ASLAM, M, MASJUKI, H, KALAM, M, ABDESSELAM, H, MAHLIA, T & AMALINA, M 2006, 'An experimental investigation of CNG as an alternative fuel for a retrofitted gasoline vehicle', Fuel, vol. 85, no. 5-6, pp. 717-724.
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Chang, CY, Chang, JS, Lin, YW, Erdei, L & Vigneswaran, S 2006, 'Quantification of air stripping and biodegradation of organic removal in acrylonitrile-butadiene-styrene (ABS) industry wastewater during submerged membrane bioreactor operation', DESALINATION, vol. 191, no. 1-3, pp. 162-168.
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With the rapid development of the petrochemical industry in Taiwan, a significant amount of nitrogenous organic wastewater is generated. Some of this wastewater contains volatile residual monomers, such as acrylonitrile-butadienestyrene (ABS) manufacturing wastewater. Because of the high volatility of the acrylonitrile monomer, this chemical will be partly removed from the aeration system by the air stripping effect. An empirical model was developed for evaluating BOD removal by air stripping and biodegradation when the wastewater was treated in an aerobic submerged membrane bioreactor (ASMBR). The results showed that the removal of BOD from ABS wastewater by air stripping was in the range of 2-10%. These results also showed that the estimation of contribution of air stripping and biodegradation in the BOD removal in the MBR is very important in the optimum design of the MBR for ABS wastewater. © 2006.
Chang, JS, Chang, CY, Chen, AC, Erdei, L & Vigneswaran, S 2006, 'Long-term operation of submerged membrane bioreactor for the treatment of high strength acrylonitrile-butadiene-styrene (ABS) wastewater: effect of hydraulic retention time', DESALINATION, vol. 191, no. 1-3, pp. 45-51.
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Charles, AL, Markich, SJ & Ralph, P 2006, 'Toxicity of uranium and copper individually, and in combination, to a tropical freshwater macrophyte (Lemna aequinoctialis)', CHEMOSPHERE, vol. 62, no. 8, pp. 1224-1233.
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Copper (Cu) and uranium (U) are of potential ecotoxicological concern to tropical freshwater biota in northern Australia, as a result of mining activities. Few data are available on the toxicity of U, and no data are available on the toxic interaction of Cu and U, to freshwater biota. This study determined the toxicity of Cu and U individually, and in combination, to a tropical freshwater macrophyte, Lemna aequinoctialis (duckweed), in a synthetic soft water (27°C; pH, 6.5; hardness, 40 mg CaCO3 l-1, alkalinity, 16 mg CaCO3 l-1), typical of many fresh surface waters in coastal northern Australia. The growth rate of L. aequinoctialis decreased with increasing Cu or U concentrations, with the concentration of Cu inhibiting growth by 50% (EC50) being 16 ± 1.0 μg l-1, with a minimum detectable effect concentration (MDEC) of 3.2 μg l-1. The concentration of U inhibiting growth by 50% (EC50) was 758 ± 35 μg l-1 with a MDEC of 112 μg l-1. The EC50 value for the exposure of L. aequinoctialis to equitoxic mixtures of Cu and U was significantly (P ≤ 0.05) higher than one toxic unit (1.35; 95% confidence interval, 1.18-1.52), indicating that the combined effects of Cu and U are less than additive (antagonistic). Therefore, inhibition of the growth rate of L. aequinoctialis was reduced when Cu and U were present in equitoxic mixtures, relative to individual metal exposures. Since non-additive (e.g. antagonistic) interactions of metal mixtures cannot be predicted using current mixture models, these results have important potential implications for the protection of freshwater ecosystems through the derivation of national water quality guidelines. © 2005 Elsevier Ltd. All rights reserved.
Doblin, MA & Dobbs, FC 2006, 'Setting a size-exclusion limit to remove toxic dinoflagellate cysts from ships' ballast water', MARINE POLLUTION BULLETIN, vol. 52, no. 3, pp. 259-263.
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Dinoflagellate cysts are well-recognized biological constituents of ships ballast tanks. They are present in ballast water, sediments and residual water in drained tanks, and in biofilms formed on interior tank Surfaces. Therefore, cysts have the potenti
Doblin, MA, Baines, SB, Cutter, LS & Cutter, GA 2006, 'Sources and biogeochemical cycling of particulate selenium in the San Francisco Bay estuary', ESTUARINE COASTAL AND SHELF SCIENCE, vol. 67, no. 4, pp. 681-694.
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As part of a study of estuarine selenium cycling, we measured the concentration, chemical form (speciation), and distribution of particulate selenium under various river flow conditions in the North San Francisco Bay (from the Golden Gate to the Sacramen
Doblin, MA, Thompson, PA, Revill, AT, Butler, ECV, Blackburn, SI & Hallegraeff, GM 2006, 'Vertical migration of the toxic dinoflagellate Gymnodinium catenatum under different concentrations of nutrients and humic substances in culture', HARMFUL ALGAE, vol. 5, no. 6, pp. 665-677.
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Vertical migration behaviour by the chainforming dinoflagellate Gymnodinium catenatum Graham was investigated using vertically-stratified laboratory columns. Under surface nutrient-deplete conditions, with nutrients added only at depth, 100% of cells underwent vertical migration (VM), starting downwards migration 3 h before the end of the light period and beginning upwards migration 3 h before the start of the light period. Cells in nutrient-replete columns showed no VM, but they were more dispersed in the upper layer during the dark compared to the light period. When surface layers (S) were nitrate-deplete (-N) and enriched with humic substances (H) contained in Huon River water and bottom waters (B) were nutrient replete (R) (SH-NBR), the pattern of VM was altered-50% of cells underwent migration and 50% remained at the pycnocline. In columns with nitrate-replete and humic-enriched surface layers (SHRBR), Most cells underwent VM, while 30% remained at the surface. Cells in SH-NBR columns showed increased N quotas and intra-cellular nitrate concentrations after 4 days, indicating nitrate uptake by G. catenatum in bottom layers. The concomitant increase in particulate organic nitrogen (PON) with the decrease in external nitrate concentrations in bottom layers provide convincing evidence that VM by G. catenatum facilitates nutrient retrieval at depth. However, addition of humic substances (a potential source of organic nitrogen) to surface layers did not ameliorate G. catenatum N depletion sufficiently to preclude the need for NO3- uptake at depth. Furthermore, there was no detectable pattern of increasing carbon (C) quota during the day (photosynthate accumulation) or increasing N quota during the night (nitrate assimilation).
