg and tea leaves). The impacts of raw materials, pyrolysis temperatures (300, 400, 500, 600 and 700 °C), and residence time (2 h and 4 h) on the removal of ammonia nitrogen at different ammonia nitrogen concentrations (5, 10, 20, 50, 100, 150 mg/L) were investigated. The batch equilibrium and kinetic experiments confirmed that a FWBB dosage of 3 g/L at 25 °C could remove up to 92.67% ammonia nitrogen. The Langmuir isotherm model had the best fit to equilibrium experimental data with a maximum adsorption capacity of 7.174 mg/g at 25 °C. The pseudo-second order kinetic model well describes the ammonia nitrogen adsorption.

Yang, S, Gao, B, Zhao, P, Wang, C, Shen, X, Yue, Q & Shon, HK 2019, 'The application of forward osmosis for simulated surface water treatment by using trisodium citrate as draw solute', Environmental Science and Pollution Research, vol. 26, no. 9, pp. 8585-8593.
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© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. In this study, trisodium citrate was used as draw solute in forward osmosis (FO) due to its biodegradability and easy reuse after FO dilution. The effect of operating conditions on FO performance was investigated. The study focused on the long-term flux performance and membrane fouling when surface water was used as feed solution. A water flux of 9.8 LMH was observed using 0.5 M trisodium citrate as draw solution in PRO mode. In the long-term FO process, trisodium citrate showed a slight decrease in total flux loss (13.06%) after 20 h of operation. The membrane fouling was significantly reduced after a two-step physical cleaning. A considerable flux recovery (> 95%) of the fouled membrane was finally obtained. Therefore, this study proves the superiority of trisodium citrate as draw solution and paves a new way in applying FO directly for surface water reclamation.

Yao, M, Ren, J, Akther, N, Woo, YC, Tijing, LD, Kim, S-H & Shon, HK 2019, 'Improving membrane distillation performance: Morphology optimization of hollow fiber membranes with selected non-solvent in dope solution', Chemosphere, vol. 230, pp. 117-126.
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© 2019 Elsevier Ltd This study aimed at improving membrane distillation (MD) performance by mixing various non-solvents (NSs) in polymer dope solutions. The effect of each NS on the inner structure and surface morphology of hollow fiber (HF) membrane was investigated. Membrane morphology is manipulated by controlling liquid-liquid (L-L) and solid-liquid (S-L) demixing time, which is a function of the viscosity and water affinity of dope solutions. Consequently, the addition of NSs altered membrane morphology by affecting the diffusion rate during NS induced phase separation (NIPS) process. The performance results showed that the dope solution composed of 11/71.2/17.8 wt% polyvinylidene fluoride (PVDF)/triethyl phosphate (TEP)/toluene produced the most promising HF membrane for MD. The optimal membrane demonstrated a unique bicontinuous structure with increased porosity and mean pore size. The addition of toluene as NS in dope solutions enhanced crystallization process, which increased the Young's modulus of membrane but slightly decreased its maximum tensile strength at break. The optimal PVDF HF membrane demonstrated a steady flux of 18.9 LMH at 60 °C/20 °C of feed/permeate temperatures and a salt rejection of 99.99% when tested for 72 h. The results suggest that incorporation of toluene as a NS into PVDF dope solutions can increase permeation performance in MD by enhancing the morphology of HF membranes.

Yao, M, Woo, YC, Ren, J, Tijing, LD, Choi, J-S, Kim, S-H & Shon, HK 2019, 'Volatile fatty acids and biogas recovery using thermophilic anaerobic membrane distillation bioreactor for wastewater reclamation', Journal of Environmental Management, vol. 231, pp. 833-842.
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© 2018 Elsevier Ltd The effects of bioreactor temperatures and salinities of an anaerobic membrane distillation bioreactor (anMDBR) on the permeation performance and their potential recovery of bioresources were fully examined in this study. To the best of our knowledge, this is the first study of a lab-scale anMDBR process utilizing sub-merged hollow fiber membranes. The hybrid system utilizing both membrane distillation (MD) and anaerobic bioreactors achieved 99.99% inorganic salt rejection regardless the operation temperatures and high initial flux from (2–4 L m−2 h−1) at 45–65 °C. However, after 7-day operation, the flux dropped by 16–50% proportional to the bioreactor temperatures. It was found that the effects of bioreactor temperatures had strong impacts on both the permeation performance and fouling behavior while salinity had insignificant effect. A compact non-porous fouling layer was observed on the membrane surface from the bioreactor operated at 65 °C while only a few depositions was found on the membrane from 45 °C bioreactor. In the present study, the optimal anMDBR temperature was found to be 45 °C, showing a balanced biogas production and membrane permeation performance including less fouling formation. At this bioreactor temperature (45 °C), the biogas yield was 0.14 L/g CODremoval, while maintaining a methane recovery of 42% in the biogas, similar recovery to those at bioreactor temperatures of 55 and 65 °C. The potential recovery of volatile fatty acids made anMDBR a more economically efficient system, in addition to its lower operation cost and smaller footprint compared with most other technologies for on-site wastewater treatment.

Ye, Y, Jiao, J, Kang, D, Jiang, W, Kang, J, Ngo, HH, Guo, W & Liu, Y 2019, 'The adsorption of phosphate using a magnesia–pullulan composite: kinetics, equilibrium, and column tests', Environmental Science and Pollution Research, vol. 26, no. 13, pp. 13299-13310.
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A magnesia-pullulan (MgOP) composite has been developed to remove phosphate from a synthetic solution. In the present study, the removal of phosphate by MgOP was evaluated in both a batch and dynamic system. The batch experiments investigated the initial pH effect on the phosphate removal efficiency from pH 3 to 12 and the effect of co-existing anions. In addition, the adsorption isotherms, thermodynamics, and kinetics were also investigated. The results from the batch experiments indicate that MgOP has encouraging performance for the adsorption of phosphate, while the initial pH value (3-12) had a negligible influence on the phosphate removal efficiency. Analysis of the adsorption thermodynamics demonstrated that the phosphate removal process was endothermic and spontaneous. Investigations into the dynamics of the phosphate removal process were carried out using a fixed bed of MgOP, and the resulting breakthrough curves were used to describe the column phosphate adsorption process at various bed masses, volumetric flow rates, influent phosphate concentrations, reaction temperatures, and inlet pH values. The results suggest that the adsorption of phosphate on MgOP was improved using an increased bed mass, while the reaction temperature did not significantly affect the performance of the MgOP bed during the phosphate removal process. Furthermore, higher influent phosphate concentrations were beneficial towards increasing the column adsorption capacity for phosphate. Several mathematic models, including the Adams-Bohart, Wolboska, Yoon-Nelson, and Thomas models, were employed to fit the fixed-bed data. In addition, the effluent concentration of magnesium ions was measured and the regeneration of MgOP investigated.

