Wastewater

J Agric Food Chem, 2002 Jul 31, 50(16), 4628 - 33
Kinetic analysis of the psychrophilic anaerobic digestion of wastewater derived from the production of proteins from extracted sunflower flour; Borja R et al.; A kinetic analysis of the anaerobic digestion process of wastewater derived from the production of protein isolates from extracted sunflower flour was carried out . The digestion was conducted in a laboratory-scale fluidized bed reactor with saponite (magnesium silicate) as support for the mediating bacteria at psychrophilic temperature (15-19 degrees C) . Soluble chemical oxygen demand (COD(s)) removal efficiencies in the range of 95.9-69.0% were achieved in the reactor at organic loading rates (OLR) of between 0.57 and 2.49 g total COD (COD(t))/L d, hydraulic retention times (HRT) of between 20.0 and 4.5 days, and average feed total COD concentration of 11.3 g/L . The yield coefficient of methane production was 0.32 L of methane (at STP) per gram of COD(t) removed . The total volatile fatty acid (TVFA) levels and the TVFA/alkalinity ratio were lower than the suggested limits for digester failure for OLR and HRT up to 2.26 g COD(t)/L d and 5.0 days, respectively . The specific rate of substrate uptake, r (g COD(s)/g VSS d), correlated with the concentration of biodegradable substrate, S (g COD(s)/L), through an equation of the Michaelis-Menten type . The maximum substrate utilization rate, k, and the Michaelis constant, K(s)(), were found to be 0.125 g COD(s)/g VSS d and 124 mg COD(s)/L, respectively . This proposed model predicted the behavior of the reactor very accurately showing deviations lower than 10% between the experimental and theoretical values of substrate uptake rates . A mass (COD(t)) balance around the reactor allowed the COD equivalent of methane volume (W(CH)4) to be obtained, which gave a value of 2.89 g COD(t)/L CH(4), which was virtually coincident with the theoretical value of 2.86 g COD(t)/L CH(4).

Bioresour Technol, 2002 Aug, 84(1), 81 - 91
Recovery of dairy manure nutrients by benthic freshwater algae; Wilkie AC et al.; Harnessing solar energy to grow algal biomass on wastewater nutrients could provide a holistic solution to nutrient management problems on dairy farms . The production of algae from a portion of manure nutrients to replace high-protein feed supplements which are often imported (along with considerable nutrients) onto the farm could potentially link consumption and supply of on-farm nutrients . The objective of this research was to assess the ability of benthic freshwater algae to recover nutrients from dairy manure and to evaluate nutrient uptake rates and dry matter/crude protein yields in comparison to a conventional cropping system . Benthic algae growth chambers were operated in semi-batch mode by continuously recycling wastewater and adding manure inputs daily . Using total nitrogen (TN) loading rates of 0.64-1.03 g m(-2) d(-1), the dried algal yields were 5.3-5.5 g m(-2) d(-1) . The dried algae contained 1.5-2.1% P and 4.9-7.1% N . At a TN loading rate of 1.03 g m(-2) d(-1), algal biomass contained 7.1% N compared to only 4.9% N at a TN loading rate of 0.64 g m(-2) d(-1) . In the best case, algal biomass had a crude protein content of 44%, compared to a typical corn silage protein content of 7% . At a dry matter yield of 5.5 g m(-2) d(-1), this is equivalent to an annual N uptake rate of 1,430 kg ha(-1) yr(-1) . Compared to a conventional corn/rye rotation, such benthic algae production rates would require 26% of the land area requirements for equivalent N uptake rates and 23% of the land area requirements on a P uptake basis . Combining conventional cropping systems with an algal treatment system could facilitate more efficient crop production and farm nutrient management, allowing dairy operations to be environmentally sustainable on fewer acres.

Bioresour Technol, 2002 Aug, 84(1), 1 - 5
Effectiveness of algae in the treatment of a wood-based pulp and paper industry wastewater; Tarlan E et al.; In this study, the ability of algae to treat a wood-based pulp and paper industry wastewater was investigated . Tests were performed in batch reactors seeded with a mixed culture of algae . Under different lighting and initial wastewater strength conditions, changes in COD, AOX and color contents of reactors were followed with time . Algae were found to remove up to 58% of COD, 84% of color and 80% of AOX from pulp and paper industry wastewaters . No remarkable differences were observed in COD and color when light intensity and wastewater strength were changed, while AOX removals were strongly affected . Algal species identification studies revealed that some green algae (Chlorella) and diatom species were dominant in the treatment . The study also showed that algae grew mixotrophically, while the main mechanism of color and organics removal from pulping effluents was partly metabolism and partly metabolic conversion of colored and chlorinated molecules to non-colored and non-chlorinated molecules . Adsorption onto algal biomass was not so effective.

Chemosphere, 2002 Jun, 47(10), 1081 - 5
Biosorption of copper(II) from aqueous solutions by pre-treated biomass of marine algae Padina sp; Kaewsarn P; Biosorption of heavy metals can be an effective process for the removal and recovery of heavy metal ions from aqueous solutions . The biomass of marine algae has been reported to have high uptake capacities for a number of heavy metal ions . In this paper, the adsorption properties of a pre-treated biomass of marine algae Padina sp . for copper(II) were investigated . Equilibrium isotherms and kinetics were obtained from batch adsorption experiments . The biosorption capacities were solution pH dependent and the maximum capacity obtained was 0.80 mmol/g at a solution pH of about 5 . The biosorption kinetics was found to be fast, with 90% of adsorption within 15 min and equilibrium reached at 30 min . The effects of light metal ions on copper(II) uptake were studied and the presence of light metal ions did not affect copper(II) uptake significantly . Fixed-bed breakthrough curves for copper(II) removal were also obtained . This study demonstrated that the pre-treated biomass of Padina sp . could be used as an effective biosorbent for the treatment of copper(II) containing wastewater streams.

Environ Pollut, 2002, 119(1), 45 - 53
Phytoremediation potential of Spirulina (Arthrospira) platensis: biosorption and toxicity studies of cadmium; Rangsayator N et al.; This study examines the possibility of using Spirulina (Arthrospira) platensis TISTR 8217 to remove low concentrations of cadmium (less than 100 mg/l) from wastewater . The cyanobacteria were exposed to six different cadmium concentrations for 96 h, and the growth rate was determined using an optical density at 560 nm . The inhibiting concentration (IC50) was estimated using probit analysis . The IC50 at 24, 48, 72, and 96 h were 13.15, 16.68, 17.28, and 18.35 mg/l Cd, respectively . Cellular damage was studied under a light microscope and a transmission electron microscope . Swollen cells and fragmented filaments were observed . Cell injury increased with increasing concentrations of cadmium . Ultrastructural changes were observed in the algae exposed to cadmium concentrations both close to IC50 (14.68 mg/l) and at IC50 (18.35 mg/l) . The alterations induced by cadmium were disintegration and disorganization of thylakoid membranes, presence of large intrathylakoidal space, increase of polyphosphate bodies, and cell lysis . In addition, the cadmium adsorption by algal cells was studied . Environmental factors were found to have an effect on biosorption . The uptake of cadmium was not affected by the temperature of the solution, but the sorption was pH dependent . The optimum pH for biosorption of algal cells was 7 . The cadmium uptake process was rapid, with 78% of metal sorption completed within 5 min . The sorption data fit well to the Langmuir isotherm . The maximum adsorption capacity for S . platensis was 98.04 mg Cd per g biomass.

Ann Chim, 2002 May-Jun, 92(5-6), 531 - 9
Treatment options for tannery wastewater II: integrated chemical and biological oxidation; Di Iaconi C et al.; This is the second of two papers each dealing with a specific technological option for replacing the Fenton's reagent with simpler processes for treating industrial wastewater . In particular, the paper reports the results of an investigation aimed to check, at lab scale, the effectiveness of an alternative wastewater treatment combining biological degradation and chemical oxidation with ozone . The treatment was carried out in a lab scale hybrid reactor fed with the biological stage effluent of a plant treating the wastewater of a large tanning district in Central Italy whose residual COD result still higher than the Italian COD Maximum Allowable Concentration (MAC) value (i.e., 160 mgO2/L) The results are very promising, considering that a removal efficiency of 41% (as COD) has been achieved by treating an influent characterized by a COD content fully biorefractory . In addition, the proposed treatment presents the significant advantage of no additional sludge production, as happens with commonly utilized tertiary processes (i.e . Fenton), that is characterized by high chemical sludge production.

Environ Technol, 2002 Jun, 23(6), 599 - 608
Sulphate-reducing laboratory-scale high-rate anaerobic reactors for treatment of metal- and sulphate-containing mine wastewater; Tuppurainen KO et al.; Upflow anaerobic sludge blanket (UASB) reactors were used in this study to evaluate the feasibility of the sulphate-reducing, anaerobic high-rate process to treat metal- and sulphate-containing mining wastewater (MWW) . Four simultaneous reactors, inoculated with different inocula (mesophilic granular sludge from two UASB reactors, one treating sugar refinery wastewater and the other board mill wastewater) and operated with different loadings, were for 95 days fed with synthetic feed consisting of glucose and sulphate . In all reactors, 23-72% of sulphate and 12-93% of COD were removed . Subsequently, two reactors were fed with diluted MWW (zinc as the main metal) for 77 days with hydraulic retention times down to 8 hours . At the onset of the runs (until day 48), over 99.9% of zinc was removed in both reactors, after which removals fell to less than 30-80% . At the end of the runs, the highest zinc content (44 mg g(-1) TS) in the reactor sludges was 21 times higher than that in the inoculum . It cannot be concluded definitively that sulphide precipitation was the only mechanism of metal removal, for biosorption may have had a role to play in the process.

Arch Environ Contam Toxicol, 2002 Aug, 43(2), 186 - 97
Incorporation of toxicity tests into the Turkish industrial discharge monitoring systems; Sponza DT; A toxicity evaluation is an important parameter in wastewater quality and in the monitoring of discharged effluents . Some organic and inorganic compounds at toxic levels have been detected in industrial discharges, resulting in plant upsets and discharge permit violations . In some cases, even though the effluent does not exceed the chemical-specific discharge limits, the results of toxicity tests show potential toxicity . Knowledge of the toxicity of effluents can benefit treatment plant operators in optimizing plant operation, protecting receiving water quality, and establishing sewer discharge permits . In the Turkish regulations only toxicity dilution factor with fish is part of the toxicity monitoring program of permissible wastewater discharge.This study investigated the acute toxicity of pulp-paper, leather, and petrochemical industry wastewaters by traditional and enrichment toxicity tests and emphasized the importance of toxicity tests in wastewater discharge regulations . The enrichment toxicity tests are novel applications indicating whether there is potential toxicity or stimulation conditions . Different organisms were used, including bacteria (Floc and Coliform bacteria) algae (Chlorella sp.), fish (Lepistes sp.), and protozoan species (Vorticella sp.) to represent four trophic levels . The toxicity test results were compared with chemical analyses to identify the pollutants responsible for the toxicity in the effluent wastewater samples . Toxicity of the effluents could not be explained by using physicochemical analyses in five cases for the leather and four cases for the pulp-paper and petrochemical industries . The results clearly showed that the use of bioassay tests produce additional information about the toxicity potential of industrial discharges and effluents.

Environ Toxicol, 2002, 17(3), 284 - 90
Direct toxicity assessment of wastewater: Baroxymeter, a portable rapid toxicity device and the industry perspective; Tzoris A et al.; Direct toxicity assessment of wastewater is becoming necessary, and new legislation may render it compulsory for the water industry . At present such assessment is performed at a laboratory away from a site, at considerable cost, and results often come too late, after a toxic event has occurred and the toxin has been released into the environment . Some of the rapid toxicity tests available today require certain conditions to function properly, or their results do not always correlate with other methods . The objective of this study was to assess a portable device, the Baroxymeter, for its suitability as an instrument to test wastewater toxicity . The way the device works is based on monitoring respiration of a bacterial culture by pressure measurements and using respiration inhibition as a toxicity alert . It has been shown that it is possible to detect toxic substances such as 3,5-dichlorophenol and bronopol within 5 min from a 1-mL sample . The benefits and future applications of the Baroxymeter as a high-throughput, cost-effective alternative for toxicity screening are discussed in this article .

Environ Toxicol, 2002, 17(3), 170 - 86
Molluscan shellfish biomarker study of the Quebec, Canada, Saguenay Fjord with the soft-shell clam, Mya arenaria; Blaise C et al.; A spatial and temporal survey of six sites in the Saguenay Fjord and of one adjacent site in the St . Lawrence River estuary (Quebec, Canada) was undertaken to study the possible effects of anthropogenic contaminant input on soft-shell clam (Mya arenaria) populations . Bivalve sampling sites were selected because they reflected a range of areas representative of either no known (or apparent) pollution sources or of areas potentially influenced by different gradients and types of contamination sources . The most upstream site selected in the Saguenay Fjord, nearest to a highly populated and industrialized sector, and the most downstream site, near its mouth with the St . Lawrence River estuary, spanned a distance of some 70 km and encompassed the entire intertidal area suitable for Mya arenaria habitat . To measure effects in collected animals, we used a comprehensive battery of biomarkers composed of metallothionein-like proteins (MT), 7-ethoxyresorufin O-deethylase activity (EROD), DNA damage (DD), lipid peroxidation (LPO), vitellinlike proteins (Vn), phagocytosis (PHAG), nonspecific esterase (NspE) activity, and condition factor (weight-to-length ratio of clams) . Vn, PHAG, DD, and NspE biomarkers were assayed in hemolymph (or hemocytes), whereas others (MT, EROD, LPO) were determined in the digestive gland . Whole-tissue metal content was also quantified in clams collected in the spatial survey . The spatial survey conducted in June 1997 showed significant effects at all sites, and principal component analysis indicated in addition that the more important responses were linked to the MT, LPO, and NspE biomarkers . Clams collected from sites closest to the upstream reaches of the fjord generally displayed higher levels of tissue metals (cadmium, manganese), as well as greater responses of NspE activity, MT, LPO, and PHAG . Animals collected from sites influenced by municipal wastewaters had higher levels of Vn, suggesting the presence of environmental estrogens . The results of the temporal survey (six monthly samplings of clams at three sites from May through October, 1997) showed that the bivalve reproductive cycle (vitellogenesis and spawning) can modulate the expression of several biomarkers . Vn levels, for example, were positively correlated with DD and EROD and negatively correlated with MT, suggesting that reproduction can influence the susceptibility of clams to some contaminants . Discrimination analysis over the 6 months of sampling revealed that the mean value of the discriminant function changed significantly over time, suggesting important changes in the relative contribution of each biomarker . In short, this study has provided evidence that clam populations in the Saguenay Fjord are impacted by multiple sources of contamination whose effects can be modulated by reproduction .

Appl Microbiol Biotechnol, 2002 Jul, 59(2-3), 353 - 60 Epub 2002 May 04.
Evaluation of white-rot fungi for detoxification and decolorization of effluents from the green olive debittering process; Aggelis G et al.; Wastewater produced by the debittering process of green olives (GOW) is rich in polyphenolics and presents high chemical oxygen demand and alkalinity values . Eight white-rot fungi ( Abortiporus biennis, Dichomitus squalens, Inonotus hispidus, Irpex lacteus, Lentinus tigrinus, Panellus stipticus, Pleurotus ostreatus and Trametes hirsuta) were grown in GOW for 1 month and the reduction in total phenolics, the decolorization activity and the related enzyme activities were compared . Phenolics were efficiently reduced by P . ostreatus (52%) and A . biennis (55%), followed by P . stipticus (42%) and D . squalens (36%), but only P . ostreatus had high decolorization efficiency (49%) . Laccase activity was the highest in all of the fungi, followed by manganese-independent peroxidase (MnIP) . Substantial manganese peroxidase (MnP) activity was observed only in GOW treated with P . ostreatus and A . biennis, whereas lignin peroxidase (LiP) and veratryl alcohol oxidase (VAOx) activities were not detected . Early measurements of laccase activity were highly correlated ( r(2)=0.91) with the final reduction of total phenolics and could serve as an early indicator of the potential of white-rot fungi to efficiently reduce the amount of total phenolics in GOW . The presence of MnP was, however, required to achieve efficient decolorization . Phytotoxicity of GOW treated with a selected P . ostreatus strain did not decline despite large reductions of the phenolic content (76%) . Similarly, in GOW treated with purified laccase from Polyporus pensitius, a reduction in total phenolics which exceeded 50% was achieved; however, it was not accompanied by a decline in phytotoxicity . These results are probably related to the formation of phenoxy radicals and quinonoids, which re-polymerize in the absence of VAOx but do not lead to polymer precipitation in the treated GOW.

Appl Microbiol Biotechnol, 2002 Jul, 59(2-3), 344 - 52 Epub 2002 May 15.
Adaptation of anaerobic ammonium-oxidising consortium to synthetic coke-ovens wastewater; Toh SK et al.; A consortium with autotrophic anaerobic ammonium oxidising (AAAO) activity was developed from municipal sludge, and its ability to remove high ammonium concentrations in a toxic wastewater such as coke ovens wastewater is presented here . The enriched AAAO consortium was acclimatised to a synthetic coke ovens wastewater to establish anaerobic ammonium oxidation (AAO) activity . Phenol was the main carbon component of the synthetic wastewater whereby it was added stepwise from 50+/-10 to 550+/-10 mg l(-1) into an anammox enrichment medium . Ammonium-N removal was initially impaired; however, it gradually recovered . After 15 months of further selection and enrichment, the ammonium removal rate reached 62+/-2 mg NH(4)(+)-N l(-1) day(-1), i.e . 1.5 times the rate in the original AAAO reactor . The new consortium demonstrated higher ammonium and nitrite removal rates, even under phenol perturbation (up to 330+/-10 mg l(-1)) . It is therefore concluded that the AAO activity in the consortium was resistant to high phenol and has potential for treating coke-ovens wastewater.

Environ Toxicol Chem, 2002 Jul, 21(7), 1490 - 6
Ecological impact and environmental fate of perfluorooctane sulfonate on the zooplankton community in indoor microcosms; Sanderson H et al.; There is presently a substantial amount of information being gathered concerning the environmental risk associated with the perfluorooctane sulfonate (PFOS) compound . The U.S . Environmental Protection Agency (U.S . EPA) is requiring that more research be completed before making definitive decisions concerning the regulatory issues covered in the significant new use rule (18/10-2000) under the Toxic Substance Control Act . However, there are no risk assessment requirements under seminatural conditions in microcosms . The PFOS can enter, and has been found in, the aquatic environment through different pathways, including spills associated with use of fire-fighting foams containing PFOS, leaching from washing Scotchgard-treated clothes with the wastewater, leaching from various coatings, discharges as residual waste from fluorochemical production, or volatilization and transportation atmospherically . The biota is the sink of PFOS rather than the sediment or soil . The aim of this article is to determine a 35-d community no-observable-effect concentration (NOECcommunity) for freshwater zooplankton and the fate of PFOS during the course of study . The PFOS persisted in the water phase with only slight reductions over the study; only the decrease from 33.9 mg/L at day 1 to 29.8 mg/L at day 35 was significant . A 90 to 100% reduction (p < 0.01) of the total zooplankton population was found after one week of exposure to 30 mg PFOS/L and a similar reduction after two weeks at 10 mg PFOS/L . The Daphnia magna 21-d NOECsurvival of 12 mg/L has previously been found in a standard laboratory bioassay by 3M . The rank order of susceptibility for the test community was Copepoda > Cladocera > Rotifera, assuming all adverse direct effects.