Guo, WS, Vigneswaran, S, Ngo, HH, Van Nguyen, TB & Ben Aim, R 2006, 'Influence of bioreaction on a long-term operation of a submerged membrane adsorption hybrid system', DESALINATION, vol. 191, no. 1-3, pp. 92-99.
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This study investigates the long-term performance of a submerged membrane adsorption hybrid system (SMAHS) for organic matter removal from synthetic wastewater representing biologically treated wastewater by using a low dose of powdered activated carbon (PAC). A simple periodic backwash system is used to de-clog the hollow fiber membrane. In this reactor, bioreaction takes place due to the growth of the biomass in the system. This hybrid system was able to remove effectively the small- and large-molecular weight organic matters from 270 to 36,270 Da. The effect of PAC replacement in the reactor was also studied and it was shown that PAC replacement could enhance both biological activity and adsorption. With PAC replacement of 2.5%(total amount) per day, the total organic carbon (TOC) removal efficiency was 10% higher than without PAC replacement. In another long-term experiment, the TOC removal efficiency was maintained over 85% even after 55-day operation (with PAC replacement rate of 2.5%(total amount) every two days). © 2006.
GUO, Z, HUANG, Z, KONSTANTINOV, K, LIU, H & DOU, S 2006, 'Electrochemical hydrogen storage properties of nonstoichiometric amorphous MgNi1+xMgNi1+x–carbon composites (x=0.05x=0.05–0.3)', International Journal of Hydrogen Energy, vol. 31, no. 14, pp. 2032-2039.
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Guo, ZP, Huang, ZG, Zhao, ZW, Menard, X & Liu, HK 2006, 'Enhanced electrochemical properties of nonstoichiometric amorphous Mg2Ni1.3 electrodes', Journal of Applied Electrochemistry, vol. 36, no. 1, pp. 11-16.
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Guo, ZP, Ng, SH, Wang, JZ, Huang, ZG, Liu, HK, Too, CO & Wallace, GG 2006, 'Electrochemical Hydrogen Storage in Single-Walled Carbon Nanotube Paper', Journal of Nanoscience and Nanotechnology, vol. 6, no. 3, pp. 713-718.
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Single-walled carbon nanotube (SWNT) papers were successfully prepared by dispersing SWNTs in Triton X-100 solution, then filtered by PVDF membrane (0.22 μm pore size). The electrochemical behavior and the reversible hydrogen storage capacity of single-walled carbon nanotube (SWNT) papers have been investigated in alkaline electrolytic solutions (6 N KOH) by cyclic voltammetry, linear micropolarization, and constant current charge/discharge measurements. The effect of thickness and the addition of carbon black on hydrogen adsorption/desorption were also investigated. It was found that the electrochemical charge–discharge mechanism occurring in SWNT paper electrodes is somewhere between that of carbon nanotubes (physical process) and that of metal hydride electrodes (chemical process), and consists of a charge-transfer reaction (Reduction/Oxidation) and a diffusion step (Diffusion).
Guo, ZP, Yuan, L, Konstantinov, K, Huang, ZG & Liu, HK 2006, 'Preparation of spherical clusters of metal oxide nanorods and their hydrogen storage behavior', Materials Letters, vol. 60, no. 29-30, pp. 3891-3894.
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Handy, SM, Coyne, KJ, Portune, KJ, Demir, E, Doblin, MA, Hare, CE, Cary, SC & Hutchins, DA 2006, 'Erratum: Evaluating vertical migration behavior of harmful raphidophytes in the Delaware Inland Bays utilizing quantitative real-time PCR (Aquatic Microbial Ecology (2005) 40, (121-132))', Aquatic Microbial Ecology, vol. 42, no. 3, p. 311.
Hill, R & Ralph, PJ 2006, 'Photosystern II heterogeneity of in hospite zooxanthellae in scleractinian corals exposed to bleaching conditions', PHOTOCHEMISTRY AND PHOTOBIOLOGY, vol. 82, no. 6, pp. 1577-1585.
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Increased ocean temperatures are thought to be triggering mass coral bleaching events around the world. The intracellular symbiotic zooxanthellae (genus Symbiodinium) are expelled from the coral host, which is believed to be a response to photosynthetic damage within these symbionts. Several sites of impact have been proposed, and here we probe the functional heterogeneity of Photosystem II (PSII) in three coral species exposed to bleaching conditions. As length of exposure to bleaching conditions (32°C and 350 μmol photons m-2 s-1) increased, the QA- reoxidation kinetics showed a rise in the proportion of inactive PSII centers (PSIIX), where QB was unable to accept electrons. PSIIX contributed up to 20% of the total PSII centers in Pocillopora damicornis, 35% in Acropora nobilis and 14% in Cyphastrea serailia. Changes in Fv/Fm and amplitude of the J step along fast induction curves were found to be highly dependent upon the proportion of . PSII X centers within the total pool of PSII reaction centers. Determination of PSII antenna size revealed that under control conditions in the three coral species up to 60% of PSII centers were lacking peripheral light-harvesting complexes (PSIIβ). In P. damicornis, the proportion of PSIIβ increased under bleaching conditions and this could be a photoprotective mechanism in response to excess light. The rapid increases in PSIIX and PSIIβ observed in these corals under bleaching conditions indicates these physiological processes are involved in the initial photochemical damage to zooxanthellae. © 2006 American Society for Photobiology.
Huang, ZG, Guo, ZP, Calka, A, Wexler, D, Lukey, C & Liu, HK 2006, 'Effects of iron oxide (Fe2O3, Fe3O4) on hydrogen storage properties of Mg-based composites', Journal of Alloys and Compounds, vol. 422, no. 1-2, pp. 299-304.
