Personal Research Database

Full Text: W\Wat Sci Tec37, 135.pdf

Abstract: Microfiltration (MF) and ultrafiltration (UF) pilot plants were operated to produce drinking water from surface water from 1992 to 1996. Microfiltration was combined with pre-coagulation by polyaluminium chloride and was operated in a dead-end mode using hollow fiber polypropylene and monolith type ceramic membranes. Ultrafiltration pilot was operated in both cross-flow and dead-end modes using hollow fiber cellulose acetate membrane and was combined occasionally with powdered activated carbon (PAC) and granular activated carbon (GAC) adsorption. Turbidity in the raw water varied in the range between 1 and 100 mg/L (as standard Kaolin) and was removed almost completely in all MF and UF pilot plants to less than 0.1 mg/L. MF and UF removed metals such as iron, manganese and aluminium well. The background organics in the river water measured as KMnO₄ demand varied in the range between 3 and 16 mg/L. KMnO₄ demand decreased to less than 2 mg/L and to less than 3 mg/L on the average by the coagulation-MF process and the sole UF process, respectively. Combination of PAC or GAC adsorption with UF resulted in an increased removal of the background organics and the trihalomethanes formation potential as well as the micropollutants such as pesticides. Filtration flux was controlled in the range between 1.5 and 2.5 m/day with the trans-membrane pressure less than 100 kPa in most cases for MF and UF. The average water recovery varied from 99 to 85%. (C) 1998 Published by Elsevier Science Ltd

Keywords: Removal, PAC, Adsorption, Coagulation, Drinking Water, Membrane, Microfiltration, Ultrafiltration

? Lee, B.K., Sung, S.W., Chun, H.D. and Koo, J.K. (1998), Automatic control for DO and pH in the activated sludge process in a coke wastewater treatment plant. Water Science and Technology, 37 (12), 141-148.

Full Text: 1998\Wat Sci Tec37, 141.pdf

Abstract: The objective of this study is to develop an automatic control system for dissolved oxygen (DO) and pH of the activated sludge process in a coke wastewater treatment plant. A discrete type autotuned proportional-integral (PI) controller using an auto-regressive exogenous (ARX) model as a process model was developed to maintain the DO concentration in aerators by controlling the speed of surface aerators. Also a nonlinear pH controller using the titration curve was used to control the pH of influent wastewater. This control system was tested in a pilot scale plant During this pilot plant experiment, there was small deviation of pH and the electric power consumption of surface aerators was reduced up to 70% with respect to the full operation when the DO set point was 2 mg/l. For real plant operation with this system, the discrete PI controller showed good tracking for set point change. The electricity saving was more than 40% of the electricity consumption when considering surface aerators. As a result of maintaining the DO constantly at the set point by the automatic control system, the fluctuation of effluent quality was decreased and overall improvement of the effluent water quality was achieved. (C) 1998 Published by Elsevier Science Ltd All rights reserved.

Keywords: Activated Sludge, ARX Model, Autotuned PI Controller, Coke Wastewater, Dissolved Oxygen, Dissolved Oxygen Control, Identification, Online, pH Control, PID Controller, Wastewater, Wastewater Treatment

Ito, A., Umita, T., Aizawa, J. and Kitada, K. (1998), Effect of inoculation of iron oxidizing bacteria on elution of copper from anaerobically digested sewage sludge. Water Science and Technology, 38 (2), 63-70.