Environ Toxicol Chem, 2002 Jul, 21(7), 1404 - 9
Reproductive characteristics of male mosquitofish (Gambusia affinis) inhabiting a small southeastern U.S . river receiving treated domestic sewage effluent; Angus RA et al.; A population of western mosquitofish (Gambusia affinis) living below a wastewater treatment plant in the vicinity of Birmingham (AL, USA) was studied for evidence of exposure to estrogens . Mosquitofish are sexually dimorphic live-bearing fish . Males have an elongated and modified anal fin, called a gonopodium, used in mating . It has been hypothesized that exposure to estrogens and/or anti-androgens in treated wastewater might inhibit the androgen-dependent development of the gonopodium . The population in this study showed no evidence of having been exposed to endocrine-disrupting chemicals . The difference in adjusted (for overall fish size via analysis of covariance) mean gonopodium length between effluent-exposed and control populations was not significant . No detectable levels of vitellogenin were observed in the blood of any of the male mosquitofish, either from the effluent-exposed or the control population . Testes and livers were weighed and examined histologically . The fish exposed to treated wastewater effluent had significantly larger adjusted mean weights for both testis and liver, but no histological changes indicating exposure to estrogens were observed.

Water Res, 2002 May, 36(9), 2394 - 404
Poorly humified peat as an adsorbent for metals in wastewater; Ringqvist L et al.; Metal adsorption and surface charge determinations were performed previously on well-characterised Sphagnum and Carex peat samples . The aim of this investigation was to determine metal adsorption from complex wastewaters onto these peat samples and compare it to the adsorption onto peat granules, clinoptilolite, glauconite and a flue dust from steel production . A sulphide mine leachate, a landfill leachate and a laundry wastewater were chosen, giving a variation in pH, ionic strength, total organic carbon and concentrations of metals . Metal adsorption was determined in batch and column experiments . The wastewater composition was of great importance for metal removal efficiency, mainly due to the difference in dominating metal species . In the sulphide mine leachate, containing free metal ions, a high metal adsorption was observed onto both peat and inorganic adsorbents . In the landfill leachate the metals formed carbonate and organic complexes and a low metal removal was achieved . Contrary to the leachates, the laundry wastewater contained suspended particles . The high amount of metals removed, 80% of the Cu and 30-60% of the Zn concentration, was probably withdrawn bound to the particle fraction . The highest removal of metal ions was obtained in the sulphide mine leachate with Carex peat, removing 97-99% of the Zn and 85-100% of the Cu content . The Sphagnum peat sample removed 37-77% of the Zn and 80-100% of the Cu content . The differences found between Sphagnum and Carex peat were attributed to the original chemistry of the plant material and the habitat conditions at the time of peat formation . Generally, the combination of glauconite or clinoptilolite with the peat samples in column experiments gave a minor improvement in metal removal.

Water Res, 2002 May, 36(9), 2304 - 18
Single- and multi-component adsorption of cadmium and zinc using activated carbon derived from bagasse--an agricultural waste; Mohan D et al.; The use of low-cost activated carbon derived from bagasse, an agricultural waste material, has been investigated as a replacement for the current expensive methods of removing heavy metals from wastewater . With a view to find a suitable application of the material, activated carbon has been derived, characterized and utilized for the removal of cadmium and zinc . The uptake of cadmium was found to be slightly greater than that of zinc and the sorption capacity increases with increase in temperature . The adsorption studies were carried out both in single- and multi-component systems . Adsorption data on derived carbon follows both the Freundlich and Langmuir models . The data are better fitted by the Freundlich isotherm as compared to Langmuir in both the single- and multi-component systems . Isotherms have been used to obtain the thermodynamic parameters . The kinetics of adsorption depends on the adsorbate concentration and the physical and chemical characteristics of the adsorbent . Studies were conducted to delineate the effect of temperature, initial adsorbate concentration, particle size of the adsorbent and solid-to-liquid ratio . On the basis of these studies, various parameters such as mass transfer coefficient, effective diffusion coefficient, activation energy and entropy of activation were evaluated to establish the mechanisms . It was concluded that the adsorption occurs through a film diffusion mechanism at low as well as at higher concentrations.

Water Res, 2002 May, 36(9), 2297 - 303
Catalytic degradation of CH2O and C6H5CH2OH in wastewaters; Christoskova ST et al.; The heterogeneous oxidation of benzyl alcohol and formaldehyde in aqueous medium has been investigated . The catalytic oxidation of these compounds is carried out in the presence of Ni-oxide system at ambient temperature . The results show that under studied conditions, a 90% conversion of CH2O to CO2 and a complete oxidation of C6H5CH2OH to C6H5COOH is achieved . Addition of H2SO4 to adjust pH to 2 further precipitates benzoic acid . The precipitate is filtered and the resulting filtrate is free of organic substances (COD is below 10 mg O2 dm(-3)) . Based on the results obtained, a technology for purification of wastewaters containing benzyl alcohol as well as a catalytic method for degradation of CH2O in aqueous solutions have been developed.

Water Res, 2002 May, 36(9), 2255 - 64
NMR spectroscopy for determination of cationic polymer concentrations; Chang LL et al.; Organic polyelectrolytes are utilized extensively in wastewater treatment, but their fate after use is poorly understood . Analytical methods used for polymer determination in less complex systems appear to fail in application to wastewater systems, contributing to the lack of knowledge . Thus, the development of 1H NMR spectroscopy is reported here for specifically quantitating certain cationic flocculant polymers in environmental samples . Proton observe frequencies of 250 or 400 MHz proton were used . A copolymer of acrylamide and acryloyloxyethyltrimethylammonium chloride was used, representative of cationic flocculant polymers possessing quaternary ammonium groups with terminal methyls that provide a sharp singlet at a chemical shift of approximately 3.06 ppm . A strong linear relationship was demonstrated between polymer concentration and either height or area of this peak . Recoveries were up to 96% at higher concentrations (250 mg/L), and were greater than when using viscosity or charge titration methods for polymer determination . Lesser recoveries at lower concentrations (70% at 5 mg/L) were attributed to adsorptive losses . The detection limit of this method was determined to be <0.5 mg/L . Use of the method was exemplified by analysis of anaerobically digested sludges for residual polymer following a range of dosages, showing the resulting isotherm.

Water Res, 2002 May, 36(9), 2233 - 42
Copper and zinc adsorption onto poorly humified Sphagnum and Carex peat; Ringqvist L et al.; Peat generally has a high adsorption capacity and has been suggested as an adsorbent for metals in polluted waters . However, the adsorption potential of peat can be expected to be strongly dependent on the chemical properties of the water . In this study, the effect of pH, ionic strength (CaCl2 and NaCl concentrations), and metal concentration on Cu and Zn adsorption onto poorly humified Sphagnum and Carex peat was investigated in batch experiments using a fractional factorial experimental design . The pH value was varied between 4 and 8, the CaCl2 and NaCl concentrations between 1.2-6.2 and 0.4-43 mM, respectively, and the Cu and Zn concentrations between 0.05 and 0.5 mM . The amount of Zn adsorbed increased more with increasing pH than the amount of Cu adsorbed . The effect of NaCl/CaCl2 concentration was minor . It was found that Zn adsorption in particular, but also Cu adsorption, increased more with pH onto Carex peat than onto Sphagnum peat . In the pH interval 4-8, the removal of Zn from the solution increased from 0% to 80% using Carex peat and from 10% to 65% using Sphagnum peat as the adsorbent . The Carex peat sample decreased the Cu concentration by 80% at pH 4 and by 95% at pH 8 and for Sphagnum peat a decrease of 85% was maintained in the pH range investigated . The differences between Sphagnum and Carex peat were attributed to the habitat conditions at the time of peat formation . Carex peat has higher ash, nitrogen and sulphur concentrations, while Sphagnum peat contains a higher amount of uronic acid . In treating polluted waters with peat, a higher degree of metal removal can be expected at high pH values than at low . The removal of Cu, which has a high affinity to the peat surface, was less dependent on pH than Zn removal . Poorly humified Carex peat should be chosen in treating wastewaters high in pH.

Water Res, 2002 May, 36(9), 2195 - 204
Removal of suspended solids by coagulation and foam separation using surface-active protein; Suzuki Y et al.; By using several kinds of surface-active proteins as a chemical agent that combined collector with frother, removal of suspended substances by coagulation and foam separation with dispersed air was examined . Milk casein showed the greatest capability of suspension removal, and coagulating flocs formed by clay particles and iron hydroxide were almost perfectly recovered in foam generated from the liquid, even in the case of freshwater and seawater suspension at neutral pH . In contrast, the removal efficiency was extremely low using sodium dodecyl sulfate (SDS) . Casein had a much greater capability for removing solids than SDS as a result of the high adsorptive activity of casein on the floc . For municipal wastewater treatment, the removal efficiency of turbidity and suspended solids was over 98% with the condition of iron coagulant (FeCl3) 20 mg-Fe/L and casein 3 mg/L and pH 5-6 . Moreover, this method proved to be an effective treatment for polluted saline water (salinity 1.5%), and the suspended solids were almost perfectly recovered in foam . Here, we show a new method for quickly removing (within 7 min) suspended solids from polluted wastewater utilizing casein and bubbles.

Water Res, 2002 May, 36(9), 2167 - 72
Enhanced photo-degradation of contaminants in petroleum refinery wastewater; Stepnowski P et al.; In order to rise efficiency of the wastewater treatment in a refinery plant, several oxidation experiments were done, testing their applicability as an additional pretreatment method . The influence of treatment with low concentrations of H2O2 combined with stirring and UV light on degradation of organic compounds present in the refinery wastewater was studied . Oxidation of the total petroleum hydrocarbons occurs at relatively low concentrations of H2O2, additional UV irradiation slightly accelerates the process due to the increased formation of hydroxyl radicals . 1,2-dichloroethane and t-butyl methyl ether degrade in the similar manner and except for the lowest H2O2 concentration used (1.17 mM), the reduction after 24 h is total . The degradation rate for dichloromethane is the lowest one, depending both on hydrogen peroxide concentration and the presence of UV . Its maximum reduction of 83% was obtained using the highest applied peroxide concentration of 11.76 mM.

Chemosphere, 2002 Jun, 47(9), 925 - 31
Kinetics of chemical decolorization of the azo dye C.I . Reactive Orange 96 by sulfide; Yoo ES; The mechanism of decolorization of azo dyes based on the extracellular chemical reduction with sulfide (H2S, HS-, S2-) was postulated for sulfate reducing environments . To design technical decolorization processes of textile wastewater treatment with sulfide produced by sulfate reducing bacteria (SRB), kinetics is of great significance . Batch experiments were made in order to investigate the kinetics of abiotic decolorization of the reactive mono-azo dye C.I . Reactive Orange 96 (RO 96) with sulfide, with varying pH . The decolorization of RO 96 by sulfide under the exclusion of O2 corresponded to first-order kinetics with respect to both dye and sulfide concentration . The decolorization of RO 96 with sulfide at neutral pH (7.1) was advantageous compared with that at pH for 4.1, 6.3, and 6.5 . This is attributed to an increase in the fraction of HS- of total sulfide species at neutral pH . The rate constants k for the decolorization at 37 degrees C were obtained as 0.01 for pH = 4.1, 0.06 for pH = 6.3, 0.08 for pH = 6.5, and 0.09 for pH = 7.1 in mM(-1) min(-1) . The high rate constants for sulfide at pH 6.5-7.1 support that the decolorization through SRB (i.e . by bio-sulfide) can be effective in anaerobic bacterial systems with sulfate.

J Chromatogr A, 2002 May 17, 956(1-2), 215 - 20
Organic analysis by ion chromatography . 1 . Determination of aromatic amines and aromatic diisocyanates by cation-exchange chromatography with amperometric detection; Zhu Y et al.; A method has been developed for the simultaneous determination of a range of aromatic amines using cation-exchange chromatography performed on a standard ion chromatography column using d.c . amperometric detection . The analytes separated were 2,4- and 2,6-toluenediamine (2,4- and 2,6-TDA), aniline, o-toluidine, benzidine, p-chloroaniline, 4,4'-diaminodiphenyl (4,4'-DDP), m-nitroaniline and 1-naphthylamine . A Dionex CS12 column was used with gradient elution from an initial eluent of 5% CH3CN+35 mM H2SO4 to 27% CH3CN+35 mM H2SO4 (at 35 min) . Detection limits in the range 2.6-22.6 microg/l were observed for all analytes except m-nitroaniline, for which the detection limit was 201 microg/l . Linear calibrations and good precision were observed and the method was applied to the determination of benzidine, p-chloroaniline and 1-naphthylamine in wastewater samples . Further, the separation was also used (after some modification of the eluent conditions) for the determination of 2,4- and 2,6-toluene diisocyanate (2,4- and 2,6-TDI) and 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) after their hydrolysis to 2,4-TDA, 2,6-TDA and 4,4'-DDP . Detection limits for 2,6- and 2,4-TDI and 4,4'-MDI were 3.8, 8.2, and 11.2 microg/l, respectively . The method was applied to the determination of diisocyanates in air.

J Chromatogr A, 2002 May 17, 956(1-2), 181 - 6
Determination of inorganic cations and ammonium in environmental waters by ion chromatography with a high-capacity cation-exchange column; Thomas DH et al.; While alkali and alkaline earth cations are commonly determined by using spectrometric techniques such as atomic absorption spectrometry or inductively coupled plasma, ammonium cation in the same sample must be measured separately by a wet chemical technique such as colorimetry, titrimetry, or ammonia-selective electrode . In a single 25-min run ion chromatography can determine all of the important inorganic cations including lithium, sodium, ammonium, potassium, magnesium and calcium . In this paper, we describe the use of ion chromatography with a new high-capacity cation-exchange column (the IonPac CS16), an electrolytically-generated methanesulfonic acid eluent and suppressed conductivity detection to determine dissolved alkali and alkaline earth cations and ammonium in drinking water wastewater and aqueous soil extracts . The IonPac CS16 is a high-capacity cation-exchange column that incorporates recent advances in polymer chemistry to enable trace-level determinations of cations even in high-ionic-strength matrices . We discuss the linear range, method detection limits, and analyte recoveries obtained with this column, and evaluate the effect of potential interferences on method performance during the analysis of typical environmental samples.

Environ Sci Technol, 2002 Jun 15, 36(12), 2772 - 6
A study of fine particulate emissions from combustion of treated pulverized municipal sewage sludge; Seames WS et al.; Municipal sewage sludge (MSS) is formed during wastewater treatment and its processing and disposal represent one of the most environmentally challenging aspects of the wastewater treating process . One disposal option currently being considered is a process involving heat treatment (to render the sludge biologically inactive) followed by dewatering, drying, pulverizing, and combustion . This research focuses on fine particle emissions from the combustion of dried, treated, MSS, cofired with either natural gas or pulverized Ohio bituminous coal as a supplemental fuel . These fuels were burned at 13 kW in a downflow laboratory combustor designed to replicate time/temperature histories and particle concentrations typical of practical combustion units yet also sufficiently well defined aerodynamically to allow elucidation of mechanisms . Size-segregated particle size distributions were obtained by isokinetic sampling followed by dilution/quenching and passage into a Berner Low-Pressure Impactor . Major and trace elements were analyzed by flame and graphite furnace atomic absorption spectroscopy . Four particle size regions were identified: furnace vapor-phase material that formed ultrafine particles either in or just before the sampling probe, submicron-sized particles formed during the combustion process, micron-sized fine particles, and larger supermicron sized bulk fly ash particles . The fuel mix appears to influence trace metal partitioning routes and the composition of fine particulate matter in the exhaust . Cofiring of MSS with coal increases the ultrafine/submicron particle emission compared to firing coal alone . This increase in ultrafine/submicron particles is most likely due to an interaction between species derived from MSS (possibly alkali metals) and those from coal (possibly sulfur and/or chlorine) . Vapor-to-solid phase partitioning of arsenic and selenium is controlled by surface reaction with active surface sites during MSS combustion with either gas or coal . Co-combustion of MSS with the Ohio bituminous coal allows the arsenic and selenium to be reactively scavenged by calcium, thus changing the speciation of the trace metal emitted . Ohio bituminous coal alone contained insufficient calcium to accomplish this same scavenging effect.

ALTEX, 2002, 19 Suppl 1, 30 - 7
Ecotoxicological assessment of surface waters: a modular approach integrating in vitro methods; Schweigert N et al.; Today ecotoxicological evaluations of surface water quality are either based on field surveys or online biomonitoring, whereas the ecotoxicological quality of wastewater is mostly determined with standardised acute toxicity tests . In this paper we present a concept for the ecotoxicological evaluation of surface waters, where mainly in vitro tests are used for the screening of water samples, presenting the first tier of a two-tiered approach . In this first tier a battery of fast and cost-efficient test-systems are used as an early warning system . Thereby, the toxic potential of water samples will be identified . This modular approach allows the exchange or addition of test-systems if necessary . If a toxic potential is identified in a water sample, this sample can be investigated more thoroughly in a second tier where organisms are used . In this paper we focus mainly on the general approach and the description of the first tier.

J Environ Monit, 2002 Jun, 4(3), 458 - 61
Turbidimetric determination of chloride in different types of water using a single sequential injection analysis system; Mesquita RB et al.; A sequential injection analysis system for the turbidimetric determination of chloride in different types of water is proposed . The determination is based on the reaction of chloride with silver ions and the subsequent measurement of the turbidity caused by silver chloride precipitation . In this method, the use of toxic reagents, such as mercury thiocyanate, commonly employed in most spectrophotometric techniques for chloride determination, is avoided . The main feature of the developed system is the use of a single configuration to carry out the determination over a wide concentration range (2-400 mg L(-1)) by changing only the aspirated sample volume . This characteristic allows the determination of chloride in ground, surface and wastewaters using the same manifold . In addition, a considerable saving of precipitating reagent is achieved due to non-continuous consumption . The results obtained with the developed system were statistically indistinguishable from those of the potentiometric titration reference method . Relative standard deviations for ten consecutive injections were lower than 3.7%, with a sampling frequency of between 55 and 57 determinations per hour.

Waste Manag, 2002, 22(5), 543 - 8
Agricultural solid waste for the removal of organics: adsorption of phenol from water and wastewater by palm seed coat activated carbon; Rengaraj S et al.; Adsorption studies for phenol removal from aqueous solution on activated palm seed coat carbon (PSCC) were carried out under varying experimental conditions of contact time, phenol concentration, adsorbent dose and pH . Adsorption equilibrium was reached within 3 h for phenolic concentrations 10-60 mg l(-1) . Kinetics of adsorption obeyed a first order rate equation . The percent removal remained constant over the pH range 4-9 for a phenolic concentration of 25 mg (l-1) . The equilibrium data could be described well by the Freundlich isotherm equation . The adsorption of phenol on PSCC follows the film diffusion process . A comparative study with a commercial activated carbon showed that PSCC is two times more effective than commercial activated carbon . The studies showed that the palm seed coat carbon can be used as an efficient adsorbent material for the removal of phenolics from water and wastewater.