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Huang, ZG, Guo, ZP, Wexler, D, Konstantinov, K & Liu, HK 2006, 'Thermal stability and hydrogen storage property of Mg1.9Cu0.1Nix (x=1.8, 1.9, 2.0 and 2.1) alloys', Journal of Alloys and Compounds, vol. 426, no. 1-2, pp. 335-340.
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Indraratna, B, Fatahi, B & Khabbaz, H 2006, 'Numerical analysis of matric suction effects of tree roots', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-GEOTECHNICAL ENGINEERING, vol. 159, no. 2, pp. 77-90.
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The use of native vegetation in the coastal regions of Australia has become increasingly popular for stabilising railway corridors built over expansive clays and compressive soft soils. The tree roots provide three stabilising functions: (a) they reinforce the soil; (b) they dissipate excess pore pressures; and (c) they establish sufficient matric suction to increase the shear strength. The matric suction generated within the tree root zone propagates radially into the soil matrix, as a function of the moisture content change. Considering soil conditions, the type of vegetation and atmospheric conditions, a mathematical model for the rate of root water uptake is developed. A conical shape is considered to represent the geometry of the tree root zone. Based on this model for the rate of root water uptake, the pore water pressure distribution and the movement of the ground adjacent to the tree are numerically analysed. Field measurements taken from the previously published literature are compared with the authors' numerical predictions. It is found that, given the approximation of the assumed model parameters, the agreement between the predicted results and field data is still promising. The study indicates that native vegetation improves the shear strength of the soil by increasing the matric suction, and also curtails soil movements.
Indraratna, B, Khabbaz, H, Salim, W & Christie, D 2006, 'Geotechnical Properties of Ballast and the Role of Geosynthetics', Institution of Civil Engineers. Proceedings. Ground..., vol. 10, no. 3, pp. 91-102.
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The ballast and its engineering behaviour have a key role in governing the stability and performance of railway tracks. The deformation and degradation behaviour of ballast under static and dynamic loads was studied based on large-scale triaxial testing. The possible use of different types of geosynthetics to improve the performance of fresh and recycled ballast was also investigated. The research findings showed that the inclusion of geosynthetics improves the performance of ballasted tracks.
Jang, N, Shon, H, Ren, X, Vigneswaran, S & Kim, IS 2006, 'Characteristics of bio-foulants in the membrane bioreactor', DESALINATION, vol. 200, no. 1-3, pp. 201-202.
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Jia, Z, Fu, Q & Huang, J 2006, 'Synthesis of Amphiphilic Macrocyclic Graft Copolymer Consisting of a Poly(ethylene oxide) Ring and Multi-Polystyrene Lateral Chains', Macromolecules, vol. 39, no. 16, pp. 5190-5193.
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Jia, Z, Fu, Q & Huang, J 2006, 'Synthesis of poly(ethylene oxide) with pending 2,2,6,6‐tetramethylpiperidine‐1‐oxyl groups and its further initiation of the grafting polymerization of styrene', Journal of Polymer Science Part A: Polymer Chemistry, vol. 44, no. 12, pp. 3836-3842.
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AbstractA new stratagem for the synthesis of amphiphilic graft copolymers of hydrophilic poly(ethylene oxide) as the main chain and hydrophobic polystyrene as the side chains is suggested. A poly(ethylene oxide) with pending 2,2,6,6‐tetramethylpiperidine‐1‐oxyls [poly(4‐glycidyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐co‐ethylene oxide)] was first prepared by the anionic ring‐opening copolymerization of ethylene oxide and 4‐glycidyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl, and then the graft copolymerization of styrene was completed with benzoyl peroxide as the initiator in the presence of poly(4‐glycidyloxy‐2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐co‐ethylene oxide). The polymerization of styrene was under control, and comblike, amphiphilic poly(ethylene oxide)‐g‐polystyrene was obtained. The copolymer and its intermediates were characterized with size exclusion chromatography, 1H NMR, and electron spin resonance in detail. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3836–3842, 2006
Jia, Z, Xu, X, Fu, Q & Huang, J 2006, 'Synthesis and self‐assembly morphologies of amphiphilic multiblock copolymers [poly(ethylene oxide)‐b‐polystyrene]n via trithiocarbonate‐embedded PEO macro‐RAFT agent', Journal of Polymer Science Part A: Polymer Chemistry, vol. 44, no. 20, pp. 6071-6082.
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AbstractAn amphiphilic multiblock copolymer [poly(ethylene oxide)‐b‐polystyrene]n [(PEO‐b‐PS)n] is synthesized by using trithiocarbonate‐embedded PEO as macro‐RAFT agent. PEO with four inserted trithiocarbonate (Mn = 9200 and Mw/Mn = 1.62) groups is prepared first by condensation of α, ω‐dihydroxyl poly(ethylene oxide) with S, S′‐Bis(α, α′‐dimethyl‐α″‐acetic acid)‐trithiocarbonate (BDATC) in the presence of pyridine, then a series of goal copolymers with different St units (varied from 25 to 218 per segment) are obtained by reversible addition‐fragmentation chain transfer (RAFT) polymerization. The synthesis process is monitored by size exclusion chromatography (SEC), 1H NMR and FT‐IR. The self‐assembled morphologies of the copolymers are strongly dependent of the length of PS block chains when the chain length of PEO is fixed, some new morphologies as large leaf‐like aggregates (LLAs), large octopus‐like aggregates (LOAs), and coarse‐grain like micelles (CGMs) are observed besides some familiar aggregates as large compound vesicles (LCVs), lamellae and rods, and the effect of water content on the morphologies is also discussed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6071–6082, 2006
Jung, MY, Kim, CS, Tijing, LD, Pak, BC & Cho, YI 2006, 'A study of the onset of biofouling using quartz crystal nanobalance', International Communications in Heat and Mass Transfer, vol. 33, no. 1, pp. 7-13.
