Altaee, A, Smith, R & Mikhalovsky, S 2008, 'The feasibility of decontamination of reduced saline sediments from copper using the electrokinetic process', Journal of Environmental Management, vol. 88, no. 4, pp. 1611-1618.
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Areerachakul, N, Vigneswaran, S, Kandasamy, J & Duangduen, C 2008, 'The degradtion of humic substance using continuous photocatalysis systems', SEPARATION SCIENCE AND TECHNOLOGY, vol. 43, no. 1, pp. 93-112.
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Photocatalytic oxidation is an emerging technology in water and wastewater treatment. Photocatalysis often leads to complete degradation of organic pollutants without the need for chemicals. This study investigated the degradation of humic substances in
Areerachakul, N, Vigneswaran, S, Ngo, HH & Kandasamy, J 2008, 'A continuous photocatalysis system in the degradation of herbicide', KOREAN JOURNAL OF CHEMICAL ENGINEERING, vol. 25, no. 4, pp. 663-669.
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The performance of both batch and continuous photo-catalytic reactors was studied to evaluate their capabilities in removing the sulfonyl urea herbicide of metsulfuron methyl (MM). It was found in a batch reactor that the addition of a small amount of powder activated carbon (PAC) significantly increased the rate of degradation of MM. The continuous photo-catalytic system resulted in 57% of MM removal. When a small dose of activated carbon was added in the photo-catalytic system, MM removal increased to 7886% MM removal for retention times between of 5.2521 min (corresponding to withdrawal rates of 1040 mLmin-1). In this study, the pseudo first order rate constants of a continuous photo-catalytic system revealed that shorter retention times were associated with lower rate constants. Solid phase micro extraction/gas chromatography (SPME/GC) results showed that high concentrations of MM were broken down to small volatile organic compounds (VOCs) by photo-catalytic oxidation. PAC adsorbed the photo-products and increased the degradation of MM.
Aryal, RK, Lee, B-K, Karki, R, Gurung, A, Kandasamy, J, Pathak, BK, Sharma, S & Giri, N 2008, 'Seasonal PM10 dynamics in Kathmandu Valley', Atmospheric Environment, vol. 42, no. 37, pp. 8623-8633.
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Data on ambient PM10 levels from six locations in the Kathmandu Valley recorded by means of continuous sampling using low volume air samplers from October 2002 to March 2007 were used to investigate PM10 concentration dynamics in the valley. Monthly average data of the urban areas, which have much higher concentrations than the rural areas, even exceeded the daily standard level of PM10, in Nepal, 120 ?m m-3. Repetitive peaks and troughs each year indicated annual patterns. Monthly average showed seasonal patterns are different between rural area and urban sites. The highest monthly average concentration was observed in February, the end of winter in urban areas where as in rural found in spring, and the lowest concentration was observed in July (monsoon period). The continuous increase in PM10 concentration from December to February in urban areas showed accumulation of PM10 in the ambient air during the wintertime. Rainfall in June and September, during the monsoon period, caused a PM10 concentration decrease, demonstrating that precipitation is effective in removing PM10 from the valley. Cross correlation analyses among the PM10 levels measured simultaneously at the sampling stations showed a poor relationship in winter; however, there were good relationships in the monsoon and post-monsoon seasons. Both the PM10 concentration and the air-mixing environment in the valley were closely associated with the temperature and wind speed.
Bignal, KL, Langridge, S & Zhou, JL 2008, 'Release of polycyclic aromatic hydrocarbons, carbon monoxide and particulate matter from biomass combustion in a wood-fired boiler under varying boiler conditions', Atmospheric Environment, vol. 42, no. 39, pp. 8863-8871.
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Particulate matter, CO and NO as well as 16 polycyclic aromatic hydrocarbons (PAHs) in both gaseous and particulate phases were measured in the stack of a woodchip-fired 50 kW boiler used for domestic heating. The concentrations of ΣPAHs in both gas and particle phases varied from 1.3 to 1631.7 μg m-3. Mean CO and NO concentrations varied from 96 to 6002 ppm and from 28 to 359 ppm, respectively. The effects of fuel parameters (moisture content (MC) and tree species) and boiler operating conditions on pollutant concentrations were investigated. A relationship was established between ΣPAHs in gaseous and particulate phases and CO concentrations. The species of tree used for woodchip was less important than MC and boiler operating conditions in affecting pollutant concentrations. It is recommended that in order to minimise PAH release woodchip fuel should have a low MC, and the boiler should be operated with a load demand (high/moderate heat requirement). Slumber modes when the boiler has no load demand and is effectively a smouldering flame should be avoided. This can be achieved by increasing automatic operation capability of wood-fired boilers, for example, by automatically varying fire rates and having auto-start capabilities. The PAH data obtained from this study is particularly useful in contributing to emissions inventories, modelling, and predictions of ambient air quality. © 2008 Elsevier Ltd. All rights reserved.
Chang, C-Y, Chang, J-S, Vigneswaran, S & Kandasamy, J 2008, 'Pharmaceutical wastewater treatment by membrane bioreactor process – a case study in southern Taiwan', Desalination, vol. 234, no. 1-3, pp. 393-401.
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A pilot-scale study of pharmaceutical wastewater treatment by a membrane bioreactor (MBR) process in southern Taiwan is presented in this paper. A 10 m3/day capacity MBR plant consisting of an aeration tank and a membrane bioreactor was installed to remove organic matter (measured in terms of chemical oxygen demand (COD)). The performance of the MBR was monitored for a period of 140 days. The removal of COD was on average over 95%. The effluent did not contain any suspended solids. During the 140 days of operation, manual cleaning was carried out twice and chemical cleaning was carried out once. A natural logarithmic evolution of the viscosity with TSS concentration was observed. The results of SEM and EDX demonstrated that the fouling on the membrane outer surface was mainly due to microorganisms and/or the sludge physiological properties. The results indicated that the MBR system has potential as a means of treating high-strength and fluctuating strength wastewater with consistent performance. © 2008 Elsevier B.V. All rights reserved.
Chang, JS, Vigneswaran, S, Kandasamy, JK & Tsai, LJ 2008, 'Effect of pore size and particle size distribution on granular bed filtration and microfiltration', SEPARATION SCIENCE AND TECHNOLOGY, vol. 43, no. 7, pp. 1771-1784.
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The paper reviews the effect of particle size distribution and pore size distribution on granular bed filter and crossflow microfiltration performance. The experimental results of the granular bed filter with pollen particles in suspension showed that the presence of large particles improved the filter efficiency of smaller particles in suspension. Microfiltration results with bi and tri-modal latex suspensions showed that the permeate flux and the quality were significantly affected by the particle size and its distribution, especially when the particle size was smaller than the pore size of the membrane. The mathematical model simulation results of granular bed filtration show that media pore size distribution is an important parameter of filtration for the particle removal and pressure drop across the filter
Chiemchaisri, C, Passananon, S, Ngo, HH & Vigneswaran, S 2008, 'Enhanced natural organic matter removal in floating media filter coupled with microfiltration membrane for river water treatment', DESALINATION, vol. 234, no. 1-3, pp. 335-343.
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This research work was carried out to determine natural organic matter (NOM) removal in floating media filter coupled with microfiltration membrane applied to the treatment of river water in Bangkok, Thailand. Polyaluminum chloride was found to be the most effective coagulant providing enhanced coagulation effect for NOM removal. Optimum filtration rate of floating media filter was 11 m3/m2 h at which highest NOM removal efficiencies of 82.2% was achieved. Subsequent treatment in microfiltration membrane unit operated at a filtration rate of 0.45 m3/m2 d provided total NOM removal of 85.786.6%. Periodical cleanings of floating media filter and microfiltration membrane were accomplished by using air scouring coupled with water flushing at every 8 and 24 h interval. As a result of NOM removal, the sum of trihalomethane (THM) ratio was reduced from 0.51.1 in raw water to 0.20.6 in treated water. Membrane fouling study revealed that both turbidity and NOM affected transmembrane pressure (TMP) built up but particulate fouling provided greater impact on TMP as compared to organic adsorption on the membrane surface.
Collier, CJ, Lavery, PS, Ralph, PJ & Masini, RJ 2008, 'Physiological characteristics of the seagrass Posidonia sinuosa along a depth-related gradient of light availability', MARINE ECOLOGY PROGRESS SERIES, vol. 353, pp. 65-79.
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Physiological plasticity has the capacity to prolong seagrass survival under reduced light conditions. However, when light is attenuated across a depth gradient, the relative importance of this over other mechanisms for tolerating long-term light reduction (such as morphological adjustments and shoot loss) has been guestioned. This study aimed to describe a number of the physiological characteristics of Posidonia sinuosa Cambridge et Kuo along a depth-related gradient of light availability (1.6 to 9.0 m depth) and infer how these characteristics are important for the long-term maintenance of the meadow. Rapid light curve-derived parameters, light harvesting pigments, photoprotective pigments and nutrient and carbohydrate concentrations exhibited few differences among depth strata, but showed some (albeit limited) adjustment between the seasons. It was inferred that some physiological plasticity is possible in P. sinuosa but that differences in the depth-related gradient of long-term light availability were not sufficient to induce physiological differences, even at the depth limit. Shoot density reductions, which reduce the effects of self-shading, possibly offset depth-related light reductions. Because the physiological characteristics we examined did not explain the adaptations by P. sinuosa to the long-term gradient of light availability, they may not be useful indicators of long-term light reduction. © Inter-Research 2008.
Demir, E, Coyne, KJ, Doblin, MA, Handy, SM & Hutchins, DA 2008, 'Assessment of microzooplankton grazing on Heterosigma akashiwo using a species-specific approach combining quantitative real-time PCR (QPCR) and dilution methods', MICROBIAL ECOLOGY, vol. 55, no. 4, pp. 583-594.
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Delaware's Inland Bays (DIB) are subject to numerous mixed blooms of harmful raphidophytes each year, and Heterosigma akashiwo is one of the consistently occurring species. Often, Chattonella subsalsa, C. cf. verruculosa, and Fibrocapsa japonica co-occur
Demir, E, Coyne, KJ, Doblin, MA, Handy, SM & Hutchins, DA 2008, 'Assessment of microzooplankton grazing on Heterosigma akashiwo using a species-specific approach combining quantitative real-time PCR (QPCR) and dilution methods (vol 55, pg 583, 2008)', MICROBIAL ECOLOGY, vol. 55, no. 4, pp. 581-582.
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Erdei, L, Arecrachakul, N & Vigneswaran, S 2008, 'A combined photocatalytic slurry reactor-immersed membrane module system for advanced wastewater treatment', SEPARATION AND PURIFICATION TECHNOLOGY, vol. 62, no. 2, pp. 382-388.