Ye, Y, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Liu, Y, Nghiem, LD, Zhang, X & Wang, J 2019, 'Effect of organic loading rate on the recovery of nutrients and energy in a dual-chamber microbial fuel cell', Bioresource Technology, vol. 281, pp. 367-373.
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This study aimed to assess the impacts of organic loading rate (OLR) (435-870 mgCOD/L·d) on nutrients recovery via a double-chamber microbial fuel cell (MFC) for treating domestic wastewater. Electricity generation was also explored at different OLRs, including power density and coulombic efficiency. Experimental results suggested the MFC could successfully treat municipal wastewater with over 90% of organics being removed at a wider range of OLR from 435 to 725 mgCOD/L·d. Besides, the maximum power density achieved in the MFC was 253.84 mW/m2 at the OLR of 435 mgCOD/L·d. Higher OLR may disrupt the recovery of PO43--P and NH4+-N via the MFC. The same pattern was observed for the coulombic efficiency of the MFC and its highest value was 25.01% at the OLR of 435 mgCOD/L·d. It can be concluded that nutrients and electrical power can be simultaneously recovered from municipal wastewater via the dual-chamber MFC.

Ye, Y, Ngo, HH, Guo, W, Chang, SW, Nguyen, DD, Liu, Y, Ni, B-J & Zhang, X 2019, 'Microbial fuel cell for nutrient recovery and electricity generation from municipal wastewater under different ammonium concentrations', Bioresource Technology, vol. 292, pp. 121992-121992.
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© 2019 Elsevier Ltd In the present study, a dual-compartment microbial fuel cell (MFC) was constructed and continuously operated under different influent concentrations of ammonium-nitrogen (5–40 mg/L). The impacts of ammonium on organics removal, energy output and nutrient recovery were investigated. Experimental results demonstrated that this MFC reactor achieved a CDO removal efficiency of greater than 85%. Moreover, excess ammonium concentration in the feed solution compromises the generation of electricity. Simultaneously, the recovery rate of phosphate achieved in the MFC was insignificantly influenced at the wider influent ammonium concentration. In contrast, a high concentration of ammonium may not be beneficial for its recovery.

Ye, Y, Ngo, HH, Guo, W, Liu, Y, Chang, SW, Nguyen, DD, Ren, J, Liu, Y & Zhang, X 2019, 'Feasibility study on a double chamber microbial fuel cell for nutrient recovery from municipal wastewater', Chemical Engineering Journal, vol. 358, pp. 236-242.
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Yeganeh, N & Fatahi, B 2019, 'Effects of choice of soil constitutive model on seismic performance of moment-resisting frames experiencing foundation rocking subjected to near-field earthquakes', Soil Dynamics and Earthquake Engineering, vol. 121, pp. 442-459.
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© 2019 Elsevier Ltd The current study investigated the extent to which the choice of the soil constitutive models can impact the predicted seismic performance of a 20-story reinforced concrete moment-resisting building with a mat foundation considering the Seismic Soil-Structure Interaction (SSSI). Since the soil, in general, is the weakest material, involved in the commonplace geotechnical engineering projects, a soil constitutive model would be able to rule the dynamic response of the system. In this research, the hardening plasticity-based soil constitutive model, named “hyperbolic hardening with hysteretic damping” in conjunction with the two simple, conventional soil models, namely, the isotropic elastic with hysteretic damping model, and elastic-perfectly plastic Mohr-Coulomb with hysteretic damping model, were invoked in the three-dimensional coupled soil-structure numerical simulations using FLAC3D software. The direct method of analysis was used for analyzing the soil-foundation-structure system in one single step without a need to separately analyze each part of the domain. The cherry-picked earthquake excitations, viz, the 1999 Chi-Chi (Taiwan), and 2011 Kohriyama (Japan), were scaled by means of the widely-used response spectrum matching method as per the design response spectrum of a strong rock. The plastic moment concept was employed so as to assign the elastic-perfectly plastic model to the superstructure and its foundation. Additionally, the strain-compatible shear modulus and damping dependency on the cyclic shear strain were considered via the programmed hysteretic damping algorithm. The numerical predictions included the response spectra at the seismic bedrock and ground surface, base shear forces, shear force distributions along the building height, maximum and permanent foundation displacements, and foundation rocking, plus the flooring lateral deflections and inter-story drifts. The life safety limits for the transient and residual total in...

Yip, HL, Fattah, IMR, Yuen, ACY, Yang, W, Medwell, PR, Kook, S, Yeoh, GH & Chan, QN 2019, 'Flame–Wall Interaction Effects on Diesel Post-injection Combustion and Soot Formation Processes', Energy & Fuels, vol. 33, no. 8, pp. 7759-7769.
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Copyright © 2019 American Chemical Society. The aim of this study is to investigate the impact of walls on soot processes of a post-injection strategy at different dwell times. The experiments were performed in an optically accessible constant-volume combustion chamber simulating compression ignition engine conditions with moderate exhaust gas recirculation. The experiments with various injection strategies were performed under ambient conditions with gas density, pressure, and temperature of 20.8 kg/m3, 6 MPa, and 1000 K, respectively, and 15 vol % O2 concentration. The main and post injections had a quantity ratio of 8:2 (main/post) totaling 10 mg, and a flat wall was placed 35 mm axially from the injector. The dwell time between the main and post injections was also varied to induce different levels of interaction between the injections. High-speed flame natural luminosity imaging and two-color pyrometry techniques were applied to observe flame characteristics and to obtain soot temperature and KL factor information, respectively. By comparing the wall jet and free jet cases with no direct jet interaction, it was found that the wall affected the post jet flame structure similarly to a single jet or the main jet. However, the post jet with a greater extent of interaction with the main jet induced by shorter dwell time can achieve better mixing for the wall jet case. Increased interaction between the main and post jets also appeared to induce a soot oxidation phase, which was otherwise not observed when the injections were more temporally separated.

Yu, C, Wang, H, Wu, Z-X, Sun, W-J & Fatahi, B 2019, 'Analytical Solution for Pollutant Diffusion in Soils with Time-Dependent Dispersion Coefficient', International Journal of Geomechanics, vol. 19, no. 10, pp. 04019109-04019109.
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Yu, Z, Hu, Y, Dzakpasu, M, Wang, XC & Ngo, HH 2019, 'Dynamic membrane bioreactor performance enhancement by powdered activated carbon addition: Evaluation of sludge morphological, aggregative and microbial properties', Journal of Environmental Sciences, vol. 75, pp. 73-83.
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© 2018 The effects of powdered activated carbon (PAC) addition on sludge morphological, aggregative and microbial properties in a dynamic membrane bioreactor (DMBR) were investigated to explore the enhancement mechanism of pollutants removal and filtration performance. Sludge properties were analyzed through various analytical measurements. The results showed that the improved sludge aggregation ability and the evolution of microbial communities affected sludge morphology in PAC-DMBR, as evidenced by the formation of large, regularly shaped and strengthened sludge flocs. The modifications of sludge characteristics promoted the formation process and filtration flux of the dynamic membrane (DM) layer. Additionally, PAC addition did not exert very significant influence on the propagation of eukaryotes (protists and metazoans) and microbial metabolic activity. High-throughput pyrosequencing results indicated that adding PAC improved the bacterial diversity in activated sludge, as PAC addition brought about additional microenvironment in the form of biological PAC (BPAC), which promoted the enrichment of Acinetobacter (13.9%), Comamonas (2.9%), Flavobacterium (0.31%) and Pseudomonas (0.62%), all contributing to sludge flocs formation and several (such as Acinetobacter) capable of biodegrading relatively complex organics. Therefore, PAC addition could favorably modify sludge properties from various aspects and thus enhance the DMBR performance.