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Kanel, SR, Choi, H, Kim, J-Y, Vigneswaran, S & Shim, WG 2006, 'Removal of Arsenic(III) from Groundwater using Low-Cost Industrial By-products-Blast Furnace Slag', Water Quality Research Journal, vol. 41, no. 2, pp. 130-139.
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Abstract Blast furnace slag (BFS), a steel industrial by-product, was tested for the removal of As(III), which is a highly toxic, mobile and predominant species in anoxic groundwater. Batch adsorption experiments were performed to determine the feasibility of BFS as an adsorbent for removing As(III) from groundwater as As(III) concentration and the pH of water were varied. The maximum As(III) adsorption capacity by BFS was 1.40 mg As(III)/g of BFS at 1 mg/L As(III) initial concentration, at 25°C, which was calculated using the Langmuir isotherm. The homogeneous surface diffusion model (HSDM) was successfully applied to predict the sorptive removal of As(III) onto the BFS. Kinetic studies indicated that the film diffusion as well as surface diffusion of As in the BFS was involved. It was found that the film diffusion coefficient (kf) was 5.27 × 10-5 to 4.06 × 10-6 m/s and surface diffusion coefficient (Ds) was 2.31 × 10-14 to 7.13 × 10-14 m2/s for the initial As(III) concentrations of 0.1 to 100 mg/L. Oxidation of As(III) to As(V) and its adsorption/precipitation onto BFS is involved during the As(III) removal mechanism. It was also found that H4SiO40, PO43-, NO3-, SO42- and HCO3- are potential interferences in the As(III) adsorption reaction. Results suggest that 99.9% As(III) at 1 mg/L can be removed by 10 g/L BFS, which can be used as a permeable reactive barrier (PRB) material to remove As(III) from groundwater. Details of As(III) adsorption and coprecipitation systems and interferences of As(III) molecular interactions were also studied.
Khirani, S, Smith, PJ, Manero, M-H, Ben Aim, R & Vigneswaran, S 2006, 'Effect of periodic backwash in the submerged membrane adsorption hybrid system (SMAHS) for wastewater treatment', DESALINATION, vol. 191, no. 1-3, pp. 27-34.
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The submerged membrane adsorption hybrid system (SMAHS) is an attractive solution in treating wastewater; however it faces membrane fouling although to a less extent. In this study, different adsorbents and resins were investigated in order to find a sub
Lee, GJ, Tijing, LD, Pak, BC, Baek, BJ & Cho, YI 2006, 'Use of catalytic materials for the mitigation of mineral fouling', International Communications in Heat and Mass Transfer, vol. 33, no. 1, pp. 14-23.
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Maskaoui, K, Hu, Z, Zhou, JL & Han, YL 2006, 'Levels of polycyclic aromatic hydrocarbons in some agricultural, industrial and urban areas along Xiamen coastal waters, China', Journal of Environmental Sciences, vol. 18, no. 2, pp. 318-322.
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An intensive investigation was conducted to study the distribution of polycyclic aromatic hydrocarbons (PAHs), to show firstly the level of pollution in the agricultural areas and analyses specifically the status of soil polluted by these persistent pollutants in some locations of Xiamen region. Soil samples collected from Jiulong agricultural catchment have been analysed for 16 PAH compounds, using gas chromatography flame ionization detection in order to determine the level of selected PAH components and to identify the factors that may control their distribution and persistence in the area. The main PAHs found in soil samples were the low molecular weight. The total PAHs detected in soil samples ranged from 0.50 to 0.95μg/g soil. The highest values of PAHs were significantly detected in the orange tree leaves, which range from 236.1 to 249.3 μg/g soil showing recent atmospheric inputs of these volatile pollutants. The distribution of PAHs in vegetable were monitored and indicating that the concentration were high and ranged from 8.24 to 58.87 μg/g. Other sediment samples were also collected and analysed from urban sewage (5.26 μg/g dw), aquacultura (0.52 μg/g dw) and industrial areas (from 0.62 to 2.09 μg/g dw), during this investigation. The contamination of Jiulong river estuary and Xiamen Western Sea by PAHs has been then widely justified by wastewater discharges and soil runoffs from these areas. The results, therefore, provide important information on the current contamination status caused by the atmospheric transport and point to the need for urgent actions to stop the release of these hydrocarbons to the environment. The necessity of implementing systematic monitoring of PAHs is also emphasized. © 2006 Science Press. All rights reserved.
Nathaporn, A, Shon, HK, Vigneswaran, S, Ngo, HH & Ong, SL 2006, 'Photocatalytic hybrid system in degradation of herbicide (metsulfuron-methyl)', Drinking Water Treatment, Supply and Management in Asia (IWA-ASPIRE 2005), vol. 6, no. 2, pp. 109-114.
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Photocatalytic oxidation is becoming an emerging technology in water and wastewater Photocatalysis often leads to complete degradation of organic pollutants without any need for chemicals. this study, the removal of the herbicide metsulfuron-methyl (MM)
NGHIEM, L, MORNANE, P, POTTER, I, PERERA, J, CATTRALL, R & KOLEV, S 2006, 'Extraction and transport of metal ions and small organic compounds using polymer inclusion membranes (PIMs)', Journal of Membrane Science, vol. 281, no. 1-2, pp. 7-41.
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Nghiem, LD, Schäfer, AI & Elimelech, M 2006, 'Role of electrostatic interactions in the retention of pharmaceutically active contaminants by a loose nanofiltration membrane', Journal of Membrane Science, vol. 286, no. 1-2, pp. 52-59.
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Ngo, HH, Nguyen, MC, Sangvikar, NG, Hoang, TTL & Guo, WS 2006, 'Simple approaches towards the design of an attached-growth sponge bioreactor (AGSB) for wastewater treatment aind reuse', WATER SCIENCE AND TECHNOLOGY, vol. 54, no. 11-12, pp. 191-197.