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type continuous photocatalytic (CP) system and an immersed hollow fibre membrane micro-ultrafilter (MF/UF) unit. The CP reactor charged with 1 g/L P-25 catalyst removed 63% dissolved organic carbon (DOC) from a synthetic wastewater (representing biologically treated sewage effluent). The addition of 0.05 g/L of powdered activated carbon (PAC) increased DOC removal up to 76%. The start-up times to achieve 60% DOC removal were 31 min and 15 min, respectively. These results show a 16 times improvement in volumetric load over a comparable batch reactor system used in previous studies by our group. Slurry type photocatalytic reactors need subsequent particle separation to retain the catalyst in the system and allow the discharge of treated effluent. The immersed membrane module accomplished this without prior slurry settling step. Membrane feed pre-treatment with pH adjustment and particle charge neutralisation with aluminium chloride coagulant led to improved critical membrane fluxes, 15.25 L/m2 h and 19.05 L/m2 h, respectively. In each experiment MF/UF produced near zero turbidity permeate, completely retained the photocatalyst, and flocculation also improved the efficiency of DOC removal. Membrane fouling was controlled by particle aggregation rather than feed DOC levels, but the latter had significant impact on coagulant demand. The complete treatment train achieved up to 92% DOC reduction with 12 mg/L AlCl3 dosage using in-line coagulation conditions. The results show that in-line coagulation offers a simple yet effective means to improve the performance of slurry type photocatalytic-MF/UF hybrid systems for advanced water and wastewater treatment applications. © 2008 Elsevier B.V. All rights reserved.
Erdei, L, Chang, C-Y & Vigneswaran, S 2008, 'In-line flocculation-submersed MF/UF membrane hybrid system in tertiary wastewater treatment', SEPARATION SCIENCE AND TECHNOLOGY, vol. 43, no. 7, pp. 1839-1851.
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Coagulation/flocculation pre-treatment of feeds can successfully mitigate the drawbacks of membrane micro- and ultra filtration processes: fouling and limited ability to remove organic pollutants. Laboratory experiments conducted with a synthetic wastewater (representing biologically treated secondary effluent) using 0.1 µm pore size hollow fiber membrane showed that simple in-line flocculation pre-treatment with inorganic coagulants dramatically reduced membrane fouling rates. The hybrid system also ensured over 70% organic matter removal in terms of dissolved organic carbon (DOC). In the experiments in in-line flocculation outperformed clarification pre-treatment at optimum coagulant dosages. Differences in floc characteristics and elevated suspended solids concentrations in the membrane tank may explain this finding, but the exact causes were not investigated in this study. The beneficial effects of in-line flocculation pre-treatment to MF/UF separation were also confirmed in the treatment of septic tank effluent in a membrane bioreactor (MBR). The fouling rate of the 0.4 µm pore size (flat-sheet) membrane was substantially reduced with 10-100 mg L-1 ferric chloride coagulant doses, and total dissolved chemical oxygen demand (DCOD) removal also increased from 66% up to 93%. These findings are consistent with the results of other experimental studies and show that pre-treatment controls submersed MF/UF filtration performance.
Fu, Q, Lin, W & Huang, J 2008, 'A New Strategy for Preparation of Graft Copolymers via “Graft onto” by Atom Transfer Nitroxide Radical Coupling Chemistry: Preparation of Poly(4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl-co-ethylene oxide)-graft-polystyrene and Poly(tert-butyl acrylate)', Macromolecules, vol. 41, no. 7, pp. 2381-2387.
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Fu, Q, Liu, C, Lin, W & Huang, J 2008, 'One‐pot synthesis of heterograft copolymers via “graft onto” by atom transfer nitroxide radical coupling chemistry', Journal of Polymer Science Part A: Polymer Chemistry, vol. 46, no. 20, pp. 6770-6779.
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AbstractHeterograft copolymers poly(4‐glycidyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐co‐ ethylene oxide)‐graft‐polystyrene and poly(tert‐butyl acrylate) (poly (GTEMPO‐co‐EO)‐g‐PS/PtBA) were synthesized in one‐pot by atom transfer nitroxide radical coupling (ATNRC) reaction via “graft onto.” The main chain was prepared by the anionic ring‐opening copolymerization of ethylene oxide (EO) and 4‐glycidyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl (GTEMPO) first, then the polystyrene and poly (tert‐butyl acrylate) with bromine end (PS‐Br, PtBA‐Br) were prepared by atom transfer radical polymerization (ATRP). When three of them were mixed each other in the presence of CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) at 90 °C, the formed secondary carbon radicals at the PS and PtBA chain ends were quickly trapped by nitroxide radicals on poly(GTEMPO‐co‐EO). The heterograft copolymers were well defined by 1H NMR, size exclusion chromatography, fourier transform infrared, and differential scanning calorimetry in detail. It was found that the density of GTEMPO groups on main chain poly(GTEMPO‐co‐EO), the molecular weights of PS/PtBA side chains, and the structure of macroradicals can exert the great effects on the graft efficiency. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6770–6779, 2008
Glibert, PM, Azanza, R, Burford, M, Furuya, K, Abal, E, Al-Azri, A, Al-Yamani, F, Andersen, P, Anderson, DM, Beardall, J, Berg, GM, Brand, L, Bronk, D, Brookes, J, Burkholder, JM, Cembella, A, Cochlan, WP, Collier, JL, Collos, Y, Diaz, R, Doblin, M, Drennen, T, Dyhrman, S, Fukuyo, Y, Furnas, M, Galloway, J, Graneli, E, Ha, DV, Hallegraeff, G, Harrison, J, Harrison, PJ, Heil, CA, Heimann, K, Howarth, R, Jauzein, C, Kana, AA, Kana, TM, Kim, H, Kudela, R, Legrand, C, Mallin, M, Mulholland, M, Murray, S, O'Neil, J, Pitcher, G, Qi, Y, Rabalais, N, Raine, R, Seitzinger, S, Salomon, PS, Solomon, C, Stoecker, DK, Usup, G, Wilson, J, Yin, K, Zhou, M & Zhu, M 2008, 'Ocean urea fertilization for carbon credits poses high ecological risks', MARINE POLLUTION BULLETIN, vol. 56, no. 6, pp. 1049-1056.
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The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed. © 2008 Elsevier Ltd. All rights reserved.
Guo, W, Ngo, H-H, Vigneswaran, S, Xing, W & Goteti, P 2008, 'A novel sponge-submerged membrane bioreactor (SSMBR) for wastewater treatment and reuse', SEPARATION SCIENCE AND TECHNOLOGY, vol. 43, no. 2, pp. 273-285.
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Membrane fouling has been regarded as one of the biggest challenges to widespread application of membrane bioreactor (MBR). This study focuses on minimizing the membrane fouling and improving the performance of submerged membrane bioreactor (SMBR) by porous sponge addition. The effects of sponge addition on sustainable flux and membrane fouling were investigated. Acclimatized sponge could significantly increase the suspended growth in SMBR with biomass of 16.7g/L(sponge). With the sponge volume fraction of 10%, SSMBR could enhance sustainable flux up to 50L/m2h compared with sustainable flux of SMBR (only 25L/m2h). SSMBR also exhibited excellent results in terms of DOC removal (over 95%), COD removal (over 97%), lower transmembrane pressure development, and oxygen uptake rate. Over 89% of NH4-N and 98% of PO4-P were removed when SSMBR was operated with a MLSS concentration of 15g/L.
Guo, W, Vigneswaran, S, Ngo, H-H, Xing, W & Goteti, P 2008, 'Comparison of the performance of submerged membrane bioreactor (SMBR) and submerged membrane adsorption bioreactor (SMABR)', BIORESOURCE TECHNOLOGY, vol. 99, no. 5, pp. 1012-1017.
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This study focuses on comparing the performance of submerged membrane bioreactor (SMBR) and submerged membrane adsorption bioreactor (SMABR) over a period of 20 days at a hydraulic retention time (HRT) of 3.1 h. The effects of PAC on critical flux and membrane fouling were also investigated. The SMABR exhibited better results in terms of mixed liquor suspended solids (MLSS) growth, DOC removal (over 96%), COD removal (over 95%), transmembrane pressure (TMP) and oxygen uptake rate. Nearly 100% of bacteria and 100% of total coliforms were removed in both systems. The addition of PAC could maintain the critical flux at a lower TMP value (7.5 kPa), while irreversible fouling caused by PAC occurred when the filtration flux exceeded critical flux.
Guo, WS, Vigneswaran, S, Ngo, HH & Xing, W 2008, 'Comparison of membrane bioreactor systems in wastewater treatment', DESALINATION, vol. 231, no. 1-3, pp. 61-70.
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This study investigated the performance of four different membrane bioreactor (MBR) systems, namely floating media biofilter-crossflow microfiltration (FMB-CFMF) system, submerged membrane bioreactor (SMBR) alone, submerged membrane adsorption bioreactor (SMABR) and sponge-SMBR system, in terms of critical flux. The results indicated that FMB could be used as a pretreatment unit prior to MBR in order to minimize membrane fouling when the FMB-CFMF system operates under sub-critical flux condition. The addition of powdered activated carbon (PAC) could maintain the sustainable flux at a lower TMP value (7.5 kPa). However, irreversible fouling occurred when the filtration flux exceeded the critical flux. The addition of 10% volume (reactor volume) fraction of sponge could increase sustainable flux of SMBR system to 2 times. © 2008.
Guo, WS, Vigneswaran, S, Ngo, HH, Kandasamy, J & Yoon, S 2008, 'The role of a membrane performance enhancer in a membrane bioreactor: a comparison with other submerged membrane hybrid systems', DESALINATION, vol. 231, no. 1-3, pp. 305-313.
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Among the membrane processes, membrane bioreactor (MBR) technologies are becoming an innovative and promising option for wastewater treatment and reuse. In this study the performance of the submerged membrane bioreactor was studied with an addition of MPE50, and it was compared against a sponge submerged membrane bioreactor (SMBR) and submerged membrane adsorption bioreactor (SMABR) in terms of TOC removal, COD removal, ammonium nitrogen (NH4-H) removal, orthophosphate (PO4-P) removal, transmembrane pressure (TMP) and oxygen uptake rate. SMBR with MPE50 addition significantly improved the sustainable flux and reduced membrane fouling. The improvement was better than even in the sponge SMBR system. SMBR with MPE50 achieved a high DOC and COD removal efficiency and NH4-N removal. PO4-P removal concentration of 62% initially which increased with time to over 99% after 7 day operation. In terms of phosphorus removal the sponge SMBR system performed better. OUR measurements showed that there was more microbial activity in the SMBR with MPE50 system
Hill, R & Ralph, PJ 2008, 'Dark-induced reduction of the plastoquinone pool in zooxanthellae of scleractinian corals and implications for measurements of chlorophyll a fluorescence', SYMBIOSIS, vol. 46, no. 1, pp. 45-56.