Waste Manag, 2002, 22(5), 507 - 13
Using organoclays to enhance carbon filtration; Alther G; Organoclays have found increased acceptance as pre-treatment for activated carbon adsorption systems in both groundwater and wastewater cleanup . The reason is that activated carbon tends to become quickly blinded by large organic molecules of low solubility, particularly oils . However, it is also well established that activated carbon is more efficient at low concentrations of organic contaminants than at higher ones, i.e . at less than 1 ppm . With organoclays it is exactly the opposite, they are better at removing organics at higher concentrations, above 3 ppm . Therefore it is cost effective in these applications to use two or more vessels in series, the first one filled with organoclay, the remainder with activated carbon . The economics make sense, even though the organoclay is not regenerated, because of the reduction in down time every time a carbon vessel has to be changed out . Use of organoclays increases the volume treated by carbon in many applications seven to nine fold . In the case of other organic contaminants, as the aqueous solubility increases, the efficiency decreases, except in the case of methylene chloride, which it removes at far higher efficiency then carbon . This article presents the results of a series of tests, including Kd determinations, jar tests, and mini-column tests . These tests determined the adsorption capacity and efficiency of organoclay and activated carbon for the removal of benzene, toluene, xylene and naphtalene from water . These tests were followed by adding the four compounds into one container to see if the combination of organoclay, followed by carbon, would be more efficient then each sorbent alone . The tests also compared the efficiency of organoclay versus carbon for the removal of various oils from water.

Waste Manag, 2002, 22(5), 471 - 80
Peanut hull pellets as a single use sorbent for the capture of Cu(II) from wastewater; Johnson PD et al.; This paper investigates the ability of peanut hulls and peanut hull pellets to adsorb copper from dilute aqueous metal ion solutions in batch and fixed bed systems . The kinetics of copper uptake onto the media have been investigated in batch systems and the influence of pH and particle size on the rate and extent of copper capture determined . The Langmuir and Freundlich isotherm theories were determined; the Langmuir model was found to best represent the equilibrium isotherm data . In normalized kinetic tests at least 75% of copper removal occurred within the first 20 min; 92% removal was effected within the first 50 min . The rate of uptake was optimum within the pH range 5-7.5, and media capacities remained relatively constant at a pH above 4.0 . Bench-scale column studies were performed using peanut hull pellets . The overall capacity of pelletized peanut hulls was higher than for unmodified peanut hulls . Due to their demonstrated ability for Cu(II) uptake and favorable structural characteristics, pelletized peanut hulls could gain use as a low-cost, once-through biomass filter medium for copper-bearing waste streams.

Water Res, 2002 Apr, 36(8), 2029 - 39
Three-dimensional pollutant transport model for the Pearl River Estuary; Chau KW et al.; In this paper, the development and implementation of a three-dimensional, numerical pollutant transport model, which is based on an orthogonal curvilinear coordinate system in the horizontal direction and a sigma coordinate system in the vertical direction, is delineated . An efficient as well as simple open boundary condition is employed for pollutant transport in this mathematical model . It is then applied to model the distribution and transport of Chemical Oxygen Demand in the Pearl River Estuary . The results from the numerical simulations illustrate that the transboundary or inter-boundary effects of pollutants, between the Guangdong Province and the Hong Kong Special Administrative Region due to the wastewater discharged from the Pearl River Delta Region, are quite strong.

Water Res, 2002 Apr, 36(8), 1993 - 2001
Anaerobic/aerobic treatment of coloured textile effluents using sequencing batch reactors; Shaw CB et al.; Conventional biological wastewater treatment plants do not easily degrade the dyes and polyvinyl alcohols (PVOH) in textile effluents . Results are reported on the possible advantages of anaerobic/aerobic cometabolism in sequenced redox reactors . A six phase anaerobic/aerobic sequencing laboratory scale batch reactor was developed to treat a synthetic textile effluent . The wastewater included PVOH from desizing and an azo dye (Remazol Black) . The reactor removed 66% of the applied total organic carbon (load F: M 0.15) compared to 76% from a control reactor without dye . Colour removal was 94% but dye metabolites caused reactor instability . Aromatic amines from the anaerobic breakdown of the azo dyes were not completely mineralised by the aerobic phase . Breakdown of PVOH by the reactor (20-30%) was not as good as previous reports with entirely aerobic cultures . The anaerobic cultures were able to tolerate the oxygen and methane continued to be produced but there was a deterioration in settlement.

Water Res, 2002 Apr, 36(8), 1947 - 54
Application of catalytic wet air oxidation for the treatment of H-acid manufacturing process wastewater; Zhu W et al.; Four types of powder catalysts whose main active components are copper (Cu), cerium (Ce), cadmium (Cd) and cobalt-bismuthide (Co-Bi) are prepared with the method of the co-deposition and are evaluated through the catalytic wet air oxidation (CWAO) treatment of H-acid solution . The comparison of the efficiencies of different catalysts shows that Ce3Cu1 (3:1) catalyst is the best one . When the reaction temperature is 200 degrees C, oxygen partial pressure is 3 MPa, pH value is 12, and reaction time is 30 min, the COD removal rate is over 90% . All the H-acid is decomposed in 5 min and is oxidized into NH4+, SO4(2-) formic acid, acetic acid and other end products . The pH value can greatly affect the COD removal and the production of organic acid . CWAO process not only can get a high reaction rate, but also can oxidize the short-chain organic acid.

Water Res, 2002 Apr, 36(8), 1927 - 38
P removal from anaerobic supernatants by struvite crystallization: long term validation and process modelling; Battistoni P et al.; In this work, a model for phosphorus crystallization in a fluidized bed reactor, able to describe the experimental results obtained during a semiscale pilot plant, is presented . In particular, the validity of the model proposed has been evenly extended with respect to a previous experiment, even at a lower contact time, and the length of each experiment has been increased, in order to verify the behaviour of the process for long term applications and to evaluate the maximum crystal growth of the system . Moreover, the state of the art of the available processes for phosphorus removal from wastewater is presented, together with a detailed review of the several models so far developed to describe the phosphorus crystallization mechanisms.

Environ Technol, 2002 May, 23(5), 537 - 45
Ozonation of textile wastewater: physicochemical and phytotoxic aspects; Radetski CM et al.; The purpose of this work was to evaluate the performance of ozonation as a technique to treat textile effluents . This performance evaluation was made using physico-chemical parameters and phytotoxic endpoints (i.e . biomass growth enzyme activities - catalase and peroxidase) . After ozonation, the color absorbance (523 nm) was reduced by 80.9% and the pH decreased from 10.9 to approximately 7.5 while COD reduction reached nearly 87% . Phytotoxicity tests carried out in solution with three plant species (i.e . soybean, rice and wheat) allowed us to compare toxicity data of both, raw and ozonated effluents . The biomass (fresh weight) of the 3 plant species clearly decreases as a function of the increase in raw effluent concentration with LOEC values of 100% for rice and wheat, and 50% for soybean . Activities of catalase and peroxidase in the 3 plant species exposed to the raw textile effluent were significantly different from plant controls . The LOEC values for catalase were 6.2% (in wheat and soybean plants), and 25% (in rice plants), while for peroxidase the LOEC values were 6.2% (in rice plants), 25% (in soybean plants), and 50% (in wheat plants) . Reduction in the phytotoxicity of textile effluent samples after ozonation is likely due to the elimination of the toxic organic fraction oxidized during this process . Regarding endpoint sensitivity, our results showed that biomass endpoint was less sensitive than biochemical endpoint . In conclusion, ozonation was relatively effective in reducing physico-chemical parameters and phytotoxic effects of textile effluents . Plant enzyme assays used in this study proved to be a sensitive tool in order to determine the toxicity of industrial effluents and may be used to evaluate efficiency of established (or emergent) wastewater treatment technology.

Syst Appl Microbiol, 2002 Apr, 25(1), 37 - 45
Novosphingobium hassiacum sp . nov., a new species isolated from an aerated sewage pond; Kampfer P et al.; The taxonomy of two strains W-51T and W-52 isolated from a wastewater treatment plant was investigated in a polyphasic approach . The yellow pigmented gram-negative organism contained a quinone system with mainly ubiquinone Q-10, and the polar lipid profile contained a sphingoglycolipid suggesting that both strains belonged to the the alpha-4 subclass of the Proteobacteria . The polar lipid profile consisted furthermore of phosphatidylethanolamine, diphosphatidylglycerol, and phosphatidylcholine and of minor amounts of phosphatidylglycerol and phosphatidylmonomethylethanolamine . Sequencing of the 16S rRNA gene supported the allocation into the genus Novosphingobium, together with the type strains of N . subterraneum, N . aromaticivorans, N . stygium, and N . capsulatum, showing similarities of 97.3%, 97.0%, 95.7% and 96.2%, respectively . This allocation was supported by the polyamine profile, which consisted mainly of spermidine . The analysis of the fatty acids revealed 2-OH 13:0, 2-OH 14:0 and 2-OH 15:0, with 2-OH 15:0 as predominant hydroxylated fatty acid . W-51T and W-52 were almost identical with respect to their phenotypic including the majority of the chemotaxonomic properties, identical in their 16S rRNA sequences, and showed 86% DNA-DNA similarity . Both strains were able to reduce nitrate and on the basis of further physiological features, a clear differentiation from all other Novosphingobium species was possible . The DNA-DNA similarities of W-51T to the type strains of N . subterraneum, N . aromaticivorans, and N . capsulatum were below 56% . For these reasons, it is proposed to create a new species with the name Novosphingobium hassiacum sp . nov.

Water Sci Technol, 2002, 45(9), 309 - 15
Nutrient management for coastal zones: a case study of the nitrogen load to the Stockholm Archipelago; Scharin H; This study investigates cost-effective solutions of decreasing the nutrient load to a coastal area, using a drainage basin approach . The study is applied to the Stockholm Archipelago, a coastal area of the Baltic Sea suffering from eutrophication caused by the load of nutrients entering the area . Nitrogen is the nutrient of concern in this study since it is the limiting nutrient of the Archipelago . The main sources of nitrogen are wastewater plants, agriculture, and atmospheric depositions . The final impact of a deposition depends on the buffering capabilities it is subject to on its trajectory from the source to the recipient . This is the reason for using a recipient oriented approach, in which the focus is to reduce the final impact of a deposition . The model integrates data over hydrology, land cover, land use, and economy in order to find the optimal allocation of measures . Results indicate that in order to achieve cost effectiveness, the major part of nitrogen load reduction to the Archipelago should be done at the wastewater plants and by constructing wetlands . The minimum annual cost of reaching a 50% reduction of the load to the Archipelago was estimated to around 191 million Swedish crowns (around $19 million).

Water Sci Technol, 2002, 45(9), 195 - 203
Evaluation of efficiencies of diffuse allochthonous and autochthonous nutrient input control in restoration of a highly eutrophic lake; Muhammetoglu A et al.; Mogan Lake is an important recreational area for Metropolitan Ankara-Turkey . It is a shallow eutrophic lake with a dense growth of macrophytes . The main contributors of nutrients and other pollutants to the lake are the creeks carrying the runoff water from the watershed and upland farming land, in addition to the domestic and industrial wastewater discharges from a nearby town and industries . Hydrodynamic and water quality modeling techniques were used to determine the optimum management schemes for the lake restoration and diffuse pollution control . Management scenarios were devised and tested to control allochthonous and autochthonous nutrient inputs to the lake . Phosphorus and nitrogen load reductions were the main test elements for the control of allochthonous nutrient inputs . The scenario analysis revealed that reduction of phosphorus and nitrogen loads from diffused sources will have a marginal effect on controlling eutrophication if macrophyte growth is left uncontrolled . Scenarios employing macrophyte harvesting and sediment dredging have been evaluated for autochthonous nutrient input control . Sediment dredging alone has been shown to yield the most favorable conditions for water quality improvement in Mogan Lake . Further, control of diffuse pollution was an essential final step to achieve an acceptable long-term sustainable water quality improvement in the lake.

Poult Sci, 2002 Jun, 81(6), 785 - 92
Recovery and utilization of useful by-products from egg processing wastewater by electrocoagulation; Xu LJ et al.; The efficacy of a laboratory electrocoagulation (EC) system for treating egg processing plant waste-water (WW) is reported . For simulated and industrial egg processing WW, chemical oxygen demand, turbidity, and total suspended solids (TSS) were reduced 92 to 97%, 97%, and 99%, respectively, after treatment with EC . The final TSS concentration and turbidity values were 30 mg/L and 5 formazin turbidity units (FTU), respectively, similar to that of potable water standards . The recovered by-product solids had a similar pattern of essential amino acids compared to that of liquid whole egg and were comparable to the Food Agriculture Organization's essential amino acid profile for an ideal protein . The relative protein digestibilities of the recovered solids and a commercial corn meal averaged 130 and 56%, respectively, compared to liquid whole egg (set at 100%) . An economic analysis of EC indicated that this treatment is economically feasible in that a savings of approximately $425,000 per year is possible in addition to recovering the capital equipment costs after about 14 mo of operation . These findings demonstrate that EC can be successfully applied to treat egg processing plant WW, yielding a high quality water suitable for recycling and valuable by-products having a highly digestible protein and fat value.

Nippon Rinsho, 2002 Jun, 60(6), 1214 - 21
{Contamination of oyster sea farm with the Norwalk virus: mechanisms and control}; Sugiyama A et al.; The Norwalk virus(NV) is widely known as a cause of nonbacterial food poisoning, infant diarrhea, and acute gastroenteritis in the winter months between November and March . While it is strongly suspected that NV that is excreted by humans flows into coastal seawaters via rivers and wastewater treatment facilities to contaminate oysters that are grown in farms in the area, light has yet to be shed on the behavior of this virus in the natural environment . We therefore conducted a polymerase chain reaction (PCR) survey of NV levels in the aquatic environment of the oyster bed area of the Shima region in Mie Prefecture, whereupon the NV was detected in marine sediment, oysters, and mule clams even during the summer months, when food poisoning is infrequent . In order to assess their similarity to human-derived strains, the detected viruses and their human-derived counterparts were subjected to genetic analysis, whereupon some of the detected viruses were found to be remarkably similar to those that were previously detected in humans infected with NV . In the interests of examining methods for decontaminating NV-contaminated oysters, we also conducted an assessment on a system of virus decontamination that focuses on seawater temperature and oyster metabolism, using Poliovirus Sabin strain . The decontamination system mentioned above was a closed loop, water circulating system, built on the same principles as those actually in use at oyster farms . Our experiment indicated that at seawater temperatures of both 10 degrees C and 20 degrees C, virus placed into the water tank was rapidly incorporated into the midgut glands of the oysters . Thereafter, when seawater irradiated with UV was circulated, the virus count in the oysters fell from 1/1,000 to 1/10,000 within 6 hours . These results indicated the utility of this system for virus decontamination, suggesting the possibility of significantly alleviating the risk of NV infection in humans by using this system to maintain the seawater temperature within the decontamination tank above a certain temperature, and to perform decontamination with an adequate water flow.

FEMS Microbiol Lett, 2002 Jun 18, 212(1), 41 - 5
Effect of olive oil mill wastewater on extracellular ligninolytic enzymes produced by Phanerochaete flavido-alba; Ruiz JC et al.; Our previous results have demonstrated that Phanerochaete flavido-alba decoloration, dephenolization and detoxification of olive oil mill wastewater (OMW) were associated with changes in the ligninolytic major exoenzymes accumulated in the cultures . This paper describes the effect of the two main OMW components (monomeric aromatic compounds and a major brownish polymeric pigment), on extracellular P . flavido-alba ligninolytic enzymes . Laccase was the sole ligninolytic enzyme detected in cultures containing monomeric aromatic compounds . Laccase and an acidic manganese-dependent peroxidase (MnPA, pI<2.8) were accumulated in cultures with OMW or polymeric pigment . Also, modified manganese-dependent peroxidases were observed mainly in OMW-supplemented cultures . Laccase was more stable to the effect of OMW toxic components and was accumulated in monomeric aromatic-supplemented cultures, suggesting a more important role than manganese-dependent peroxidases in OMW detoxification . Alternatively, MnPA accumulated in cultures containing the polymeric pigment seems to be more essential than laccase for degradation of this recalcitrant macromolecule by P . flavido-alba.

Environ Sci Technol, 2002 Jun 1, 36(11), 2519 - 22
UV disinfection of Giardia lamblia cysts in water; Linden KG et al.; The human and animal pathogen Giardia lamblia is a waterborne risk to public health because the cysts are ubiquitous and persistent in water and wastewater, not completely removed by physical-chemical treatment processes, and relatively resistant to chemical disinfection . Given the recently recognized efficacy of UV irradiation against Cryptosporidium parvum oocysts, the inactivation of G . lamblia cysts in buffered saline water at pH 7.3 and room temperature by near monochromatic (254 nm) UV irradiation from low-pressure mercury vapor lamps was determined using a "collimated beam" exposure system . Reduction of G . lamblia infectivity for gerbils was very rapid and extensive, reaching a detection limit of >4 log within a dose of 10 JM-2 . The ability of UV-irradiated G . lamblia cysts to repair UV-induced damage following typical drinking water and wastewater doses of 160 and 400 JM(-2) was also investigated using experimental protocols typical for bacterial and eucaryotic DNA repair under both light and dark conditions . The infectivity reduction of G . lamblia cysts at these UV doses remained unchanged after exposure to repair conditions . Therefore, no phenotypic evidence of either light or dark repair of DNA damage caused by LP UV irradiation of cysts was observed at the UV doses tested . We conclude that UV disinfection at practical doses achieves appreciable (much greater than 4 log) inactivation of G . lamblia cysts in water with no evidence of DNA repair leading to infectivity reactivation.

Environ Sci Technol, 2002 Jun 1, 36(11), 2322 - 9
Occurrence and environmental behavior of the bactericide triclosan and its methyl derivative in surface waters and in wastewater; Lindstrom A et al.; The bactericide triclosan and methyl triclosan, an environmental transformation product thereof, were detected in lakes and in a river in Switzerland at concentrations of up to 74 and 2 ng L(-1), respectively . Both compounds were emitted via wastewater treatment plants (WWTPs), with methyl triclosan probably being formed by biological methylation . A regional mass balance for a lake (Greifensee) indicated significant removal of triclosan by processes other than flushing . Laboratory experiments showed that triclosan in the dissociated form was rapidly decomposed in lake water when exposed to sunlight (half-life less than 1 h in August at 47 degrees latitude) . Methyl triclosan and nondissociated triclosan, however, were relatively stable toward photodegradation . Modeling these experimental data for the situation of lake Greifensee indicated that photodegradation can account for the elimination of triclosan from the lake and suggested a seasonal dependence of the concentrations (lower in summer, higher in winter), consistent with observed concentrations . Although emissions of methyl triclosan from WWTPs were only approximately 2% relative to those of triclosan, its predicted concentration relative to triclosan in the epilimnion of the lake increases to 30% in summer . Passive sampling with semipermeable membrane devices (SPMDs) indicated the presence of methyl triclosan in lakes with inputs from anthropogenic sources but not in a remote mountain lake . Surprisingly, no parent triclosan was observed in the SPMDs from these lakes . Methyl triclosan appears to be preferentially accumulated in SPMDs under the conditions in these lakes, leading to concentrations comparable to those of persistent chlorinated organic pollutants.

