Personal Research Database

Full Text: W\Wat Res31, 621.pdf

Abstract: The equilibrium isotherms of zinc adsorption onto natural bentonite show that the data correlate well with Freundlich and Langmuir models and that the adsorption is physical in nature. The operating parameters (agitation-speed, solid-liquid ratio, temperature, particle size and initial zinc concentration) influenced the rate of adsorption. The maximum monomolecular capacity eo according to the Langmuir model is 52.91 mgg^-1 for an initial zinc concentration of 300 mgL^-1 at 20℃.

Michalakos, G.D., Nieva, J.M., Vayenas, D.V, and Lyberatos, G. (1997), Removal of iron from potable water using a trickling filter. Water Research, 31 (5), 991-996.

Full Text: W\Wat Res31, 991.pdf

Abstract: A trickling filter for iron removal from potable water has been constructed and tested. Iron removal was found to be caused by both biological and physico-chemical iron oxidation. The extent of each oxidation type was assessed. in addition, iron concentration profiles were taken along the filter depth, for both biological and physico-chemical iron oxidation, under the same operating conditions. Significant quantities of iron precipitated, mandating a periodic filter backwash. The possible duration of the filter operating cycles was studied as a function of the inlet iron concentration and. the volumetric Bow-rate. The limits of feed iron concentration and hydraulic loadings on the filter were determined and appropriate operating diagrams were constructed. (C) 1997 Elsevier Science Ltd.

Keywords: Biofilm, Biological Oxidation, Iron Removal, Physico-Chemical Oxidation, Potable Water, Trickling Filter, Manganese

Artola, A., Balaguer, M.D. and Rigola, M. (1997), Heavy metal binding to anaerobic sludge. Water Research, 31 (5), 997-1004.

Full Text: W\Wat Res31, 997.pdf

Abstract: Heavy metal interaction with anaerobically digested sludge was investigated using copper, cadmium and nickel chloride salt solutions. The behaviour of the well-known glycine-metal aqueous system was compared with the behaviour of the sludge-metal system. When equilibrium pH values are presented against the initial metal concentration for the glycine-copper system the profile obtained shows a sharp peak. This behaviour is similar to the behaviour of the experimental sludge-copper system. The peak also appears for cadmium and nickel-glycine systems. However, it is not as pronounced as in the glycine-copper system and cannot be observed in the sludge-metal systems. The similar behaviour of both copper systems suggests that the metal binding mechanism of the sludge involves amino acid functional groups which are present in the cell wall. Due to this similarity, an apparent molarity of the sludge can be evaluated by sludge titration with copper(II). The value obtained can be expressed as mmols of equivalent glycine per gram of sludge.

Keywords: Biosorption, Binding Capacity, Heavy Metals, Digested Sludge, Cadmium, Copper, Nickel, Sludge Titration

Loaëc, M., Olier, R. and Guezennec, J. (1997), Uptake of lead, cadmium and zinc by a novel bacterial exopolysaccharide. Water Research, 31 (5), 1171-1179.

Full Text: W\Wat Res31, 1171.pdf

Abstract: The biosorption of the three metallic ions, lead, cadmium and zinc, in single component and bi-component mixtures in aqueous solutions by an exopolysaccharide (EPS) is reported. The isotherms are plotted to obtain the maximum of uptake capacities and apparent dissociation constants. A comparison is made between the one metal sorption system and the influence of a second metal on the uptake of the primary one. The competitive effect on the uptake of various heavy metals on the Alteromonas macleodii subsp fijiensis has been studied using the Langmuir model for bisolute systems; The isotherms indicate a competition for the same binding site with zinc and cadmium. Lead is preferentially complexed by EPS in the bi-component solutions. The hydrothermal bacterial exopolysaccharide is shown to possess an affinity for the tested metal ions which makes its use as a biosorbent a possible alternative to the other common methods. (C) 1997 Elsevier Science Ltd.