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Fluorometric measurements of maximum quantum yield (Fv/F m) and fast induction curves (FICs) require coral samples to be dark-adapted (DA). Pathways causing dark-reduction of the plastoquinone (PQ) pool are shown here to be active in corals. Early morning sunlight and far-red light successfully increased Fv/Fm and lowered the O and J steps of FICs in corals that were darkened overnight. The thick-tissued massive coral, Cyphastrea serailia, was shown to be more prone to reduction of the PQ pool, with significant reductions in Fv/Fm occurring after 10 min of DA, and elevated J steps occurring within 200 s following a far-red flash. In thinner-tissued branching species, Pocillopora damicornis and Acropora nobilis, elevation of the J step also occurred within 200 s of DA, but a drop in Fv/Fm was only manifested after 30 min. Pre-exposure to far-red light is an effective and simple procedure to ensure determination of the true maximum quantum yield of Photosystem II (PSII) and accurate FICs which require a fully oxidised inter-system electron transport chain and open PSII reaction centres. ©2008 Balaban.
Hill, R & Ralph, PJ 2008, 'Impact of bleaching stress on the function of the oxygen evolving complex of zooxanthellae from scleractinian corals', JOURNAL OF PHYCOLOGY, vol. 44, no. 2, pp. 299-310.
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Global climate change is leading to the rise of ocean temperatures and is triggering mass coral bleaching events on reefs around the world. The expulsion of the symbiotic dinoflagellate algae is believed to occur as a result of damage to the photosynthetic apparatus of these symbionts, although the specific site of initial impact is yet to be conclusively resolved. Here, the sensitivity of the oxygen evolving complex (OEC) to bleaching stress was studied as well as its natural variation between seasons. The artificial electron donor, diphenyl carbazide (DPC), was added to cultured, freshly isolated and expelled (bleaching treatments only) zooxanthellae suspensions. Chl a fluorescence and oxygen production measurements showed that upon addition of DPC, no restoration of diminished photochemical efficiency occurred under control or bleaching conditions. This result was consistent between 12 h and 5 d bleaching treatments on Pocilloporadamicornis, indicating that the OEC is not the primary site of damage, and that zooxanthellae expulsion from the host is a nonselective process with respect to the functioning of the OEC. Further experiments measuring fast induction curves (FICs) revealed that in both summer and winter, the temperature when OEC function was lost occurred between 7°C and 14°C above the sea surface temperature. FIC and oxygen production measurements of P. damicornis during exposure to bleaching stress demonstrated that the thermotolerance of the OEC increased above the temperature of the bleaching treatment over a 4 h period. This finding indicates that the OEC has the capacity to acclimate between seasons and remains functional at temperatures well above bleaching thresholds. © 2008 Phycological Society of America.
Hoang, TTL, Vigneswaran, S, Ngo, HH, Kandasamy, J, Shim, WG, Chaudhary, DS, Gotety, P & Peiris, P 2008, 'Performance evaluation and mathematical modelling of granular activated carbon biofiltration in wastewater treatment', KOREAN JOURNAL OF CHEMICAL ENGINEERING, vol. 25, no. 2, pp. 259-267.
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Biological filtration is an effective technique for removing organic matter from wastewater. The performance of a biofilter can be influenced by a range of operational conditions. In this study the performance of biofilters was investigated for the influence of filter media depth, influent concentrations, filtrations rates and backwashing. The results show that performance of GAC filters decreased with shallower filter bed depths. In addition, the GAC performed better at lower influent concentration and lower filtration rates. The daily backwash adopted to avoid the physical clogging of the biofilter did not have any significant effect on the organic removal efficiency of the filter. The concentration, activity and characteristics of the biomass are quantified and described. A mathematical model was developed to simulate the organic removal of the GAC biofiltration system. The performance of the GAC filter under different influent organic concentration levels, filtration rates and filter bed depths was adequately simulated by the mathematical model developed for this study. © 2008 Springer.
Indraratna, B, Muttuvel, T, Khabbaz, H & Armstrong, R 2008, 'Predicting the erosion rate of chemically treated soil using a process simulation apparatus for internal crack erosion', JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING, vol. 134, no. 6, pp. 837-844.
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Chemical stabilization is an effective ground improvement technique for controlling erosion. Two stabilizers, lignosulfonate and cement, were used to study how effectively they could stabilize erodible silty sand collected from Wombeyan Caves, NSW, Australia. To conduct this research, four dosages of cement (0.5, 1, 1.5, and 2%) and four dosages of lignosulfonate (0.1, 0.2, 0.4, and 0.6%) by dry weight of soil were selected. All treated and untreated soil specimens were compacted to 90 and 95% of their maximum dry density to study the effect of compaction level on erodibility. The erosion characteristics of treated and untreated soil samples were investigated using a process simulation apparatus for internal crack erosion designed and built at the University of Wollongong. The findings of this study indicated that both chemical stabilizers increased the resistance to erosion because of their cementing properties. It was also found that the critical shear stress increased linearly with the amount of stabilizer, and the coefficient of soil erosion decreased as a power function of the critical shear stress. © 2008 ASCE.
Indraratna, B, Muttuvel, T, Khabbaz, H & Armstrong, R 2008, 'Predicting the Erosion Rate of Chemically Treated Soil Using a Process Simulation Apparatus for Internal Crack Erosion', Journal of Geotechnical and Geoenvironmental Engineering, vol. 134, no. 6, pp. 837-844.
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Chemical stabilization is an effective ground improvement technique for controlling erosion. Two stabilizers, lignosulfonate and cement, were used to study how effectively they could stabilize erodible silty sand collected from Wombeyan Caves, NSW, Australia. To conduct this research, four dosages of cement 0.5, 1, 1.5, and 2% and four dosages of lignosulfonate 0.1, 0.2, 0.4, and 0.6% by dry weight of soil were selected. All treated and untreated soil specimens were compacted to 90 and 95% of their maximum dry density to study the effect of compaction level on erodibility. The erosion characteristics of treated and untreated soil samples were investigated using a process simulation apparatus for internal crack erosion designed and built at the University of Wollongong. The findings of this study indicated that both chemical stabilizers increased the resistance to erosion because of their cementing properties. It was also found that the critical shear stress increased linearly with the amount of stabilizer, and the coefficient of soil erosion decreased as a power function of the critical shear stress.
Indraratna, B, Trani, LDO & Khabbaz, H 2008, 'A critical review on granular dam filter behaviour – from particle sizes to constriction-based design criteria', Geomechanics and Geoengineering, vol. 3, no. 4, pp. 279-290.
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Over emphasis on tests results involving base soils with increasing coefficient of uniformity (Cu) makes the reliability of an empirical particle-based criterion for effective filters questionable. Extra measures such as regrading of base soil are then necessary in order to capture the effectiveness of filter constriction sizes in trapping eroding fines. Recent studies which focused on the role of the sizes of filter voids on overall filtration behaviour have deployed constriction size approaches that were shown to be equally acceptable methods for distinguishing between effective and ineffective filters. This paper examines the evolution of this approach, starting from past empirical and mathematical investigations and proceeding to the eventual development of geometric-probabilistic methods with special reference to embankment dams. Models based on dominant and controlling constriction sizes are introduced, and subsequently the constriction-based retention criteria for granular filters are presented. The proposed retention criteria were verified based on extensive experimental data taken from small- and large-scale filtration tests carried out by various authors. The integration of filter compaction, porosity and Cu, together with the incorporation of analytical principles, provides alternative and rigorous design approaches that remove most limitations of the conventional particle-based criteria, thus making the models essentially more comprehensive and quantifiable.
Jimenez, IM, Kuehl, M, Larkum, AWD & Ralph, PJ 2008, 'Heat budget and thermal microenvironment of shallow-water corals: Do massive corals get warmer than branching corals?', LIMNOLOGY AND OCEANOGRAPHY, vol. 53, no. 4, pp. 1548-1561.
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Coral surface temperature was investigated with multiple temperature sensors mounted on hemispherical and branching corals under (a) artificial lighting and controlled flow; (b) natural sunlight and controlled flow; and (c) in situ conditions in a shallo
Kalam, MA & Masjuki, HH 2008, 'Potential and properties of palm diesel as alternative fuel for automotive engines', International Energy Journal, vol. 9, no. SPEC. ISSUE, pp. 37-42.
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This paper presents the potential, properties and test results of palm diesel as an alternative fuel for automotive engines. The palm diesel was tested with different blending ratio with diesel fuel as well as with antioxidant additive. Total three fuels were tested such as 100% diesel fuel, 20% palm diesel with 80% diesel fuel (B20); and B20 with 1% antioxidant additive. The pure diesel fuel was used for comparison purposes. A multi cylinder diesel engine was used in this investigation. The data presented are palm diesel production and potential status, physicochemical properties such as fuel standardization, engine brake power, fuel consumption and emissions results. It can be said that the palm diesel production, properties and test results have reached to a point as it is ready to be implemented in diesel engine. According to a stationary dynamometer-engine test, it is found that the 20% palm diesel with antioxidant additive shows better results such as less HC, CO and NOx emissions as compared to pure diesel fuel. The details test results including palm diesel price consideration have been presented with discussions.
Kalam, MA & Masjuki, HH 2008, 'Testing palm biodiesel and NPAA additives to control NOx and CO while improving efficiency in diesel engines', Biomass and Bioenergy, vol. 32, no. 12, pp. 1116-1122.
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Kalam, MA, Masjuki, HH, Saifullah, MG & Seng, TB 2008, 'Envo diesel test on automotive engine - An analysis of its performance and emissions results', International Journal of Mechanical and Materials Engineering, vol. 3, no. 1, pp. 55-60.
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If the agricultural products market is limited and much of agricultural land is not utilized as is the case in many countries in the world at present, then agriculture should be directed to the production of new alternative products. The land can be used to produce non-food products including biofuels for the domestic energy market to diminish imports. Much research has been conducted on biofuels over the last 20 years. At present, concern about environmental regulations, green house gases and fossil fuel reservartion (including natural) have been the major reasons to look for alternative fuels that come from renewable resources. A significant level in terms of physico-chemical properties of biofuel has been obtained mostly from methyl ester of food based vegetable oils; it is now the issue to be concerned about human food oil versus biofuel production. This paper presents the experimental results carried out to evaluate performance and exhaust emissions of a diesel engine operated on 'Envo Diesel' which consists of 5% palm oil and 95% ordinary diesel fuel (as P5). The Envo diesel is a policy of Malaysian government that emphasises on usage of waste palm oil with diesel fuel without esterification. This investigation also includes a benchmarking study with 5% coconut oil with 95% diesel fuel (as C5). However, all the results have been compared with pure diesel fuel (B0). The results show that fuels P5 and C5 reduce brake power 1.2% and 0.7% respectively as compared to B0. However, both the fuels P5 and C5 reduce exhaust emissions such as reduce HC, smoke, CO and NOx concentration. The paper contains the test results, properties of P5 and C5 biofuel and comparison with other biofuels that obtained from various vegetable oils. The results of this investigation will be used to find compatible lubricant/additive for biofuel operated engines.