J Air Waste Manag Assoc, 2002 Jun, 52(6), 722 - 31
Stabilization of APC residues from waste incineration with ferrous sulfate on a semi-industrial scale; Lundtorp K et al.; A stabilization method for air pollution control (APC) residues from municipal solid waste incineration (MSWI) involving mixing of the residue with water and FeSO4 has been demonstrated on a semi-industrial scale on three types of APC residues: a semidry (SD) APC residue, a fly ash (FA), and an FA mixed with sludge (FAS) from a wet flue gas cleaning system . The process was performed in batches of 165-175 kg residue . It generates a wastewater that is highly saline but has a low content of heavy metals such as Cd, Cr, and Pb . The stabilized and raw residues have been subject to a range of leaching tests: the batch leaching test, the pH-static leaching test, the availability test, and the column test . These tests showed that the stabilized residues have remarkably improved leaching properties, especially with respect to Pb but also with respect to Cd, Cu, and Zn . The release of Pb was reduced by a factor of 250-36,000.

Prep Biochem Biotechnol, 2002 May, 32(2), 127 - 33
An enzymatic method for removal of phenol from industrial effluent; Singh N et al.; Phenols in an aqueous solution were removed after treatment with peroxidase in the presence of hydrogen peroxide . Phenols occur in wastewater of a number of industries, such as high temperature coal conversion, petroleum refining, resin and plastic, wood and dye industries, etc . It can be toxic when present at elevated levels and is known to be carcinogeneous . Thus, removal of such compound from these industrial effluents is of great importance . An enzymatic method for removal of phenols from industrial wastewater, using turnip peroxidase, has been developed . Phenol-containing industrial wastewater was treated with immobilized turnip peroxidase in the presence of hydrogen peroxide . In the reaction, a number of phenols are oxidized to form the corresponding free radicals in the presence of hydrogen peroxide as an oxidant . Free radicals polymerize to form substances that are less soluble in water than the original substances . The precipitates were removed by conventional methods and residual phenol was estimated . The present report describes the immobilization of turnip peroxidase on silica via covalent coupling, and its utility in phenol removal . A comparative study was also carried out with other immobilization techniques, viz., calcium alginate entrapment, polyacrylamide gel entrapment, etc . Peroxidase, covalently bound to silica, showed 95% removal of phenol, whereas naphthol was removed up to 99%.

J Biotechnol, 2002 Aug 7, 97(2), 125 - 31
Effects of culture conditions on the production of polyhydroxyalkanoates by Azotobacter chroococcum H23 in media containing a high concentration of alpechín (wastewater from olive oil mills) as primary carbon source; Pozo C et al.; Large amounts of homopolymers containing beta-hydroxybutyrate (PHB) and copolymers containing beta-hydroxyvalerate (P{HB-co-HV}) are produced by Azotobacter chroococcum strain H23 when growing in culture media amended with alpechin (wastewater from olive oil mills) as the sole carbon source . Copolymer was formed when valerate (pentanoate) was added as a precursor to the alpechin medium, but it was not formed with the addition of propionate as a precursor . A . chroococcum formed homo- and copolymers of polyhydroxyalkanoates (PHAs) up to 80% of the cell dry weight, when grown on NH(4)(+)-medium supplemented with 60% (v/v) alpechin, after 48 h of incubation at 100 rev min(-1) and 30 degrees C . Production of PHAs by strain H23 using alpechin looks promising, as the use of a cheap substrate for the production of these materials is essential if bioplastics are to become competitive products.

J Chromatogr A, 2002 Apr 12, 953(1-2), 79 - 87
Solid-phase microextraction coupled to high-performance liquid chromatography to determine phenolic compounds in water samples; Penalver A et al.; Solid-phase microextraction (SPME) coupled to high-performance liquid chromatography (HPLC) with ultraviolet (UV) and electrochemical detection (ED) has been applied to determine 11 phenolic compounds considered priority pollutants by the US Environmental Protection Agency . 85 microm polyacrylate fibers were used to extract the analytes from the aqueous samples . Two different designs of the liquid chromatograph were compared in combination with SPME . Dynamic and static modes of desorption in both HPLC designs were compared and the variables affecting both absorption and desorption processes in SPME-HPLC were optimized . Static desorption in both HPLC systems showed better recoveries for the phenolic compounds . The performance of the SPME-HPLC-UV-ED method was evaluated with river water and wastewater samples . The method enabled the determination of phenolic compounds at low levels in these water samples.

Bioresour Technol, 2002 May, 83(1), 65 - 70
An economic analysis of biomass gasification and power generation in China; Wu CZ et al.; With vast territory and abundant biomass resources China appears to have suitable conditions to develop biomass utilization technologies . As an important decentralized power technology, biomass gasification and power generation (BGPG) has a potential market in making use of biomass wastes . In spite of the relatively high cost for controlling secondary pollution by wastewater, BGPG is economically feasible and can give a financial return owing to the low price of biomass wastes and insufficient power supply at present in some regions of China . In this work, experimental data from 1 MW-scale circulating fluidized bed (CFB) BGPG plants constructed recently in China were analyzed; and it was found that the unit capital cost of BGPG is only 60-70% of coal power station and its operation cost is much lower than that of conventional power plants . However, due to the relatively low efficiency of small-scale plant, the current BGPG technology will lose its economic attraction when its capacity is smaller than 160 kW or the price of biomass is higher than 200 Yuan RMB/ton . The development of medium-scale BGPG plants, with capacity ranging from 1000 to 5000 kW, is recommended; as is the demonstration of BGPG technology in suitable enterprises (e.g . rice mill and timber mill) in developing countries where large amounts of biomass wastes are available so that biomass collection and transportation can be avoided and the operation cost can be lowered.

Bioresour Technol, 2002 Jun, 83(2), 81 - 7
Growth of ornamental plants in two composts prepared from agroindustrial wastes; Garcia-Gomez A et al.; Two composts prepared from agroindustrial wastes were assayed as substrates: C1 from brewing waste (yeast and malt) plus lemon tree prunings; and C2 from the solid fraction of olive mill wastewater plus olive leaves . Sixteen substrates were prepared by combining each compost with Sphagnum peat or a commercial substrate (CS) in different proportions . The nutrients (N and K) provided by the composts, which acted as slow-release fertilisers, influenced especially the development of calendula, although the physical and physico-chemical properties such as total pore space and electrical conductivity (EC) were also relevant . On the other hand, in the salt-sensitive calceolaria hybrid, EC and chloride concentration were the main factors influencing growth . Adequate substrates for the development of calendula can be prepared by mixing C1 at up to 75% with peat or at up to 50% with CS, and C2 at up to 50% with peat or CS . For calceolaria, the substrate should have a lower proportion of compost, C1 at up to 50% and C2 at up to 25%, both mixed with peat or CS . Therefore, composts of agroindustrial origin such as these can be used as an alternative to peat and CSs for growing ornamental plants . provided the mixture contains at least 25% peat or CS.

Ecotoxicol Environ Saf, 2002 May, 52(1), 46 - 56
Regulatory implications of using constructed wetlands to treat selenium-laden wastewater; Lemly AD et al.; The practice of using constructed wetlands to treat selenium-laden wastewater is gaining popularity in the United States and elsewhere . However, proponents of treatment wetlands often overlook important ecological liabilities and regulatory implications when developing new methods and applications . Their research studies typically seek to answer a basic performance question--are treatment wetlands effective in improving water quality--rather than answering an implicit safety question-are they hazardous to wildlife . Nevertheless, wetland owners are responsible for both the operational performance of treatment wetlands and the health of animals that use them . This is true even if wetlands were not created with the intent of providing wildlife habitat; the owner is still legally responsible for toxic hazards . If poisoning of fish and wildlife occurs, the owner can be prosecuted under a variety of federal and state laws, for example, the Migratory Bird Treaty Act and the Endangered Species Act . In considering this type of treatment technology it is important to document the selenium content of the wastewater, understand how it cycles and accumulates in the environment, and evaluate the threat it may pose to fish and wildlife before deciding whether or not to proceed with construction . Many of the potential hazards may not be obvious to project planners, particularly if there is no expressed intention for the wetland to provide wildlife habitat . Ecological risk assessment provides an approach to characterizing proposed treatment wetlands with respect to wildlife use, selenium contamination, and possible biological impacts . Proper application of this approach can reveal potential problems and the associated liabilities, and form the basis for selection of an environmentally sound treatment option.

Sci Total Environ, 2002 Apr 22, 289(1-3), 133 - 44
An evaluation of biomarkers of reproductive function and potential contaminant effects in Florida largemouth bass ( Micropterus salmoidesfloridanus) sampled from the St . Johns River; Sepulveda MS et al.; The objective of this study was to describe and compare several reproductive parameters for Florida largemouth bass (Micropterus salmoides floridanus) inhabiting the St . Johns River and exposed to different types and/or degrees of contamination . Welaka was selected as the reference site in this study because of its low urban and agricultural development, Palatka is in close proximity to a paper mill plant, the Green Cove site is influenced by marine shipping activities and Julington Creek site receives discharges of domestic wastewater and storm water runoff from recreational boating marinas . For this study, bass were sampled both prior to (September 1996) and during the spawning season (February 1997) . In order to characterize chemical exposure, bass livers were analyzed for up to 90 trace organics and 11 trace metal contaminants . Reproductive parameters measured included gonadosomatic index (GSI), histological evaluation of gonads and plasma concentrations of vitellogenin (VTG), 17beta-estradiol (E2) and 11-ketotestosterone (11-KT) . In general, the sum of organic chemicals was highest in livers from Palatka bass and bass from Green Cove and Julington Creek had higher hepatic concentrations of low molecular polycyclic aromatic hydrocarbons and polychlorinated biphenyls when compared to fish from Welaka . Metals were more variable across sites, with highest mean concentrations found in bass from either Julington Creek (Ag, As, Cr, Cu, Zn) or Welaka (Cd, Hg, Pb, Se, Tn) . Female bass from Palatka and Green Cove had lower concentrations of E2, VTG and lower GSI in relation to Welaka . Males from Palatka and Green Cove showed comparable declines in 11-KT in relation to males from Julington Creek and GSI were decreased only in Palatka males . These results indicate a geographical trend in reproductive effects, with changes being most pronounced at the site closest to the paper mill (Palatka) and decreasing as the St . Johns River flows downstream . Since reproductive alterations were most evident in bass sampled from the site closest to the paper mill discharge, it is possible that exposure to these effluents might explain at least some of the results reported here . However, the presence of reproductive alterations in fish sampled at a considerable distance from the mill discharge (Green Cove, 40 km) would suggest exposure to chemicals released from sources other than the paper mill plant . It is clear that additional studies are needed to evaluate the potential impact of these reproductive changes in populations of Florida largemouth bass inhabiting the St . Johns River.

Huan Jing Ke Xue, 2002 Mar, 23(2), 87 - 91
{Stability of HDTMA modified montmorillonite}; Yang L et al.; In order to probe the stability of organic montmorillonite, the nature montmorillonite was modified with hexadeeyltrimethylammonium (HDTMA) in different cation exchange capacity (CEC) . The results of experiments showed that the stability of modified montmorillonite declined as its CEC was big and HDTMA was desorbed from 1.0 CEC modified montmorillonite . HDTMA bound to the montmorillonite surface was resistant to temperature(70 degrees C) and instable to strong ultrasonic and to vibrational intensity(180 r/min) . The result also indicated that the stability of modified montmorillonite increased to NaCl(1.8 mol/L) but decreased to CaCl2 (1.8 mol/L) and modified montmorillonite was more stable in high-pH environment(12.00) than in low-pH environment(2.06) . On the basis of the results of these studies, low CEC modified montmorillonite appeared suitable as a sorbent for wastewater chemical treatment and as carrier for wastewater biotreatment in low stir environment.

Huan Jing Ke Xue, 2002 Mar, 23(2), 69 - 72
{Effects of polyacrylamide on settling and separation of oil droplets in polymer flooding produced water}; Deng S et al.; The research found anion polyacrylamide (HPAM) had positive and negative effects on oil-water separation . Polymer made oily wastewater's viscosity increase and reduce rising velocity, and polymer can also increase intensity of water films between oil droplets and lengthen coalescence time of oil droplets . Those were not in favor of settling and separation for oil droplets . The positive effects on separation were that polyacrylamide had flocculating activity and made small droplets contact each other and combine into big droplets . When polymer's molecular weight was 2.72 x 10(6), and concentration was less than 800 mg/L, polymer was in favor of oil droplets settling and separation . The prime reason for oily wastewater of polymer flooding difficult to dispose was that initial median diameters of oil droplets were small . The transverse flow oil separator can intensify oil droplets combination and shorten rising time . The locale experiments showed the separator was suitable for dealing with oily wastewater of polymer flooding.

Huan Jing Ke Xue, 2002 Mar, 23(2), 39 - 44
{The application of nanofiltration membrane in the concentration and separation of lincomycin wastewater}; Zhu A et al.; Two spiral nanofiltration membranes, MPS-44 (1.4 m2) and DLNF2-30 (0.24 m2), were connected in series to test the concentration process of lincomycin wastewater . Results indicated when the water inflow concentration was about 200 mg/L, the lincomycin concentration can reach 2000 mg/L after being concentrated for about 10-20 times . Such concentration can reach the demand of reuse, and the concentrating time was 60-70 h . During the concentration process, the CODCr retention was always above 80%, and the lincomycin retention was always over 90%, and the lincomycin recycle rate was over 90%.

Huan Jing Ke Xue, 2002 Mar, 23(2), 113 - 6
{Recovery process of nitric acid, copper and nickel in deplating wastewater}; Liu Z et al.; The recovery process of nitric acid, copper and nickel in deplating wastewater was developed by using the combined technique of distillation, solvent extraction and precipitation . The conditions of the separation of copper and nickel by solvent extraction using P507 in kerosene and stripping copper with H2SO4 were specially investigated and the optimal parameters were determined . The results of experiment indicated that the recovery ratio of nitric acid was 97.8%, and under the optimized conditions of extraction process, concentration of original effluence ranged in 15-20 mg/mL copper, 5-10 mg/mL nickel, pH 1-2, concentration of extractant was 35% (V/V), saponification degree was 60%, phase ratio was 1:1, reaction time was 2 min, temperature ranged in 20 degrees C-25 degrees C, the one stage extraction efficiency of copper was higher than 90%, the separation ratio of copper and nickel was up to 75; copper and nickel could be completely separated by a continuous countercurrent three-stage extraction . The nickel could be recovered from the water phase by precipitating with NaOH and the recovery ratio of nickel reached up to 99.9% by controlling pH in solution within 10-11 . After these treatment, the effluent could meet the national standards of wastewater discharge.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2002, 37(4), 745 - 57
Long-term effects of municipal sewage on soils and pastures; van de Graaff RH et al.; Land application of municipal wastewater is widely practised worldwide as a means of treating wastes and obtaining a benefit from the water and nutrients by growing pastures, trees, and sometimes edible crops such as vegetables, fruit and fibre, etc . Irrigation of pastures by treated and untreated sewage near Melbourne, Australia, for more than a century has increased heavy metals concentrations in the soil, but appears not to have increased their concentrations in the herbage and in animal tissues of animals grazed on these pastures . There seem to be sound reasons why this practice may be sustainable.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2002, 37(4), 499 - 507
Persistent organic pollutants (POPs) in surface sediments of Donghu Lake, Wuhan, Hubei, China; Wang H et al.; Surface sediment samples from five different sites were collected in Donghu Lake, Wuhan City, Hubei Province, China during November 2000 . Over 180 organic chemicals were detected using GC-MS controlled by a Hewlett Packard Chemstation after soxhlet extraction . Derivatives of benzene, phthalate esters, PAHs, phenols, isophorone as priority pollutants or endocrine disruptors, respectively, were detected . The concentration of organic pollutants were found to be highest at the sampling site located at Southwest Donghu Lake (Shuiguo), caused most probably by the untreated wastewater discharge, average at the southern and lowest at the northern part of the lake.

J Environ Sci (China), 2002 Apr, 14(2), 250 - 4
Start-up strategies of UASB reactor for treatment of pharmaceutical wastewater; Zheng P et al.; Two start-up strategies of upflow anaerobic sludge blanket (UASB) reactor for treatment of pharmaceutical wastewater were investigated . The results showed that both of them were workable . Compared with the strategy that started up the reactor directly using chloromycetin wastewater, the strategy that started up the reactor first using mixed wastewater and then using chloromycetin wastewater could save time by 23% . When the latter strategy was adopted the development of sludge activity fluctuated more largely and its final activity was lower, but the sludge grew faster in the course of start-up.

J Environ Sci (China), 2002 Apr, 14(2), 245 - 9
Addition of anaerobic tanks to an oxidation ditch system to enhance removal of phosphorus from wastewater; Liu JX et al.; The oxidation ditch has been used for many years all over the world as an economic and efficient wastewater treatment technology . It can remove COD, nitrogen and a part of phosphorus efficiently . In the experiment described, a pilot scale Pasveer oxidation ditch system has been tested to investigate the removal of phosphorus from wastewater . The experimental results showed that influent total phosphorus(TP) was removed for 35%-50% . After this, two anaerobic tanks with total volume of 11 m3 were added to the system to release phosphorus . As a result, the TP removal efficiency increased by about 20% . At an anaerobic HRT of about 6 hours, a TP removal efficiency of 71% was achieved.

Arch Environ Contam Toxicol, 2002 Jul, 43(1), 11 - 8
An evaluation of the use of colonized periphyton as an indicator of wastewater impact in near-coastal areas of the Gulf of Mexico; Lewis MA et al.; Receiving water impacts of point source discharges to the Gulf of Mexico are seldom reported on indigenous flora . The objective of this research was to evaluate the ability of colonized periphyton to provide this information . Water quality and biomass and pigment concentrations of the periphyton were determined at 27 stations located above and below 8 wastewater discharges . Most physicochemical parameters and concentrations of pesticides and PCBs were either unchanged or below detection in the receiving waters, which contrasted occasional increases in concentrations of several trace metals and nutrients . The response of the periphyton was specific to the wastewater, colonization station, response parameter, and colonization period . Statistically significant differences in biomass and pigment content occurred for at least one colonization station located below each of the eight outfalls . This represented a total of 18 of the 21 stations located in wastewater-impacted areas . Phytostimulation was more common than inhibition . Ash-free dry weight increased, on average, by 181% (+/- 1 SD = 123%) and chlorophyll a increased by 356% (+/- 593%) in wastewater-impacted areas . The in situ phytostimulation paralleled the stimulatory trend observed in standardized NPDES whole effluent tests conducted with cultured microalgae for four of eight wastewaters . The use of colonized periphyton as an indicator of wastewater impact was not simple . Spatial variation in response needs consideration to ensure relevancy of the results if this assessment methodology is used for near-coastal wastewater hazard evaluations.