Keywords: Xopolysaccharide, Deep-Sea Hydrothermal Vent Bacterium, Heavy Metals, Complexation, Mechanism, Selectivity, Saccharomyces-Cerevisiae, Biosorption, Polysaccharides, Spectroscopy, Copper, Sludge, Cu

Notes: highly cited

? Young, L. and Yu, J. (1997), Ligninase-catalysed decolorization of synthetic dyes. Water Research, 31 (5), 1187-1193.

Full Text: 1997\Wat Res31, 1187.pdf

Abstract: Many synthetic dyes in industrial wastewaters are resistant to degradation in conventional biological treatment process. Decolorization of eight synthetic dyes including azo, anthraquinone, metal complex and indigo were examined in white-rot fungal cultures and by fungal peroxidase-catalysed oxidation. The dyes were not decolorized by manganese-dependent peroxidase (MnP) while above 80% color was removed by ligninase-catalysed oxidation. Dye decolorization rate increased linearly with ligninase doses. Compared with fungal cultures in which ligninase was detected, partially purified ligninase showed a consistent and higher extent of dye decolorization with other essential components being provided such as veratryl alcohol, hydrogen peroxide and acidic pH (3.5–5). Veratryl alcohol had a critical concentration level above which no further effect on dye decolorization was observed. Depending on the influence of H₂O₂ on dye decolorization, the eight dyes can be divided into two groups; one had an optimum H₂O₂ concentration and the other showed increased decolorization with high H₂O₂ doses. Dye concentration had a negative effect on decolorization rate in general. The dye concentration above which the negative effect was observed varied from 10 to 125 mg/L, depending on individual dye structure. These results indicate that a highly efficient bioprocess using white-rot fungi to remove color from industrial effluents should produce ligninase, H₂O₂, veratryl alcohol continuously and coordinately under acidic condition and controlled back-mixing flow of wastewater.

Keywords: Dye, Decolorization, White-Rot Fungi, Peroxidase, Ligninase, Wastewater, Enzymatic Oxidation

Ginter, M.O. and Grobicki, A.M. (1997), Manganese removal mechanisms in a stirred USAB reactor. Water Research, 31 (6), 1261-1268.

Full Text: W\Wat Res31, 1261.pdf

Abstract: The mechanisms of the removal from anaerobically treated wastewaters of those metal ions which do not form precipitates with sulphide or carbonate ions, or which form highly soluble precipitates, has been little studied to date. Therefore, the removal of manganese as a representative of this group was specifically investigated in the course of a wider project studying metal removal in laboratory-scale UASB reactors. Mn removal, in the absence of sulphate in the reactor feed, was low at 7.2%, but up to 40% Mn removal could be achieved in the presence of sulphate. Mn was removed by adsorption onto the existing solids in the sludge and onto newly grown biomass, and also by co-precipitation processes, which can be strongly enhanced by other heavy metal ions in solution. In the presence of cadmium in the reactor feed, manganese removal could be increased to 56%.

Keywords: Bacterial Sulfate Reduction, Heavy-Metals, Anaerobic-Digestion, Sludge, UASB, Manganese, Cadmium, Heavy Metals, Bio-Accumulation, Metal Removal, Acid-Insoluble Substances, Acid-Soluble Substances

Teunis, P.F.M., Medema, G.J., Kruidenier, L. and Havelaar, A.H. (1997), Assessment of the risk of infection by Cryptosporidium or Giardia in drinking water from a surface water source. Water Research, 31 (6), 1333-1346.