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Wastewater treatment and reuse is being emphasized due to the shortage of water sources and the continuous deterioration of the aquatic environment. In this study, a novel sponge bioreactor was studied as a low cost, high efficiency alternative for an attached growth biological system. This was designed by combining of number of sponge trays. This emerging technology has many beneficial properties in wastewater treatment and reuse. The approaches towards the conditions for system design were: (i) selection of sponge types; (ii) selection of sponge shapes; and (iii) selection of designated slope of sponge tray. They were determined through a series of experiments using a laboratory-scale unit with synthetic wastewater. It was then tested with a pilot-scale unit at the predetermined optimum conditions. The results indicate that the highest biomass growth was found at the sponge type with a cell count of 7090 cells/in2 (6.45 cm2) The relationship between biomass growth and biological oxygen consumption was well established. The prism-shaped sponge (triangular polyurethane sponge of 7090 cells/in2 with designated slope of sponge tray at 10 degrees) led to the best performance in terms of both organic and nutrient removal efficiency.
Nguyen, TV, Vigneswaran, S, Ngo, HH, Pokhre, D & Viraraghavan, T 2006, 'Iron-coated sponge as effective media to remove arsenic from drinking water', WATER QUALITY RESEARCH JOURNAL OF CANADA, vol. 41, no. 2, pp. 164-170.
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Arsenic (As) contamination in drinking water is a serious problem in a number of countries in the world, especially in small communities and developing countries. Arsenic is related to many health diseases. Several technologies such as coagulation, adsorption, ion exchange and membrane processes, etc., are used in removing arsenic from water. In this study, a new material, namely iron-coated sponge (IOCSp), was developed and used to remove As, and it was found that IOCSp has a high capacity for removing both As(V) and As(III). Each gram of IOCSp adsorbed about 160 μg of As upon a 9-h contact of IOCSp with As solution. A dynamic filter column conducted showed that even a small quantity of IOCSp (8 g) could reduce As from 156 μg/L to a concentration of less than 50 μg/L while treating 75 L of groundwater contaminated with arsenic. Both the filtration rate and the size of the sponge had an effect on effluent quality, and the amount of water treated to the acceptable quality. Copyright © 2006, CAWQ.
Nguyen, TV, Vigneswaran, S, Ngo, HH, Pokhrel, D & Viraraghavan, T 2006, 'Specific treatment technologies for removing arsenic from water', ENGINEERING IN LIFE SCIENCES, vol. 6, no. 1, pp. 86-90.
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Arsenic (As) is a highly toxic metalloid found in ground and surface water. Arsenic contamination in drinking water leads to harmful effects on human health. To eliminate arsenic from drinking water, several technologies such as coagulation, adsorption, ion exchange, filtration, membrane processes, etc., have been used. In this study, three technologies were evaluated for arsenic removal. Results from batch kinetic experiments showed that iron coated sand (IOCS-2) can remove more than 90% of As from synthetic water. Experiments were conducted with three different pH values (6, 7, and 8) and an initial As concentration of 260 μg/L. A new material, developed in this study, namely iron coated sponge (IOCSp), was found to have a high capacity in removing both As (V) and As (III). Each gram of IOCSp adsorbed about 160 μg of As within a 9-hour contact period of IOCSp with As solution. Low pressure nanofiltration removed more than 94% of As from an influent containing 440 μg/L As. The applied pressure was varied from 85 to 500 kPa. © 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Ryan, KG, Hegseth, EN, Martin, A, Davy, SK, O'Toole, R, Ralph, PJ, McMinn, A & Thorn, CJ 2006, 'Comparison of the microalgal community within fast ice at two sites along the Ross Sea coast, Antarctica', ANTARCTIC SCIENCE, vol. 18, no. 4, pp. 583-594.
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Diverse microbial communities survive within the sea ice matrix and are integral to the energy base of the Southern Ocean. Here we describe initial findings of a four season survey (between 1999-2004) of community structure and biomass of microalgae within the sea ice and in the underlying water column at Cape Evans and Cape Hallett, in the Ross Sea, Antarctica as part of the Latitudinal Gradient Project. At Cape Evans, bottom-ice chlorophyll a levels ranged from 4.4 to 173 mg Chl a m-2. Dominant species were Nitzschia stellata, N. lecointei, and Entomoneis kjellmanii, while the proportion of Berkeleya adeliensis increased steadily during spring. Despite being obtained later in the season, the Cape Hallett data show considerably lower standing stocks of chlorophyll ranging from 0.11 to 36.8 mg Chl a m-2. This difference was attributed to a strong current, which may have ablated much of the bottom ice biomass and provided biomass to the water below. This loss of algae from the bottom of the ice may explain why the ice community contributed only 2% of the standing stock in the total water column. Dominant species at Cape Hallett were Nitzschia stellata, Fragilariopsis curta and Cylindrotheca closterium. The low biomass at Cape Hallett and the prevalence of smaller-celled diatoms in the bottom ice community indicate that the ice here is more typical of pack ice than fast ice. Further data will allow us to quantify and model the extent to which ice-driven dynamics control the structure and function of the sea ice ecosystem and to assess its resilience to changing sea ice conditions. © Antarctic Science Ltd.
Seery, CR, Gunthorpe, L & Ralph, PJ 2006, 'Herbicide impact on Hormosira banksii gametes measured by fluorescence and germination bioassays', ENVIRONMENTAL POLLUTION, vol. 140, no. 1, pp. 43-51.
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The innovative bioassay described here involves chlorophyll a fluorescence measurements of gametes from the macroalgae, Hormosira banksii, where gametes (eggs) were exposed to Diuron, Irgarol and Bromacil. Response was assessed as percent inhibition from control of effective quantum yield (ΔF/Fm′) of photosystem II, herein referred to as % PSII Inhibition. This was measured with the dual-channelled pulse amplitude modulated (PAM) fluorometer, ToxY-PAM. The fluorescence bioassay was run simultaneously with an established H. banksii germination bioassay to compare sensitivity, precision, and time-to-result. The fluorescence bioassay gave highly sensitive results evidenced by EC 50s (% PSII Inhibition) for Diuron, Irgarol and Bromacil being three, four and three orders of magnitude (respectively) lower than EC50s generated from the germination bioassays. Precision of the fluorescence bioassay was demonstrated with low coefficient of variations (<30%) for all three toxicants. With regard to time, the fluorescence bioassay gave results within 6 h, as opposed to more than 50 h for the germination bioassay. © 2005 Elsevier Ltd. All rights reserved.
