Personal Research Database

Full Text: W\Wat Res33, 1918.pdf

Abstract: An innovative process for removing heavy metals including Cu, Ni and Zn From industrial wastewater has been developed. The new technology was based on inducing the nucleated precipitation of heavy metals on the sand surface in a fluidized bed reactor. The results showed that pH had a great effect on heavy metal removal efficiency and the optimum pH was about 9.0 to 9.1. At this pH value, heavy metal removal efficiency could be achieved above 92 and 95% when influent heavy metal concentrations were 10 and 20 mg/l, respectively. When pH was greater than 8.7, above 92.4% of the precipitation was composed of metal hydroxide. Hydraulic retention time (HRT) had almost no effect on heavy metal removal efficiency when HRT was greater than 7.1 min. Scanning electron microscope (SEM) analysis indicated that carbonate injection with a drip-wise manner was more conducive than that with a slug dosing manner for precipitation to be coated on the sand surface. (C) 1999 Elsevier Science Ltd. All rights reserved.

Keywords: Heavy Metal Removal, Fluidized Bed Reactor, Discrete Precipitation, Nucleation Precipitation, Precipitation Composition, Slug Dosing, Drip-Wise Dosing, Metal Carbonate, Metal Hydroxide, SEM, Sludge Generation

Yin, P.H., Yu, Q.M., Jin, B. and Ling, Z. (1999), Biosorption removal of cadmium from aqueous solution by using pretreated fungal biomass cultured from starch wastewater. Water Research, 33 (8), 1960-1963.

Full Text: W\Wat Res33, 1960.pdf

Abstract: The biosorption removal of cadmium ions from aqueous solutions by using the fungal biomass obtained from cultivation using starch wastewater as a substrate was investigated. Batch experimental results showed that the biosorption capacities of the pretreated fungal biomass of R. oryzae, R. oligosporus, A. oryzae and R. arrhizus were up to 0.28, 0.35. 0.40 and 0.56 mmol Cd²⁺/g (dry weight), respectively. Pretreatment of the biomass with calcium solution and heat improved the stability and settling property and increased heavy metal uptake capacities of the biomass. The biosorption capacities were solution pH dependent. The effects of other cations (Pb²⁺, Cu²⁺. Cd²⁺ and Zn²⁺) were also investigated and the biosorption affinity sequence for the biomass is Pb²⁺ > Cu²⁺ > Cd²⁺ > Zn²⁺. This study indicated that the fungal biomass of R. arrhizus has a high capacity for cadmium.

Keywords: Heavy-Metal Biosorption, Rhizopus-arrhizus, Uranium, Radiata, pH, Cadmium Removal, Biosorption of Heavy Metals, Fungal Biomass, Starch Wastewater, R-arrhizus

Kondo, H., Ishiguro, Y., Ohno, K., Nagase, M., Toba, M. and Takagi, M. (1999), Naturally occurring arsenic in the groundwaters in the southern region of Fukuoka Prefecture, Japan. Water Research, 33 (8), 1967-1972.

Full Text: W\Wat Res33, 1967.pdf

Abstract: In March, 1994, arsenic over the permissible level for drinking use (0.01 mg/l) was detected in wellwaters in the southern region of Fukuoka Prefecture, Japan. The highest concentration found was 0.293 mg/l, being quite high compared to other arsenic-containing wellwaters reported in japan. The polluted wellwaters contained NaHCO₃ as the major dissolved inorganic component, which made the water weakly alkaline. The concentration of dissolved oxygen was much lower than those in unpolluted areas. The organic arsenic was not detected. These data combined with geological-geochemical inspections by boring proved that the arsenic pollution did not originate artificially but occurred naturally through an elution process long ongoing on the rocks and soils by the stagnant underground water. The mechanisms of arsenite/arsenate elution from the soil proposed were which involved (i) anion exchange with OH^- and (ii) reductive labilization of arsenic through conversion of arsenate to arsenite. (C) 1999 Elsevier Science Ltd. All rights reserved.

Keywords: Arsenic Pollution, Wellwaters, Physicochemical Characteristics, Arsenic Species, Ionic Components, Drinking-Water, Release, Area

Navarro, R.R., Sumi, K. and Matsumura, M. (1999), Improved metal affinity of chelating adsorbents through graft polymerization. Water Research, 33 (9), 2037-2044.