Full Text: W\Wat Res31, 1333.pdf

Abstract: The significance of the presence in drinking water of the protozoan microparasites Cryptosporidium parvum and Giardia lamblia for public health may be analyzed by means of risk assessment. This requires quantitative knowledge of all the contributing factors, from the concentration of these organisms in the source water to the dose-response relation for the probability of infection or disease in a human host. The major contributing factors are: the concentration of cysts or oocysts in raw water, the recovery of the detection method, the viability of recovered cysts or oocysts, the removal of organisms in the treatment process, and the daily consumption of unboiled tap water. To enable analysis of the uncertainty in the calculated risk of infection, each of these factors is treated as a stochastic variable, for which a suitable distribution is proposed. A frequency distribution for the probability of infection is then constructed with standard sampling techniques. This first evaluation of the calculation of the risk of infection due to exposure to Cryptosporidium oocysts and Giardia cysts via drinking water, shows that the uncertainty in the estimated removal efficiency of the treatment process dominates over uncertainties in other contributing factors. (C) 1997 Elsevier Science Ltd.

Keywords: Drinking Water, Water Treatment, Infection, Risk Assessment, Uncertainty Analysis, Cryptosporidium, Giardia, Distributions, Inactivation, Outbreak, Disease, Viruses, Parvum, Ozone

Ćurković, L., Cerjan-Stefanović, Š. and Filipan, T. (1997), Metal ion exchange by natural and modified zeolites. Water Research, 31 (6), 1379-1382.

Full Text: W\Wat Res31, 1379.pdf

Abstract: The lead and cadmium removal from wastewaters by natural and pretreatment zeolites was examined by using a batch-type method. The results demonstrated that the natural zeolites contained a complement of exchangeable Na, K and Ca ions but exposing them to 2 M NaCl solution at 22 and 70°C, respectively, converted them to a near homoionic state in Na-form. Lead and cadmium removal results using natural zeolites and treated zeolites showed that treatment improved both the exchange capacity and the removal efficiency. The influence of the temperature on the ion-exchange process was examined. It was found that the metal uptake was increased with increasing temperature during the ion-exchange process. Natural and modified zeolites remove toxic metals from waste waters. (C) 1997 Elsevier Science Ltd.

Keywords: Natural Zeolites, Modified Zeolites, Ion Exchange, Lead Removal, Cadmium Removal, Heavy-Metals, Clinoptilolite, Removal

Schramm, K.W., Winkler, R., Casper, P. and Kettrup, A. (1997), PCDD/F in recent and historical sediment layers of Lake Stechlin, Germany. Water Research, 31 (6), 1525-1531.

Full Text: W\Wat Res31, 1525.pdf

Abstract: Lake Stechlin sediment layers were dated and analysed for PCDD/F. The concentrations of PCDD/F in the investigated sediment have increased by a factor of about 100 since the last century and have decreased by a factor of two since the 1970s. The latter finding can be confirmed by recent temporal trends in human samples and herring-gull eggs. The homologue patterns especially for PCDF are subject to temporal variations and can be mainly related to municipal waste incineration and the impact of the precursor PCB. The overall time trend corresponds roughly with the anthropogenic world-wide production of chlorine. (C) 1997 Elsevier Science Ltd.

Keywords: Lake Stechlin, PCDD/F, Dated Sediment, Dibenzofurans, Soils, River

Notes: highly cited

Chang, J.S., Law, R. and Chang, C.C. (1997), Biosorption of lead, copper and cadmium by biomass of Pesudomonas aeruginosa PU21. Water Research, 31 (7), 1651-1658.