Full Text: W\Wat Sci Tec38, 63.pdf

Abstract: The effect of inoculation of iron oxidizing bacteria on elution of Cu from anaerobically digested sewage sludge was investigated without adding ferrous sulfate as a substrate. The inoculation of iron oxidizing bacteria to the sludge brought about the effective elution of Cu at pH 2 and 3. Ferric ion produced by the biological oxidation of ferrous ion which was eluted from the sludge or ferric ion eluted directly from the sludge and iron oxidizing bacteria caused the elution of Cu. Furthermore, both chemical and biological leachings of Cu from CuS were studied at pH 2, 3 and 4. It was found that both ferric ion and iron oxidizing bacteria could elute Cu. The elution rate of Cu with ferric ion decreased as the pH increased and two moles of Fe(III) eluted I mole of Cu. The biological leaching by iron oxidizing bacteria eluted Cu more effectively than the chemical one with sulfuric acid or ferric sulfate at pH 2, 3 and 4. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Keywords: Anaerobically Digested Sewage Sludge, Copper Sulfide, Elution of Copper, Iron Oxidizing Bacteria, pH, Municipal Sludge, Metals Removal, Heavy-Metals, Recovery, Acid

Lo, I.M.C. and Mak, R.K.M. (1998), Transport of phenolic compounds through a compacted organoclay liner. Water Science and Technology, 38 (2), 143-150.

Full Text: W\Wat Sci Tec38, 143.pdf

Abstract: The transport of phenolic compounds through a compacted liner improved with organically modified bentonite (organoclay BE-40) was studied. Organoclay BE-40 is one of the manufactured products of Biomin International, Inc. and is modified with 40 lb of dicetyldimethylammonium per 100 lb of clay. The adsorption of phenolic compounds onto organoclay BE-40 is found to be significant, which could be attributed to the formation of hydrophobic bending. The hydraulic conductivities of organoclay BE-40 are 1.9810^-7, 2.2810^-7 and 5.4910^-7 cm/sec for the phenol cell, a-chlorophenol cell and 2,4,6-trichlorophenol cell, respectively. The experimental results of adsorption tests and hydraulic conductivity tests were input into the computer program ‘Pollute v9’ to simulate the transport of phenolic compounds through a compacted organoclay liner material. The simulation result was then compared with phenol transport through the conventional soil liner (90% silty sand and 10% natural clay mineral). It indicates that the retardation of the transport of phenolic compounds using organoclay as a liner material is more significant than using the conventional soil liner, particularly for higher hydrophobic organics. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Keywords: Adsorption, Hydraulic Conductivity, Landfill Liners, Organoclay, Pollutant Transport, Waste

Liu, J.C. and Huang, J.G. (1998), Using iron-coated spent catalyst as an alternative adsorbent to remove Cr(VI) from water. Water Science and Technology, 38 (4-5), 155-162.

Full Text: W\Wat Sci Tec38, 155.pdf

Abstract: The feasibility of utilizing iron-coated spent catalyst to adsorb Cr(VI) from aqueous solution was studied. Various factors, such as types and concentrations of iron salt, pH, and Initial Cr(VI) concentration were investigated. A significant increase in Cr(VI) removal capacity can be achieved through iron-coating. The maximum adsorption was found at pH of 3.0-4.0. The presence of chloride and sulfate ions were found to suppress Cr(VI) adsorption. Langmuir adsorption isotherm was utilized to describe the adsorption reaction. Results from zeta potential measurement indicate that Cr(VI) is adsorbed largely through electrostatic interaction onto iron-coated spent catalyst. This study shows that spent catalyst can be converted to a useful adsorbent for Cr(VI) removal. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Keywords: Adsorption, Cr(VI), pH, Spent Catalyst, Zeta Potential Chromium

Chang, J.S., Huang, J.C., Chang, C.C. and Tarn, T.J. (1998), Removal and recovery of lead fixed-bed biosorption with immobilized bacterial biomass. Water Science and Technology, 38 (4-5), 171-178.