Yuan, Z, Dong, L, Gao, Q, Huang, Z, Wang, L, Wang, G & Yu, X 2019, 'SnSb alloy nanoparticles embedded in N-doped porous carbon nanofibers as a high-capacity anode material for lithium-ion batteries', Journal of Alloys and Compounds, vol. 777, pp. 775-783.
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© 2018 SnSb alloy is a promising anode material for lithium-ion batteries due to its high specific capacity. However, the large volume change in the process of charge/discharge causes significant pulverizing of SnSb alloy particles, which leads to a rapid capacity fading. This paper reports the synthesis of homogenous SnSb nanoparticles that are embedded in N-doped porous carbon nanofibers through electrospinning technique with LiN3 serving as poregen agent. This distinctive structure prevents the direct contact of SnSb nanoparticles with the electrolyte and provides enough space for the volume change of SnSb alloy during the Li+ insertion/extraction process, enabling this material to deliver a high reversible capacity of 892 mA h g−1 after 100th cycle at 100 mA g−1, and a stable capacity of 487 mA h g−1 after 1000 cycles at 2000 mA g−1. These results highlight the importance of the synergistic effect of SnSb alloy nanoparticles and N-doped porous carbon nanofibers for the high performance of lithium-ion batteries.

Zhang, L, Ma, C, Liu, L, Pan, J & Wang, Q 2019, 'Fabrication of novel particle electrode γ-Al2O3@ZIF-8 and its application for degradation of Rhodamine B', Water Science and Technology, vol. 80, no. 1, pp. 109-116.
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Abstract Due to the high Brunauer–Emmett–Teller (BET) surface area of zeolitic imidazolate framework (ZIF)-8, a secondary crystallization method was used to prepare a particle electrode of γ-Al2O3@ZIF-8. According to the results from a field emission scanning electron microscope (SEM) and X-ray diffractometer (XRD), the particle electrode of γ-Al2O3 was successfully loaded with ZIF-8, and the BET surface area (1,433 m2/g) of ZIF-8 was over ten times that of γ-Al2O3. The key operation parameters of cell voltage, pH, initial RhB concentration and electrolyte concentration were all optimized. The observed rate constant (kobs) of the pseudo-first-order kinetic model for the electrocatalytic oxidation (ECO) system with the particle electrode of γ-Al2O3@ZIF-8 (15.2 × 10−2 min−1) was over five times higher than that of the system with the traditional particle electrode of γ-Al2O3 (2.6 × 10−2 min−1). The loading of ZIF-8 on the surface of γ-Al2O3 played an important role in improving electrocatalytic activity for the degradation of Rhodamine B (RhB), and the RhB removal efficiency of the three-dimensional (3D) electrocatalytic system with the particle electrode of γ-Al2O3@ZIF-8 was 93.5% in 15 min, compared with 27.5% in 15 min for the particle electrode of γ-Al2O3. The RhB removal efficiency was kept over 85% after five cycles of reuse for the 3D electrocatalytic system with the particle electrode of γ-Al2O3@ZIF-8.

Zhang, L, Pan, J, Liu, L, Song, K & Wang, Q 2019, 'Combined physical and chemical activation of sludge-based adsorbent enhances Cr(Ⅵ) removal from wastewater', Journal of Cleaner Production, vol. 238, pp. 117904-117904.
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© 2019 Elsevier Ltd To enhance the adsorption properties of sludge-based adsorbents (SBAs), the physical activation and the combined physical and chemical activation were examined comparatively. The surface composition and structure of modified SBAs were characterized using BET surface area, XRD and FTIR, the adsorption behavior of modified SBAs was investigated for Cr(Ⅵ) removal from wastewater. For CSU-NaOH, the optimum adsorption time and pH were 0.5 h and 2.5, respectively. The maximum adsorption capacity by CSU-NaOH was 15.3 mg g−1 for Cr(VI) removal, which was over 2 times of those by carbonized sludge and carbonized sludge with urea addition at 25 °C. The adsorption kinetics could be fitted with the pseudo second-order model for three adsorbents, the adsorption isotherm could be fitted with Langmuir model. The thermodynamic analysis indicated that the adsorption process of three adsorbents for Cr(Ⅵ) removal was spontaneous and endothermic. The reusability tests showed that the removal rate of Cr(VI) was kept over 95% by desorbed CSU-NaOH sample until the fifth cycle. The enhancement of adsorption properties can be attributed to both the increase of BET surface area and the improvement of surface functional groups of SBAs. The advantages of higher adsorption capacity and adsorption rate of CSU-NaOH suggest that CSU-NaOH is an effective adsorbent for Cr(Ⅵ) removal.

Zhang, X, Fatahi, B, Khabbaz, H & Poon, B 2019, 'Assessment of the Internal Shaft Friction of Tubular Piles in Jointed Weak Rock Using the Discrete-Element Method', Journal of Performance of Constructed Facilities, vol. 33, no. 6, pp. 04019067-04019067.
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© 2019 American Society of Civil Engineers. This study focuses on the internal shaft friction of open-ended tubular piles induced by jointed weak rock plugs. To investigate the bearing mechanism of the plug, push-up load tests were carried out on the jointed mudstone inside a tubular pile. The discrete-element method (DEM) was used in order to consider heterogeneity and to reproduce the discrete nature of the rock mass. A flat-joint model was used to reproduce the mechanical behavior of mudstone, and a smooth-joint contact model was used to replicate natural joints. The push-up load tests were carried out using the calibrated properties of a weak mudstone. The effects of joint density and joint dip were examined in detail and, as expected, the push-up force of the rock plug was influenced by the joint properties because joint density and joint dip had to some extent affected the plug resistance. The existing joints reduced the push-up force when the joints were steep, whereas the horizontal joints had a minimal effect on altering the inner shaft friction compared with the intact rock mass. The reduced friction along the pile was amplified with joint density, while the exponential increase of vertical stress from the top of the rock plug to the bottom revealed that the inner shaft resistance was mainly mobilized at the bottom portion of the rock plug. The findings of this study increase our understanding of joint dip and joint density affecting the internal shaft resistance of open-ended tubular piles; this knowledge can be used further to develop a design methodology for open-ended tubular piles in weak rock while assessing plugging effects.