Full Text: W\Wat Res33, 2037.pdf

Abstract: Modification of cellulose for heavy metal adsorption was conducted by the graft polymerization of glycidyl methacrylate utilizing ceric ammonium nitrate initiator, followed by the reaction with polyethyleneimine to introduce nitrogenous ligands. Infrared (IR) spectra of the reaction intermediates and products qualitatively revealed the presence of significant functional groups. Low amine to epoxide ratio (2 amines/epoxide) from elemental analysis of the products confirmed the occurrence of crosslinking between PEI and poly(GMA) side chain. Comparisons between metal adsorption isotherms of poly(CGMAPEI) adsorbent and cellulose-PEI, a previously synthesized adsorbent having extensive PEI crosslinking with the matrix, showed a higher metal affinity in the former. Based on these properties, an adsorbent structure model where ligands acquire an improved mobility was suggested. Optimization experiments further revealed that the metal affinity of the this adsorbent is affected by the amount of initiator during polymerization. (C) 1999 Elsevier Science Ltd. All rights reserved.

Keywords: Adsorption, Cellulose, Chelating Adsorbent, Initiator, Graft Polymerization, Heavy Metals

Angelakis, A.N., Marecos Do Monte, M.H.F., Bontoux, L. and Asano, T. (1999), The status of wastewater reuse practice in the Mediterranean basin: Need for guidelines. Water Research, 33 (10), 2201-2217.

Full Text: W\Wat Res33, 2201.pdf

Abstract: In Mediterranean environments, uneven distribution of precipitation and runoff spacially and temporarily, requires the construction of costly water storages and higher levels of wastewater treatment. Also, uneven occupation of the territory leads to a significant stress in coastal areas and requires the diversion of significant volumes of water. In most Mediterranean countries, the main problem may not be scarcity of water in terms of average per capita, but the high cost of making water available at the right place, at the right time with the required quality. In these countries, more than anywhere else, an integrated approach for water resources management including wastewater reclamation and reuse locally is required. As a result, and following a general increase in wastewater treatment, wastewater reclamation and reuse is expected to increase sharply in the Mediterranean basin over the next decade and become an important aspect of integrated water resources management. Important projects are being developed and wastewater reclamation and reuse facilities have been built. These projects have followed local or national guidelines where available such as for example in Israel, France, Tunisia or Cyprus. Regulations on wastewater reclamation and reuse are essential. They help protect public health, increase water availability, prevent coastal pollution and enhance water resources and nature conservation policies. Unifying wastewater reclamation and reuse regulations around the Mediterranean basin would also contribute to secure economic and touristic exchanges in the region. However, there is still a controversy between the defenders of strict water quality standards for an absolute protection of public health and the defenders of a pragmatic stance recognizing existing wastewater reuse practices and promoting non-potable water uses with less restrictive water quality standards. Despite the high potential for wastewater reclamation and reuse in the Mediterranean countries, only a few have systematically exploited this resource. This paper presents the status of wastewater reclamation and reuse around the Mediterranean basin and discusses existing guidelines and regulations. The possibility of developing uniform wastewater reuse standards is also presented.

Keywords: Water Resources Management, Water Availability, Wastewater Reclamation, Water Management, Wastewater Reuse Criteria, Guidelines and Regulations, Irrigation with Reclaimed Wastewater

Notes: highly cited

? Beun, J.J., Hendriks, A., Van Loosdrecht, M.C.M., Morgenroth, E., Wilderer, P.A. and Heijnen, J.J. (1999), Aerobic granulation in a sequencing batch reactor. Water Research, 33 (10), 2283-2290.

Full Text: 1999\Wat Res33, 2283.pdf

Abstract: In a sequencing batch reactor (SBR) granules of aerobic heterotrophic microorganisms were cultured. The effect of different operational conditions on the formation of these aerobic granules were studied. The time allowed for settling was the main parameter to select for growth of bacteria in well settling granules. Both a short HRT and a relative high shear were found favorable for granulation. A substrate loading rate of 7.5 kg COD/(m³ day) was applied. This Ted to formation of granules with an average diameter of 3.3 mm and a biomass density of 11.9 gVSS/l(granule). Based on microscopic observations a hypothesis for the granulation process was formulated. The reactor was started up without any carrier material present. At the beginning filamentous fungal pallets dominated the reactor. These pellets functioned as an immobilization matrix in which bacteria could grow out to colonies. After a certain rime the fungal pellets fell apart due to lysis in the inner parr of the pellets, the bacterial colonies could now remain in the reactor because they were large enough to settle sufficiently Fast. These colonies further grew out to granules. This paper shows that granule formation in aerobic reactors is feasible and can be exploited to increase the volumetric conversion capacity of such reactors. (C) 1999 Elsevier Science Ltd. All rights reserved.