Full Text: W\Wat Sci Tec38, 171.pdf

Abstract: Fixed-bed columns packed with immobilized biomass of Pseudomonas aeruginosa PU21 were utilized to remove lead (Pb) from the contaminated water. Effects of the immobilization method, bed length, flow rate, and the particle size on the performance of Pb removal by the biosorption columns were systematically investigated. Calcium alginate-immobilized cells were found to bold better Pb capacity than polyacrylamide (PAA)-entrapped cells. Typical saturation capacity of calcium alginate (CA)-immobilized cells was 280 mgPb/g, and 31 mgPb/g for PAA-immobilized cells. Results of fixed-bed biosorption showed that the breakthrough time (tb) appeared to increase with the bed length, but decreased with the flow rate. The typical overall adsorption efficiency (Q) was within 50-60%, and did not appreciably fluctuate with changes in the operation conditions or the particle size. The initial rate of adsorption was facilitated nearly 40% as the size of immobilized cells was reduced from 3.5 mm to 2 mm, whereas the particle sim did not affect the equilibrium adsorption of the immobilized biomass. The length of unused bed (LUB) remained constant with different bed length, while it slightly increased with the raising of the Pb loading rate. The metal-laden column was regenerated by elution of HCl solution (pH 2.0). For up to four adsorption/desorption (A/D) cycles, the metal recovery efficiency of each cycle was over 98%, and the recovery ratio was 8: 1 and 27: 1 for PAA and CA-immobilized cells, respectively. The regenerated beds were able to restore over 66% of their original adsorption capacity after four successive ND cycles.

Keywords: Pseudomonas-Aeruginosa PU21, Cadmium, Copper, Metals, Immobilized Cells, Biosorption, Alginate, Polyacrylamide, Fixed-Bed Reactor, Lead, Pseudomonas aeruginosa

Beydilli, M.I., Pavlostathis, S.G. and Tincher, W.C. (1998), Decolorization and toxicity screening of selected reactive azo dyes under methanogenic conditions. Water Science and Technology, 38 (4-5), 225-232.

Full Text: W\Wat Sci Tec38, 225.pdf

Abstract: The objective of this research was to generate technical background for the development of a fixed-film anaerobic reactor to renovate reactive textile dyebaths and reuse the high salt-containing mixture in the dyeing process. Six commercial reactive azo dyes (Black-5; Red-2 and 120; Yellow-3, 15 and 17) were chosen for this study. Using an anaerobic, methanogenic culture enriched from municipal sewage sludge, batch assays were performed to evaluate potential toxicity of the selected dyes to the anaerobic microorganisms as well as to determine the anaerobic biodegradability of these dyes. Total gas and methane production were monitored. No significant toxic effects were observed at 300 mg/L concentration for all dyes tested. At the end of three consecutive feeding cycles all dyes exhibited overall color removals in the range of 77.8 and 97.1%. An assay intended to determine the toxic limit and kinetics of color removal of Red-2 revealed that up to 300 mg/L, this dye was not toxic and contributed to increased total gas and methane production over that of a control. However, higher concentrations of Red-2 (500, 1000 and 2000 mg/L) depressed gas production despite continued decolorization. These results suggest that color removal under the low redox conditions maintained by the methanogenic culture occurs irrespective of the culture activity level. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Keywords: Azo Dyes, Biotransformation, Color Removal, Methanogenesis, Reactive Dyes, Textiles, Microbial Consortium, Degradation

Wang, Y.X. and Yu, J. (1998), Adsorption and degradation of synthetic dyes on the mycelium of Trametes versicolor. Water Science and Technology, 38 (4-5), 233-238.

Full Text: W\Wat Sci Tec38, 233.pdf

Abstract: Adsorption and degradation of three synthetic dyes with representative chromophores (azo, anthraquinone and indigo) were investigated on living mycelium of white rot fungus, Trametes versicolor. The maximum adsorption capacity (Q_max) and adsorption affinity (K) of the dead and living fungal mycelia to the three dyes were measured and estimated by using the Langmuir model; Q_max has a range from 50 to 105 mgdye/g dry mycelium and K from 17 to 120 mgdye/L. The adsorbed dye molecules could be degraded by the extracellular and/or intracellular enzymes that were produced by a 10-day old fungal mycelium after the essential nitrogen nutrient (NH₄⁺) had been consumed completely. Fungal mycelium was saturated by the dyes in one hour and its adsorption capacity was regenerated at different rates depending on dye structure and enzymes. Compared to the enzymatic regeneration of dye-saturated living mycelium (8-19 mgdye/g dry mycelium. h), physical desorption of adsorbed dye molecules was consistent ranging from 2-3 mgdye/g dry mycelium. h.