Water Res, 2002 Apr, 36(7), 1814 - 24
Characteristics of metal removal using carboxylated alginic acid; Jeon C et al.; Carboxylated alginic acid prepared through oxidation reaction with potassium permanganate had a high uptake capacity of 3.1 mmol/g dry mass at pH 4 and showed higher affinity to heavy metals compared to alkaline metals (Ca2+, Mg2+) in mixed metal system . The pHzpc value of the carboxylated alginic acid was 2.31, which was lower than pHzpc (2.83) of natural alginic acid . The increased number of carboxyl groups was confirmed by IR and 13C-NMR spectrum analysis, elemental analysis and carboxyl group number count . Lead adsorption by carboxylated alginic acid is an endothermic process since binding was increased as the temperature increased . When the temperature of wastewater is higher than room temperature, carboxylated alginic acid has an advantage over general adsorbents whose uptake capacity decreases as the temperature increases . Also, lead adsorbed on carboxylated alginic acid was desorbed effectively by about 80% by nitrilotriaceticacid.

Water Res, 2002 Apr, 36(7), 1783 - 93
Kinetics of adsorption of Co(II) removal from water and wastewater by ion exchange resins; Rengaraj S et al.; The capacity of ion exchange resins, IRN77 and SKN1, for removal of cobalt from aqueous solution has been investigated under different conditions namely initial solution pH, initial metal-ion concentration, and contact time . The equilibrium data obtained in this study have been found to fit both the Langmuir and Freundlich adsorption isotherms . The adsorption of Co(II) on these resins follows first-order reversible kinetics . The film diffusion of Co(II) in these ion exchange resins was shown to be the main rate limiting step . The studies showed that these cation exchange resins can be used as efficient adsorbent material for the removal of Co(II) from aqueous solutions.

Water Environ Res, 2002 Mar-Apr, 74(2), 200 - 9
Empirical equations for the limiting solids flux of final clarifiers; Yuen WA; Using the solids flux theory, two quantities (i.e., the dimensionless limiting solids flux {G = kGL/v(o)} and the dimensionless underflow velocity {U = FR/(Av(o))} are introduced for a final clarifier based on the Vesilind equation of sludge zone-settling velocity (v = v(o) exp{-kX}, where X is the suspended solids concentration, v(o) and k are empirical coefficients, and GL, FR, and A are the limiting solids flux, recycle flowrate, and surface area of the settling tank, respectively) . In this paper, the dimensionless limiting solids flux is shown to be a function of the dimensionless underflow velocity only and is accurately represented by empirical equations . The limiting solids flux can, thus, be easily calculated by using the empirical equations without resorting to tedious numerical procedures . Furthermore, using the dimensionless quantities (G and U), two final clarifier equations that express the relationship among suspended solids concentration, surface area of the clarifier, recycle flowrate, and wastewater flowrate are derived . Their applications to final clarifier analysis and to determining required surface area of final clarifier are illustrated.

Water Environ Res, 2002 Mar-Apr, 74(2), 170 - 6
Low-strength wastewater treatment using an anaerobic baffled reactor; Manariotis D et al.; A 14.7-L, three-chamber anaerobic baffled reactor (ABR) was used to evaluate the treatment of low-strength synthetic wastewater (chemical oxygen demand {COD} of 300 to 400 mg/L) and assess process reactivation after a prolonged period of inactivity . The reactor was inoculated with anaerobic seed and start-up was immediate . At 26 degrees C and hydraulic retention times (HRTs) of 24 and 12 hours, COD removal averaged 87.2 and 91.0%, respectively, and biogas yield for methane (CH4) was 0.184 and 0.102 m3 CH4/kg COD removed, respectively . The ABR was reactivated after two years without feeding . Response was prompt and removal averaged 85.3% even during the initial 10-day period . Lowering temperature to 16 degrees C did not impair removal efficiency at HRTs of 24 and 12 hours . However, biogas release decreased by 30% and apparent COD conversion to methane dropped by 24 and 31%, respectively . At the end of the study, biomass was mostly in the bottom of the reactor and had moved from the first to the second chamber, while organic stabilization was occurring essentially in the first two chambers (56.1 and 22.4%, respectively, in terms of COD).

Water Environ Res, 2002 Mar-Apr, 74(2), 149 - 58
Anaerobic digestion of aircraft deicing fluid wastes: interactions and toxicity of corrosion inhibitors and surfactants; Gruden CL et al.; Corrosion inhibitors and surfactants are present in aircraft deicing fluids (ADFs) at significant concentrations (> 1% w/w) . The purpose of this research was to study the interactions of a common nonionic surfactant with the commercially significant corrosion inhibitors used in modern ADF (4- and 5-methylbenzotriazole {MeBT}), and to determine the effects of their mixture on the conventional anaerobic digestion process . In mesophilic anaerobic microcosms codigesting wastewater solids, propylene glycol, and MeBT, increasing surfactant levels resulted in enhanced MeBT sorption on digester solids . As judged by anaerobic toxicity assays, responses from digesters containing surfactant concentrations below their critical micelle concentration (CMC) suggested that low nonionic surfactant concentrations could facilitate a reduction in the apparent toxicity of MeBT . In microcosms exposed to surfactant concentrations above their CMC, no increase in MeBT solubility was observed, and the anaerobic toxicity response corresponded to control systems not containing surfactant . Direct microscopic measurements of digesting biomass using fluorescent phylogenetic probes (fluorescent in situ hybridization) revealed that members of the domain Bacteria were more sensitive to MeBT in the presence of surfactant than were members of the domain Archaea.

Water Environ Res, 2002 Mar-Apr, 74(2), 136 - 41
Removal of solids and oxygen demand from aquaculture wastewater with a constructed wetland system in the start-up phase; Lin YF et al.; A pilot-scale, constructed wetland system consisting of a free water surface (FWS) and a subsurface flow (SF) wetland operated in series was set up for treating aquaculture farm wastewater . This study examined the system start-up phenomena and evaluated its performance in removing suspended solids, algae, and chemical oxygen demand (COD) under various hydraulic loading rates (1.8 to 13.5 cm/d) . The SF wetland achieved stable effluent qualities without an adaptation period, while the FWS wetland required approximately 5 months to reach consistent removal levels for suspended solids and algae . Macrophyte density was a critical factor affecting the reduction of suspended solids and chlorophyll for the FWS wetland, but not for the SF wetland . Suspended solids removals in both of the wetlands and the combined system (47 to 86%) decreased significantly as the hydraulic loading rate increased, strongly following the first-order mass-decrease equation . Phytoplankton solids (biomass and detritus) were a primary source of suspended solids in the aquaculture wastewater . Both chlorophyll reduction (76 to 95%) and COD removal (25 to 55%) in the constructed wetland system were apparently not affected by hydraulic loading . While algae died out because of limited sunlight in both wetlands, algae detritus probably still contributed fine particles that were difficult to remove from the water by either filtering or settling out . Removed suspended solids did not result in the increase of COD and nutrients, indicating that further solids stabilization occurred in the wetland system.

Appl Environ Microbiol, 2002 Jun, 68(6), 2763 - 9
Involvement of Rhodocyclus-related organisms in phosphorus removal in full-scale wastewater treatment plants; Zilles JL et al.; The participation of organisms related to Rhodocyclus in full-scale enhanced biological phosphorus removal (EBPR) was investigated . By using fluorescent in situ hybridization techniques, the communities of Rhodocyclus-related organisms in two full-scale wastewater treatment plants were estimated to represent between 13 and 18% of the total bacterial population . However, the fractions of these communities that participated in polyphosphate accumulation depended on the type of treatment process evaluated . In a University of Cape Town EBPR process, the percentage of Rhodocyclus-related cells that contained polyphosphate was about 20% of the total bacterial population, but these cells represented as much as 73% of the polyphosphate-accumulating organisms (PAOs) . In an aerated-anoxic EBPR process, Rhodocyclus-related PAOs were less numerous, accounting for 6% of the total bacterial population and 26% of the total PAO population . In addition, 16S ribosomal DNA sequences 99.9% similar to the sequences of Rhodocyclus-related organisms enriched in acetate-fed bench-scale EBPR reactors were recovered from both full-scale plants . These results confirmed the involvement of Rhodocyclus-related organisms in EBPR and demonstrated their importance in full-scale processes . In addition, the results revealed a significant correlation between the type of EBPR process and the PAO community.

Comp Biochem Physiol C Toxicol Pharmacol, 2002 May, 132(1), 75 - 84
Vitellogenin levels in mussel hemolymph--a suitable biomarker for the exposure to estrogens?
Riffeser M, Hock B.
Increased vitellogenin (vtg) levels in the blood of male fish are frequently used as an indicator of estrogenic exposure . Similar responses are expected for mussels, where the concentration of vtg-like proteins has been reported to depend on estrogens . To verify the role of hemolymph during vitellogenesis of mussels, the saltwater mussel Mytilus edulis and the freshwater mussel Anodonta cygnea were exposed to 17beta-estradiol (E2) and wastewater treatment plant effluents, known for their estrogenic potential . Gel electrophoresis did not reveal any significant induction (or repression) of plasma proteins compared to control plasma . Our results do not support the hypothesis that mussel hemolymph is a carrier of estrogen-dependent major egg-yolk precursors (vtg-like proteins) . However, additional information on a 35+/-2-kDa hemolymph protein, previously reported to bind heavy metals, was obtained by high-resolution two-dimensional electrophoresis . It was resolved in a cluster of single proteins with properties that match the characteristics of a previously reported histidine-rich glycoprotein.

J Am Dent Assoc, 2002 May, 133(5), 577 - 84; quiz 623-5
Laboratory evaluation of amalgam separators; Fan PL et al.; BACKGROUND: Amalgam in dental wastewater is receiving increasing scrutiny from regulators because of national, state and local initiatives to reduce or virtually eliminate the discharge of mercury and mercury-containing items into the environment . Amalgam separators are considered to be one means of reducing the amount of amalgam that dental offices discharge into sewers . The purpose of this study was to evaluate the amalgam removal efficiency of commercially available amalgam separators and the total mercury concentration in the effluent from laboratory testing . METHODS: The authors evaluated the amalgam removal efficiency of 12 amalgam separators according to International Organization for Standardization, or ISO, Standard 11143 for Amalgam Separators . Total mercury concentration in the effluent was calculated using the mass of amalgam particles larger than 1.2 micrometers and the volume of effluent, together with U.S . Environmental Protection Agency, or EPA, Method 245.1 for amalgam particles smaller than 1.2 microm . Total dissolved mercury also was determined . RESULTS: The results show that all 12 amalgam separators exceeded the ISO 11143 requirement of 95 percent amalgam removal efficiency . Statistical differences were found in the efficiencies of the separators . Both the total mercury concentration and total dissolved mercury concentration in the effluent demonstrated large variations . CONCLUSIONS AND CLINICAL IMPLICATIONS: This laboratory evaluation shows that amalgam separators removed at least 96.09 percent of the amalgam in samples with particle-size distribution as specified in ISO 11143 . Total mercury concentration and total dissolved mercury concentration in the effluent varied widely for each amalgam separator . Additional research is needed to develop test methods to evaluate the efficiency of amalgam separators in removing small amalgam particles, colloidal amalgam particles and ionic mercury in solution.

Can J Microbiol, 2002 Apr, 48(4), 305 - 10
Improved method for recovery of bacteriophage from large volumes of water using negatively charged microporous filters; Scott TM et al.; Current virus-recovery procedures using negatively charged microporous filters provide an inexpensive, reliable method for the recovery and detection of enteroviruses from water and wastewater; however, adjustment of the test samples to pH 3.5 to promote enterovirus adsorption results in significant inactivation of bacteriophage and an inability to simultaneously recover them from large volumes of water using this procedure . Procedures specifically designed for the detection of bacteriophage are currently in use but generally are only effective for small volumes of water . Positively charged filters can be used to recover both enteroviruses and bacteriophage from large volumes of water at neutral pH; however, the filters are expensive . The addition of manganese chloride to test solutions at pH 3.5 prior to filtration through negatively charged Filterite filters allowed for sampling of larger volumes of water by reducing the inactivation of bacteriophage and increasing the recovery of PRD1, MS2, and naturally isolated bacteriophage by a factor of four or five when compared with recoveries from solutions without MnCl2 . This method provides an inexpensive, reliable alternative to large-volume bacteriophage recovery procedures that use positively charged filters at neutral pH.

Lett Appl Microbiol, 2002, 34(6), 407 - 12
High organic loading influences the physical characteristics of aerobic sludge granules; Moy BY et al.; AIMS: The effect of high organic loading rate (OLR) on the physical characteristics of aerobic granules was studied . METHODS AND RESULTS: Two column-type sequential aerobic sludge blanket reactors were fed with either glucose or acetate as the main carbon source, and the OLR was gradually raised from 6 to 9, 12 and 15 kg chemical oxygen demand (COD) m(-3) d(-1) . Glucose-fed granules could sustain the maximum OLR tested . At a low OLR, these granules exhibited a loose fluffy morphology dominated by filamentous bacteria . At higher OLRs, these granules became irregularly shaped, with folds, crevices and depressions . In contrast, acetate-fed granules had a compact spherical morphology at OLRs of 6 and 9 kg COD m(-3) d(-1), with better settling and strength characteristics than glucose-fed granules at similar OLRs . However, acetate-fed granules could not sustain high OLRs and disintegrated when the OLR reached 9 kg COD m(-3) d(-1) . CONSLUSIONS: The compact regular microstructure of the acetate-fed granules appeared to limit mass transfer of nutrients at an OLR of 9 kg COD m(-3) d(-1) . The looser filamentous microstructure of the glucose-fed granules and the subsequent irregular morphology delayed the onset of diffusion limitation and allowed significantly higher OLRs to be attained . SIGNIFICNACE AND IMPACT OF THE STUDY: High organic loading rates are possible with aerobic granules . This research would be helpful in the development of aerobic granule-based systems for high-strength wastewaters.

Environ Sci Technol, 2002 May 1, 36(9), 2101 - 6
Urban wastewater treatment by a nutrient film technique system with a valuable commercial plant species (Chrysanthemum cinerariaefolium Trev.); Vaillant N et al.; Urban wastewater causes rapid eutrophication of natural waters and requires treatment before discharge . This is expensive and produces huge quantities of sludge . In the European Community, it will no longer be lawful to dispose of this sludge as landfill after 2005 (European Directive 91/271/CEE of May 21, 1991) . Wastewater treatment by the Chrysanthemum cinerariaefolium plants in horizontal flow was investigated using the nutrient film technique (NFT), a widely used hydroponic system in the commercial greenhouse industry . After a 48 h plant treatment, the purification efficiency was 95%, 91%, and 99% with respect to suspended solids (SS), biochemical oxygen demand (BOD5), and chemical oxygen demand (COD), and the elimination of nutrients (total nitrogen and total phosphorus) varied between 40% and 80% . SS and thus indirectly BOD5 and COD were removed by filtration and adsorption; the solids trapped in the root systems were then decomposed and mineralized . The system with 25 plants purified 30 L of wastewater in 48 h . One-hundred people communities wastewater could be treated with a 6 m2 area of production . Pyrethrin contents and chlorophyll a fluorescence of plants grown on raw urban waters were not significantly different from those grown on a standard nutrient solution.

Environ Sci Technol, 2002 May 1, 36(9), 2094 - 100
Photodegradation of a ternary iron(III)-uranium(VI)-citric acid complex; Dodge CJ et al.; The mechanisms of photodegradation of binary iron- and uranium-citrate and ternary iron-uranium-citrate complexes were elucidated . Citric acid degradation products were identified by HPLC and GC, and the metal precipitates were identified by XRD and EXAFS . Photodegradation of a binuclear iron-citrate complex occurred as a result of two one-electron oxidations of citric acid with the formation of 3-oxoglutarate and two ferrous ions . The ferrous ions were reoxidized by a photo-Fenton reaction, resulting in the precipitation of iron as two-line ferrihydrite Fe(OH)3 . The citric acid in the uranium-citrate complex underwent a two-electron oxidation to acetoacetate with the concomitant reduction of U(VI) to U(IV) . The U(IV) was subsequently photooxidized in the presence of dioxygen with precipitation of uranium as the mineral schoepite (UO3 x 2H2O) . A two-step electron reduction of two ferric ions to two ferrous ions wasthe primary mechanism for photodegradation of the ternary iron-uranium-citrate complex with oxidation of citric acid to 3-oxoglutarate; reduction of uranium was not observed . The iron precipitated as ferrihydrite and the uranyl ion as a uranyl hydroxide species . These results show the potential application of photochemical treatment of wastewater and decontamination solutions containing binary and ternary iron- and uranium-citrate complexes.

Environ Sci Technol, 2002 May 1, 36(9), 1899 - 906
Cross-shelf transport at Huntington Beach . Implications for the fate of sewage discharged through an offshore ocean outfall; Boehm AB et al.; In this study, we evaluate the potential for internal tides to transport wastewater effluent from the Orange County Sanitation District (OCSD) ocean outfall toward Huntington Beach . Results of plume tracking studies show that OCSD effluent occasionally moves shoreward into water less than 20 m deep . Analyses of current and temperature observations indicate cold water is regularly advected cross-shelf, in to and out of the nearshore, at both semi-diurnal and diurnal frequencies . Isotherms typically associated with the waste field near the outfall are observed just outside the Huntington Beach surf zone, where the total depth is less than 6 m, highlighting the extent of the cross-shelf transport . This advection is attributed to a mode 1 internal motion, or internal tide . On the basis of the analyses presented here, the OCSD plume cannot be ruled out as a contributor to poor bathing-water quality at Huntington Beach.

J Environ Qual, 2002 May-Jun, 31(3), 917 - 25
Nitrogen contamination in the Yellow River basin of China; Xia X et al.; Nitrogen contamination is one of the most serious problems in the Yellow River of China . This study was conducted to analyze monitoring data on nitrogen contamination for the Yellow River basin in the years 1980, 1990, 1997, and 1999 . Several significant results have arisen from the study . First, in conjunction with an increase in economic indexes from the Yellow River's upper basin to its lower basin, the nitrogen concentration in the tributaries also showed an increasing trend from the upper to the lower basin, which, in turn, led to an increase in the nitrogen concentration of the mainstream from the upper to the lower reaches . Second, nitrogen in the river water in the mainstream and the tributaries of the Yellow River was attributed mainly to point sources . In spite of the fact that the ratio of point to nonpoint sources decreased from 2.7 in 1990 to 1.8 in 1997 for total inorganic nitrogen in river water at the Tongguan Station in the lower basin, point sources increased more than nonpoint sources . Third, the ammonium nitrogen and total inorganic nitrogen content of the river water increased significantly in the mainstream and the tributaries during the 1980-1999 period, a change caused by an increase in wastewater discharge and nitrogenous fertilizer application in the Yellow River catchment.