Keywords: Aerobic Granules, Bacteria, Biofilms, Biomass, Capacity, Elsevier, Granulation, SBR, Science, Settling Time, Shear, Sludge

Juang, R.S., Wu, F.C. and Tseng, R.L. (1999), Adsorption removal of copper(II) using chitosan from simulated rinse solutions containing chelating agents. Water Research, 33 (10), 2403-2409.

Full Text: W\Wat Res33, 2403.pdf

Abstract: The adsorption ability of Cu(II) using chitosan from simulated rinse solutions containing chelating agents was studied. Four chelating agents including ethylenediaminetetraacetic acid (EDTA), citric acid, tartaric acid and sodium gluconate were selected. It was shown that the concentration ratio of chelating agent to Cu(II) as well as the NaOH concentration significantly affected the adsorption capacity. Competition between coordination of Cu(II) with unprotonated chitosan and electrostatic interaction of Cu(II) chelates with protonated chitosan played an important role in this adsorption system. The maximum adsorption capacity was found within each optimal pH range. This work provided a simple criteria for adsorption removal of Cu(II) from such industrial rinse solutions (0.3-5.0 mol/m³) using chitosan. (C) 1999 Elsevier Science Ltd. Aii rights reserved.

Keywords: Activated Carbon, Heavy-Metals, Uranyl Ions, Edta, Sorption, Water, Crosslinking, Equilibrium, Isotherms, Uranium, Adsorption, Isotherm, Chitosan, Copper Ions, Rinse Solution, Chelating Agents

Notes: highly cited

Bailey, S.E., Olin, T.J., Bricka, R.M. and Adrian, D.D. (1999), A review of potentially low-cost sorbents for heavy metals. Water Research, 33 (11), 2469-2479.

Full Text: W\Wat Res33, 2469.pdf

Abstract: The use of low-cost sorbents has been investigated as a replacement for current costly methods of removing heavy metals from solution. Natural materials or waste products from certain industries with a high capacity for heavy metals can be obtained, employed, and disposed of with little cost. Modification of the sorbents can also improve adsorption capacity, fn this review, an extensive list of sorbent literature has been compiled to provide a summary of available information on a wide range of potentially low-cost sorbents, including bark, chitosan, xanthate, zeolite, clay, peat moss, seaweed, dead biomass, and others. Some of the highest adsorption capacities reported for cadmium, chromium, lead and mercury are: 1587 mg Pb/g lignin, 796 mg Pb/g chitosan, 1123 mg Hg/g chitosan, 1000 mg Hg/g CPEI cotton, 92 mg Cr(III)/g chitosan, 76 mg Cr(III)/g pear, 558 mg Cd/g chitosan, and 215 mg Cd/g seaweed. (C) 1999 Elsevier Science Ltd. All rights reserved.

Keywords: Adsorption, Adsorption Capacity, Aqueous-Solutions, Biomass, Cadmium, Cadmium Removal, Capacity, Chitosan, Chitosan Beads, Chromium, Clay, Cotton, Economic, Elsevier, Fly-Ash, Heavy Metals, Ion Binding, Lead, Literature, Marine-Algae, Mercury, Metals, Modification, Peat, Review, Science, Sorption, Sorption, Sphagnum Moss Peat, Usa, Waste-Water, Water, Zeolite

Barker, D.J., Mannucchi, G.A., Salvi, S.M.L. and Stuckey, D.C. (1999), Characterisation of soluble residual chemical oxygen demand (COD) in anaerobic wastewater treatment effluents. Water Research, 33 (11), 2499-2510.

Full Text: W\Wat Res33, 2499.pdf

Abstract: Anaerobic wastewater treatment processes cannot usually achieve discharge levels of COD without some form of post-treatment due to the high levels of soluble residual COD in the effluent. However, there is very little information in the literature on the nature of this material, and hence the aim of this work was to characterise effluents from several different anaerobic processes by their: molecular weight (MW) distributions (using the techniques of ultrafiltration and size exclusion chromatography); biodegradability (both aerobic and anaerobic) and activated carbon adsorption characteristics. The MW distribution data indicated that the majority (up to 89% w/w) of the material present in the effluents was in the low MW range (i.e. MW < 1 kDa), although there was a significant amount (up to 22% w/w) in the high MW range (i.e. MW > 300 kDa). Differences in the distributions were observed according to reactor type, with effluents From anaerobic baffled reactors (ABRs) containing a higher proportion of high MW material than effluents From other reactor types. Aerobic degradation of the effluents was significantly more successful than anaerobic, despite the fact that the low MW material was found to be the most difficult to degrade aerobically. Activated carbon adsorption revealed that the low MW material was more difficult to adsorb than the high MW compounds. The data was fitted to Freundlich, Langmuir and BET isotherms and it was concluded that the Freundlich model was the most accurate for predicting removal efficiencies especially with regard to scale up. Some generic patterns emerged with respect to the characterisation of the effluents and these will assist in decisions regarding post-treatment. Nevertheless, in order for these generic patterns to be confirmed more work is needed on characterising effluent samples from anaerobic treatments. (C) 1999 Elsevier Science Ltd. All rights reserved.