Zhao, L-S, Zhou, W-H, Geng, X, Yuen, K-V & Fatahi, B 2019, 'A closed-form solution for column-supported embankments with geosynthetic reinforcement', Geotextiles and Geomembranes, vol. 47, no. 3, pp. 389-401.
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© 2019 Elsevier Ltd Soil arching effect results from the non-uniform stiffness in a geosynthetic-reinforced and column-supported embankment system. However, most theoretical models ignore the impact of modulus difference on the calculation of load transfer. In this study, a generalized mathematical model is presented to investigate the soil arching effect, with consideration given to the modulus ratio between columns and the surrounding soil. For simplification, a cylindrical unit cell is drawn to study the deformation compatibility among embankment fills, geosynthetics, columns, and subsoils. A deformed shape function is introduced to describe the relationship between the column and the adjacent soil. The measured data gained from a full-scale test are applied to demonstrate the application of this model. In the parametric study, certain influencing factors, such as column spacing, column length, embankment height, modulus ratio, and tensile strength of geosynthetic reinforcement, are analyzed to investigate the performance of the embankment system. This demonstrates that the inclusion of a geosynthetic reinforcement or enlargement of the modulus ratio can increase the load transfer efficiency. When enhancing the embankment height or applying an additional loading, the height of the load transfer platform tends to be reduced. However, a relatively long column has little impact on the load transfer platform.

Zhao, N, Ngo, HH, Li, Y, Wang, X, Yang, L, Jin, P & Sun, G 2019, 'A comprehensive simulation approach for pollutant bio-transformation in the gravity sewer', Frontiers of Environmental Science & Engineering, vol. 13, no. 4.
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© 2019, Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature. Presently, several activated sludge models (ASMs) have been developed to describe a few biochemical processes. However, the commonly used ASM neither clearly describe the migratory transformation characteristics of fermentation nor depict the relationship between the carbon source and biochemical reactions. In addition, these models also do not describe both ammonification and the integrated metabolic processes in sewage transportation. In view of these limitations, we developed a new and comprehensive model that introduces anaerobic fermentation into the ASM and simulates the process of sulfate reduction, ammonification, hydrolysis, acidogenesis and methanogenesis in a gravity sewer. The model correctly predicts the transformation of organics including proteins, lipids, polysaccharides, etc. The simulation results show that the degradation of organics easily generates acetic acid in the sewer system and the high yield of acetic acid is closely linked to methanogenic metabolism. Moreover, propionic acid is the crucial substrate for sulfate reduction and ammonification tends to be affected by the concentration of amino acids. Our model provides a promising tool for simulating and predicting outcomes in response to variations in wastewater quality in sewers. [Figure not available: see fulltext.]

Zheng, M, Duan, H, Dong, Q, Ni, B-J, Hu, S, Liu, Y, Huang, X & Yuan, Z 2019, 'Effects of ultrasonic treatment on the ammonia-oxidizing bacterial (AOB) growth kinetics', Science of The Total Environment, vol. 690, pp. 629-635.
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© 2019 Elsevier B.V. Ultrasound has in the past few decades found applications in a variety of disciplines including chemistry, medicine, physics, and to a much less extent microbiology. Our previous studies found that ultrasonic treatment increases the activity of ammonia-oxidizing bacteria (AOB) while suppressing nitrite-oxidizing bacteria (NOB), resulting in beneficial effects in wastewater treatment. In this study, the kinetic and microbiological features of nitrifying microorganisms in activated sludge intermittently treated with ultrasound were investigated to gain an improved understanding of the mechanism involved in ultrasound-induced stimulation of AOB kinetics. The nitrifying microorganisms were initially enriched over 100 days in a laboratory sequential batch reactor (SBR). Ultrasonic treatment of the sludge was then applied with the treatment time in each 12 h SBR cycle progressively increased from 4 to 24 min. Application of the treatment for 21 days led to a doubled maximum specific ammonia oxidation rate, and also the enhanced dominance of known AOB Nitrosomonas genus in the biomass. This stimulatory effect is well described by a modified enzyme catalyzed reaction model, showing a good linear relationship between the natural logarithm value of μmax,AOB and the applied ultrasonic energy density. This result suggests that ultrasonic treatment likely reduced the activation energy of key enzymes involved in ammonium oxidation.

Zhou, X, Jin, W, Han, S-F, Li, X, Gao, S-H, Chen, C, Xie, G-J, Tu, R, Wang, Q & Wang, Q 2019, 'The mutation of Scenedesmus obliquus grown in municipal wastewater by laser combined with ultraviolet', Korean Journal of Chemical Engineering, vol. 36, no. 6, pp. 880-885.
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© 2019, The Korean Institute of Chemical Engineers. Mutagenetic breeding is an efficient technique for the enhancement of lipid productivity from microalgae. In this study, oil-rich microalga Scenedesmus obliquus were treated by Laser-UV composite mutagenesis. Among the 35 mutant strains, X5 was primely screened. Afterwards, a twice UV mutagenizing was operated on X5, and the optimal mutant strain X5-H13 was obtained. The growth rate, dry weight, lipid yield and lipid content of X5-H13 were 0.698×107 cells/mL·d, 0.99 g/L, 0.49 g/L and 48.8% while cultivated in municipal wastewater, respectively, which were increased by 45%, 58%, 109% and 32% than the original strain. The results of the subculture of repeated mutant showed that the biomass and lipid content of strain X5-H13 were up to 0.99 g/L and 48.8%. The growth of each generation was stable. Furthermore, the random amplified polymorphic DNA analysis indicated that the mutant strain X5-H13 was different from the starting strain, with their genetic similarity coefficient value of 0.815.

Zhou, X, Jin, W, Tu, R, Guo, Q, Han, S-F, Chen, C, Wang, Q, Liu, W, Jensen, PD & Wang, Q 2019, 'Optimization of microwave assisted lipid extraction from microalga Scenedesmus obliquus grown on municipal wastewater', Journal of Cleaner Production, vol. 221, pp. 502-508.
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© 2019 Elsevier Ltd Efficient cost effective lipid extraction from microalgae is a challenging topic for large scale production of microalgae-based biodiesel. In this study, a microwave-assisted lipid extraction process was applied to the oil-rich green microalga Scenedesmus obliquus grown on municipal wastewater. N-hexane/isopropanol solvent was used as alternative solvent. Optimal extraction parameters were determined as: operational temperature of 130 °C, extraction time of 0.25 h, solvent ratio of N-hexane/isopropanol of 3:2 (V:V), phase ratio of co-solvent/biomass was 50:1 (mL:g). Relative extraction rates of lipid and fatty acid methyl esters (FAMEs) achieved using microwave-assisted extraction (MAE) were 88.25% and 95.58%, respectively, which is higher than traditional water bath heating extraction process (WHE). In addition, compared with WHE, the apparent first order rate constant of MAE was enhanced by 18 times compared to traditional methods. Analysis using scanning electron microscopy indicated that disruption of the cell wall of Scenedesmus obliquus by microwave led to the enhancement of solvents’ penetration and lipid extraction.