Shon, H, Erdei, L & Kim, J 2006, 'Constituent of Natural Organic Matter (NOM) and its effect in water', Journal of the Korean Industrial and Engineering Chemistry, vol. 17, no. 2, pp. 119-124.
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Natural organic matter (NOM) should be carefully considered in terms of its constituent and effect because NOM is complex substances that occur in spatially and seasonally varying concentrations in natural water. This review presents characteristics of natural organic matter present in water. These compounds mainly include humic substances, carbohydrates, proteins (amino acids), hexosamines, fats, oils, greases, and trace organic compounds (endocrine disrupting chemicals and pharmaceuticals and personal care products)
Shon, H-K, Kim, S-H, Erdei, L & Vigneswaran, S 2006, 'Analytical methods of size distribution for organic matter in water and wastewater', KOREAN JOURNAL OF CHEMICAL ENGINEERING, vol. 23, no. 4, pp. 581-591.
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Organic matter (OM), such as natural organic matter (NOM) in surface waters, and effluent organic matter (EfOM) in wastewaters causes many problems. For example, color, taste and odor derogate potable water quality, while the presence of endocrine disrup
Shon, HK, Vigneswaran, S & Ngo, HH 2006, 'Effect of partial flocculation and adsorption as pretreatment to ultrafiltration', AICHE JOURNAL, vol. 52, no. 1, pp. 207-216.
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In this study, the sufficiency of flocculation and adsorption with reduced doses of ferric chloride and powdered activated carbon (PAC) as pretreatment to ultrafiltration. (UF) was investigated. A 50 mg/L dose of FeCl3 and 0.5 g/L of PAC removed a majori
Shon, HK, Vigneswaran, S & Snyder, SA 2006, 'Effluent Organic Matter (EfOM) in Wastewater: Constituents, Effects, and Treatment', Critical Reviews in Environmental Science and Technology, vol. 36, no. 4, pp. 327-374.
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Wastewater reuse is being increasingly emphasized as a strategy for conservation of limited resources of freshwater and as a mean of safeguarding the aquatic environment due to contaminants present in wastewater. Although secondary and tertiary treated wastewater is often discharged into surface waters, it cannot be reused without further treatment. One of the parameters of concern for human and environmental health is components of organic matter originating from wastewater treatment plant (WWTP) effluents. This effluent organic matter (EfOM) should be carefully characterized in order to find an optimum treatment method for water reuse. This review presents the components of EfOM present in WWTP effluents and various treatment methods that may be employed for reduction of EfOM. These processes include flocculation, adsorption, biofiltration, ion exchange, advanced oxidation process, and membrane technology. The removal efficiency is discussed in terms of removal of total organic carbon, endocrine-disrupting chemicals (EDCs), pharmaceuticals and personal care products (PPCPs), different polarity fractions (such as hydrophobic and hydrophilic), and molecular weight distribution of organic matter. Copyright © Taylor & Francis Group, LLC.
Shon, HK, Vigneswaran, S, Kim, IS, Cho, J & Ngo, HH 2006, 'Fouling of ultrafiltration membrane by effluent organic matter: A detailed characterization using different organic fractions in wastewater', JOURNAL OF MEMBRANE SCIENCE, vol. 278, no. 1-2, pp. 232-238.
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Membrane fouling caused by hydrophobic (HP), transphilic (TP), and hydrophilic (HL) fractions in biologically treated sewage effluent (BTSE) are still not well understood. Some researches reported that the HP fraction (humic substances) were the major pr
Shon, HK, Vigneswaran, S, Ngo, HH, Johnston, A, Kim, IS & Cho, J 2006, 'Performance of flocculation and adsorption pretreatments to ultrafiltration of biologically treated sewage effluent: The effect of seasonal variations', SEPARATION SCIENCE AND TECHNOLOGY, vol. 41, no. 16, pp. 3585-3596.
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The effect of seasonal variations on ultrafiltration (UF) following pretreatment was investigated in terms of organic removal, removal of fraction, and molecular weight (MW) distribution. The MW range of effluent organic matter (EfOM) in biologically treated sewage effluent during winter (BTSE-W) consisted of large MW. However, the MW ranged from 3000 to 200 daltons in biologically treated sewage effluent in the summer (BTSE-S). During filtration experiments of BTSE-S, the UF NTR 7410 filter showed rapid flux decline with time without pretreatment. FeCl3 flocculation removed the hydrophobic (HP) and hydrophilic (HL) fractions with different trends. In winter the HP fraction was removed up to 68.5%, whereas during the summer season, the HL fraction was removed by up to 59.8%. Flocculation removed large MW organics together with small MW, while PAC removed the majority of small MW organics. The flux decline with adsorption was also more severe than that with flocculation. Considering MW distribution, when large MW was removed by flocculation, the flux decline was minimized, whereas PAC adsorption which removed small MW still decreased the permeate flux.
Smith, AJ 2006, 'Continued Psychometric Evaluation of an Intuition Instrument for Nursing Students', Journal of Holistic Nursing, vol. 24, no. 2, pp. 82-89.
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Purpose: The purpose of this study was to evaluate the psychometric properties of a revised intuition instrument developed for nursing students. Method: Principal component factor analysis was used to establish construct validity, and the Cronbach’s alpha was used to examine reliability. Findings: Statistical analysis resulted in a 26-item intuition instrument with 6 factors accounting for 62% of the variance. The factors were labeled as Feelings That Reassure (27.7%), Spiritual Connections (10.9%), Feelings That Alert (8.4%), Feelings That Forewarn (5.8%), Physical Sensations That Alert (4.7%), and Reading Physical Cues (4.2%). Eigenvalues ranged from 1.100 to 7.225, and factor loadings ranged from .572 to .848. The overall Cronbach’s alpha was .89 with a range of .73 to .85 for each factor. Conclusions: The 26-item intuition instrument showed evidence of construct validity and reliability. Implications: The intuition instrument can serve as a stimulus to foster students’ intuitive abilities.