J Environ Qual, 2002 May-Jun, 31(3), 896 - 903
Modeling the fate of benzo{a}pyrene in the wastewater-irrigated areas of Tianjin with a fugacity model; Wang XL et al.; A Level III fugacity model was applied to characterize the transfer processes and environmental fate of benzo{a}pyrene in wastewater-irrigated areas of Tianjin, China . The physical-chemical properties and transfer parameters of benzo{a}pyrene were used in the model and the concentration distribution of benzo{a}pyrene in sediment, soil, water, air, fish, and crop compartments, as well as transfer fluxes across the compartments, were then derived under steady-state assumptions . The calculated results were compared with monitoring data for air, soil, water, and sediment collected from the literature . The results indicate that there was generally good agreement and the differences were within an order of magnitude for air, soil, and sediment . The concentration of benzo{a}pyrene in the ambient air in the area was very low with a majority present sorbed to aerosol . In the water compartment, approximately 70% of benzo{a}pyrene dissolved in water phase . Relatively high concentrations of the compound were found in the soil and sediment, with the soil serving as the dominant sink in the area . Benzo{a}pyrene, with a slow metabolic rate, was found to accumulate in fish in the area.

J Environ Qual, 2002 May-Jun, 31(3), 1010 - 6
Temperature and wetland plant species effects on wastewater treatment and root zone oxidation; Allen WC et al.; Constructed wetlands are widely used for wastewater treatment, but there is little information on processes affecting their performance in cold climates, effects of plants on seasonal performance, or plant selection for cold regions . We evaluated the effects of three plant species on seasonal removal of dissolved organic matter (OM) (measured by chemical oxygen demand and dissolved organic carbon) and root zone oxidation status (measured by redox potential {Eh} and sulfate {SO4(2-)}) in subsurface-flow wetland (SSW) microcosms . A series of 20-d incubations of simulated wastewater was conducted during a 28-mo greenhouse study at temperatures from 4 to 24 degrees C . Presence and species of plants strongly affected seasonal differences in OM removal and root zone oxidation . All plants enhanced OM removal compared with unplanted controls, but plant effects and differences among species were much greater at 4 degrees C, during dormancy, than at 24 degrees C, during the growing season . Low temperatures were associated with decreased OM removal in unplanted controls and broadleaf cattail (Typha latifolia L.) microcosms and with increased removal in beaked sedge (Carex rostrata Stokes) and hardstem bulrush {Schoenoplectus acutus (Muhl . ex Bigelow) A . & D . Love var . acutus} microcosms . Differences in OM removal corresponded to species' apparent abilities to increase root zone oxygen supply . Sedge and bulrush significantly raised Eh values and SO4(2-) concentrations, particularly at 4 degrees C . These results add to evidence that SSWs can be effective in cold climates and suggest that plant species selection may be especially important to optimizing SSW performance in cold climates.

Microb Ecol, 2001 Dec, 42(4), 635 - 643
Seawater Activation of Escherichia coli Gene Promoter Elements: Dominance of rpoS Control; Rozen Y et al.; The release of non-disinfected wastewater into the marine environment is a common practice in many countries; nevertheless, the molecular mechanisms involved in determining the survival of enteric bacteria in seawater are poorly understood, in spite of the obvious public health implications . In a methodological attempt to address this issue, a plasmid-based collection of 687 Escherichia coli distinct promoter::luxCDABE fusions was screened to identify promoters that are induced upon exposure to seawater . The luminescence driven by 22 out of these promoters reproducibly increased at least two-fold in an artificial seawater medium; only 9 of the corresponding genes have previously been assigned a function . The most prominent characteristic of the induced genes was that most (18 out of 22) were under rpoS control . The induction of these seawater-responsive promoters was evaluated in different media to identify the cause of the increased transcription . Salinity or osmolarity was instrumental in only four cases, and in three promoters, increased pH also seemed to play a role; however, the most significant environmental effector in inducing the majority of the seawater-induced promoters appeared to be nutrient limitation.

J Environ Biol, 2001 Oct, 22(4), 251 - 6
Assessment of industrial effluent and its impact on soil and plants; Barman SC et al.; The present study deals with the assessment of industrial water of an electronic component manufacturing unit with electroplating and its subsequent effects on soil and plants receiving the effluent . The physico-chemical parameters of the effluent samples showed higher value than that of ground water . The treated effluent was within the permissible limit . Microtox test was conducted and determined the degree of toxicity of untreated, treated effluents as well as the water sample collected at effluent discharge point of receiving river (confluence point) . The physico- mechanical parameters of the soil samples were not changed due to irrigation of the treated effluent, but the concentration of metals were comparatively higher than the control soil . Higher accumulation of metals was found in the plant parts in naturally growing weeds and cultivated crop plant irrigated with treated effluent . Elevated accumulation of metals in Eichhornia crassipes and Marsilea sp . growing along the effluent channel has been identified as a potential source of biomonitoring of metals particularly for Cu and Ca and can be utilised for the removal of heavy metal from wastewater.

Indian J Exp Biol, 2001 Aug, 39(8), 824 - 6
Alginate immobilization of Spirulina platensis for wastewater treatment; Patnaik S et al.; Immobilization of cyanobacterium Spirulina platensis in sodium alginate (1.5 %) gave the best quality of bead and 15-16 beads were formed per mL of aqueous solution of alginate . The immobilized cells were used in a batch process for treatment of diluted sewage . After 8 days, 95 % of BOD5, 77 % of COD, 90 % of ammonia, and 94 % of TSS were removed.

Waste Manag Res, 2002 Feb, 20(1), 80 - 9
Treatment of waste incinerator air-pollution-control residues with FeSO4: laboratory investigation of design parameters; Jensen DL et al.; The key design parameters of a new process for treatment of air-pollution-control (APC) residues (the Ferrox-process) were investigated in the laboratory . The optimisation involved two different APC-residues from actual incinerator plants . The design parameters considered were: amount of iron oxide supplied, the liquid-to-solid ratio of the process, the separation of solids and wastewater, the sequence of material mixing, the possibilities of reuse of water, the feasibility of using secondary (brackish) water, and simple means to improve the wastewater quality . The investigation showed that an optimum process configuration could be obtained yielding a stabilised solid product with low leaching of heavy metals and a dischargable wastewater with high contents of salts (in order to remove salts from the solid product) and low concentrations of heavy metals . The amount of iron added to the APC-residues must be optimised for each residue . The overall water use can be limited to a L/S-ratio of 3 l kg(-1) including water used for washing of the treated products.

Waste Manag Res, 2002 Feb, 20(1), 69 - 79
Treatment of waste incinerator air-pollution-control residues with FeSO4: concept and product characterisation; Lundtorp K et al.; This paper describes a new concept for treatment of air pollution-control (APC) residues from waste incineration and characterises the wastewater and stabilised residues generated by the process . The process involves mixing of APC-residues with a ferrous sulphate solution and subsequent oxidation of the suspension (Ferrox-process 1996) . The process results in a significant reduction in the leaching of salts and heavy metals from the residue, by washing out most of the salts and by binding the heavy metals in the iron oxides formed . In the laboratory, a semidry gas-cleaning residue and a fly ash were treated by the process . The generated wastewater contained low concentrations of heavy metals (e.g . Pb: 27-39 microg l(-1) and Cd: 2.6-4.6 microg l(-1)), but high concentrations of salts (e.g . Cl, Na, K, and Ca) . The treatment process redUced the leaching of Pb from the residues by more than two orders of magnitude at fixed pH as determined by pH-static leaching tests . Likewise, the leaching of Cd, Zn and Cu was significantly reduced . The effect on elements that form oxyanions (e.g . Cr) is marginal and in the current process there is no reduction in the release of Hg.

Water Sci Technol, 2002, 45(8), 53 - 64
Global water dynamics: issues for the 21st century; Simonovic SP; The WorldWater system dynamics model has been developed for modeling the global world water balance and capturing the dynamic character of the main variables affecting water availability and use in the future . Despite not being a novel approach, system dynamics offers a new way of addressing complex systems . WorldWater simulations are clearly demonstrating the strong feedback relation between water availability and different aspects of world development . Results of numerous simulations are contradictory to the assumption made by many global modelers that water is not an issue on the global scale . Two major observations can be made from early simulations: (a) the use of clean water for dilution and transport of wastewater, if not dealt with in other ways, imposes a major stress on the global world water balance; and (b) water use by different sectors is demonstrating quite different dynamics than predicted by classical forecasting tools and other water-models . Inherent linkages between water quantity and quality sectors with food, industry, persistent pollution, technology, and non-renewable resources sectors of the model create shoot and collapse behavior in water use dynamics . This paper discusses a number of different water-related scenarios and their implications on the global water balance . In particular, two extreme scenarios (business as usual - named "Chaos", and unlimited desalination - named "Ocean") are presented in the paper . Based on the conclusions derived from these two extreme cases a set of more moderate and realistic scenarios (named "Conservation") is proposed and their consequences on the global water balance are evaluated.

Water Sci Technol, 2002, 45(8), 24 - 33
Water from (waste)water--the dependable water resource; Asano T; Water reclamation and reuse provides a unique and viable opportunity to augment traditional water supplies . As a multi-disciplined and important element of water resources development and management, water reuse can help to close the loop between water supply and wastewater disposal . Effective water reuse requires integration of water and reclaimed water supply functions . The successful development of this dependable water resource depends upon close examination and synthesis of elements from infrastructure and facilities planning, wastewater treatment plant siting, treatment process reliability, economic and financial analyses, and water utility management . In this paper, fundamental concepts of water reuse are discussed including definitions, historical developments, the role of water recycling in the hydrologic cycle, categories of water reuse, water quality criteria and regulatory requirements, and technological innovations for the safe use of reclaimed water . The paper emphasizes the integration of this alternative water supply into water resources planning, and the emergence of modern water reclamation and reuse practices from wastewater to reclaimed water to repurified water.

Water Sci Technol, 2002, 45(8), 191 - 3
Workshop 7 (synthesis): trade-offs in water for food and environmental security--urban/agricultural trade-off; Rahman AU et al.; Severe stresses are being generated by increasing demand for competing water uses, above all between agriculture and urban needs . Amongst potential solutions considered, two dominated the workshop: virtual water and water reuse . Virtual water implies indirect water use: water-poor countries importing food rather than attempting self-sufficiency and thereby keeping their real water resources for economically more beneficial uses . There are serious political and economic risks associated; one proposed solution is an international virtual water trading council . Improved forms of water reuse, particularly use of treated urban wastewater for irrigation, can maximise the use made of limited supply.

Biol Trace Elem Res, 2002 Jun, 86(3), 227 - 36
Selective recovery of uranium and thorium ions from dilute aqueous solutions by animal biopolymers; Ishikawa S et al.; Selective actinide ion recovery from dilute, aqueous, multication waste streams is an important problem . The recovery of uranium (U) and thorium (Th) by various animal biopolymers was examined . Of four species of biopolymers tested, a high uptake of uranium and thorium was found in hen eggshell membrane (ESM) and silk proteins, with the maximum uranium and thorium recovery exceeding 98% and 79%, respectively . The uptake of U and Th was significantly affected by the pH of the solution . The optimum pH values were 6 and 3 for the uptake of U and Th, respectively . The effect of temperature differed with the metal . The uptake of U decreased with increasing temperature (30-50 degrees C), whereas the Th uptake increased with increasing temperature . Selective recovery of U and Th from dilute aqueous binary and multimetal solutions was also examined . ESM and silk proteins tested were effective and selective for removing each metal by controlling the pH and temperature of the solution . In multimetal systems, the order of sorption of ESM proteins was preferential: U > Cu > Cd > Mn > Pb > Th > Ni > Co > Zn at pH 6 and Th > U > Cu > Pb > Cd > Mn > Co > Ni = Zn at pH 3 . These biopolymers appear to have potential for use in a commercial process for actinide recovery from actinide-containing wastewater.

Environ Toxicol Chem, 2002 May, 21(5), 1065 - 75
A comparison of stream biological responses to discharge from wastewater treatment plants in high and low population density areas; Dyer SD et al.; The ultimate purpose of this study was to identify broad relationships that may have relevance for the risk assessment of chemicals and materials that are discharged to receiving streams via municipal wastewater treatment plant (WWTP) effluents (e.g., consumer product ingredients) . The effects of municipal wastewaters occurring in high population density (>500 persons per square mile, urban) and low population density (<500 persons per square mile, rural) environments were determined via analysis of biological, habitat, and water chemistry data collected both immediately upstream and downstream of 221 WWTPs in Ohio, USA . Several biological and chemistry indicators demonstrated poorer water quality in urban areas compared to rural areas . After considering the effect of river size, adverse effects downstream of WWTPs for both fish and macroinvertebrate communities were clearly identified for only urban areas . These data indicate that WWTP potency may be greater in urban areas compared to rural areas.

Environ Toxicol Chem, 2002 May, 21(5), 1040 - 51
Use of ethylenediaminetetraacetic acid in pulp mills and effects on metal mobility and primary production; Eklund B et al.; Over the last decade, the use of ethylenediaminetetraacetic acid (EDTA) has increased by a factor of three within the Swedish pulp industry . The effects of pulp mill wastewater in combination with EDTA on metal mobility and the consequences for ecologically relevant organisms have been studied . Ethylenediaminetetraacetic acid was added to pulp mill effluent water in the laboratory and compared to wastewater without EDTA . Degradation of the water was followed over a experimental period up to eight weeks and samples were taken five times for chemical analysis and at the beginning and the end for biological tests . Half a year later, the experiment was repeated . The results from both experiments showed that EDTA markedly increased the solubility of zinc, cadmium, lead, iron, nickel, and copper, whereas the solubility of vanadium, molybdenum, thallium, arsenic, and chromium was not changed by the presence of EDTA . No measurable degradation of EDTA occurred even after 5.5 months . The toxicity of the pulp mill effluent water was low, and only a slight toxic effect was observed on the reproduction of Ceramium strictum . The most pronounced effect was a stimulation in the growth of three algal species in 5 to 20% (v/v) total effluent wastewater with and without EDTA . The presence of EDTA in the dissolved fraction of the pulp mill effluent water increased the growth stimulation in 20 to 40% (v/v), possibly because of the increased availability of essential metals like iron, zinc, and copper . The capacity of the pulp mill wastewater to support algal growth was nearly as good as a rich nutrient medium for algae . The combination of poorly degradable EDTA and the increasing availability of metals might further enhance eutrophication in the recipient areas of pulp mills.

Anal Bioanal Chem, 2002 May, 373(1-2), 119 - 22 Epub 2002 Apr 11.
A flow system with in-line blank correction applied to the spectrophotometric determination of total iron and chromium (VI) in wastewaters; Morais IP et al.; A flow system using the sample as the carrier with a propulsion device located after the detector is presented . This approach allows the correction of the intrinsic color of the sample, as it provides baseline adjustment for each sample . A confluence situated just after the selection valve allows the sample composition to be adjusted for the colorimetric measurement . The developed methodology was applied to the colorimetric determination of total Fe and Cr (VI) in wastewaters at 0.1-6.0 mg L-1 and 0.03-1.0 mg L-1, respectively . RSDs lower than 3% and a sampling rate of approximately 40 h-1 were obtained.

Environ Monit Assess, 2002 May, 75(3), 241 - 52
Occurrence of Cryptosporidium oocysts in sewage effluents and correlation with microbial, chemical and physical water variables; Bonadonna L et al.; Contaminated water are recognized as a potential source of Cryptosporidium oocysts . In Italy studies on the environmental spread of the parasite are still scarce even if a high frequency of serological responses could suggest high rates of endemic Cryptosporidium infections . In this investigation the occurrence of the parasite in water samples from a municipal wastewater treatment plant was monitored with the aim to evaluate possible correlation between oocysts and bacterial indicators, pathogens and physico-chemical parameters using a multivariate analysis . Data collected showed high numbers of oocysts, with a high percentage of positive samples and a significant correlation with pH, redox potential and total organic carbon . No correlation was found between Cryptosporidium concentration and that of the other microrganisms . The results, through a probing statistical analysis, show that none of the selected microrganisms was a reliable predictor of the presence of the parasite.

Bioresour Technol, 2002 Apr, 82(2), 123 - 9
Anaerobic digestion of alcohol sulfate (anionic surfactant) rich wastewater--batch experiments . Part II: influence of the hydrophobic chain length; Feitkenhauer H et al.; High-strength wastewater of some industries contains high concentrations of surfactants and readily biodegradable compounds like starch and other carbohydrates . Wastewater of this type is found in the textile wet-processing industry (e.g., cotton desizing) . The anaerobic degradation process in such wastewater is inhibited due to the high surfactant content . Alcohol sulfate (AS) of increasing hydrophobic chain length (C8 to C18, surfactant) and soluble starch (size) were used as model compounds in a series of batch experiments with high loadings of the biomass (65 g AS/kg cell dry weight; 910 g starch/kg cell dry weight) . The strongest inhibition of the hydrolysis, acidogenesis and acetogenesis was found in reactors containing medium chain ASs like dodecyl sulfate . Starch hydrolyzation rates decreased by nearly 90% in the presence of dodecyl sulfate . Decyl sulfate caused the strongest inhibition of the methanogenesis and a decrease of the methane evolution by 75% within 87 days experimental time . It was found that short as well as long chain ASs caused only minor inhibition phenomena . The presented data can be used as a basis for the selection of suitable surfactants that do not (or not seriously) inhibit the anaerobic digestion of industrial effluents.

Chemosphere, 2002 Mar, 46(9-10), 1485 - 9
Triclosan, a commonly used bactericide found in human milk and in the aquatic environment in Sweden; Adolfsson-Erici M et al.; High levels of the commonly used, effective bactericide Triclosan was found in three out of five randomly selected human milk samples . It was also found in the bile of fish exposed to municipal wastewater and in wild living fish from the receiving waters of the three wastewater treatment plants.

Environ Technol, 2002 Mar, 23(3), 319 - 29
Effectiveness of selected chemicals for controlling emission of malodorous sulfur gases in sewage sludge; Devai I et al.; The effectiveness of various oxidants or redox buffers (ferric chloride, sodium hypochlorite, potassium permanganate, hydrogen peroxide and potassium nitrate) for controlling or reducing emission of reduced sulfur gases (hydrogen sulfide, carbonyl sulfide, methanethiol, dimethyl sulfide and carbon disulfide) produced from sewage sludge collected from a wastewater treatment plant was studied under laboratory conditions . Sludge was treated with 0, 30, 300 and 1000 ppm of each chemical and changes in emission of the various reduced sulfur gases were monitored over a period of 24 hours . Potassium permanganate and hydrogen peroxide were shown to be the best chemicals for reducing hydrogen sulfide (the dominant reduced sulfur gas measured) emission . Sodium hypochlorite was also effective in reducing hydrogen sulfide emission followed by the ferric chloride addition . Since considerably smaller quantities of other reduced sulfur gases were evolved, the influence of the various chemical additions were not as significant as the reduction observed for hydrogen sulfide emission . Potassium permanganate and hydrogen peroxide were effective in reducing methanethiol and dimethyl sulfide emission . To a lesser degree sodium hypochlorite and ferric chloride also reduced emission of these two reduced sulfur gases . Potassium nitrate had no effect on reducing hydrogen sulfide or any of the reduced sulfur gases over the 24 hour experimental period . Each of the chemicals used in the study had a little or no effect in reducing carbonyl sulfide and carbon disulfide emission from the sludge material.