Zhou, Y, Xu, X, Han, R, Li, L, Feng, Y, Yeerken, S, Song, K & Wang, Q 2019, 'Suspended particles potentially enhance nitrous oxide (N2O) emissions in the oxic estuarine waters of eutrophic lakes: Field and experimental evidence', Environmental Pollution, vol. 252, no. Pt B, pp. 1225-1234.
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© 2019 Elsevier Ltd Estuaries are considered hot spots for the production and emissions of nitrous oxide (N2O) and easily occur suspended particles (SPS), however, current understanding about the role of SPS in the N2O emissions from the oxic estuarine waters of lacustrine ecosystems is still limited. In this study, field investigations were performed in the estuaries of hypereutrophic Taihu Lake, and laboratory simulations were simultaneously conducted to ascertain the characteristics of N2O emissions with different SPS concentrations. The results showed that the N2O emission fluxes ranged from 9.75 to 118.38 μg m−2 h−1, indicating a high spatial heterogeneity for the N2O emissions from the estuaries of Taihu Lake. Although the dissolved oxygen (DO) concentrations were up to 7.85 mg L−1 in the estuarine waters, from where the N2O emissions fluxes were approximately three times that of the lake regions. Multiple regression model selected the total nitrogen (TN), SPS, and DO concentrations as the crucial factors influencing the N2O emission fluxes. Particularly for SPS, the simulation results showed that the N2O concentrations increased gradually with the increase in the SPS concentrations of an oxic water column containing 4 mg L−1 of NO3−-N, indicating that a high SPS concentration can accelerate the N2O emissions. It was related to the change of denitrifying bacteria population in the SPS, as evidenced by its significantly positive correlation with N2O emissions (p < 0.01). Our findings will draw attentions to the role of SPS playing in the N2O productions and emissions in eutrophic lakes, and its effect on nitrogen cycle should be considered in the future study.

Aghayarzadeh, M, Khabbaz, H & Fatahi, B 1970, 'Evaluation of Reaction Piles Effect on Test Piles in Static Load Testing Using Three-Dimensional Numerical Analysis', ASTM Special Technical Publication, International Conference on Stress Wave Theory and Testing Methods for Deep Foundations, ASTM International, San Diego, California, USA, pp. 68-80.
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Copyright © 2019 by ASTM International. Static load testing includes the direct measurement of pile head displacements when a physical test load is applied. It is known as the most fundamental form of pile load testing and generally considered as a benchmark for pile performance assessment. During static load testing, the load is commonly applied using a hydraulic jack acting against a reaction beam, which is restrained by an anchorage system. The anchorage system may be in the form of cable anchors or reaction piles installed into the ground to provide tension resistance. In this paper, PLAXIS 3D software incorporating elastic-perfectly-plastic Mohr-Coulomb and hardening-soil constitutive models is initially used to simulate a real static load test conducted in stiff overconsolidated clay. Then, in order to assess the effect of the reaction system on the test results, a similar model using the hardening-soil model is simulated. In the three-dimensional model, different numbers of reaction piles, identical to the test pile, are located in different distances from the test pile. Subsequently, the influences of spacing, length, diameter of reaction piles, and type of reaction piles on the load-displacement behavior of test piles are assessed. This paper can provide insight to practicing civil engineers on how to design the loading systems for static pile load tests.

Al Taee, AA, Khushaba, RN & Al-Jumaily, A 1970, 'Spatially Filtered Low-Density EMG and Time-Domain Descriptors Improves Hand Movement Recognition', 2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2019 41st Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), IEEE, Berlin, Germany, pp. 2671-2674.
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Surface Electromyogram (EMG) pattern recognition has long been utilized for controlling multifunctional myoelectric prostheses. In such an application, a number of EMG channels are usually utilized to acquire more information about the underlying activity of the remaining muscles in the amputee stump. However, despite the multichannel nature of this application, the extracted features are usually acquired from each channel individually, without consideration for the interaction between the different muscles recruited to achieve a specific movement. In this paper, we proposed an approach of spatial filtering, denoted as Range Spatial Filtering (RSF), to increase the number of EMG channels available for feature extraction, by considering the range of all possible logical combinations of each n channels. The proposed RSF method is then combined with conventional time-domain (TD) feature extraction, as an extension of the conventional single channel TD features that are heavily considered in this field. We then show how the addition of a new feature, specifically the minimum absolute value of the range of each two windowed EMG signals, can significantly reduce the different patterns misclassification rate achieved by conventional TD features (with and without our RSF method). The performance of the proposed method is verified on EMG data collected from nine transradial amputees (seven traumatic and two congenital), with six grip and finger movements, for three different levels of forces (low, medium, and high). The classification results showed significant reduction in classification error rates compared to other methods (nearly 10% for some individual TD features and 5% for combined TD features, with Bonferroni corrected p-values <; 0.01).

Awan, Z, Kahlke, T, Ralph, P & Kennedy, P 1970, 'Chemical Named Entity Recognition with Deep Contextualized Neural Embeddings', Proceedings of the 11th International Joint Conference on Knowledge Discovery, Knowledge Engineering and Knowledge Management, 11th International Conference on Knowledge Discovery and Information Retrieval, SCITEPRESS - Science and Technology Publications, Austria, pp. 135-144.
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Copyright © 2019 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved Chemical named entity recognition (ChemNER) is a preliminary step in chemical information extraction pipelines. ChemNER has been approached using rule-based, dictionary-based, and feature-engineered based machine learning, and more recently also deep learning based methods. Traditional word-embeddings, like word2vec and Glove, are inherently problematic because they ignore the context in which an entity appears. Contextualized embeddings called embedded language models (ELMo) have been recently introduced to represent contextual information of a word in its embedding space. In this work, we quantify the impact of contextualized embeddings for ChemNER by using Bi-LSTM-CRF (bidirectional long short term memory networks - conditional random fields) networks. We benchmarked our approach using four well-known corpora for chemical named entity recognition. Our results show that incorporation of ELMo results in statistically significant improvements in F1 score in all of the tested datasets.