Kalam, MA, Saifullah, MG, Masjuki, HH, Husnawan, M & Mahlia, TMI 2008, 'PAH and other emissions from account oil blended fuels', Journal of Scientific and Industrial Research, vol. 67, no. 11, pp. 1031-1035.
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This paper presents results of a multi-cylinder diesel engine operated on blends of ordinary coconut oil (COCO; 10%, 20%,30%,40%,50%) with ordinary diesel oil (OD). Methyl esters from cooking oil are less encouraging to be used as biofuel. because this affects food-fuel crisis. However, biofuel obtained from waste cooking oil is more appreciated due to energy savings and environmental issues. Test results indicated that COCO blended fuels (10-30 %) produced similar brake power and net heat release rate as OD. Increasing coconut oil in blend decreases exhaust emissions. Carbon deposited on injector nozzles was observed where no hard carbon was found on injector tip when engine run on COCO blends.
Kalam, MA, Sultana, Y, Samad, A, Ali, A, Aqil, M, Sharma, M & Mishra, AK 2008, 'Gelrite‐Based In Vitro Gelation Ophthalmic Drug Delivery System of Gatifloxacin', Journal of Dispersion Science and Technology, vol. 29, no. 1, pp. 89-96.
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Kandasamy, J, Beecham, S & Dunphy, A 2008, 'Stormwater sand filters in water-sensitive urban design', Proceedings of the Institution of Civil Engineers - Water Management, vol. 161, no. 2, pp. 55-64.
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This paper investigates the suitability of sand filters for harvesting and treating stormwater for non-potable reuse purposes. A stormwater sand filtration device was constructed in a small urban catchment in Sydney, Australia. A sand filter is typically used in water-sensitive urban design (WSUD) as a component of a treatment train to remove pollution from stormwater before discharge to receiving waters, to groundwater or for collection and reuse. This paper describes an 18 month field study undertaken to determine the effectiveness and pollutant removal efficiency of a sand filter, and the differences in the pollutant removal efficiency of two grades of sand. A comparison of pollutant removal with previous literature on sand filters showed similar efficiencies but nutrient removal was higher than expected. A further unexpected result was that the coarse filter media performed as well as the fine media for most pollutant types and was superior in suspended solids removal. Improved modelling equations for predicting suspended solids and total phosphorus removal in sand filters are also presented in this paper.
Kannapiran, A, Chanan, A, Singh, G, Tambosis, P, Jeyakumaran, J & Kandasamy, J 2008, 'Strategic asset management planning of stormwater drainage systems', Water Practice and Technology, vol. 3, no. 3, pp. 1-8.
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Management of the urban water cycle in an integrated manner is an essential task to protect, restore and enhance in a sustainable manner. Strategic asset management planing is being developed as local government authorities face many challenges associated with managing the urban water cycle system. Statistical or conventional mathematical modelling approach has been found not practical for assessment of deteriorating infrastructures. Alternatively, application of fuzzy-based models is found more suitable as it links engineering judgment, experience and scarce field data of the deteriorating assets. In this study, a representative network of buried stormwater system's data is drawn and a pipe condition index is derived by linking the field data and reasoning using fuzzy approach. The inferred results are found to be useful and relevant for asset maintenance and future development programs.
Kim, S-H, Ngo, HH, Shon, HK & Vigneswaran, S 2008, 'Adsorption and photocatalysis kinetics of herbicide onto titanium oxide and powdered activated carbon', SEPARATION AND PURIFICATION TECHNOLOGY, vol. 58, no. 3, pp. 335-342.
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The adsorption and photocatalysis kinetics of metsulfuron-methyl (MM) onto titanium oxide (TiO2) and powdered activated carbon (PAC) were studied at varying adsorbent amount and MM concentration. The overall mass transfer in adsorption was estimated from concentration decay curves obtained in the batch adsorber. The maximum adsorption capacity decreased with increasing adsorbent amount in TiO2 adsorption. The adsorption isotherms of MM could be plotted using the Langmuir isotherm model with a reasonable degree of accuracy having higher r2 values rather than Freundlich isotherm model. Linear driving force approximation (LDFA) kinetic equation with Langmuir adsorption isotherm model was successfully applied to predict the adsorption kinetics data in various concentrations of MM in photobatch reactor. The estimated mass transfer coefficient was used to be 3.0 × 10-5, 5.5 × 10-5, 9.1 × 10-5 m/s in PAC adsorption and 2.0 × 10-5, 1.1 × 10-5, 9.0 × 10-6 m/s in TiO2 adsorption for a different MM concentration of 20, 50 and 70 mg/L, respectively. Photocatalysis kinetics was same with TiO2 of 0.2 g/L regardless of TiO2 amounts and the MM degradation kinetics was enhanced by TiO2 catalysis rather than only UV light degradation. Among the photocatalysis kinetics model with first-order, second-order and LangmuirHinshelwood (LH) model, a second-order kinetic model was found to well present the experimental data of MM by TiO2 catalyst for the range of various TiO2 amounts and MM concentration studied.
Kuehl, M, Holst, G, Larkum, AWD & Ralph, PJ 2008, 'Imaging of oxygen dynamics within the endolithic algal community of the massive coral Porites lobata', JOURNAL OF PHYCOLOGY, vol. 44, no. 3, pp. 541-550.
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We used transparent planar oxygen optodes and a luminescence lifetime imaging system to map (at a pixel resolution of <200 ?m) the two-dimensional distribution of O2 within the skeleton of a Porites lobata colony. The O2 distribution was closely correlated to the distribution of the predominant endolithic microalga, Ostreobium quekettii Bornet et Flahault that formed a distinct green band inside the skeleton. Oxygen production followed the outline of the Ostreobium band, and photosynthetic O2 production was detected at only 0.2 ?mol photons m-2 · s-1, while saturation occurred at ?37 ?mol photons m-2 · s-1. Oxygen levels varied from ?60% to 0% air saturation in the illuminated section of the coral skeleton in comparison to the darkened section. The O2 production within the Ostreobium band was lower in the region below the upward facing surface of the coral and elevated on the sides. Oxygen consumption in darkness was also greatest within the Ostreobium zone, as well as in the white skeleton zone immediately below the corallites. The rate of O2 depletion was not constant within zones and between zones, showing pronounced heterogeneity in endolithic respiration. When the coral was placed in darkness after a period of illumination, O2 levels declined by 50% within 20 min and approached steady-state after 4050 min in darkness. Our study demonstrates the use of an important new tool in endolith photobiology and presents the first data of spatially resolved O2 concentration and its correlation to the physical structures and specific zones responsible for O2 production and consumption within the coral skeleton.
Lamei, A, van der Zaag, P & von Münch, E 2008, 'Basic cost equations to estimate unit production costs for RO desalination and long-distance piping to supply water to tourism-dominated arid coastal regions of Egypt', Desalination, vol. 225, no. 1-3, pp. 1-12.
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An integrated photocatalysismembrane hybrid system was investigated for wastewater treatment with the main focus on improving the cross flow microfiltration (MF) permeate flux. Photocatalysis with TiO2 (P25 Degussa) suspension as photocatalyst was applied both as pre-treatment and as inline treatment with MF. The TiO2 slurry was found to have significant effect in permeate flux for wastewater with lower dissolved organic carbon concentration. The MF flux decline due to TiO2 slurry cake on the membrane surface was minimized by allowing the TiO2 slurry to settle and by using only the supernatant for further treatment using the hybrid system. The investigation also included the study on the effect of photocatalytic reaction time and the slurry settling times on the MF permeate flux. The irradiation of ultraviolet on the MF surface in presence of TiO2 catalyst in suspension yielded in an increase in permeate flux.
Lim, GT, Kim, KH, Kim, KS, Li, HJ, Song, SJ, Shon, H & Cho, DL 2008, 'A study on the dry cleaning of aluminium surfaces by low temperature plasma process', Journal of the Korean Industrial and Engineering Chemistry, vol. 19, no. 6, pp. 640-644.
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Lubricating oil on aluminium surfaces was cleaned by a low temperature plasma process. Oxygen plasma mixed with argon was used, and process parameters were the mixing ratio of argon in oxygen, discharge power, and negative DC potential. The aluminium surfaces were analyzed with FTIR and EDX after the cleaning. It was found that almost all of the oil was eliminated in 20 min. if the oil was pure. Elimination efficiency was highly dependent on operational conditions of the process. The highest efficiency was obtained when treated at 300 W with oxygen plasma mixed with 30% argon applying negative potential more than -500 V on the aluminium surfaces. However, efficiency higher that 60% cannot be obtained at any condition if the oil contained inorganic materials.
Lin, W, Fu, Q, Zhang, Y & Huang, J 2008, 'One-Pot Synthesis of ABC Type Triblock Copolymers via a Combination of “Click Chemistry” and Atom Transfer Nitroxide Radical Coupling Chemistry', Macromolecules, vol. 41, no. 12, pp. 4127-4135.
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Liu, S-Y, Chen, Y-P, Fang, F, Li, S-H, Ni, B-J, Liu, G, Tian, Y-C, Xiong, Y & Yu, H-Q 2008, 'Innovative Solid-State Microelectrode for Nitrite Determination in a Nitrifying Granule', Environmental Science & Technology, vol. 42, no. 12, pp. 4467-4471.
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Nghiem, LD & Coleman, PJ 2008, 'NF/RO filtration of the hydrophobic ionogenic compound triclosan: Transport mechanisms and the influence of membrane fouling', Separation and Purification Technology, vol. 62, no. 3, pp. 709-716.
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Nghiem, LD, Vogel, D & Khan, S 2008, 'Characterising humic acid fouling of nanofiltration membranes using bisphenol A as a molecular indicator', Water Research, vol. 42, no. 15, pp. 4049-4058.
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Ngo, H-H, Guo, W & Xing, W 2008, 'Evaluation of a novel sponge-submerged membrane bioreactor (SSMBR) for sustainable water reclamation', BIORESOURCE TECHNOLOGY, vol. 99, no. 7, pp. 2429-2435.
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A novel sponge-submerged membrane bioreactor (SSMBR) to treat a high strength wastewater for water reclamation was developed in this study. The performance of this system was evaluated using two kinds of polyester-urethane sponges (coarse sponge with hig
Nguyen, TV, Vigneswaran, S, Ngo, HH, Kandasamy, J & Choi, HC 2008, 'Arsenic removal by photo-catalysis hybrid system', SEPARATION AND PURIFICATION TECHNOLOGY, vol. 61, no. 1, pp. 44-50.