Keywords: Soluble Microbial Products (SMP), Molecular Weight Distribution, Anaerobic Process Effluent, Biodegradability, Post-Anaerobic Treatment Processes, Activated Carbon, Microbial Products Smp, Molecular-Weight Distribution, Dissolved Organic-Matter, Baffled Reactor, Chromatography, Performance, Adsorption, Biodegradability, Waters

? Ledakowicz, S. and Gonera, M. (1999), Optimisation of oxidants dose for combined chemical and biological treatment of textile wastewater. Water Research, 33 (11), 2511-2516.

Full Text: 1999\Wat Res33, 2511.pdf

Abstract: A test of inhibition of microbial growth of activated sludge in a synthetic textile wastewater under the influence of various oxidants applied in the advanced oxidation process (AOP) pretreatment has been proposed. The inhibitory action of single constituents of the textile wastewater was determined in terms of effective concentration, EC50. for a dyestuff and two detergents employed. The most inhibiting component of the textile wastewater (EC50 = 28 mg dm^-3) appeared to be anthraquinone dyestuff, while the surfactants seemed to be partly biodegradable (EC50 = 128 mg dm^-3 for the softening agent Tetrapol CLB and EC50 = 1700 mg dm^-3 for the anionic detergent Avivage KG concentrate). The application of AOPs prior to biodegradation showed that the most advisable AOP is the ozonation combined with UV radiation or the combination of O₃/UV/H₂O₂. The inhibitory effect of the AOPs on microbial growth during subsequent biodegradation of textile wastewater accounts for only 10%, while untreated wastewater exhibits 47% of inhibitory action. The applied biotest is one of the simplest methods of process optimisation of oxidant or radiation dose for the integrated chemical and biological oxidation of industrial wastewater. (C) 1999 Elsevier Science Ltd. All rights reserved.

Keywords: Textile Wastewater, Advanced Oxidation Processes, Biodegradation, Integrated Biological and Chemical Treatment, Activated Sludge, Inhibition Test, Effective Concentration

Notes: highly cited

? Lay, J.J., Lee, Y.J. and Noike, T. (1999), Feasibility of biological hydrogen production from organic fraction of municipal solid waste. Water Research, 33 (11), 2579-2586.

Full Text: 1999\Wat Res33, 2579.pdf

Abstract: Organic municipal solid waste (OFMSW) and two seed microorganisms, namely heat-pretreated digested sludge and hydrogen-producing bacteria enriched from soybean-meal silo, were varied according to a full factorial central composite experimental design with the aim of assessing the feasibility of hydrogen production from OFMSW. A simple model developed from the Gompertz equation was suitable for estimating the hydrogen production potential and rate. Through response surface methodology, empirical equations for specific hydrogen production potential and rate were fitted and plotted as contour diagrams in order to facilitate examination of experimental results. The contour plots showed that high hydrogen production potentials of 140 and 180 ml H-2.g TVS-1 occurred when the pretreated digested sludge and the hydrogen-producing bacteria consumed OFMSW, respectively. A high hydrogenic activity for the pretreated digested sludge (45 ml.g VSS-1.h^-1) was obtained at a high food-ro-microorganism (F/M) ratio; however, that for the hydrogen-producing bacteria(36 ml.g VSS-1.h^-1) was found at a low F/M ratio. The experimental results showed that the hydrogen composition of the biogas was greater than 60% except For initial incubation and no significant methane was found throughout this study. Further experiments confirmed that the results of this study were highly reliable and the OFMSW had a considerable potential on biological hydrogen production. Metabolic responses confirmed that characteristics of the heat-pretreated digested sludge converting the OFMSW into hydrogen were similar to that of anaerobic spore-forming bacteria of the genus Clostridium. (C) 1999 Elsevier Science Ltd. All rights reserved.

Keywords: Acetone, Acid, Bacteria, Batch Cultures, Butanol, Characteristics, Clostridium, Clostridium-Acetobutylicum, Composite, Digested Sludge, Digestion, Elsevier, Factorial Central Composite Experimental Design, Hydrogen, Methane, Methane Production, Model, Organic Fraction of Municipal Solid Waste, pH, Response Surface Methodology, Science, Sludge, Solvent Production

Young, P.L. and Komisar, S.J. (1999), The variability introduced by partial sample analysis to numbers of Cryptosporidium oocysts and Giardia cysts reported under the information collection rule. Water Research, 33 (11), 2660-2668.