Dang, LC, Dang, CC & Khabbaz, H 1970, 'Numerical Modelling of Embankment Supported by Fibre Reinforced Load Transfer Platform and Cement Mixed Columns Reinforced Soft Soil', 17th European Conference on Soil Mechanics and Geotechnical Engineering, ECSMGE 2019 - Proceedings.
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This paper presents the numerical modelling of a new ground modification technique utilising fibre reinforced load transfer platform (FRLTP) and columns supported (CS) embankment constructed on top of multilayers of soft soil. To investigate the influences of thickness and tensile strength of FRLTP on the embankment behaviour, a series of finite element analyses (FEA) was conducted on the full geometry of a CS embankment reinforced without or with an FRLTP. The FRLTP thickness varied in a range of 0∼3 m, and the FRLTP tensile strength ranged from 10 kPa to 240 kPa, which were considered in this numerical modelling. The numerical results reveal that an increase in the FRLTP thickness significantly improved the stress concentration ratio between columns and surrounding soil, meanwhile resulted in a considerable reduction of the lateral deformation and hence, effectively improved the stability of the embankment system. The findings of the parametric study also indicate that when the FRLTP tensile strength increased in the investigated range, the embankment lateral displacement was found to reduce to a certainly low value, and then it remained almost unchanged. It is also found that the time-dependent embankment behaviour was considerably affected by the changes in the tensile strength and the thickness of FRLTP.

El-Hawat, O, Fatahi, B & Edmonds, C 1970, 'Earthquake Geotechnical Engineering for Protection and Development of Environment and Constructions', 7th International Conference on Earthquake Geotechnical Engineering, CRC Press, Roma, Italy, pp. 2241-2248.
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El-Hawat, O, Fatahi, B & Edmonds, C 1970, 'The Effectiveness of Restrainers to Enhance the Seismic Performance of Bridges with Rocking Foundations', Australian Earthquake Engineering Society 2019 Conference, Newcastle, NSW, Australia.

Guan, Z, Qin, H, Yager, K, Choo, Y & Yu, D 1970, 'Automatic X-ray scattering image annotation via double-view Fourier-Bessel convolutional networks', British Machine Vision Conference 2018, BMVC 2018.
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X-ray scattering is a key technique towards material analysis and discovery. Modern x-ray facilities are producing x-ray scattering images at such an unprecedented rate that machine aided intelligent analysis is required for scientific discovery. This paper articulates a novel physics-aware image feature transform, Fourier-Bessel transform (FBT), in conjunction with deep representation learning, to tackle the problem of annotating x-ray scattering images with a diverse label set of physics characteristics. We devise a novel joint inference model, Double-View Fourier-Bessel Convolutional Neural Network (DVFB-CNN) to integrate feature learning in both polar frequency and image domains. For polar frequency analysis, we develop an FBT estimation algorithm for partially observed x-ray images, and train a dedicated CNN to extract structural information from FBT. We demonstrate that our deep Fourier-Bessel features well complement standard convolutional features, and the joint network (i.e., DVFB-CNN) improves mean average precision by 13% in multilabel annotation. We also conduct transfer learning on real experimental datasets to further confirm that our joint model is well generalizable.

Hassoun, M, Fatahi, B & Mirlatifi, S 1970, 'Seismic effectiveness of different restraining systems for skewed bridge decks supported on elastomeric bearings', Earthquake Geotechnical Engineering for Protection and Development of Environment and Constructions- Proceedings of the 7th International Conference on Earthquake Geotechnical Engineering, 2019, International Conference on Earthquake Geotechnical Engineering, CRC Press, Rome, Italy, pp. 2812-2819.
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Past earthquakes have shown that isolated bridges are susceptible to excessive movements at the expansion joints. Reconnaissance reports have exposed various isolated bridges that have collapsed due to this excessive movement in a phenomenon known as unseating. This problem is particularly evident in skewed bridges as the bridge experience coupled lateral and rotational movements. The study seeks to understand the effectiveness of various restrainers, namely cable restrainers and viscous dampers in limiting both lateral and rotational movements of the bridge deck. In order to approximate the complex behavior of isolated restrained bridges, the models used in this study include the effect of soil-structure interaction behind the abutment backwall and the pile foundations. Moreover, the inelastic behavior of highly damaged bridge elements such as abutment backwall, pier and shear-keys are studied, and results are presented.

Huang, B, Fatahi, B & Terzaghi, S 1970, 'Investigating effects of wave incident angle and joint depth on ground surface motion considering multiple reflections via coupled discrete element and finite difference method', Earthquake Geotechnical Engineering for Protection and Development of Environment and Constructions- Proceedings of the 7th International Conference on Earthquake Geotechnical Engineering, 2019, International Conference on Earthquake Geotechnical Engineering (VII ICEGE), CRC Press, Roma, Italy, pp. 2883-2890.
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In this study, the effects of incident angle and joint depth on the ground surface motion induced by the shear wave propagation across the rock mass were numerically assessed. A three-dimensional coupled discrete element-finite difference model consisting of a 40-m deep rock mass with a single joint, was developed using 3DEC software. The continuously yielding joint model was adopted to replicate the nonlinear behaviour of the joint under the influence of the seismic wave. Moreover, the role of the multiple reflections occurring between the ground surface and the joint in the ground surface motion was determined via the comparison between the models with and without the presence of the free surface. The results of this parametric study showed that a larger incident angle could lead to the amplification of both the horizontal and vertical components of the peak particle velocity captured on the ground surface. In addition, it was found that the multiple reflections can significantly amplify the ground surface motion, particularly when the joint with the shallow depth was present. Hence, it is critical for practicing engineers to take into account the joint spatial properties such as the joint orientation and depth, in conjunction with the multiple reflections, when making the prediction of the ground surface motion.

Huang, B, Fatahi, B & Zargarbashi, S 1970, 'Coupled discrete element and finite difference modelling of wave propagation across rock mass considering multiple reflections between ground surface and joint', 13th Australia New Zealand Conference on Geomechanics, Australia New Zealand Conference on Geomechanics, Australian Geomechanics Society, Perth, Australia, pp. 889-896.
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Ground surface motion induced by the upward propagating seismic waves could cause severe damage to structures on ground surface. The propagation of seismic wave could be significantly affected by the presence of joints embedded in a rock mass. The joints could attenuate and slow down the travelling wave. Moreover, the multiple wave reflections occurring between the ground surface and the joint could significantly alter the behaviour of the wave travelling through the near-ground rock mass. In this study, the S-wave propagating through the jointed rock mass and its induced ground surface motion were numerically investigated. A three-dimensional coupled discrete element-finite difference model was developed using 3DEC software to study seismic wave propagation across a 30-m deep rock mass with a single horizontal joint in the middle. Continuously yielding joint model was adopted to capture the nonlinear progressive damage of joints under shear. The influences of the shear stress ratio and the frequency of the incident S-wave on the wave propagation across the rock mass and the associated ground surface motion were studied, considering multiple wave reflections between the free ground surface and rock joint. Moreover, a comparison was made between the models with and without the presence of the free surface, to better understand the impact of the multiple reflections on the wave propagation and the ground surface motion. It was showed that the multiple reflections could conspicuously intensify the wave propagation across the rock mass, and therefore amplifying the ground surface motion, particularly when the frequency was low. Moreover, the ground surface motion became insensitive to the variation of the shear stress ratio when the ratio was either too small or too large, in conjunction with the multiple wave reflections. Hence, the effect of multiple reflections should be carefully considered, when predicting the ground surface motion caused by the wave p...