Full Text: W\Wat Res31, 1651.pdf

Abstract: In this study, the biosorption kinetics of lead (Pb), copper (Cu) and cadmium (Cd) ions on the biomass of Pseudomonas aeruginosa PU21 (Rip64) was investigated. Effects of environmental factors and growth conditions on the biosorption were studied. Efficiency of metal ion recovery from metal-loaded biomass and subsequent regeneration of the biosorbent were also determined. The results show that, at pH 5.5, the resting cells were able to uptake up to 110 mgPb/g dry cell and the inactivated cells can adsorb 70 mgPb/g dry cell. Biomass of P. aeruginosa PU21 (Rip64) had lower adsorption capacities for Cu and Cd ions than for lead ions. The resting cells had the maximum uptake of 23 mgCu/g dry cell (at pH 5.0) and had 58 mgCd/g dry cell (at pH 6.0). The saturation uptake capacities of inactivated cells were 19 mgCu/g dry cell (at pH 5.0) and 43 mgCd/g dry cell (at pH 6.0). The resting cells held optimal Pb adsorption capacity at the early stationary phase, whereas the best uptake of cadmium was observed with the cells which were of exponential growth phase. The growth phase exhibited no effects on the adsorption of Cu, however. The increase in mercury concentration (from 0 to 50 mgHg²⁺/litre) in the growth media did not significantly affect the adsorption capacities of Pb²⁺, CU²⁺ and Cd²⁺. However, the saturation uptake capacity and metal-cell affinity tended to increase as pH increased, until metals precipitated as metal hydroxides when the pH exceeded some threshold values. Adjusting the pH value to about 2.0 resulted in 98, 98 and 82% recovery of Pb, Cu and Cd, respectively. The biomass resulted from desorption processes was able to retain approximately 80% of original adsorption capacity fbr Pb and Cu with four repeated adsorption and recovery runs. Regeneration of biomass appears to enhance the uptake capacity of Cd by nearly 35% after four adsorption/desorption cycles.

Chegrouche, S., Mellah, A. and Telmoune, S. (1997), Removal of lanthanum from aqueous solutions by natural bentonite. Water Research, 31 (7), 1733-1737.

Full Text: W\Wat Res31, 1733.pdf

Abstract: The aim of this work is the investigation of possible use of natural bentonite in the removal of lanthanum contained in aqueous solutions. The effect of temperature was examined in order to establish Langmuir and Freundlich adsorption isotherms. Langmuir and Freundlich constants were also determined.

Bousher, A., Shen, X.D. and Edyvean, R.G.J. (1997), Removal of coloured organic matter by adsorption onto low-cost waste materials. Water Research, 31 (8), 2084-2092.

Full Text: W\Wat Res31, 2084.pdf

Abstract: Twelve different adsorbents, originating from waste materials, were used to treat an effluent. of complex composition. from a chemical Herbs. The effectiveness of each adsorbent was measured in terms of its effect on the colour (absorbance at 450 nm) and COD levels of the effluent and also in terms of its adsorption capacity towards individual constituents of the effluent, The results showed that all adsorbents would physically adsorb constituents in reversible processes. Some constituents were more readily adsorbed than others. This meant that little correlation was observed between changes to the colour and COD levels of the effluent, because individual constituents made different contributions to these properties. The problem is further complicated by adsorbents, particularly those which had not been processed, contributing new constituents to the effluent. Thermodynamic data obtained from this study were used to predict the relative distribution of three constituents on the surface of different adsorbents. These results suggest that, for this effluent, adsorption onto waste material would be most effectively applied by using it in combination with other removal techniques.

Keywords: Natural Adsorbents, Acid Dye, Equilibrium, Desorption, Effluents, Adsorption, Waste Material, Biomass, Colour Removal, COD Removal, Industrial Effluent, Adsorption Capacity

Walker, G.M. and Weatherley, L.R. (1997), Adsorption of acid dyes on to granular activated carbon in fixed beds. Water Research, 31 (8), 2093-2101.

Full Text: W\Wat Res31, 2093.pdf

Abstract: This work involved the treatment of industrial wastewater from a nylon-carpet printing plant in Northern Ireland which currently receives no treatment and is discharged straight to sea. As nylon is particularly difficult to dye, acid dyes are required for successful colouration, but they cause major problems with the plant’s effluent disposal. Granular activated carbon Filtrasorb 400 was used to treat this effluent in a fixed-bed column system. Breakthrough curves from the fixed-bed column were shallow, even at low flow rates, which indicated a large mass transfer zone and inefficient use of adsorbent. Decrease in adsorbent particle size and decrease in linear flow rate produced a better bed performance. The bed depth service time (BDST) model proved effective for comparison of column variables, with calculated BDST constants providing a useful indication of bed performance. The BDST model also gave good approximation in predicting a bed performance using the relationships postulated by Hutchins (1973).