Environ Technol, 2002 Mar, 23(3), 273 - 86
Sensitivity analysis of stabilization pond system design parameters; Economopoulou MA et al.; Two stabilization pond systems are examined . A sensitivity analysis is undertaken, aimed at investigating the influence of the pond depths on stabilization pond surface area and pond volume for the specific combination of temperature, wastewater characteristics and effluent requirements . The dependencies are presented in a functional form, allowing for the graphical solution of the unit pond volume, area, and hydraulic residence time as a function of the respective pond depths . Based on these graphs, designers can determine the most appropriate depth value for each type of pond that minimizes the required area or volume, or balances excavation versus land acquisition and floor lining costs, taking under consideration the topographic and other local characteristics of the site area.

Environ Sci Technol, 2002 Apr 1, 36(7), 1377 - 82
Fluorescence excitation-emission matrix characterization of river waters impacted by a tissue mill effluent; Baker A; Fluorescence excitation-emission matrix (EEM) spectrophotometry was applied to five neighboring rivers, including one that is impacted by wastewater from a large tissue mill, to determine if fluorescence spectrophotometry could be used to differentiate between the river waters . River water samples from both the tissue mill effluent and the impacted river, the Park Burn, exhibited significantly higher fluorescence intensity than the other sites . This fluorescence was dominated by tryptophan fluorescence and a fluorescence center possibly due to the presence of fluorescent whitening agents . In contrast, the three other rivers exhibited lower fluorescence intensities typical of river systems with tryptophan (sewage), humic-like (peat derived color), and fulvic-like (natural organic matter) sources . It is suggested that fluorescence EEM spectrophotometry has the potential to provide a useful tool for pollution detection, monitoring, and control of paper industry impacts on river systems.

Water Res, 2002 Mar, 36(6), 1527 - 38
Characterisation of novel modified active carbons and marine algal biomass for the selective adsorption of lead; Malik DJ et al.; This paper discusses the sorption performance of novel materials for the removal of lead(II) and copper(II) from near-neutral aqueous solutions . Active carbons with surface heteroatoms of oxygen and phosphorus have been prepared . The surface functional groups display weakly acidic ion exchange characteristics . The optimum solution pH for maximum metal sorption is related to the pK values of the surface functional groups . In oxygenated active carbons, pK values are not distinct but can be obtained by describing proton binding to the heterogeneous adsorbent surface as a continuous proton affinity distribution . Information derived from zeta-potential measurements combined with knowledge of the pK distribution function and concentration of surface functional groups has been used to explain the selectivity of oxidised active carbons towards lead(lI) in the presence of copper(II) from multi-metal bearing solutions . Marine algal-based biosorbents have been challenged with lead(II) and copper(II)-bearing wastewater . The weakly acidic carboxyl groups of structural polysaccharides present within the algal matrix display high sorption capacity for both metals . The negative surface charge of algal particles results in electrostatic interactions as well as coordination between metal species and the adsorbent surface . Proton affinity for the algal surface lowers the negative surface potential at pH values around 2 . The surface functional groups in algae unlike those in oxidised active carbons may be represented by discrete acid-dissociation constant values . The influence of conformational differences in uronic-acid segments upon metal ion selectivity is discussed.

Water Res, 2002 Mar, 36(6), 1609 - 19
Removal of mercury(II) from aqueous solutions and chlor-alkali industry wastewater using 2-mercaptobenzimidazole-clay; Manohar DM et al.; The 2-mercaptobenzimidazole loaded natural clay was prepared for the removal of Hg(II) from aqueous media . Adsorption of the metal ions from aqueous solution as a function of solution concentration, agitation time, pH, temperature, ionic strength, particle size of the adsorbent and adsorbent dose was studied . The adsorption process follows a pseudo-second-order kinetics . The rate constants as a function of initial concentration and temperature were given . The adsorption of Hg(II) increased with increasing pH and reached a plateau value in the pH range 4.0-8.0 . The removal of Hg(II) was found to be >99% at an initial concentration of 50 mg/l . Mercury(II) uptake was found to increase with ionic strength and temperature . Further, the adsorption of Hg(II) increased with increasing adsorbent dose and decrease with adsorbent particle size . Sorption data analysis was carried out using Langmuir and modified Langmuir isotherms for the uptake of metal ion in an initial concentration range of 50-1,000 mg/l . The significance of the two linear relationships obtained by plotting the data according to the conventional Langmuir equation is discussed in terms of the binding energies of the two population sites involved which have a widely differing affinity for Hg(II) ions . Thermodynamic parameters such as changes of free energy, enthalpy, and entropy were calculated to predict the nature of adsorption . It was found that the values of isosteric heat of adsorption were varied with surface loading . The chlor-alkali industry wastewater samples were treated by MBI-clay to demonstrate its efficiency in removing Hg(II) from wastewater.

Water Res, 2002 Mar, 36(6), 1585 - 95
The influence of contact zone configuration on the flow structure in a dissolved air flotation pilot plant; Lundh M et al.; The dissolved air flotation process is used in water and wastewater treatment . Among many parameters the fluid dynamics determine the capacity of the process . The contact zone is assumed to be important for the removal function, as it is believed to be the location for the aggregation of bubbles and flocs . This paper presents an experimental study on the flow structure in a contact zone of a DAF pilot tank and the influence of contact zone configuration . The flow structure in the contact zone was examined for different horizontal lengths of the zone and for different heights and inclinations of the shaft wall . The hydraulic surface loading was 11 m/h over the total tank surface area and the recycle rate was constant at 10% of the main flow . The examined hydraulic surface loading over the contact zone ranged from 40 to 98 m/h . Water velocities in the longitudinal, central section of the tank were measured with an acoustical Doppler velocimeter in a grid net for the different contact zone configurations, giving an insight into the flow structure . The result showed that the flow structure in the contact zone was characterised by a turbulent lower region and a plug-flow higher region . The hydraulic surface loading, a function of the length of the contact zone, seemingly determined the extension of the turbulent region . A higher hydraulic surface loading decreased the turbulent region while the lower loading increased it . A hydraulic surface loading of 65 m/h was suggested for design . It was not possible to determine the turbulent intensity quantitatively due to the measurement method . The height and inclination of the shaft wall did not seem to have a significant influence on the turbulent region . However, an increased height of the contact zone enhanced the higher, plug flow region and a recommended height of 0.81 m or higher for the recommended hydraulic surface loading was suggested when both mixing and plug-flow are desired . The separation zone was characterised by a stratified flow structure, mainly influenced by the cross-flow velocity that is a function of the distance between the shaft wall top and the water surface . A cross-flow velocity of 37m/h or higher resulted in a clearly defined stratification, believed to be crucial for an efficient separation of flocs . Finally, the extension of the lower, denser plug-flow region in the separation zone increased when the shaft wall height increased.

Chemosphere, 2002 Apr, 47(3), 241 - 8
Aniline degradation by Electro-Fenton and peroxi-coagulation processes using a flow reactor for wastewater treatment; Brillas E et al.; The degradation of 10-30 l of a 1000 ppm aniline solution in 0.050 M Na2SO4 + H2SO4 at pH 3.0 and 40 degrees C by Electro-Fenton and peroxi-coagulation processes at constant current until 20 A has been studied using a pilot flow reactor in recirculation mode with a filter-press cell containing an anode and an oxygen diffusion cathode, both of 100 cm2 area . H2O2 is produced by the two-electron reduction of O2 at the cathode, being accumulated with a current efficiency between 60% and 80% at the first stages of electrolyses performed with a Ti/Pt anode . In the presence of 1 mM Fe2+, less H2O2 is accumulated, but it is not detected using an Fe anode . The Electro-Fenton process with 1 mM Fe2+ and a Ti/Pt or DSA anode yields an insoluble violet polymer, while the soluble total organic carbon (TOC) is gradually removed, reaching 61% degradation after 2 h at 20 A . In this treatment, pollutants are preferentially oxidized by hydroxyl radicals formed in solution from reaction of Fe2+ with H2O2 . The peroxi-coagulation process with an Fe anode has higher degradation power, allowing to remove more than 95% of pollutants at 20 A, since some intermediates coagulate with the Fe(OH)3 precipitate formed . Both advanced electrochemical oxidation processes (AEOPs) show moderate energy costs, which increase with increasing electrolysis time and applied current.

Water Environ Res, 2002 Jan-Feb, 74(1), 57 - 67
The role of poly-hydroxy-alkanoate form in determining the response of enhanced biological phosphorus removal biomass to volatile fatty acids; Liu YH et al.; Anaerobic-aerobic batch experiments indicated that poly-hydroxy-alkanoate (PHA) form was important in determining the net phosphorus removal resulting from different volatile fatty acids (VFAs) . Poly-3-hydroxy-butyrate (3HB) content was found to correlate fairly well with higher observed aerobic phosphorus uptake per unit PHA carbon degraded . Poly-3-hydroxy-valerate (3HV) correlated with lower aerobic phosphorus uptakes per unit PHA carbon degraded . These experiments, conducted with synthetic wastewater, imply that VFA speciation might have a significant effect on aerobic phosphorus uptakes and net phosphorus removal . In addition, the model parameter fP.UPT (Barker and Dold, 1997) could vary with the proportion of acetic to propionic acid received (i.e., the acetic/propionic acid ratio may be an important parameter for these systems) . Carbohydrate data implied that the lower aerobic phosphorus uptake resulting from 3HV might have been caused by a greater fraction of PHA carbon shunting to carbohydrate biosynthesis during aerobiosis.

Water Environ Res, 2002 Jan-Feb, 74(1), 51 - 6
The effect of chlorination on organocyanide compounds; Yi Y et al.; Results are presented that explore the possibility of organocyanide compounds in wastewater contributing to elevated cyanide levels in the chlorinated effluents of publicly owned treatment works . Four model compounds, acetonitrile, amygdalin, cyanocobalamin, and 2-acetoxy-3-butenenitrile, were selected and tested with varying chlorine dosages for release of cyanide by total and diffusible cyanide procedures . The coenzyme form of vitamin B12, which does not contain cyanide, was also tested . It was found that acetonitrile and amygdalin do not yield cyanide with or without chlorination, cyanocobalamin had increased release with increased chlorine dosages, and 2-acetoxy-3-butenenitrile had generally decreased release of cyanide with increased chlorine dosages . Both cyanocobalamin and coenzyme vitamin B12 gave evidence of the formation of the cobalt-cyanide complex after chlorination, even though the molecular structure of the coenzyme vitamin B12 contains no cyanide.

J Environ Manage, 2002 Feb, 64(2), 171 - 7
Land application of phosphorus-laden sludge: a feasibility analysis; Viraraghavan T et al.; An investigation was conducted to examine aerobic digestion of the phosphorus-laden sludge produced at the Regina Wastewater Treatment Plant and feasibility of land use of this sludge combined with the dewatered anaerobically digested primary sludge from this plant . Experimental studies showed that aerobic digestion can be employed for the stabilization of the chemical sludge . Results of the feasibility analysis showed that mixing the two digested sludges met the heavy metal criteria set by various guidelines for agricultural use, presented the advantage of an increased concentration of nutrients and a decreased concentration of heavy metals, and a longer useful life of the agricultural site compared to using dewatered anaerobically digested primary sludge alone . Land application of the mixed digested sludges would be a more appropriate method of sludge disposal compared to the present practice of landfilling the dewatered sludge and lagooning the chemical sludge.

Arch Environ Contam Toxicol, 2002 May, 42(4), 431 - 6
Selenium in a Wyoming grassland community receiving wastewater from an in situ uranium mine; Ramirez P Jr et al.; Water, soil, vegetation, grasshoppers, bird eggs, and bird livers collected at a 23.5-ha (58 acres) grassland irrigated with wastewater from an in situ uranium mine (study area) and a reference site in 1998 were analyzed for selenium and other trace elements . Selenium concentrations in the uranium mine wastewater applied onto the grassland ranged from 340 to 450 microg/L . Selenium in the upper 15 cm (6 in) of soil from the irrigated grassland at the mine ranged from 2.6 to 4.2 microg/g dry weight (DW) . Mean selenium concentrations in soil and water were 5 and 15 times higher at the study area than at the reference site . Selenium concentrations in grasses and grasshoppers ranged from 6.8 to 24 microg/g and 11 to 20 microg/g DW, respectively . Selenium in red-winged blackbird eggs and livers collected from the study area ranged from 13.2 to 22 microg/g and 33 to 53 microg/g DW, respectively, and concentrations were well in excess of toxic thresholds . Mean selenium concentrations in grasses, grasshoppers, and bird eggs and livers were 5.8 to 30 times higher at the study area than at the reference site . Elevated selenium concentrations in water, soil, grasshoppers, and red-winged blackbird eggs and livers collected from the study area demonstrate that selenium is being mobilized and is bioaccumulating in the food chain.

Environ Sci Technol, 2002 Apr 15, 36(8), 1671 - 5
Discrimination of aerial deposition sources of polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran downwind from a pulp mill near Ketchikan, Alaska; Peek DC et al.; Drinking water is supplied by individual roof-catchment systems for homes and businesses near a dissolving sulfite pulp mill (now closed) located just north of Ketchikan in southeast Alaska . This study was conducted to determine if polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) found in the sediments of the roof-catchment cisterns resulted from historical deposition of stack emissions from the pulp mill's multi-fuel power boilers . Fly ash from the power boilers had maximum total PCDD/F concentrations of 3.08 x 10(5)-3.10 x 10(6) ng/kg, which resulted from combustion of bleach plant wastewater sludge and saltwater-soaked wood waste . Cistern sediments had maximum total PCDD/F concentrations of 7.71 x 10(4) ng/kg . Potential sources of PCDDs/Fs in the cistern sediments were considered to be automobile exhaust, heating oil combustion, and private trash burning as well as pulp mill boiler emissions . Discriminant analysis was used to analyze differences between profiles of tetra through octa homologue classes of PCDDs/ Fs (defined as proportional contributions to total concentration) from different source terms . Homologue profiles of potential sources from Ketchikan included in this analysis were fly ash collected from the mill's power boilers and soils collected from background areas (areas with similar PCDD/F sources as the residences {e.g., auto exhaust and burn barrels} near the mill but beyond the zone of aerial deposition of emissions from the mill) . Profiles for emissions from automobile exhaust, fertilizers, oil heating, residential trash burning, and residential wood heating were also included in the source "training" data set (for the discriminant analysis) using data from published literature . The classification rules developed from the discriminant analysis were applied to the following test media sampled at Ketchikan: roof-catchment cistern sediments and soils collected from areas in the vicinity of the mill's power boilers (i.e., nearby residential or commercial {developed} areas, on the mill property, and nearby forestlands) . The homologue profiles of cistern sediment and nearby developed area soil samples were similar to background soils, whereas the profiles for the forestland soil samples (influenced by emissions from the mill but not other anthropogenic sources) closely matched the fly ash pattern . The homologue profiles of the emission sources from published data were more similar to one another than either background soils or fly ash . Soil samples from the mill property were classified as members of all source groups . On the basis of these analyses, the composition of PCDDs/Fs detected in the cistern sediments is typical of Ketchikan background conditions and not reflective of mill emissions.

Ann Chim, 2002 Jan-Feb, 92(1-2), 53 - 60
Optimization of cyanide elimination from an industrial wastewater on a pilot plant scale; Movassaghi K et al.; A pilot plant scale reactor was modelled and assembled to experimentally study the cyanide elimination process . The process was performed by using Ca(OCl)2, Cl2 and H2O2 . The elimination was optimized at 25 degrees C for time of reaction, pH and amount of oxidant in a pilot plant scale reactor with synthetic solutions . Moreover some tests were carried out by using a real effluent deriving from a gold production industry.

Ann Chim, 2002 Jan-Feb, 92(1-2), 127 - 34
Dapsone a new diazotizing reagent for the spectrophotometric determination of nitrite in waste and natural water samples; Nagaraja P et al.; A new diazotizing reagent for the spectrophotometric determination of nitrite is described . The method is based on diazotization-coupling reaction between dapsone and phloroglucinol in hydrochloric acid medium . The reactions were conducted at room temperature, the molor absorptivity at 425 nm is 4.28 x 10(4) l mol-1cm-1 and was stable for 50 h . Beer's law was obeyed in the nitrite range of 0.008-1.0 microgram ml-1 . Tolerance limits were tested for 33 species . The method has been found to be applicable for the determination of nitrite in natural and wastewater.

Ying Yong Sheng Tai Xue Bao, 2002 Feb, 13(2), 229 - 32
{Nonpoint pollution control for rural areas of China with ecological engineering technologies}; Yin C et al.; Nonpoint pollution from rural areas is the results of the ecosystem degradation, and ecological engineering technologies are good ways for the restoration of watershed and enhancing material cycling . There are two types of treatment strategies: to control the polluted runoff and to reduce the pollutants from the sources . Six control technologies are introduced and they are multipond systems, grassed filter trips, wetland systems, eco-agriculture, slope ecological engineering, ecological treatment of wastewater and solid waste . These technologies need to be combined systematically in order to form a watershed ecological engineering . In the control program, it is important to use countermeasure suitable to the local conditions . In addition, the input of sufficient investment, management and education is necessary.

Ying Yong Sheng Tai Xue Bao, 2002 Feb, 13(2), 217 - 20
{Evaluating ground water vulnerability in West Lake Watershed by using DRASTIC model}; Dong L et al.; Supported by Blackland GRASS Geographic Information System (GIS), the basic and special environmental databases of West Lake Watershed were established . The vulnerability map of ground water pollution was calculated and drawn by integrating GIS and DRASTIC model . Comparing to the present situation of land use, critical area of ground water pollution had been determined . The residential area accounted for 14.7% of the high susceptible area, and wastewater in the residential area should be piped and treated first.

Ying Yong Sheng Tai Xue Bao, 2002 Feb, 13(2), 163 - 6
{Effects of land utilization of sewage sludge on crops and soils}; Wang X et al.; Effects of land utilization of sewage sludge on crops and soil environment were studied using sewage sludge from the Northern Shenyang Plant of Wastewater Treatment . The results showed that contents of nitrogen, phosphorus and organic matter in the soil were increased after the utilization of sewage sludge, thus being advantageous to growth and development of crops . The biomass of rice after having applied 22.5 and 45 t.hm-2 of sewage sludge was increased by 11.48%-11.83% compared with the control . There was no evident harmful effect of heavy methals from sewage sludge on quality of soil environment, agricultural products and underground water when the application of sewage sludge was controlled within the range of 45 t.hm-2.