Le, TM, Dang, LC & Khabbaz, H 1970, 'Combined Effects of Bottom Ash and Lime on Behaviour of Expansive Soil', Recent Advancements on Expansive Soils, International Congress and Exhibition on Sustainable Civil Infrastructures, Springer International Publishing, Cairo, Egypt, pp. 28-44.
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This study illustrates the effectiveness of combining bottom ash and hydrated lime to enhance the engineering properties of expansive soil. The bottom ash was collected from Eraring Power Station in New South Wales, Australia, as a by-product of coal-fired power stations, and soil specimens were used as artificial soil including kaolinite, bentonite and fine sand in a reasonable ratio to stimulate soil samples with characteristics of expansive soil. The stabilised soil samples were prepared by altering the bottom ash content from 0% to 30% on a dry weight basis of expansive soil as well as with constant percentage of 5% in hydrated lime. Through conducting a series of experimental tests including linear shrinkage and unconfined compressive strength (UCS) in various curing time, the shrinkage and strength behaviour of treated soils were investigated and compared with untreated soil samples. The results revealed that the combination of bottom ash and hydrated lime significantly reduced the linear shrinkage, while it increased the strength of expansive soil. The use of bottom ash alone is not recommended due to a slight increase of linear shrinkage and a minor negative impact on the soil strength. The optimum content of combined bottom ash and hydrated lime to stabilise expansive soils is also presented.

Mirzababaei, M, Decourcy, T & Fatahi, B 1970, 'Sustainable Use of Reclaimed Ballast Rejects for Construction of Rail Corridor Access Road-an Australian Experience', Springer International Publishing, pp. 257-269.
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Nguyen, TAH, Ngo, HH, Guo, WS, Pham, TQ, Cao, TH & Nguyen, THH 1970, 'Applicability of zirconium loaded okara in the removal and recovery of phosphorus from municipal wastewater', IOP Conference Series: Earth and Environmental Science, International Forum on Sustainable Future in Asia, IOP Publishing, Hanoi, Vietnam, pp. 012004-012004.
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© 2019 Published under licence by IOP Publishing Ltd. Recently, there is a new trend to consider wastewater as a precious resource. Since phosphorus is a limited non-renewable element, and MAP (Magnesium Ammonium Phosphate - MgNH4PO4.6H2O) is a valuable slow-release fertilizer, the recovery of phosphorous as MAP has received special attention from scientists all over the world. However, the application of this process with municipal wastewater is still a challenge, due to low concentration of phosphorus and high volume of municipal wastewater. This study investigates the potential of reclaiming MAP from municipal wastewater by combination of adsorption and crystallization. Soybean milk residue (okara) was loaded with Zirconium (Zr) to prepare the adsorbent (ZLO). Adsorption and desorption experiments were conducted in a semi-pilot scale ZLO packed colum system. Effects of P: N: Mg molar ratios, chemical sources and temperature on the formation of MAP were examined in an attempt to identify the optimal crystallization conditions. The attained precipitate was characterized using XRD, SEM, FTIR techniques. It was found that the ZLO packed column adsorption-desorption system could pre-concentrate phosphorus from municipal wastewater up to 28.36 times, fitting well the minimum requirement (50 mg P/L) for the economical MAP recovery. Up to 95.19% of dissolved phosphorus in desorption solution was recovered at pH = 9, Mg: N: P molar ratio = 2:2:1, using a combination of MgCl2.6H2O and NH4Cl. The harvested MAP exhibited high purity (92.59%), high P-availability (89% by mass), and extremely low levels of heavy metals. The results prove that it is viable to recover MAP from municipal wastewater by employing ZLO as adsorbent, followed by crystallization. This paves the way for mining phosphorus from municipal wastewater and reducing okara as an agricultural byproduct in a green way.

Pham Ngoc, T, Fatahi, B & Khabbaz, H 1970, 'Impact of Liquid Whey Waste on Strength and Stiffness of Cement Treated Clay', New Developments in Soil Characterization and Soil Stability, Civil Infrastructures Confronting Severe Weathers and Climate Changes Conference, Springer International Publishing, Hangzhou, China, pp. 1-10.
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The reuse of whey waste, a by-product of the dairy industry, is an emerging issue due to the environmental impacts. Some previous experimental studies have indicated that whey waste can be used as an admixture for cement-based materials, including mortar and concrete, to reduce the setting time and increase the workability, thus reduce the amount of required cement. However, influence of whey waste on cemented soil has not received sufficient attention. This study investigates variations of unconfined compressive strength (UCS) and Young's modulus (E) of cemented Kaolin clay when water in cement slurry was replaced by different whey waste proportions. Unconfined compression tests were conducted on treated specimens after two different curing times, namely 14 days and 56 days. Stress-strain relationship in each test was used to compute UCS and E at different dosages of cement and whey waste. Results of the experiments show improvements of UCS and E only for specimens when less than 10% water in cement slurry was replaced by liquid whey waste at 56 day-curing age, regardless of cement dosage. For the other cases, the presence of whey waste resulted in reductions of both UCS and E, indicating that although whey waste can be used to improve mechanical properties of cement treated clay, the optimum dosage should be selected very carefully to minimize the adverse effects. Different responses of UCS and E with curing age, dosages of cement and liquid whey waste are explained while discussing about the effects of lactose (milk sugar) available in whey waste acting as a retarding agent.

Soudagar, MEM, Nik-Ghazali, N-N, Badruddin, IA, Kalam, MA, Kittur, MDI, Akram, N, Ullah, MA, Khan, TMY & Mokashi, I 1970, 'Production of honge oil methyl ester (HOME) and its performance test on four stroke single cylinder VCR engine', ADVANCES IN BASIC SCIENCE (ICABS 2019), ADVANCES IN BASIC SCIENCE (ICABS 2019), AIP Publishing.
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Surawski, NC, Macdonald, LM, Baldock, JA, Sullivan, AL, Roxburgh, SH & Polglase, PJ 1970, 'Exploring the properties of pyrogenic carbon with solid state ¹³C nuclear magnetic resonant spectroscopy: A combustion wind tunnel study', 12th Asia-Pacific Conference on Combustion, ASPACC 2019.
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Increasing the production of aryl carbon from wildland fire may be beneficial since it can be stored in soils for long periods of time rather than being emitted to the atmosphere or stored in soils in a less recalcitrant form. In this study, solid state 13C nuclear magnetic resonant spectroscopy is used to explore the properties of pyrogenic carbon produced by fires burning with different fire spread modes. Forest litter fuels were burnt using in a combustion wind tunnel using a replicated experimental design. Experiments were performed with three different fire spread modes, involving heading fires that spread with the wind, backing fires that spread against the wind and flanking fires that spread perpendicular to the wind. Results show that heading fires produce significantly more aryl carbon than flanking fires. Analysis of the results with principal component analysis show that maximising the residence time of high temperature combustion and the combustion factor could be an effective method for increasing the production of aryl carbon from fire.