Keywords: Decolorization, Dye Adsorption, Dye Degradation, Trametes versicolor, Wastewater Treatment

Guiot, S.R., Stephenson, R.J., Frigon, J.C. and Hawari, J.A. (1998), Single-stage anaerobic/aerobic biotreatment of resin acid-containing wastewater. Water Science and Technology, 38 (4-5), 255-262.

Full Text: W\Wat Sci Tec38, 255.pdf

Abstract: The present study compares the coupled anaerobic/aerobic integrated system (CANOXIS) operated at different aeration and liquid recycle rates to the conventional upflow anaerobic sludge bed (UASB) system for the laboratory scale treatment of a resin acid-containing effluent. Dehydroabietic and abietic acids were added in equal proportions to a sucrose-based feed stock. Even under oxygenation conditions, methane was formed, indicating that the aerobic and facultative microorganisms consumed oxygen fast enough to maintain a reduced microenvironment essential to the methanogens. Eight weeks of resin acid loading at 100 mg/L exerted no significant effects on the high efficiency and stable performance of UASB reactors. The CANOXIS systems showed with time a reduced discharge of residual resin acids in the effluent and a decrease of the amount of resin acids adsorbed onto the biomass when compared to the UASB reactor. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Keywords: Anaerobic, Aerobic, Coupling, Resin Acid, Abietic Acid, Dehydroabietic Acid, Pulp and Paper, CTMP Effluent, Paper-Mill, Toxicity, Pulp, Reactor, Removal, Scale, Batch, Water

Butter, T.J., Evison, L.M., Hancock, I.C. and Holland, F.S. (1998), The kinetics of metal uptake by microbial biomass: Implications for the design of a biosorption reactor. Water Science and Technology, 38 (6), 279-286.

Full Text: W\Wat Sci Tec38, 279.pdf

Abstract: The kinetics of copper ion biosorption by free cell suspensions of inactivated Penicillium biomass was investigated. During the first 15 seconds of the metal uptake reaction copper biosorption was extremely rapid, becoming progressively slower until equilibrium was achieved. At a biomass concentration of 5.48 g dry weight/l, the copper biosorption reaction reached approximately 90% of the equilibrium position in one minute. This is in contrast with biosorption onto immobilised biomass which is known to take up to 24 hours or longer to reach equilibrium. However, the conventional reactor design for free cell suspensions, the stirred tank, may make inefficient use of the equipment and process due to the extended retention time. A plug-flow biosorption reactor with a limited retention time has been developed and demonstrated in the laboratory. The biomass and metal solution were mixed together using static in-line mixers and pumped along a length of pipe before discharging the mixed liquor into a settling tank to achieve phase separation. Desorption of the bound copper ions was achieved by drawing an eluant solution through metal-loaded biomass immobilised as a filter cake. The combination of metal uptake using free cells, and desorption using immobilised cells, optimises the kinetic and mass transfer effects for both processes and minimises the equipment requirements. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Keywords: Biosorption Kinetics, Copper, Heavy Metals, Penicillium Chrysogenum, Wastewater Treatment

Vagliasindi, F.G.A. and Benjamin, M.M. (1998), Arsenic removal in fresh and NOM-preloaded ion exchange packed bed adsorption reactors. Water Science and Technology, 38 (6), 337-343.