Smith, PJ, Shon, HK, Vigneswaran, S, Ngo, HH & Nguyen, H 2006, 'Productivity enhancement in a cross-flow ultrafiltration membrane system through automated de-clogging operations', JOURNAL OF MEMBRANE SCIENCE, vol. 280, no. 1-2, pp. 82-88.
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A membrane system only has a limited operational lifetime, whereby it becomes so severely fouled that continued operation must be stopped. In the cross-flow configuration of membrane filtration of wastewater, both increased cross-flow velocities and decr
Smith, PJ, Vigneswaran, S, Ngo, HH, Ben-Aim, R & Nguyen, H 2006, 'A new approach to backwash initiation in membrane systems', JOURNAL OF MEMBRANE SCIENCE, vol. 278, no. 1-2, pp. 381-389.
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Smith, PJ, Vigneswaran, S, Ngo, HH, Nguyen, HT & Ben-Aim, R 2006, 'Application of an automation system and a supervisory control and data acquisition (SCADA) system for the optimal operation of a membrane adsorption hybrid system', WATER SCIENCE AND TECHNOLOGY, vol. 53, no. 4-5, pp. 179-184.
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The application of automation and supervisory control and data acquisition (SCADA) systems to municipal water and wastewater treatment plants is rapidly increasing. However, the application of these systems is less frequent in the research and developmen
Tijing, LD, Pak, BC, Baek, BJ & Lee, DH 2006, 'A study on heat transfer enhancement using straight and twisted internal fin inserts', International Communications in Heat and Mass Transfer, vol. 33, no. 6, pp. 719-726.
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Ulstrup, KE, Berkelmans, R, Ralph, PJ & van Oppen, MJH 2006, 'Variation in bleaching sensitivity of two coral species across a latitudinal gradient on the Great Barrier Reef: the role of zooxanthellae', MARINE ECOLOGY PROGRESS SERIES, vol. 314, pp. 135-148.
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The ability of corals to cope with environmental change, such as increased temperature, relies on the physiological mechanisms of acclimatisation and long-term genetic adaptation. We experimentally examined the bleaching sensitivity exhibited by 2 species of coral, Pocillopora damicornis and Turbinaria reniformis, at 3 locations across a latitudinal gradient of almost 6 degrees on the Great Barrier Reef (GBR), Target bleaching temperature was reached by using a ramping rate of 0.2 degrees C/h. We found that the bleaching sensitivity and recovery of both species differed between corals with clade D symbionts and those with clade C. However, in F damicornis bleaching susceptibility corresponded more strongly with latitude than with zooxanthella type and hence, temperature history, suggesting that local adaptation has occurred. The observed bleaching sensitivity was shown by a decrease in photochemical efficiency (F-v/F-m) in both species of coral. The rate of recovery in T reniformis was highest in explants containing clade D symbionts. The occurrence of clade D in the northern section of the GBR may reflect a long-term response to high sea water temperatures, while the presence of clade D in low abundance in T reniformis at Heralds Prong Reef and Percy Island may be a result of recent bleaching events.
Varman, M, Mahlia, TMI & Masjuki, HH 2006, 'Method for calculating annual energy efficiency improvement of TV sets', Energy Policy, vol. 34, no. 15, pp. 2429-2432.
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Wan, D, Fu, Q & Huang, J 2006, 'Synthesis of a thioether modified hyperbranched polyglycerol and its template effect on fabrication of CdS and CdSe nanoparticles', Journal of Applied Polymer Science, vol. 102, no. 4, pp. 3679-3684.
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AbstractA thioether‐containing hyperbranched polyglycerol (PG) was synthesized by a simple and effective two‐step reaction; first a part of the hydroxyls of PG was transformed to carbamates by the reaction with the highly reactive 2‐chloroethyl isocyanate, and then the chlorine group was S‐alkylated with HS(CH2)nOH (n = 2, 6, 11). The resulting PGs with various molecular weights were successfully used as template for synthesis of nanoscale cadmium chalcogenide quantum dots (QDs). It was found that the size of these QDs was dependent on the polymer template. Moreover, after solvent evaporation, the polymer was assembled into large cluster, and a variety of morphologies were formed by the cluster inside the QDs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3679–3684, 2006
Wan, D, Fu, Q & Huang, J 2006, 'Synthesis of amphiphilic hyperbranched polyglycerol polymers and their application as template for size control of gold nanoparticles', Journal of Applied Polymer Science, vol. 101, no. 1, pp. 509-514.
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AbstractAmphiphilic thioether‐containing core‐shell polymers were synthesized by two‐step reaction of hyperbranched polyglycerol (PG): first the hydroxyls of PG were O‐alkylated with 1‐bromo‐3‐chloropropane by improved Williamson reaction, and 31.6% of the hydroxyls were transformed to allyl groups and 22.4% of hydroxyls to 3‐chloropropyl; then the residual 3‐chloropropyl groups were efficiently S‐alkylated with 1‐dodecanethiol. Thus the amphiphilic polymers composed of hydrophobic thioether‐containing shell and hydrophilic PG core were formed and could be used as template for the synthesis of zero‐valent gold nanoparticles by the coordination interaction between gold species and thioether. The resulting colloids were stable and the size of the encapsulated gold nanoparticles could be adjusted by changing the molecular weight/size of the PG core of the amphiphilic derivatives. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 509–514, 2006
Wilhelm, SW, Carberry, MJ, Eldridge, ML, Poorvin, L, Saxton, MA & Doblin, MA 2006, 'Marine and freshwater cyanophages in a Laurentian Great Lake: Evidence from infectivity assays and molecular analyses of g20 genes', APPLIED AND ENVIRONMENTAL MICROBIOLOGY, vol. 72, no. 7, pp. 4957-4963.