Keywords: Acid Dyes, Activated Carbon, Adsorbent, Adsorption, Bdst, Bed Depth Service Time, Breakthrough Curve, Dye, Dyes, Dyestuffs, Fixed Bed, Fixed Beds, Fixed-Bed Column, Flow Rate, Granular Activated Carbon, Model, Particle, Wastewater

Khan, A.R., Al-Bahri, T.A. and Al-Hadad, A. (1997), Adsorption of phenol based organic pollutants on activated carbon from multi-component dilute aqueous solutions. Water Research, 31 (8), 2102-2112.

Full Text: W\Wat Res31, 2102.pdf

Abstract: Five organic phenolic compounds (phenol, o-chlorophenol, m-chlorophenol, p-chlorophenol and m-cresol) hale been used to determine the adsorption isotherms for single and bisolute systems from dilute aqueous solutions on activated carbon. An experimental technique for the analysis of the equilibrium concentration of a bisolute in aqueous solutions using a UV spectrophotometer has been successfully developed and employed. Experimental data were obtained by conducting experiments in a shaker-incubator at 30 C (local average ambient temperature). All common types of reported isotherms, including Langmuir. Freundlich, BET (Brunauer, Emmett and Teller) and empirical types, were tried. For single solute systems the experimental data were found to be best represented by the Freundlich isotherm for all cases except for phenol, which followed the Langmuir isotherm. For bisolute systems, the coefficients for all the most commonly used models were determined accurately applying a modified Rosenbrock method for non-linear optimization. The present and previous published experimental data and predicted model results have been analysed statistically to validate the applicability of the models. The generalized and empirical models have shown a better fit than the other most commonly used models (Langmuir and Freundlich). The empirical model has minimal error between predicted and experimental values due to more constants in the expression as compared to the generalized model, The generalized model has a unique characteristic, covering both extremes, Langmuir as well as Freundlich type isotherms, and could represent all types of data for multi-component systems with fewer coefficients with almost the same degree of accuracy as the empirical model. (C) 1997 Elsevier Science Ltd.

Keywords: Organic Pollutants, Multi-Component, Equilibrium, Adsorption Isotherm, Activated Carbon, Solutes

? Fang, H.H.P. and Chan, O.C. (1997), Toxicity of phenol towards anaerobic biogranules. Water Research, 31 (9), 2229-2242.

Full Text: 1997\Wat Res31, 2229.pdf

Abstract: Toxity of phenol towards upflow anaerobic sludge blanket (UASB) biogranules treating wastewater containing different substrates was investigated. Under shock-loading conditions, the specific methanogenic activity (SMA) of the biogranules decreased with the increase of phenol concentration. The C-1.50 (i.e, the concentration at which bioactivity was 50% of the control) was 1750, 1000 and 1700 mg-phenol litre^-1 for acetate-, propionate- and benzoate-degrading biogranules, respectively. Under continuous-loading conditions, however, phenol toxicity was not progressive. Instead, phenol had a threshold toxicity level for each type of biogranules: 1050-1600, >850 and 1100-1700 mg litre^-1 for benzoate-, propionate- and acetate-degrading biogranules, respectively. Below these threshold levels, phenol was not inhibitive to the activity of biogranules; but above them, the inhibition was nearly 100%. Phenol toxicity was neither cumulative nor permanent. Once the phenol concentration in wastewater was lowered to levels below the threshold, biogranules were able to gradually regain 100% of their activity. Lowering substrate concentration expedited the recovering process. (C) 1997 Elsevier Science Ltd.