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Arsenic is a toxic semi-metallic element that can be fatal to human health. Arsenic pollution in water is found in many parts of the world, especially in developing countries such as Bangladesh, India, Nepal, and Vietnam. Photo-oxidation experiments with titanium dioxide (TiO2) as photo-catalyst showed that photo-oxidation of As(III) to As(V) is possible within minutes. Further, TiO2 can also adsorb both As(III) and As(V) on its surface. Photo-catalysis reaction with TiO2 reduced about 98% of arsenite from water containing 500 μg/L of arsenite. By adding nano-scale zero valent iron (nZVI) of 0.05 g/L in the photo-reactor, arsenic removal can be significantly enhanced. Further the TiO2 requirement is five times less in this photo-catalysis nZVI hybrid system. The photo-catalytic degradation processes was modeled using the first-order, second-order and Langmuir-Hinshelwood kinetics equations and removal rates were simulated. © 2007 Elsevier B.V. All rights reserved.
Ni, B & Yu, H 2008, 'Growth and storage processes in aerobic granules grown on soybean wastewater', Biotechnology and Bioengineering, vol. 100, no. 4, pp. 664-672.
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AbstractAerobic granules in a sequencing batch reactor (SBR) are subjected to alternative feast and famine conditions, and are able to take up carbon substrate in wastewater rapidly and to store it as intracellular storage products when the substrate is in excess. This phenomenon could not be described by the widely used activated sludge model No.3 (ASM3). In this work, taking adsorption process, microbial maintenance, and substrate diffusion into account, the simultaneous growth and storage processes occurring in an aerobic‐granule‐based SBR are investigated with experimental and modeling approaches. A new model is established and successfully validated with the experimental results of an SBR fed with soybean‐processing wastewater. Simulation results show that our approach is appropriate for elucidating the fates of major model components. Comparison between ASM3 and the model established in this work demonstrates that the latter is better to describe the substrate removal mechanisms and simultaneous growth and storage processes in aerobic granules. Biotechnol. Bioeng. 2008;100: 664–672. © 2008 Wiley Periodicals, Inc.
Ni, B & Yu, H 2008, 'Storage and growth of denitrifiers in aerobic granules: Part I. model development', Biotechnology and Bioengineering, vol. 99, no. 2, pp. 314-323.
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AbstractA mathematical model, based on the Activated Sludge Model No.3 (ASM3), is developed to describe the storage and growth activities of denitrifiers in aerobic granules under anoxic conditions. In this model, mass transfer, hydrolysis, simultaneous anoxic storage and growth, anoxic maintenance, and endogenous decay are all taken into account. The model established is implemented in the well‐established AQUASIM simulation software. A combination of completely mixed reactor and biofilm reactor compartments provided by AQUASIM is used to simulate the mass transport and conversion processes occurring in both bulk liquid and granules. The modeling results explicitly show that the external substrate is immediately utilized for storage and growth at feast phase. More external substrates are diverted to storage process than the primary biomass production process. The model simulation indicates that the nitrate utilization rate (NUR) of granules‐based denitrification process includes four linear phases of nitrate reduction. Furthermore, the methodology for determining the most important parameter in this model, that is, anoxic reduction factor, is established. Biotechnol. Bioeng. 2008;99: 314–323. © 2007 Wiley Periodicals, Inc.
Ni, B, Yu, H & Xie, W 2008, 'Storage and growth of denitrifiers in aerobic granules: Part II. model calibration and verification', Biotechnology and Bioengineering, vol. 99, no. 2, pp. 324-332.
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AbstractA mathematical model to describe the simultaneous storage and growth activities of denitrifiers in aerobic granules under anoxic conditions has been developed in an accompanying article. The sensitivity of the nitrate uptake rate (NUR) toward the stoichiometric and kinetic coefficients is analyzed in this article. The model parameter values are estimated by minimizing the sum of squares of the deviations between the measured and model‐predicted values. The model is successfully calibrated and a set of stoichiometric and kinetic parameters for the anoxic storage and growth of the denitrifiers are obtained. Thereafter, the model established is verified with three set of experimental data. The comparison between the model established with the ASM1 model and ASM3 shows that the present model is appropriate to simulate and predict the performance of a granule‐based denitrification system. Biotechnol. Bioeng. 2008;99: 324–332. © 2007 Wiley Periodicals, Inc.
Ni, B-J & Yu, H-Q 2008, 'An approach for modeling two-step denitrification in activated sludge systems', Chemical Engineering Science, vol. 63, no. 6, pp. 1449-1459.
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Ni, B-J & Yu, H-Q 2008, 'Characterization of the granules in an ANAMMOX reactor after accelerated startup', Journal of Biotechnology, vol. 136, pp. S651-S651.
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Ni, B-J & Yu, H-Q 2008, 'Kinetic modeling microbial storage process in activated sludge under anoxic conditions', Chemical Engineering Science, vol. 63, no. 10, pp. 2785-2792.
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Ni, B-J & Yu, H-Q 2008, 'Simulation of heterotrophic storage and growth processes in activated sludge under aerobic conditions', Chemical Engineering Journal, vol. 140, no. 1-3, pp. 101-109.
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Ni, B-J, Fang, F, Xie, W-M & Yu, H-Q 2008, 'Growth, maintenance and product formation of autotrophs in activated sludge: Taking the nitrite-oxidizing bacteria as an example', Water Research, vol. 42, no. 16, pp. 4261-4270.
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Ni, B-J, Yu, H-Q & Sun, Y-J 2008, 'Modeling simultaneous autotrophic and heterotrophic growth in aerobic granules', Water Research, vol. 42, no. 6-7, pp. 1583-1594.
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Petrou, K, Doblin, MA, Smith, RA, Ralph, PJ, Shelly, K & Beardall, J 2008, 'State transitions and nonphotochemical quenching during a nutrient-induced fluorescence transient in phosphorus-starved Dunaliella tertiolecta', JOURNAL OF PHYCOLOGY, vol. 44, no. 5, pp. 1204-1211.
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Assessments of nutrient-limitation in microalgae using chl a fluorescence have revealed that nitrogen and phosphorus depletion can be detected as a change in chl a fluorescence signal when nutrient-starved algae are resupplied with the limiting nutrient. This photokinetic phenomenon is known as a nutrient-induced fluorescence transient, or NIFT. Cultures of the unicellular marine chlorophyte Dunaliella tertiolecta Butcher were grown under phosphate starvation to investigate the photophysiological mechanism behind the NIFT response. A combination of low temperature (77 K) fluorescence, photosynthetic inhibitors, and nonphotochemical quenching analyses were used to determine that the NIFT response is associated with changes in energy distribution between PSI and PSII and light-stress-induced nonphotochemical quenching (NPQ). Previous studies point to state transitions as the likely mechanism behind the NIFT response; however, our results show that state transitions are not solely responsible for this phenomenon. This study shows that an interaction of at least two physiological processes is involved in the rapid quenching of chl a fluorescence observed in P-starved D. tertiolecta: (1) state transitions to provide the nutrient-deficient cell with metabolic energy for inorganic phosphate (Pi)-uptake and (2) energy-dependent quenching to allow the nutrient-stressed cell to avoid photodamage from excess light energy during nutrient uptake. © 2008 Phycological Society of America.
Roff, G, Ulstrup, KE, Fine, M, Ralph, PJ & Hoegh-Guldberg, O 2008, 'Spatial heterogeneity of photosynthetic activity within diseased corals from the great barrier reef', JOURNAL OF PHYCOLOGY, vol. 44, no. 2, pp. 526-538.
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Morphological diagnosis and descriptions of seven disease-like syndromes affecting scleractinian corals were characterized from the southern Great Barrier Reef (GBR). Chl a fluorescence of PSII was measured using an Imaging-PAM (pulse amplitude modulated) fluorometer, enabling visualization of the two-dimensional variability in the photophysiology of endosymbiotic dinoflagellates (zooxanthellae) by measuring rapid light curves. Three of four syndromes associated with active tissue loss (type a) were spatially homogenous (white syndrome, brown band, and skeletal eroding band), with no impact on the photochemical function of zooxanthellae populations at or behind the lesion borders. However, a decline in maximum quantum yield (Fv/F m) and elevated levels of maximum nonphotochemical quenching (NPQmax) occurred in visually healthy tissue of black band disease adjacent to the lesion borders, possibly due to hypoxic conditions caused by the black band cyanobacterial mat. Two out of three syndromes associated with pathological change of intact tissue with no active tissue loss (type b) showed variable photophysiological responses (neoplasia and pigmentation response). Only the bleached foci associated with white patch syndrome appeared to impact primarily on the symbiotic dinoflagellates, as evidenced by declines in minimum fluorescence (F0) and maximum quantum yield (Fv/F m), with no indication of degeneration in the host tissues. Our results suggest that for the majority of coral syndromes from the GBR, pathogenesis occurs in the host tissue, while the impact on the zooxanthellae populations residing in affected corals is minimal. © 2008 Phycological Society of America.
Sabina, L, Kus, B, Shon, H-K & Kandasamy, J 2008, 'Membrane fouling propensity after adsorption as pretreatment in rainwater: a detailed organic characterisation', WATER SCIENCE AND TECHNOLOGY, vol. 58, no. 8, pp. 1535-1539.
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Organic characterisation in rainwater was investigated in terms of dissolved organic carbon (DOC) and molecular weight distribution (MWD) after powdered activated carbon (PAC) adsorption. PAC adsorption was used as pretreatment to membrane filtration to
Samad, A, Sultana, Y, Khar, RK, Aqil, M, Kalam, MA, Chuttani, K & Mishra, AK 2008, 'Radiolabeling and evaluation of alginate blend-isoniazid microspheres by99mTc for the treatment of tuberculosis in rabbit model', Journal of Drug Targeting, vol. 16, no. 6, pp. 509-515.
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Shon, HK, Phuntsho, S & Vigneswaran, S 2008, 'Effect of photocatalysis on the membrane hybrid system for wastewater treatment', DESALINATION, vol. 225, no. 1-3, pp. 235-248.
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Shon, HK, Vigneswaran, S & Cho, J 2008, 'Comparison of physico-chemical pretreatment methods to seawater reverse osmosis: Detailed analyses of molecular weight distribution of organic matter in initial stage', JOURNAL OF MEMBRANE SCIENCE, vol. 320, no. 1-2, pp. 151-158.