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While it is well established that viruses play an important role in the structure of marine microbial food webs, few studies have directly addressed their role in large lake systems. As part of an ongoing study of the microbial ecology of Lake Erie, we have examined the distribution and diversity of viruses in this system. One surprising result has been the pervasive distribution of cyanophages that infect the marine cyanobacterial isolate Synechococcus sp. strain WH7803. Viruses that lytically infect this cyanobacterium were identified throughout the western basin of Lake Erie, as well as in locations within the central and eastern basins. Analyses of the gene encoding the g20 viral capsid assembly protein (a conservative phylogenetic marker for the cyanophage) indicate that these viruses, as well as amplicons from natural populations and the ballast of commercial ships, are related to marine cyanophages but in some cases form a unique clade, leaving questions concerning the native hosts of these viruses. The results suggest that cyanophages may be as important in freshwater systems as they are known to be in marine systems. Copyright © 2006, American Society for Microbiology. All Rights Reserved.
Yadav, NN, Maheswaran, S, Shutthanandan, V, Thevuthasan, S, Hart, TR, Ngo, HH & Vigneswaran, S 2006, 'Comparison of analytical techniques for analysis of arsenic adsorbed on carbon', WATER QUALITY RESEARCH JOURNAL OF CANADA, vol. 41, no. 2, pp. 185-189.
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Activated carbon (AC) has been used extensively to treat arsenic-contaminated groundwater for a number of years. To date, attempts to quantify directly the amount of arsenic removed by the activated carbon using nondestructive methods has been limited. H
Yadav, NN, Maheswaran, S, Shutthanandan, V, Thevuthasan, S, Ngo, HH & Vigneswaran, S 2006, 'Quantification of arsenic in activated carbon using particle induced X-ray emission', NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, vol. 251, no. 1, pp. 191-196.
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To date, the trace elemental analysis of solids with inhomogencous internal structure has been limited, particularly in the case of adsorbents. High-energy ion beam based particle induced X-ray emission (PIXE) is an ideal analytical too] suitable for sim
Zhang, R, Vigneswaran, S, Ngo, HH & Nguyen, H 2006, 'Magnetic ion exchange (MIEX®) resin as a pre-treatment to a submerged membrane system in the treatment of biologically treated wastewater', Desalination, vol. 192, no. 1-3, pp. 296-302.
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Magnetic ion exchange (MIEX®) resin can remove a majority of hydrophilic compounds and a significant amount of hydrophobic compounds from biologically treated secondary effluent within a short contact time of 20 min. It removed a majority of small molecular weight organic compounds from the wastewater. MIEX® resin can easily be regenerated and even after several regenerations, it gives almost the same organic removal efficiency. MIEX® process, when used as pre-treatment to a submerged membrane reactor, resulted in a very high organic removal while significantly reducing the membrane fouling. The membrane fouling was further reduced by an addition of a small dose of powdered activated carbon (PAC) in the submerged membrane reactor. Combining MIEX® process with other pre-treatment methods such as adsorption, very high removal of organic matter can be achieved. © 2006.
Zhang, ZL, Hibberd, A & Zhou, JL 2006, 'Optimisation of derivatisation for the analysis of estrogenic compounds in water by solid-phase extraction gas chromatography–mass spectrometry', Analytica Chimica Acta, vol. 577, no. 1, pp. 52-61.
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An optimisation of derivatisation methods for the simultaneous determination of endocrine disrupting chemicals (EDCs) in water by solid-phase extraction (SPE) gas chromatography-mass spectrometry (GC-MS) was developed in this study. Seven highly potent EDCs including 17β-estradiol (E2), estrone (E1), 16α-hydroxyestrone, 17α-ethynylestradiol (EE2), bisphenol A, 4-nonylphenol and 4-tert-octylphenol were selected as the target compounds. The SPE technique, followed by the derivatisation with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) was used for the extraction recoveries of compounds from water and effluent samples. The stability of the silylation derivatives under different reaction conditions was investigated. The combined use of BSTFA and pyridine as derivatisation reagents, together with the use of hexane as the final solvent, was preferred in order to generate more stable derivatives of EDCs. The relative response factor (RRF) of all derivatives except that of EE2 was stable 120 h after derivatisation. The addition of pyridine as derivatisation reagent with BSTFA can prevent the conversion of EE2 to other products during the reaction. Several parameters that may affect the recovery of EDCs, such as the SPE flow rate, and water properties including aquatic colloid content and surfactant concentration were tested. The results showed that the flow rate (1-25 mL min-1), colloid concentration (0-50 mg L-1) and surfactants concentration (0-10 μg L-1) did not cause significant decrease in the EDCs recovery. © 2006 Elsevier B.V. All rights reserved.
Zhou, JL 2006, 'Sorption and Remobilization Behavior of 4-tert-Octylphenol in Aquatic Systems', Environmental Science & Technology, vol. 40, no. 7, pp. 2225-2234.
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The sorption and desorption of 4-tert-octylphenol in aquatic systems were studied to unravel the underlying controls. The sorption process was relatively slow, reaching a final sorption equilibrium in 10 d. The sorption process was interpreted as consisting of two stages: an initial rapid adsorption on particle surface followed by a slow intraparticle diffusion. The key parameter affecting the sorption of 4-tert-octylphenol by sediment is the occurrence of colloids, which in turn explains the so-called sediment concentration (SC) effect. This was confirmed by the increasing amount of colloids with increasing SC, and the relative constancy of intrinsic partition coefficient of 4-tert-octylphenol between sediment and water (Kp) and between colloids and water (Kc). Further evidence was from the nonoccurrence of SC effect from the addition of the same amount of colloids in different SC. The adsorption equilibrium is best described by the Freundlich model at low equilibrium concentrations. The adsorption of 4-tert-octylphenol was enhanced in the presence of salts, due to the salting out effect, and a salting constant of 1.3 L/mol was obtained. Desorption experiments showed that the release of 4-tert-octylphenol from contaminated sediments was highly dependent on the 'age' of sediments, with kinetics of desorption being much faster in fresh sediments than in 'aged' sediments. © 2006 American Chemical Society.