Full Text: W\Wat Sci Tec38, 337.pdf

Abstract: Arsenic speciation and removal in continuous-flow packed bed adsorption reactors was investigated using a strong base anion exchange resin as the adsorbent. Preloading of the media was investigated passing arsenic-free Lake Washington water through columns packed with the resin prior to feeding influent spiked with arsenic. NOM preloading did not affect the systems, but sulfate adsorbed during the preloading and the subsequent adsorption steps caused chromatographic displacement of the adsorbed arsenic. Significant arsenic speciation changes occurred in the arsenic-spiked feeding solution that need further investigation. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Keywords: Arsenic, Adsorption, Natural Organic Matter, Preloading, Arsenic Speciation, Ion Exchange, Dissolved Organic-Matter

Wiebusch, B., Ozaki, M., Watanabe, H. and Seyfried, C.F. (1998), Assessment of leaching tests on construction material made of incinerator ash (sewage sludge): Investigations in Japan and Germany. Water Science and Technology, 38 (7), 195-205.

Full Text: W\Wat Sci Tec38, 195.pdf

Abstract: Heavy metal release from bricks or blocks made of sewage sludge considerably decreases by sintering or cement consolidation. With such treatment, the enviromnental compatibility of recycled material can be ensured. In the framework of joint German-Japanese research, two types of leaching tests were introduced to develop a standardized test for construction material made of sewage sludge. One type is considered as a worst-case-test with low pH-values of 4-5 which describes the leaching availability under strong natural conditions (e.g. acid rain). The other type is a standardized test without pH-control. Both types of tests are investigated by using crushed samples of blocks.

Generally, there are two different ways for a sustainable assessment of the enviromnental compatibility. One way is to use a test with a low pH-value like the worst-case-tests. The other way is to crush the sample in small particles to produce large surfaces when using a standardized test. The smaller the particle size is, the higher is the concentration of heavy metals in the eluate. From the Japanese point of view, blocks are usually utilized in original shape, small particles are not appropriate as samples. That is why medium-sized particles are used for the leaching tests. But using ‘bigger’ particles, lower pH-values can be used. Therefore, a modified Swiss method is assumed to be suitable as a new standardized test for the effect of acid rain. This method is discussed from the point of view of sample diameter. From the German point of view, crushed samples with diameter <10 mm are used in combination with a standardized test. The heavy metal release from Japanese re-products is very low, and it has a close relationship with the release of the alkaline and alkaline earth metals. This effect can be shown on ash bricks from Germany also. Considering recommended limits in Germany, higher firing temperatures of >1100°C should be used. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Keywords: Sewage Sludge, Construction Material, Sludge Ash, Sludge Reuse, Leaching Test, Environmental Compatibility, Sample Preparation, Sludge Ash Bricks

Wang, Y.T. and Chirwa, E.M. (1998), Simultaneous removal of Cr(VI) and phenol in chemostat culture of E. coli ATCC 33456 and P. putida DMP-1. Water Science and Technology, 38 (8-9), 113-119.

Full Text: W\Wat Sci Tec38, 113.pdf

Abstract: A chemostat coculture consisting of a phenol-degrading organism, P. putida, and a Cr(VT)-reducing strain, E. coil ATCC 33456, was evaluated for its potential to simultaneously remove phenol and Cr(VI). Steady-state operating conditions were obtained with near complete removal of phenol and Cr(VI) under a range of influent concentration of phenol (233-2541 mg/l), influent Cr(VI) (1-10.3 mg/l), and liquid detention time (2-6.7 days). (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Keywords: Chromium, Phenol, Biological Reduction, Coculture, E-Coli, P-Putida, Hexavalent Chromium Reduction, Escherichia-Coli, Enzymatic Reduction, ATCC-33456, Chromate

Lee, S.Z., Chang, L.Z., Chen, C.M., Liu, M.C. and Tsai, L.J. (1998), Development of soil metal criteria to preserve groundwater quality. Water Science and Technology, 38 (11), 131-139.