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In desalination, effective pretreatment is the key to reduce membrane fouling that occurs during the seawater reverse osmosis (SWRO) process. However, it is difficult to compare the flux decline after different pretreatments using a small-scale reverse osmosis filtration unit. In this study, we successfully evaluated the effect of pretreatment on SWRO in terms of molecular weight distribution (MWD) of seawater organic matter (SWOM) after 20 h of SWRO operation. Microfiltration (MF), ultrafiltration (UF), ferric chloride (FeCl3) flocculation and powdered activated carbon (PAC) adsorption, were used as pretreatment. The effluents and the retentates after each pretreatment and 20 h of SWRO operation were characterized in terms of MWD. Although the normalized flux of SWRO showed similar flux decline (J/J0 = 0.17) with/without pretreatment, SWOM concentration in the retentates after different pretreatments was different in quantity and it increased linearly with time. The slope of the SWOM increase was 0.110, 0.096, 0.077 and 0.059 after MF, FeCl3 flocculation, UF and PAC adsorption pretreatments, respectively. MW peaks for the seawater used in this study consisted of 1200 Da (biopolymers), 950 Da (fulvic acids), 650 Da (hydrolysates of humic substances), 250 Da (low MW acids) and 90 Da (low MW neutrals and amphiphilics). FeCl3 flocculation preferentially removed 1200 Da (biopolymers), while PAC adsorption mostly removed 950 Da (fulvic acids). UF and NF removed only a marginal amount of relatively large organics, while RO removed the majority of organics. The intensity of 1200, 950, 650 and 250 Da MW in the RO retentates increased with the RO operation time. The organics of MW around 1200 Da (biopolymers) had a relatively low rate of increase with time compared with those of lower MW. This suggests that the SWOM of 1200 Da MW was preferentially retained on the membrane surface. © 2008 Elsevier B.V. All rights reserved.
Shon, HK, Vigneswaran, S, Kandasamy, J & Shim, WG 2008, 'Ultraflitration of wastewater with pretreatment: evaluation of flux decline models', DESALINATION, vol. 231, no. 1-3, pp. 332-339.
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Three different mathematical models relating the flux decline were investigated to quantify the effects of pretreatment in a membrane filtration system. The models used are empirical flux decline model, series resistance flux decline model and modified series resistance flux decline model. A cross flow ultrafiltration unit was used to study flux decline and organic removal from synthetic wastewater. Flocculation and adsorption pretreatments were carried out with ferric chloride (FeCl3) and activated carbon of different doses. The three models could predict flux decline after different pretreatments and could be used as a pretreatment index to ultrafiltration.
Thiruvenkatachari, R, Vigneswaran, S & Moon, IS 2008, 'A review on UV/TiO2 photocatalytic oxidation process (Journal Review)', Korean Journal of Chemical Engineering, vol. 25, no. 1, pp. 64-72.
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Advanced oxidation processes (AOPs) with UV irradiation and photocatalyst titanium dioxide (TiO2) are gaining growing acceptance as an effective wastewater treatment method. A comprehensive review of the UV-TiO 2 photocatalytic oxidation process was conducted with an insight into the mechanism involved, catalyst TiO2, irradiation sources, types of reactors, comparison between effective modes of TiO2 application as immobilized on surface or as suspension, and photocatalytic hybrid membrane system. Photocatalytic degradation technique with titanium dioxide is generally applied for treating wastewater containing organic contaminants due to its ability to achieve complete mineralization of the organic contaminants under mild conditions such as ambient temperature and ambient pressure. Recently, photocatalysis studies using TiO2 have been gaining attention for the degradation of persistent organic pollutants and other organic chemicals which are known to be endocrine disruptors. Treatment of wastewater in a titanium dioxide-suspended slurry reactor has been widely utilized due to its simplicity and enhanced degradation efficiency. However, this system requires separation of TiO2 from water after the photocatalytic process. The final section of the manuscript focuses on the removal of TiO2 using a membrane hybrid system. A two-stage coagulation and sedimentation process coupled with microfiltration hollow-fibre membrane process was found to achieve complete removal of TiO2, and the recovered TiO2 can be reused for a photocatalytic process after regeneration. © 2008 Springer.
Thiruvenkatachari, R, Vigneswaran, S & Naidu, R 2008, 'Permeable reactive barrier for groundwater remediation', Journal of Industrial and Engineering Chemistry, vol. 14, no. 2, pp. 145-156.
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This article aims to provide an overview of the upcoming technology of permeable reactive barriers for groundwater remediation. A comprehensive list of references and web-links are also provided for further in-depth understanding. A brief discussion on the Australian perspective on this emerging technology is also included. © 2008.
Tijing, LD, Pak, BC, Lee, DH & Cho, YI 2008, 'Heat-Treated Titanium Balls for the Mitigation of Mineral Fouling in Heat Exchangers', Experimental Heat Transfer, vol. 21, no. 2, pp. 115-132.
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Turner, BD, Binning, PJ & Sloan, SW 2008, 'A calcite permeable reactive barrier for the remediation of Fluoride from spent potliner (SPL) contaminated groundwater', Journal of Contaminant Hydrology, vol. 95, no. 3-4, pp. 110-120.
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Ulstrup, KE, Hill, R, van Oppen, MJH, Larkum, AWD & Ralph, PJ 2008, 'Seasonal variation in the photo-physiology of homogeneous and heterogeneous Symbiodinium consortia in two scleractinian corals', MARINE ECOLOGY PROGRESS SERIES, vol. 361, pp. 139-150.
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Seasonal variation in the composition of the algal endosymbiont community and photophysiology was determined in the corals Pocillopora damicornis,w hich show high local fidelity to one symbiont type (Symbiodinium C1) and Acropora valida, with a mixed Symbiodinium synbiont community, compromising members of both clades A and C. The relative abundances of Symbiodinium types varied overtime. A significant decline in symbiont densities in both coral species during the summer of 2005 coincided with a NOAA 'hotspot' warning for Heron Island. This also coincided with a relayiove increase in the presence and dominance of clade A in A. valida particularl in sun-adapted surfaces.
Xia, H, Guo, WW, Wu, X, Pi, YL & Bradford, MA 2008, 'Lateral dynamic interaction analysis of a train–girder–pier system', Journal of Sound and Vibration, vol. 318, no. 4-5, pp. 927-942.
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A dynamic model of a coupled train-girder-pier system is developed in this paper. Each vehicle in a train is modeled with 27 degrees-of-freedom for a 4-axle passenger coach or freight car, and 31 for a 6-axle locomotive. The bridge model is applicable to
Xing, W, Guo, W, Ngo, H, Listowski, A & Cullum, P 2008, 'Specific Anaerobic Fluidized Bed Bioreactors as Pretreatment to Microfiltration in Domestic Wastewater Treatment for Reuse', Journal of Applied Membrane Science & Technology, vol. 8, no. 2, pp. 1-8.
Xing, W, Ngo, HH, Kim, SH, Guo, WS & Hagare, P 2008, 'Adsorption and bioadsorption of granular activated carbon (GAC) for dissolved organic carbon (DOC) removal in wastewater', BIORESOURCE TECHNOLOGY, vol. 99, no. 18, pp. 8674-8678.
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In this study, the performances of GAC adsorption and GAC bioadsorption in terms of dissolved organic carbon (DOC) removal were investigated with synthetic biologically treated sewage effluent (BTSE), synthetic primary treated sewage effluent (PTSE), real BTSE and real PTSE. The main aims of this study are to verify and compare the efficiency of DOC removal by GAC (adsorption) and acclimatized GAC (bioadsorption). The results indicated that the performance of bioadsorption was significantly better than that of adsorption in all cases, showing the practical use of biological granular activated carbon (BGAC) in filtration process. The most significance was observed at a real PTSE with a GAC dose of 5 g/L, having 54% and 96% of DOC removal by adsorption and bioadsorption, respectively. In addition, it was found that GAC adsorption equilibrium was successfully predicted by a hybrid Langmuir-Freundlich model whilst integrated linear driving force approximation (LDFA) + hybrid isotherm model could describe well the adsorption kinetics. Both adsorption isotherm and kinetic coefficients determined by these models will be useful to model the adsorption/bioadsorption process in DOC removal of BGAC filtration system. © 2008 Elsevier Ltd. All rights reserved.
Xing, W, Ngo, HH, Kim, SH, Guo, WS & Hagare, P 2008, 'Physico-chemical processes for landfill leachate treatment: Experiments and mathematical models', SEPARATION SCIENCE AND TECHNOLOGY, vol. 43, no. 2, pp. 347-361.
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Zhang, R, Vigneswaran, S, Ngo, H & Nguyen, H 2008, 'Fluidized bed magnetic ion exchange (MIEX®) as pre-treatment process for a submerged membrane reactor in wastewater treatment and reuse', Desalination, vol. 227, no. 1-3, pp. 85-93.
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Magnetic ion exchange (MIEX®) resin can effectively remove significant amounts of organic matter from biologically treated sewage effluent. The MIEX® process has mainly been used as a batch process, which requires a large area for accommodating both contact tank and settling tank in the treatment process. In this study, a fluidized bed MIEX® reactor (a semi-continuous process) was used as a pre-treatment for a submerged membrane. When used as a pre-treatment for a submerged membrane, the fluidized bed MIEX® contactor could remove a significant amount of organic matter in the wastewater (80% removal). This pre-treatment helped to reduce membrane fouling and keep transmembrane pressure low during the membrane operation of 8 h (less than 19 kPa). The regeneration of MIEX® resin (number of regeneration, regeneration time, etc.) did not have any adverse effect on the organic removal by MIEX®. © 2008.
Zhang, Y & Zhou, JL 2008, 'Occurrence and removal of endocrine disrupting chemicals in wastewater', Chemosphere, vol. 73, no. 5, pp. 848-853.
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This paper discusses the occurrence and removal of endocrine disrupting chemicals (EDCs) in Horsham sewage treatment plant (STP), West Sussex, UK. Photodegradation aided by a catalyst (TiO2) was studied for its efficiency of removing EDCs from wastewater. The degradation of estrone and 17β-estradiol under natural sunlight followed a pseudo-first-order kinetics, with a rate constant of 0.01 h-1. The degradation by sunlight is also independent of initial chemical concentration, suggesting some potential of using this environmentally friendly method for waste minimisation. In comparison, more efficient degradation was observed with UV irradiation (253 nm), with the rate constants being increased to 2.7 and 2.5 h-1 for the two compounds. Subsequent application of the photocatalysis method to real effluent treatment at Horsham STP was successful, as demonstrated by the non-detection of the target compounds following treatment. © 2008 Elsevier Ltd. All rights reserved.
Zhang, Z, Hibberd, A & Zhou, JL 2008, 'Analysis of emerging contaminants in sewage effluent and river water: Comparison between spot and passive sampling', Analytica Chimica Acta, vol. 607, no. 1, pp. 37-44.
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Passive sampling is highly complimentary to spot sampling in environmental analysis. A polar organic chemical integrative sampler (POCIS) was extensively tested to optimize its performance under both controlled and field conditions. The passive sampler was subsequently used for the sampling and analysis of estrone, 17β-estradiol, 17α-ethynylestradiol, bisphenol A, propranolol, sulfamethoxazole, meberverine, thioridazine, carbamazepine, tamoxifen, indomethacine, diclofenac and meclofenamic acid in sewage effluent and river water. Under laboratory conditions, the kinetics of compound uptake by POCIS were linear during 10-day of exposure. POCIS sampling rates of the target compounds were significantly greater by using polyethersulfone instead of polysulfone membrane, and enhanced with increasing sorbent exposure area. Together with spot water sampling, the optimized POCIS was deployed in the River Ouse, West Sussex, UK to obtain field-derived sampling rates which, for endocrine disrupting chemicals (EDCs), were significantly higher than those from laboratory experiments. Both spot and passive sampling demonstrated that most of the target chemicals were frequently detected in sewage effluent and river waters, and that the daily changes in the pollutant concentrations were greater for pharmaceuticals than for EDCs. The aqueous concentrations of all compounds were elevated at a sewage outfall, which is confirmed to be an important source of the target compounds in the river. The validated POCIS was then successfully used to estimate the concentrations of the target compounds in effluent and river water, which were in good agreement with those from spot sampling for pharmaceuticals. © 2007 Elsevier B.V. All rights reserved.