Full Text: W\Wat Res33, 2660.pdf

Abstract: Subsampling of the concentrated sample pellet resulting from the information collection rule (ICR) method for detection of Cryptosporidium oocysts and Giardia cysts is often required to facilitate the terminal microscopy step. Variability in counts of (oo)cysts in subsamples suggests that sampling error may occur as a consequence of subsampling and subsequent partial analysis of this pellet. Variability is modeled hers as a Poisson distribution and is incorporated into a model that accounts for other uncertainties in the detection procedure. The result is to greatly expand confidence intervals (CI) around reported concentrations. For example, the 90% CI around the concentration reported based on detection of one (oo)cyst in a pellet subsample is increased nearly threefold when sampling error arising from partial sample analysis is added to other potential sources of variability. Consideration of a distribution in which (oo)cysts are clumped, such as a negative binomial distribution, further increases uncertainty, producing confidence intervals ranging over several orders of magnitude. The relevance of the uncertainty arising from partial sample analysis to risk assessment is demonstrated. For example, to produce water with an acceptable 1 in 10,000 risk of infection, the level of water treatment prescribed may increase from 3- to 4.5- for greater log removal of(oo)cysts. Implications of this additional uncertainty in the ICR method on reported (oo)cyst concentrations argue for expanded reporting procedures to include an indication of the uncertainties associated with reported concentrations and/or improvements in the detection method. (C)! 1999 Elsevier Science Ltd. All rights reserved.

Keywords: Cryptosporidium, Giardia, Uncertainty Analysis, Statistics, Drinking Water, Microbiological Risk Assessment, Drinking-Water

Bailey, H.C., Elphick, J.R., Potter, A. and Zak, B. (1999), Zinc toxicity in stormwater runoff from sawmills in British Columbia. Water Research, 33 (11), 2721-2725.

Full Text: W\Wat Res33, 2721.pdf

Abstract: Samples of stormwater runoff from three sawmills on Vancouver Island BC, were tested for acute toxicity with juvenile rainbow trout. All except one of the 27 samples tested exhibited toxicity. Causes of toxicity were investigated using toxicity identification evaluation techniques; specifically, treatment with the chelating agent EDTA. Toxicity was attributed to divalent cations, particularly zinc, in 24 of these samples. The very low hardness associated with most of the samples increased the potential for metals toxicity. Zinc toxicity showed a strong dependence on hardness, with a range of LC(50)s of 72-272 µg/L between hardnesses of 9-100 mg/L. (C) 1999 Elsevier Science Ltd. All rights reserved.

Keywords: Toxicity Identification Evaluation, Stormwater Runoff, Zinc, Sawmill, Rainbow Trout, Trout Salmo-Gairdneri, Rainbow-Trout, Hardness, pH, Alkalinity, Copper, Lethality, Water

Asami, M., Aizawa, T., Morioka, T., Nishijima, W., Tabata, A. and Magara, Y. (1999), Bromate removal during transition from new granular activated carbon (GAC) to biological activated carbon (BAC). Water Research, 33 (12), 2797-2804.

Full Text: W\Wat Res33, 2797.pdf

Abstract: Bromate removal by activated carbon after ozonation in a subject of concern, since bromate is commonly found in the ozonation of bromide-containing water. Though new GAC (granular activated carbon) shows the capacity to reduce bromate to bromide, n the long-term use of GAC following ozonation, its bromate removal rate apparently decreases during transition from new GAC to BAC (biological activated carbon) after 3 months. Batch bromate reduction experiments using new GAC and BAC confirmed new GAC’s ability and BAC’s inability to reduce bromate to bromide. Our experiment also indicated that ion exchangeable bromate adsorption on new GAC was very limited. Based on the results of our long-term experiment, the bromate removal rate during the transition from new GAC to BAC was calculated: 1.5 mg BrO₃/g carbon when bromate concentration was 50 µg/l. BAC’s inability to reduce bromate makes it necessary to optimize ozonation conditions to minimize the formation of bromate and other by-products while maintaining target levels trf organic matter decomposition. (C) 1999 Elsevier Science Ltd. All rights reserved.

Keywords: Drinking Water, Bromate, Chloride, GAC, Biological Activated Carbon (BAC)

Jang, L.K., Nguyen, D. and Geeesey, G.G. (1999), An equilibrium model for absorption of multiple divalent metals by alginate gel under acidic conditions. Water Research,