Full Text: W\Wat Sci Tec38, 131.pdf

Abstract: The principal impediment in the remediation of contaminated sites and in the protection of groundwater quality is the lack of appropriate and reasonable standards for heavy metals in soils. There are no standards applicable to predict the potential for groundwater contamination by heavy metals in Taiwan. Lack of these soil standards may result in subjective judgment regarding the remediation needed. The migration of heavy metals through the unsaturated zone to groundwater is controlled by sorption to the soil, A. highly pH-dependent process, and the hydrological regime. Soil sorption behavior is the criterion upon which to establish a standard based on a maximum permissible concentration in groundwater. The maximum level of metal in soil for which the equilibrium soluble metal does not exceed the Drinking Water Standard can be computed, at ally pH, from the measured adsorption coefficient for any metal and soil. These metal criteria can be used as soil standards that will be protective of groundwater quality. Criteria for soil remediation are based on specific soil types and the effect of pH on metal sorption because the partitioning of trace metals is highly dependent on the solution pH and the chemical nature of the soil. (C) 1998 IAWQ. Published by Elsevier Science Ltd. All rights reserved.

Keywords: Cadmium, Adsorption, Sorption, Copper, Zinc, Adsorption Coefficient, Groundwater, Heavy Metal, Soil, Soil Standard

Adelman, D.D., Stansbury, J. and Tabidian, M.A. (1998), A risk/cost analysis to manage viral contamination of groundwater. Water Science and Technology, 38 (12), 1-6.

Full Text: W\Wat Sci Tec38, 1.pdf

Abstract: Under the proposed groundwater disinfection rule of the 1986 Safe Drinking Water Act, municipal water systems have four options to demonstrate that natural disinfection of viruses occurs between the virus source and the municipal well. One option is to demonstrate that the necessary set-back distance exists between these facilities. The objective of this research was to evaluate the risk that virus concentrations at a municipal well would exceed recommended levels even though the virus source was separated from the well by the setback distance recommended by the EPA. Groundwater transport modeling was used to evaluate this risk and compute the necessary distance upgradient from each Nebraska municipal well for sufficient virus die-off to occur. The number of wells with computed die-off distances greater than the regulatory set-back distances were divided by the total number of wells. The results of this research show that the potential risk for virus concentrations will exceed recommended virus levels in municipal wells using EPA’s set-back distances. (C) 1998 IAWQ published by Elsevier Science Ltd. All rights reserved.

Keywords: Adsorption, Advection, Die-Off, Groundwater, Risk, Cost, Set-Back Distances

Notes: highly cited

? Gujer, W., Henze, M., Mino, T. and van Loosdrecht, M. (1999), Activated sludge model No. 3. Water Science and Technology, 39 (1), 183-193.

Full Text: 1999\Wat Sci Tec39, 183.pdf

Abstract: The Activated Sludge Model No. 3 (ASM3) can predict oxygen consumption, sludge production, nitrification and denitrification of activated sludge systems. It relates to the Activated Sludge Model No. 1 (ASM1) and corrects for some defects of ASM I. In addition to ASM1, ASM3 includes storage of organic substrates as a new process. The lysis (decay) process is exchanged for an endogenous respiration process. ASM3 is provided as a reference in a form which can be implemented in a computer code without further adjustments. Typical kinetic and stoichiometric parameters are provided for 10°C and 20°C together with the composition of a typical primary effluent in terms of the model components. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved.

Keywords: Activated Sludge, Activated Sludge Model No.1, Activated Sludge Model No. 3, ASM1, ASM3, Computer, Consumption, Denitrification, Effluent, Elsevier, Kinetic, Kinetics, Mathematical Modeling, Model, Nitrification, Oxygen Consumption, Primary, Science, Sludge, Sludge Production, Stoichiometry, Storage, Storage of Organic Substrates

Gromaire-Mertz, M.C., Garnaud, S., Gonzalez, A. and Chebbo, G. (1999), Characterisation of urban runoff pollution in Paris. Water Science and Technology,