Keywords: Anaerobic, Biogranule, Inhibition, Methanogenic Activity, Phenol, Shock, SMA, Toxicity, UASB, Waste-Water, Methanogenic Ecosystems, Granular Sludge, UASB Treatment, Gen-Nov, Benzoate, Bacteria, Wastewaters, Biosorption, Degradation

Kratochvil, D., Volesky, B. and Demopoulos, G. (1997), Optimizing Cu removal/recovery in a biosorption column. Water Research, 31 (9), 2327-2339.

Full Text: W\Wat Res31, 2327.pdf

Abstract: Biosorption of Cu²⁺ by Sargassum fluitans seaweed biomass protonated by an acidic wash or loaded with Ca²⁺ is based on ion exchange. The uptake of Cu²⁺ is respectively accompanied by a release of either H⁺ or Ca²⁺ into the solution phase. The effects of Ca-, H- and H/Ca-cycles on the performance of a continuous-flow biosorption fixed-bed were established. The Ca-cycle applied to Sargassum biomass in a packed bed led to a high degree of a column utilization but did not allow an effective Cu recovery. The H-cycle permitted 100% Cu recovery but also shortened the sorption column service time. The combined Ca/H-cycle was shown to be inefficient due to the time consuming regeneration of biomass from the H-form to the Ca-form. Biomass pretreatment with 1% (w) solution of CaCl₂ and with 0.1 ha HCl resulted in the same Cu uptake of 75 mg/g. The Ca-pretreated biomass lost approximately 30% of its Cu capacity with subsequent acidic wash. The equilibrium aspects of Cu removal and recovery in a biosorption column were analyzed through the concept of ion-exchange isotherms. The dynamics of Cu sorption and of biomass regeneration in a fixed-bed column was predicted by numerically solving the equations of a proposed ion-exchange model. (C) 1997 Elsevier Science Ltd.

Keywords: Biosorption, Ion-Exchange, Cu Removal, Cu Recovery, Fixed-Bed Column, Regeneration, Ion-Exchange, Alginate Gel, Equilibria, Biomass, Removal, Models, Metals, Copper, pH

Kummerer, K., Steger Hartmann, T. and Meyer, M. (1997), Biodegradability of the anti-tumour agent ifosfamide and its occurrence in hospital effluents and communal sewage. Water Research, 31 (11), 2705-2710.

Full Text: W\Wat Res31, 2705.pdf

Abstract: A portion of administered pharmaceuticals are excreted unmetabolised by patients and can be found in hospital effluent and municipal sewage. Some pharmaceuticals such as anti-tumour agents are carcinogenic, mutagenic, teratogenic and fetotoxic. Little is known about their environmental impact. Therefore, the biodegradability of the widely used anti-tumour agent ifosfamide (IF) was assessed with the modified Zahn-Wellens test (OECD 302 B) and a test simulating biological sewage treatment. The biodegradation was monitored by DOC and GC/MS. The concentration of IF in hospital effluent, communal sewage and the effluent from a communal sewage treatment plant (STP) was analysed as well as calculated by the amounts of water and IF used in hospitals. The expected concentration of IF in German surface waters was calculated. IF was not biodegradable in the Zahn-Wellens test and the STP simulation test. It was not adsorbed by the sewage sludge. The concentrations measured in the hospital effluents, the STP influent and the STP effluent were of the same order of magnitude as the calculated ones, indicating that no adsorption, biodegradation or other elimination of IF took place to any noticeable extent. (C) 1997 Elsevier Science Ltd.

Keywords: Anti-Tumour Agent, Ifosfamide, Biodegradability, Hospital Effluent, Communal Sewage, Sewage Treatment, Surface Water, Magnetic-Resonance Spectroscopy, Urinary-Excretion, Cyclophosphamide, Metabolites, Chromatography

Leighton, I.R. and Forster, C.F. (1997), The adsorption of heavy metals in an acidogenic thermophilic anaerobic reactor. Water Research,