Sutherland, D, Buxton, L & Ralph, P 1970, 'Algae and waste in a circular economy. Oral Presentation', Organix19, Sydney, Australia.

Tan, ES, P, K, Indra, TMI, Tokimatsu, K & Yoshikawa, K 1970, 'Impact of biodiesel application on fuel savings and emission reduction for power generation in Malaysia', Energy Procedia, 10th International Conference on Applied Energy (ICAE), Elsevier BV, Hong Kong, HONG KONG, pp. 3325-3330.
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Uddin, MN, Taweekun, J, Techato, K, Rahman, MA, Mofijur, M & Rasul, MG 1970, 'Sustainable Biomass as an Alternative Energy Source: Bangladesh Perspective', Energy Procedia, Elsevier BV, Sydney, AUSTRALIA, pp. 648-654.
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Uddin, MN, Techato, K, Rasul, MG, Hassan, NMS & Mofijur, M 1970, 'Waste coffee oil: A promising source for biodiesel production', Energy Procedia, Elsevier BV, Sydney, AUSTRALIA, pp. 677-682.
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The oil from waste coffee possesses the potential as a feedstock for biodiesel production. In this study, waste coffee grounds were collected from Turkey. Then the oil was extracted from waste coffee grounds using N-hexane. The two-step acid-base catalyst transesterification process was used to produce biodiesel as the acid value of the crude oil was found higher (15.4 mgKOH/g).This was followed by an investigation of some physical and chemical properties. It was found that the properties of waste coffee biodiesel fell within the limit of ASTM standards. So the studied physicochemical properties of the waste coffee biodiesel suggest that this fuel can be used as a fuel in diesel engines.

Xu, R & Fatahi, B 1970, 'Assessment of Soil Plasticity Effects on Seismic Response of Mid-Rise Buildings Resting on End-Bearing Pile Foundations', Springer International Publishing, pp. 146-159.
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Yeganeh, N, Fatahi, B & Mirlatifi, S 1970, 'Effects of hyperbolic hardening parameters on seismic response of high rise buildings considering soil-structure interaction', Earthquake Geotechnical Engineering for Protection and Development of Environment and Constructions- Proceedings of the 7th International Conference on Earthquake Geotechnical Engineering, 2019, International Conference on Earthquake Geotechnical Engineering, Associazione Geotecnica Italiana, Roma, Italy, pp. 5754-5761.
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Seismic soil-structure interaction is referred to the process wherein the soil dynamic response is influenced by the structure motion whilst the latter is also affected by the soil motion. To assess the seismic response of the soil-structure systems, selecting the appropriate soil model parameters is of great importance and the predictions can be significantly impacted if the simply assumptive parameters, presented in the literature, are employed. In this study, the strain hardening soil constitutive model, named “hyperbolic hardening with hysteretic damping”, was employed in the 3D coupled soil-structure interaction numerical simulations using FLAC3D. Utilizing the numerical simulations, the impact of the choice of the soil model parameters, in the range, recommended in the literature, on the seismic response of a moment-resisting building was assessed. It was concluded that the relation between the hyperbolaand Mohr-Coulomb failurecriterion hasa major contribution to the prediction of the seismic response of a building considering the soil-structure interaction.

Zhang, X, Fatahi, B & Khabbaz, H 1970, 'Investigating Effects of Individual Fracture Length on Behaviour of Weak Rock Using Discrete Element Method', Proceedings of the 5th GeoChina International Conference 2018 – Civil Infrastructures Confronting Severe Weathers and Climate Changes: From Failure to Sustainability, GeoChina International Conference, Springer International Publishing, Wuhan, pp. 46-56.
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In this paper weak rock specimens with different individual fracture lengths are numerically simulated using the discrete element method (DEM). Effects of micro or macro-mechanical responses of intact and fractured specimens subjected to triaxial test have been studied. Various individual fracture lengths with a given fracture density within the weak rock specimens were reproduced using the particle flow code in three-dimension software (PFC3D). Different lengths of fractures were simulated by altering the size of each fracture to give insight over the influence of continual fractures and non-persistent fractures within bonded assemblies. As expected, for a given fracture density the individual fracture length affected the strength and deformability of rock mass. For an individual fracture length to specimen width ratio (the normalized fracture length) less than a limiting value, the effects of the individual fracture length on the stress-strain behaviour of rock specimens were more evident. Indeed, the strength decreased with decreasing the normalized fracture length. However, with a ratio above the limiting value, the effects of the individual fracture length were minimal. It can be concluded that for a given fracture density, present of shorter mini-fractures could be potentially more detrimental to stiffness and strength of the rock mass in comparison to longer major fractures.

Baird, ME, Wild-Allen, KA, Parslow, J, Mongin, M, Robson, B, Skerratt, J, Rizwi, F, Soja-Woznaik, M, Jones, E, Herzfeld, M, Margvelashvili, N, Andrewartha, J, Langlais, C, Adams, MP, Cherukuru, N, Gustafsson, M, Hadley, S, Ralph, PJ, Rosebrock, U, Schroeder, T, Laiolo, L, Harrison, D & Steven, ADL 2019, 'CSIRO Environmental Modelling Suite (EMS): Scientific description of the optical and biogeochemical models (vB3p0)', Copernicus GmbH.
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Abstract. Since the mid 1990s, Australia's Commonwealth Science Industry and Research Organisation (CSIRO) has developed a biogeochemical (BGC) model for coupling with a hydrodynamic and sediment model for application in estuaries, coastal waters and shelf seas. The suite of coupled models is referred to as the CSIRO Environmental Modelling Suite (EMS) and has been applied at tens of locations around the Australian continent. At a mature point in the BGC model's development, this paper presents a full mathematical description, as well as links to the freely available code and User Guide. The mathematical description is structured into processes so that the details of new parameterisations can be easily identified, along with their derivation. The EMS BGC model cycles carbon, nitrogen, phosphorous and oxygen through multiple phytoplankton, zooplankton, detritus and dissolved organic and inorganic forms in multiple water column and sediment layers. The underwater light field is simulated by a spectrally-resolved optical model that includes the calculation of water-leaving reflectance for validation with remote sensing. The water column is dynamically coupled to the sediment to resolve deposition, resuspension and benthic-pelagic biogeochemical fluxes. With a focus on shallow waters, the model also includes particularly-detailed representations of benthic plants such as seagrass, macroalgae and coral polyps. A second focus has been on, where possible, the use of geometric derivations of physical limits to constrain ecological rates, which generally requires population-based rates to be derived from initially considering the size and shape of individuals. For example, zooplankton grazing considers encounter rates of one predator on a prey field based on summing relative motion of the predator with the prey individuals and the search area, chlorophyll synthesis includes a geometrically-derived self-shading term, and the bottom coverage of benthic plants is gen...