Zhou, JL 2008, 'Occurrence and persistence of antifouling biocide Irgarol 1051 and its main metabolite in the coastal waters of Southern England', Science of The Total Environment, vol. 406, no. 1-2, pp. 239-246.
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The toxicity and persistence of antifouling booster biocides are of major concern. This study reports the occurrence of Irgarol 1051 and its degradation product M1, in coastal waters of Southern England, during 2004-2005. The highest concentrations of Irgarol 1051 were 89 ng/L in water and 45 ng/g dry weight in sediments, with an overall mean (n = 108) of 13 ng/L and 16 ng/g in water and sediments, respectively. As the degradation product of Irgarol 1051, M1 was less widespread, with the highest concentration of 30 ng/L in water and 14 ng/g in sediments, with an overall mean (n = 108) of 5 ng/L and 4 ng/g in water and sediments, respectively. Overall, the concentration of Irgarol 1051 and M1 decreased significantly during the sampling period and in comparison to earlier studies during 2000 to early 2004, indicating that control measures by restricting the use of Irgarol 1051 are effective in reducing its concentrations in coastal waters. The distribution of Irgarol 1051 between sediments and water was significantly related to sediment organic carbon content. In addition, significantly higher concentrations of Irgarol 1051 were detected in paint particles than in sediment. The rate of release of Irgarol 1051 from paint residues is very slow, with a half life of approximately 1 y. Two important findings are emerging, first the importance of organic rich sediments and paint residues as major sites of storage for Irgarol 1051, and secondly Irgarol 1051 may be classified as a persistent organic pollutant due to its long half life. © 2008 Elsevier B.V. All rights reserved.
Aoki, Y, Sri Ravindrarajah, R & Khabbaz, H 1970, 'Environmentally friendly sustainable pervious concrete', Futures in Mechanics of Structures and Materials - Proceedings of the 20th Australasian Conference on the Mechanics of Structures and Materials, ACMSM20, Australasian Conference on the Mechanics of Structures and Materials, Taylor & Francis Group, Toowoomba, Queensland, Australia, pp. 567-570.
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Portland cement is considered as one of the environmentally unfriendly materials due to its contribution to the increased liberation of carbon dioxide to the environment during production. In addition to its impervious nature, when it is used for pavement application, it contributes to increased stormwater runoff to drainage systems, over-burdening the infrastructure and causing excessive flooding in built-up areas. This paper presents the results of an experimental investigation associated with quantifying the properties of pervious concrete containing fly ash, up to 50% as partial replacement for cement. The main goal of this research is to promote the utilisation of fly ash for developing durable and sustainable pervious concrete, which creates less negative environmental impacts. © 2009 Taylor & Francis Group, London.
Chanan, AP, ghetti, I & Kandasamy, JK 1970, 'From El Nino to La Nina and Back: Challenges of managing coastal areas through climate change', IWA World Water Congress 2008, Vienna, Austria, IWA World Water Congress, IWA Publishing, Vienna, Austria, pp. 113-114.
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In Australia (particularly eastern Australia), La Niña events are associated with increased probability of wetter conditions, whereas El Niño events are associated with an increased probability of drier conditions For an urbanised coastal council like Kogarah there are a number of impacts associated with climate change. For instance, the risk of flood may be increased due to more intense rainfalls, when couple with rising sea levels. Coastal Councils may also experience increased coastal flooding and coastal erosion due to increased storm surges and rising sea levels. Water restrictions are already in place due to severe droughts and it is further predicted that councils will have limited water supply available for irrigation needed to provide parks and well-maintained sporting facilities for the community. Given that the science of climate change is not an exact science there are obvious technical and socio-political challenges that are to be addressed. The paper shares Kogarah Councils experiences in dealing with these challenges and provides a snapshot of programs currently being implemented in response to climate change. By investing in proactive measure to reduce risk and vulnerability it is possible to build a powerful resilience to climate change.
Chanan, AP, Kandasamy, JK & Sharma, D 1970, 'A Role for Input-Output Analysis in Urban Water Policy Decisions in Australia', Input - Output & Environment Website, Input - Output & Environment, IIOA, Saville Spain, pp. 1-18.
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Discussion on water reuse and its role in sustainable water resource management in Australia has been on the agenda of policy makers and scientific community for the last three decades. Despite that, promulgation of water reuse especially in metropolitan Australia has been a rather slow process. To advance sustainable urban water management, water policy shift towards `co-management and `higher value use is critical. Input Output Analysis provides an ideal mechanism for water policy makers to prepare a case for this much needed policy shift. The paper discusses the methodology available for such an exercise, with special reference to Kogarah Local Government Area, located within the Sydney Metropolitan.
Fatahi, B, Indraratna, B & Khabbaz, H 1970, 'Numerical and Experimental Study of Tree Influence on the Ground', GeoCongress 2008, GeoCongress 2008, American Society of Civil Engineers, New Orleans, USA, pp. 694-701.
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A mathematical model for the rate of root water uptake has been developed considering ground conditions, type of vegetation and climatic parameters. The three independent features in the root water uptake model incorporated in detail are soil suction, root distribution, and potential transpiration. A two dimensional finite element approach has been employed to solve the transient coupled flow and deformation equations in vicinity of a tree. To validate the model, an array of field measurements and the data have been compared with the numerical predictions. The predicted results acquired from the numerical analysis have been compared favourably with the field and the associated laboratory measurements, justifying the assumptions upon which the model has been developed. Copyright ASCE 2008.
Fatahi, B, Khabbaz, H & Indraratna, B 1970, 'Analysis of Matric Suction Effects Induced by Tree Roots on Rail Track Subgrade', Conference Proceedings: CORE2008 Conference on Railway Engineering, Conference on Railway Engineering, RTSA, Perth, WA, Australia, pp. 599-610.
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This study investigates the eflects of vegetation on soil matric suction and ground deformation. This paper highlights the inter-related parameters contributing to the development of a conceptual evapo-transpiration and root water uptake equilibrium model that is then incorporated in a comprehensive numerical model. The developed numerical model based on the finite element analysis (ABAQUS) considers fully coupled flowdeformation behaviour of soil. The model formulation is based on the effective stress approach developed for unsaturated soils. Based on the proposed model, the distribution of the matric suction proflle adjacent to the tree has been numerically anaiysed. To validate the model, an array of field measurements conducted at Miram site in Victoria, Australia have been compared with the numerical predictions. Then behaviour of a single tree on improving soil behaviour underneath rail tracks has been described. II is found that root water uptake and associated matric suction stabilise the soft soil beneath railway lines and a pattern of trees grown systematically along rail corridors may olter a cost eltective and environmentally attractive solution for the soft ground improvement in the long-term.
Guo, W, Ngo, H, Palmer, CG, Xing, W, Yen-Jung, H & Listowski, A 1970, 'Enhanced biological nutrient removal by a single stage sponge-submerged membrane bioreactor in waste water treatment for reuse', Proc.IWA Regional Conference, IWA Regional Conference, IWA, Moscow, pp. 168-173.
Guo, W, Xing, W, Ngo, H, Hu, YA, Palmer, CG & Zhang, R 1970, 'Enhancement of organics removal by an integrated non woven media biofilter-submerged membrane adsorption hybrid system', Proc. 6th Regional Symposium on Membrane Science & Technology, Regional Symposium on Membrane Science & Technology, Prince of Songkla University, Thailand, pp. 1-8.
Hannan, J & Kandasamy, J 1970, 'Experience of 1D and 2D flood modelling in Australia—a guide to model selection based on channel and floodplain characteristics', Flood Risk Management: Research and Practice - Proceedings of the European Conference, European Conference on Flood Risk Management: Research and Practice, CRC Press, Oxford, UK, pp. 273-280.
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The average annual cost of flooding in Australia is $318 million per year (BTE, 2001). Some 100 flood studies, floodplain management studies and plans are currently being undertaken in Australia to seek to reduce the potential flood risk to residents and properties in flood-affected areas. Consequently, a great body of knowledge and experience in flood modelling practices has been acquired, from one-dimensional (1D) steady-state models through to two-dimensional (2D) finite element hydrodynamic models. This paper critically appraises 1D and 2D hydraulic modelling techniques based on a quantitative comparison of MIKE-11, HEC-RAS and RMA-2 modelling results for a creek system in Australia. Based on the findings of the case study, the paper provides practical guidance for modellers on the suitability of 1D and 2D modelling for common physical channel and floodplain characteristics.
Ho, DP, Vigneswaran, S, Ngo, H, Shon, H & Kandasamy, JK 1970, 'Adsorption and Photocatalysis Kinetics of UV Light Responsive and Visible Light Responsive Titanium Dioxide in Wastewater Treatment', Proceedings of the IWA World Water Congress and Exhibition 2008, IWA World Water Congress, International Water Association (IWA), Vienna, Austria, pp. 1-8.
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The possible use of photocatalysis with TiO2 in wastewater treatment has been the focus of numerous studies in recent years. In this study, the adsorption and photocatalytic oxidation of organic compounds by UV light responsive titanium dioxide (P25) and visible light responsive titanium dioxide (Vis-TiO2) were investigated. Firstly, the adsorption behavior of the two photocatalysts was examined by the adsorption isotherm and kinetics experiments. The photocatalytic reactivity of the catalysts was then compared at different operating conditions. The results indicate that Freundlich model well described the adsorption capacity of both materials. The photocatalytic kinetics showed that the highest removal of NOM was achieved at an optimum concentration of 1.0 g/L of both photocatalysts. In case of P25, one-hour irradiation of UV light at the intensity of 184.64 mW/cm2 resulted in approximately 57% of TOC removal. It was observed that visible light photoexciting Vis- TiO2 required a longer irradiation time of 2 days to remove 65% of organic matters.
Indraratna, B & Khabbaz, H 1970, 'Geotechnical aspects of ballasted rail tracks and stabilising underlying soft soil formation', ADVANCES IN TRANSPORTATION GEOTECHNICS, 1st International Conference on Transportation Geotechnics, CRC PRESS-TAYLOR & FRANCIS GROUP, Nottingham, ENGLAND, pp. 593-599.
Indraratna, B, Khabbaz, H & Fatahi, B 1970, 'Conceptual development and numerical modelling of vegetation induced suction and implications on rail track stabilisation', 12th International Conference on Computer Methods and Advances in Geomechanics 2008, International Conference of International Association for Computer Methods and Advances in Geomechanics, Indian Institute of Technology, Bombay, Goa, India, pp. 4335-4344.
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The effects of tree roots on soil suction and ground settlement are investigated. This paper highlights the inter-related parameters contributing to the development of a conceptual evapo-transpiration and root water uptake equilibrium model that is then incorporated in a comprehensive numerical model. The developed numerical model based on the finite element analysis (ABAQUS) considers fully coupled flow-deformation behaviour of soil. Field measurements obtained by the authors from a field site in western Victoria and from past literature are used to validate the model. The predicted results show acceptable agreement with the field data in spite of the assumptions made for simplifying the effects of soil heterogeneity and anisotropy. The numerical analysis proves that the proposed root water uptake model can reliably predict the region of maximum matric suction away from the tree axis. The paper also compares the natural favourable effect of tree roots with the stabilising mechanisms of geosynthetic vertical drains subjected to vacuum pressure. Although this analogy is only justified for shallow vertical drains, the comparison still emphasises the obvious economical advantages of native vegetation.
Indraratna, B, Muttuvel, T & Khabbaz, H 1970, 'Investigating Erosional Behaviour of Chemically Stabilised Erodible Soils', GeoCongress 2008, GeoCongress 2008, American Society of Civil Engineers, New Orleans, Louisiana, USA, pp. 670-677.
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Chemical stabilisation is a popular technique to improve the erosion resistance of soils. In this study, two chemical stabilisers, namely lignosulfonate and general purpose Portland cement were tested on two different soils, a silty sand and dispersive clay. A series of erosion tests were performed to study the effectiveness of the stabilisation on increasing the erosion resistance. Results showed that an increase in the critical shear stress of the silty sand with only 0.6% lignosulfonate treatment was equivalent to that with around 2.5% cement treatment. However, the stabilisation of the dispersive clay with 0.6% cement was more effective than 0.6% lignosulfonate. The findings of this research also indicated that the coefficient of soil erosion decreased as a power function of the critical shear stress. Copyright ASCE 2008.
Kalam, MA, Masjuki, HH, Redzuan, M, Mahlia, TMI, Fuad, MA, Mohibah, M, Halim, K, Ishak, A, Khair, M, Shahrir, A & Yusof, A 1970, 'Development and Test of a New Catalytic Converter for Natural Gas Fueled Engine', SAE Technical Paper Series, 2008 SAE International Powertrains, Fuels and Lubricants Congress, SAE International.
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This paper presents exhaust gas emissions characteristcs of a new direct injection (DI) compressed natural gas (CNG) engine using a low cost catalytic conveter (Catco). The pollutants exhaust gas emissions measured were CO, HC and NOx with and without Catco. The Catco was developed based on catalyst materials consisting of metal oxides such as titanium dioxide (TiO2) and cobalt oxide (CoO) with wiremesh substrate. Both of the catalyst materials (such as TiO2 and CoO) are inexpensive in comparison to conventional catalysts (noble metals) such as palladium or platinum. In addition, the noble metals such as platinum group metal are now indentified as human health risk due to their rapid emissions in the environment from various resources like conventional catalytic converter, jewelers and other medical usages. It can be mentioned that both the CNG-DI engine and TiO2/CoO based catalytic converter were developed under a research collaboration program. The original engine manufacture catalytic conveter (OEM Catco) was tested for comparison purposes. The OEM Catco was based on noble metal catalyst with honeycomb ceramic substrate. It is experimentally found that the conversion efficiencies of TiO2/CoO based catalytic converter are 93%, 89% and 82% for NO x, CO and HC emissions respectively. It is calculated that the TiO2/CoO based catalytic converter reduces 24%,41% and 40% higher NOx, CO and HC emissions in comparison to OEM Catco respectively. The objective of this paper is to develop a low cost three way catalytic converter to be used with the newly developed CNG-DI engine. Detailed review on catalytic converter, low cost catalytic converter development characteristics and CNG-DI engine test results have been presented with discussions. © 2008 SAE International.
Kannapiran, A, Chanan, AP, Singh, G, Tambosis, P, Jeyakumaran, JM & Kandasamy, JK 1970, 'Strategic asset management planning of stormwater drainage systems', Proceedings of the IWA World Water Congress and Exhibition 2008, IWA World Water Congress, International Water Association (IWA), Vienna, Austria, pp. 1-8.
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Management of the urban water cycle in an integrated manner is an essential task to protect, restore and enhance in a sustainable manner. Strategic asset management planing is being developed as local government authorities face many challenges associated with managing the urban water cycle system. Statistical or conventional mathematical modelling approach has been found not practical for assessment of deteriorating infrastructures. Alternatively, application of fuzzy-based models is found more suitable as it links engineering judgment, experience and scarce field data of the deteriorating assets. In this study, a representative network of buried stormwater system s data is drawn and a pipe condition index is derived by linking the field data and reasoning using fuzzy approach. The inferred results are found to be useful and relevant for asset maintenance and future development programs.
Listowski, A, Ngo, H, Guo, W, Vigneswaran, S & Palmer, CG 1970, 'Assessment Framework of Urban Water Reuse Based on a Novel Integrated Water Cycle Concept', Proceedings of the IWA World Water Congress and Exhibition 2008, IWA World Water Congress, International Water Association (IWA), Vienna, Austria, pp. 1-8.
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To achieve sustainability of the water reclamation and urban reuse technologies, it would be necessary to develop and apply comprehensive assessment methodology and processes that would consider critical elements of urban water cycle, sustainability criteria and appropriate performance assessment standards as an integrated framework. When trying to study the rationale behind the urban water reuse approaches from social, economic, technical and ecological point of view, the outcomes are often lacking cohesion and appropriate balance. The assessment methods are further complicated by the lack of consistency, specific and accurate information and methodologies, which ultimately impair the process. Taking into consideration complexity and uniqueness of the integrated water cycle concept, this paper introduces to a novel assessment framework. This enables to identify suitable assessment process consisting of logical steps and including relevant objectives, principles from which a broad selection of criteria s and performance indicators would be derived. The final step in the process would be focused on validation of the quantitative analysis and model preparation. A considerable effort would also be necessary to establish baseline indicators of sustainability and operational tools to evaluate performance of the urban water systems.
Mohammed Abdul, J, Areerachakul, N, Shon, H, Vigneswaran, S & Kandasamy, JK 1970, 'Biofilter and Photo-Catalytic Treatment Processes of Groundwater Contaminated with Landfill Leachate', Proceedings of the IWA World Water Congress and Exhibition 2008, IWA World Water Congress, International Water Association (IWA), Vienna, Austria, pp. 1-8.
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Landfill leachate is produced when rainwater infiltrates into the landfill and permeates through the decomposing waste within the landfill leaching out with it contaminants and pollutants. Untreated leachates can permeate ground water or mix with surface waters and contribute to the pollution of soil, ground water, and surface water. In this study, the processes such as GAC bio-filtration and photocatalysis and bio-filter were evaluated in treating synthetic landfill leachate. The Total organic carbon (TOC) removal efficiency (of landfill leachate) was evaluated by sequential adsorption/bio-sorption (on GAC) and compared with photocatalysis. GAC bio-filtration led to a consistent TOC removal even after a long period of operation without the need to regenerate the activated carbon. Even after 35 days of continuous running, the TOC of the effluent from the GAC bio-filter was approximately 60% of the influent quality (i.e. 40% removal). Biofiltration with a post treatment of advanced oxidation with Fenton reagent led to more 70% of removal of TOC. Also, the treatment of biofilter redcued significantly the concentration of Fenton reagent. On the other hand photocatalysis with TiO2 as a separate treatment led to only 40% TOC reduction.
Nguyen, V, Vigneswaran, S & Ngo, H 1970, 'A Novel Iron Oxide Coated Sponge Adsorption System To Remove Arsenic From Drinking Water', Proceedings of the World Water Congress and Exhibition 2008, IWA World Water Congress, International Water Association (IWA), Vienna, Austrlia, pp. 1-8.
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Millions of people worldwide are at risk from the presence of arsenic in groundwater. There is a global need to develop appropriate technologies to remove arsenic from water for household and community water supply systems. In this study, a new material namely iron oxide coated sponge (IOCSp) was developed and used to remove As. It was found that IOCSp has a high capacity in removing both As (V) and As (III). The adsorption capacity of IOCSp was up to 4.6 mg As/g IOCSp, higher than a number of other materials. A filter packed even with very small amount of 25 g IOCSp maintained a consistent arsenic removal efficiency of 95% from synthetic water containing arsenic concentration of as high as 1,000μg/L. This produced a throughput volume of 153 and 178L of water containing As(III) and As(V) respectively before any need for regeneration or disposal of IOCSp. It was found to provide comparable results with advanced technologies such as nanofiltration system with in line addition of nano zero valent iron. In addition, the initial results also showed that the exhausted IOCSp can safely be disposed of through the solidification/stabilization technique.
Sanjay, S, Turner, BD & Sloan, SW 1970, 'Bicarbonate alkalinity effect on the fluoride removal efficiency of activated alumina', GEOCHIMICA ET COSMOCHIMICA ACTA, 18th Annual V M Goldschmidt Conference, PERGAMON-ELSEVIER SCIENCE LTD, Vancouver, CANADA, pp. A823-A823.
Xing, W, Guo, WS, Ngo, HH, Listowski, A & Cullum, P 1970, 'Specific Anaerobic Fluidized Bed Bioreactors as Pretreatment to Microfiltration in Domestic Wastewater Treatment for Reuse', Journal of Applied Membrane Science & Technology, Regional Symposium on Membrane Science & Technology, Penerbit UTM Press, Thailand, pp. 1-8.
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Practical use of an anaerobic granular activated carbon (GAC) fluidized bed bioreactor (FBBR) as pretreatment to microfiltration was experimentally verified. A nature starch based cationic flocculants (GF) was employed in this study for testifying its impact on the performance of GAC–FBBR. The GAC–FBBR with and without addition of GF was evaluated in terms of dissolved organic carbon (DOC) removal from biologically treated sewage effluent (BTSE). With only a daily addition of 200 mg GF to GAC– FBBR and a depth of GAC of 500 mm, the biomass of GAC increased from 1.5 g/L to 4.2 g/L within operation period of 30 days while the system resulted in 5% better DOC removal. The results indicate that the GAC–FBBR as pretreatment could effectively remove the dissolved organics and improve the critical flux. Compared with the critical flux of BTSE with submerged microfiltration (SMF) alone (20 L/m2.h), the pretreatment by GAC–FBBR successfully increased the critical flux to 30 L/m2.h. Moreover, the addition of GF into GAC–FBBR could help in raising the critical flux to 35 L/m2.h.