J Hazard Mater, 2002 May 27, 92(2), 161 - 83
Removal of mercury(II) from aqueous solutions and chlor-alkali industry effluent by steam activated and sulphurised activated carbons prepared from bagasse pith: kinetics and equilibrium studies; Anoop Krishnan K et al.; The adsorption of mercury from aqueous solutions and chlor-alkali industry effluent on steam activated and sulphurised steam activated carbons prepared from bagasse pith have been studied comparatively . The uptake of mercury(II) (Hg(II)) was maximum by steam activated carbon in presence of SO(2) and H(2)S (SA-SO(2)-H(2)S-C) followed by steam activated carbon in presence of SO(2) (SA-SO(2)-C), steam activated carbon in presence of H(2)S (SA-H(2)S-C) and steam activated carbon (SA-C) at the same concentration, pH and temperature of the solution . Adsorption experiments demonstrate that the adsorption process corresponds to the pseudo-second-order kinetic model and equilibrium results correspond to the Langmuir adsorption isotherm . Kinetic parameters as a function of initial concentration, for all adsorbents were calculated . Batch studies indicated that the optimum pH range for the adsorption of Hg(II) on sulphurised carbons was between 4 and 9 and for sulphur free carbon was between 6 and 9 at 30 degrees C . The adsorptive behaviour of the activated carbons is explained on the basis of their chemical nature and porous texture . Decrease in ionic strength and increase in temperature of the solution has been found to improve the uptake of Hg(II) . Synthetic and chlor-alkali industrial wastewaters were also treated by sulphurised activated carbons to demonstrate their efficiencies in removing Hg(II) from wastewaters . Some feasibility experiments have been carried out with a view to recover the adsorbed Hg(II) and regenerate the spent activated carbons using 0.2M HCl solution . The data obtained point towards viable adsorbents, which are both effective as well as economically attractive for Hg(II) removal from wastewaters.

Biotechnol Bioeng, 2002 Jun 20, 78(6), 670 - 82
Hybrid neural network modeling of a full-scale industrial wastewater treatment process; Lee DS et al.; In recent years, hybrid neural network approaches, which combine mechanistic and neural network models, have received considerable attention . These approaches are potentially very efficient for obtaining more accurate predictions of process dynamics by combining mechanistic and neural network models in such a way that the neural network model properly accounts for unknown and nonlinear parts of the mechanistic model . In this work, a full-scale coke-plant wastewater treatment process was chosen as a model system . Initially, a process data analysis was performed on the actual operational data by using principal component analysis . Next, a simplified mechanistic model and a neural network model were developed based on the specific process knowledge and the operational data of the coke-plant wastewater treatment process, respectively . Finally, the neural network was incorporated into the mechanistic model in both parallel and serial configurations . Simulation results showed that the parallel hybrid modeling approach achieved much more accurate predictions with good extrapolation properties as compared with the other modeling approaches even in the case of process upset caused by, for example, shock loading of toxic compounds . These results indicate that the parallel hybrid neural modeling approach is a useful tool for accurate and cost-effective modeling of biochemical processes, in the absence of other reasonably accurate process models .

Bioresour Technol, 2002 May, 82(3), 215 - 7
Effect of synthetic and natural culture media on laccase production by white rot fungi; Kahraman SS et al.; Laccase is among the major enzymes of white rot fungi involved in lignocellulose degradation . The present paper reports its production by two white rot fungi (Coriolus versicolor, Funalia trogii) under different nutritional conditions . Various synthetic culture media and natural culture medium (molasses wastewater) were tested . Enzyme production in various synthetic culture media, molasses wastewater (vinasse) culture medium and in the absence or presence of cotton stalk supplements showed that vinasse culture medium was a better laccase-inducer medium than the synthetic culture medium . Addition of cotton stalk to various media enhanced the enzyme production . The highest laccase activity was obtained in vinasse culture medium with cotton stalk.

Anal Sci, 2001 Mar, 17(3), 443 - 7
Univariate and simplex optimization for the flow-injection spectrophotometric determination of copper using nitroso-R salt as a complexing agent; Purachat B et al.; A simple colorimetric flow-injection system for the determination of Cu(II) based on a complexation reaction with nitroso-R salt is described . The chemical and FIA variables were established using the univariate and simplex methods . A small volume of Cu(II) was mixed with merged streams of nitroso-R salt and acetate buffer solutions . The absorbance of the complex was continuously monitored at 492 nm . The calibration curve over the concentration range 1.0-7.0 microg ml(-1) was obtained . The relative standard deviation for determining 4.0 microg ml(-1) Cu(II) was 0.47% (n = 11) . The detection limit (3sigma) was 0.68 microg ml(-1) and the sample throughput was 150 h(-1) . The validity of the method has been satisfactorily examined for the determination of Cu(II) in wastewater and copper ore samples . The accuracy was found to be high, because the student t-values were calculated to be less than the theoretical values when the results were compared with those obtained by FAAS.

J Environ Sci Health B, 2002 Mar, 37(2), 141 - 50
Determination of PAHs in wastewater irrigated agricultural soil using accelerated solvent extraction; Tao S et al.; A procedure was developed for determination of 16 polycyclic aromatic hydrocarbons (PAHs) in heavily contaminated paddy soil from wastewater irrigated farmland near Tianjin . The sample was distilled with accelerated solvent extraction (ASE), purified by a silica gel column, and measured with GC/MS . The optimal conditions for the distillation were at 140 degrees C (1500 psi) with a 1:1 mixture of dichloromethane and acetone for 5 min . Application of cyclohexane for extract transfer improved the recovery when the ASE extraction was followed by a silica gel cleanup procedure . Recoveries from the method for 16 PAHs ranged from 57-140% with the coefficients of variation of the results ranging from 0.35% to 5.75% . The total 16 PAHs in a composite sample collected from a wastewater irrigated paddy field near Tianjin was 3.90 mg/kg.

J Environ Sci Health B, 2002 Jan, 37(1), 65 - 74
Photocatalytic oxidation of pesticide rinsate; Kuo WS; Pesticide rinsate has been considered as one of the major threats for the environment . In this study, photocatalysts such as TiO2 and O3 were used to promote the efficiency of direct UV photolysis to prevent such wastewater pollution . Carbofuran (a carbamate pesticide) and mevinphos (an organophosphate pesticide) with a concentration of 100 mg/L were selected as the test pesticide rinsates . Parent pesticide compound, COD, and microtoxicity analysis were employed to investigate the effect of photocatalyst on the degradation efficiency of pesticide in rinsate . It was found that the photocatalytic oxidation process (UV/O3, UV/TiO2) showed much higher COD removal and microtoxicity reduction efficiency for pesticide rinsate than did direct UV photolysis under the imposed conditions, suggesting that photocatalytic oxidation processes such as UV/O3 and UV/TiO2 could be a better alternative to treat pesticide rinsate . In addition, it was noted that increasing the initial pH of mevinphos rinsate to a basic level was required to reach higher COD removal efficiency and positive microtoxicity reduction efficiency while it was not necessary for the treatment of carbofuran rinsate.

Water Sci Technol, 2002, 45(7), 75 - 82
Using typical daily flow patterns and dry-weather scenarios for screening flow rate measurements in sewers; Piatyszek E et al.; Monitoring systems for measuring rainfall, as well as flow rates and pollutant quantities conveyed by sewers and/or discharged by stormwater overflow devices, have become a common feature in many municipal sewer services, in part spurred by recent regulatory requirements . However, the state of measurement conditions in sewer facilities does not always ensure reliable results . For this reason, it is essential that measured values be carefully screened prior to their use, since many sources of disruption capable of skewing data can be encountered . The present article describes a method for validating dry-weather data a posteriori . This method relies upon flow rate forecasts, a combination of standard daily wastewater flow profiles and an estimation of infiltration flows . Measurement results are then compared with this forecast and an appropriate series of statistical tests are run to detect all major data anomalies . A number of diagnostic rules are then applied in order to derive an initial interpretation of these anomalies and, in particular, to identify the influence of rainfall events.

Water Sci Technol, 2002, 45(6), 77 - 87
Experience with guidelines for wastewater characterisation in The Netherlands; Roeleveld PJ et al.; In this paper experiences and results are presented with guidelines for wastewater characterisation that are standardised in The Netherlands for modelling purposes with ASM . The wastewater characterisation is based on a physical-chemical method to characterise the soluble and particulate fractions, combined with a BOD-analysis for characterising the biodegradable fraction of the influent COD . By following the guidelines, a sufficiently detailed and practical characterisation is obtained, and the results can be used for simulation studies on treatment plants for process optimisation, trouble-shooting and design assistance . At present, five years of experience is gained with the guidelines and they were used for the simulation of circa 100 treatment plants . The guidelines are evaluated as simple and easy to implement in routine analysis programs.

Water Sci Technol, 2002, 45(6), 25 - 40
Processes and modeling of hydrolysis of particulate organic matter in aerobic wastewater treatment--a review; Morgenroth E et al.; Carbon cycling and the availability of organic carbon for nutrient removal processes are in most wastewater treatment systems restricted by the rate of hydrolysis of slowly biodegradable (particulate) organic matter . To date, the mechanisms of hydrolysis are not well understood for complex substrates and mixed populations . Most mathematical models use a simple one-step process to describe hydrolysis . In this article, mechanisms of hydrolysis and mathematical models to describe these processes in wastewater treatment processes are reviewed . Experimental techniques to determine mechanisms of hydrolysis and rate constants are discussed.

Water Sci Technol, 2002, 45(6), 229 - 33
The use of mathematical models in teaching wastewater treatment engineering; Morgenroth E et al.; Mathematical modeling of wastewater treatment processes has become increasingly popular in recent years . To prepare students for their future careers, environmental engineering education should provide students with sufficient background and experiences to understand and apply mathematical models efficiently and responsibly . Approaches for introducing mathematical modeling into courses on wastewater treatment engineering are discussed depending on the learning objectives, level of the course and the time available.

Water Sci Technol, 2002, 45(6), 209 - 18
Experiences with computer simulation at two large wastewater treatment plants in northern Poland; Makinia J et al.; Mathematical modelling and computer simulation have became a useful tool in evaluating the operation of wastewater treatment plants (WWTPs) in terms of nutrient removal capability . In this study, steady-state simulation results for two large biological nutrient removal WWTPs are presented . The plants are located in two neighbouring cities Gdansk and Gdynia in northern Poland . Simulations were performed using a pre-compiled model and layouts (MUCT and Johannesburg processes) implemented in the GPS-X simulation package . The monthly average values of conventional parameters, such as COD, Total Suspended Solids, total N, N-NH4+, P-PO4- were used as input data . The measured effluent concentrations of COD, N-NH4+, N-NO3- and P-PO4- as well as reactor MLSS were compared with model predictions . During calibration, performed from the process engineering perspective, default values of only five model parameters were changed . The opportunities for further applications of such models in municipal WWTPs are discussed.

Huan Jing Ke Xue, 2002 Jan 30, 23(1), 58 - 61
{Municipal wastewater treatment using the up-biological aerated filter}; Guo T et al.; Up Biological Aerated Filter(UBAF) was used for the advanced wastewater treatment . The average removal rate of CODCr, BOD5, SS, NH4(+)-N and turbidity was 22.2%, 55%, 84.4%, 49%, 75.6% respectively . The hydraulic and COD load of influent influenced directly the quality of effluent.

Huan Jing Ke Xue, 2002 Jan 30, 23(1), 50 - 3
{Stability of the two-stage SBR system treating dyeing wastewater during a long-term operation}; Fu L et al.; The stability of the two-stage SBR system treating dyeing wastewater was investigated during a 120-cycle continuous operation . The system was fed with influent of low dye concentration and high dye concentration . The results showed that the two-stage SBR system was adaptable to the change of influent quality and operation conditions during the long-term operation . It could efficiently remove the pollutants in the wastewater, the average dyestuff and COD removal rates were 81% to 92.5% and 89.4% to 93.1% respectively for low and high influent loading, and could produce continuous good quality effluent . In the two-stage SBR system, the anaerobic sludge had the characteristics of high activity and strong pollutant degradation ability, and the aerobic sludge existed in the form of aggregate structure, which helped stabilize the effluent quality.

Ying Yong Sheng Tai Xue Bao, 2002 Jan, 13(1), 113 - 7
{Treatment effect of constructed wetlands on organic matter in wastewater from pig farm}; Liao X et al.; Using plant species Vetiveria zizanioides and Cyperus alternifolius respectively, two constructed wetlands (CWS) with size of 1.0 m x 0.5 m x 0.8 m were established . The purifying function and its change pattern with season, influent concentration and hydraulic retention time (HRT) of the constructed wetlands on the organic matters in wastewater from a pig farm were studied throughout four seasons in the year . The results showed that the two CWS had very stable effects on the removal of COD and BOD, while the organic matters in wastewater changed . The removal rate of COD and BOD was 70% and 80% respectively by HRT 1-2 d in spring . The removal rate of COD reached 90% with the influent of COD 1000-1400 mg.L-1 in summer . The removal rate of COD and BOD was 50-60% and 50% respectively by HRT 1-2 d in autumn . The removal rate of COD reached 70% with the influent of COD 1003 mg.L-1 in winter . There was no significant difference between two CWS in the removal of COD, BOD and SS . The rule of contaminants decreased with the HRT in CWS followed exponential function: Yt = Y0.exp(-kt) . The relation between the concentration of contaminants in influent (x) and outflow (y) at the same HRT followed linear relation: y = a + bx.

Waste Manag Res, 2001 Oct, 19(5), 450 - 5
Economic considerations of chromium recovery from tanning wastewater; Panswad T et al.; The chrome recovery from tanning wastewater was investigated in field conditions using a real-sized pilot plant . The tested wastewaters were from the tanning process both without and with tanning additives, whereas the precipitating chemicals of interest were magnesium oxide (MgO) and sodium carbonate (Na2CO3) . The precipitation with MgO followed by 1 hour sedimentation was the best solution . The optimal dosages were 2 and 4 times that of stoichiometric requirements for conditions without and with the additives, respectively . By redissolving the obtained sludge with 1:1 diluted sulfuric acid and maintaining the pH between 2.5 and 2.8, the chromium recovery were 97.6 and 88.6%, respectively . Another alternative of using Na2CO3 as the precipitant was not promising because of its high chemical cost and excessive sludge-settling period (15-20 hours) . The MgO precipitation scenario proved to be able to pay back economically within 3 years for the "without-additive" waste stream whereas that of "with-additive" wastewater was not worth the investment . This is because the "with-additive" discharge contains low chromium content whereas it requires high chemical doses.

Chemosphere, 2002 Mar, 46(8), 1173 - 81
Solar light induced and TiO2 assisted degradation of textile dye reactive blue 4; Neppolian B et al.; Aqueous solutions of reactive blue 4 textile dye are totally mineralised when irradiated with TiO2 photocatalyst . A solution containing 4 x 10(-4) M dye was completely degraded in 24 h irradiation time . The intensity of the solar light was measured using Lux meter . The results showed that the dye molecules were completely degraded to CO2, SO4(2-), NO3-, NH4+ and H2O under solar irradiation . The addition of hydrogen peroxide and potassium persulphate influenced the photodegradation efficiency . The rapidity of photodegradation of dye intermediates were observed in the presence of hydrogen peroxide than in its absence . The auxiliary chemicals such as sodium carbonate and sodium chloride substantially affected the photodegradation efficiency . High performance liquid chromatography and chemical oxygen demand were used to study the mineralisation and degradation of the dye respectively . It is concluded that solar light induced degradation of textile dye in wastewater is a viable technique for wastewater treatment.

Environ Technol, 2002 Feb, 23(2), 207 - 15
The effect of carbonate on the precipitation of calcium phosphate; Song Y et al.; In order to facilitate the recovery of phosphorus from wastewater, the effect of carbonate on the precipitation of calcium phosphate has been studied . The effect of carbonate concentrations up to 5.00 millimoles per liter on the precipitation of 20 milligrammes phosphorus per liter phosphate was studied . At pH 8.00 the precipitation rate of phosphate was greatly retarded by carbonate and the corresponding precipitation efficiency also decreased, but at pH values > or = 9.00 the effect of carbonate on the precipitation of phosphate was very small . This indicates that carbonate may decrease the precipitation rate and efficiency of calcium phosphate, but the solution pH value is still a key factor influencing the precipitation process . The effect of carbonate on the precipitation of phosphate was attributed to the formation of ion pairs between carbonate and calcium and the decrease of free calcium ions . This resulted in the decrease of the thermodynamic driving force for the precipitation of calcium phosphate, so the effect of carbonate on the precipitation of phosphate was in fact a competing one, although this competing effect was not so obvious at pH > or = 9.00 . Carbonate may be coprecipitated with phosphate from solution, especially at pH 9.00-11.00, and this will decrease the relative phosphorus content of the precipitate . The increases in solution pH value and initial Ca/P ratio are two approaches to overcome the influence of carbonate on the precipitation of phosphate, but the solution pH values should be lower than 10.00 and the initial Ca/P ratios should not exceed 5.00.

Environ Pollut, 2002, 118(2), 239 - 48
Nitrogen sources to watersheds and estuaries: role of land cover mosaics and losses within watersheds; Valiela I et al.; Across most of the World's coastal zone there has been a geographic transition from naturally vegetated to human-altered land covers, both agricultural and urban . This transition has increased the nitrogen loads to coastal watersheds, and from watersheds to receiving estuaries . We modeled the nitrogen entering the watershed of Waquoit Bay, Massachusetts, and found that as the transition took place, nitrogen loads to watersheds increased from 1938 to 1990 . The relative magnitude of the contribution by wastewater, fertilizers, and atmospheric deposition depends on the land cover mosaics of a watershed . Atmospheric deposition was the major input to the watershed surface during this period, but because of different rates of loss within the watershed . wastewater became the major source of nitrogen flowing from the watershed to the receiving estuaries . Atmospheric deposition prevails in watersheds dominated by natural vegetation such as forests, but wastewater may become a dominant source in watersheds where urbanization increases . Increased nitrogen loads resulting from conversion of natural to human-altered watershed surfaces create eutrophication of receiving waters, with attendant changes in water quality, and marked shifts in the flora and food webs of the affected estuaries . Management efforts for restoration of eutrophied estuaries require maintenance of forested land, and control of wastewater and fertilizer inputs, the major terms in most affected places subject to local management . Wastewater and fertilizer nitrogen derive from within the watershed, which means local measures may effectively be used to control eutrophication of receiving waters.

J Capillary Electrophor, 2002, 7(1-2), 15 - 8
Comparison of high-performance capillary electrophoresis and liquid chromatography with ultraviolet detection for the isomers of o-, m-, and p-diphenol; Zhang S et al.; The separation conditions and determination of isomers of o-, m-, and p-diphenol in wastewater by high-performance capillary electrophoresis (HPCE) and HPLC with ultraviolet detection at 280 nm have been studied systematically . The study showed that both methods gave comparable results in retention time, linear range, recovery, reproducibility, and the amount of diphenols in real samples.

Water Sci Technol, 2002, 45(4-5), 61 - 8
On-line titration of non-ionic surfactants in wastewater treatment plants using a specific electrode; Feitkenhauer H et al.; Textile finishing industry wastewater often contains high concentrations of surfactants . Non-ionic surfactants like alcohol ethoxylates are among the most used surfactants and are discharged from batch-processes in widely varying concentrations . The anaerobic biomass and especially methanogenic microorganisms have been shown to be inhibited by surfactants . To protect these microorganisms from irreversible inhibition a measurement of the surfactant concentration is useful for the process control, but most analytical methods are too complicated and expensive for an on-line process control . It was shown that the titration of non-ionic surfactants is possible in the presence of biomass and in wastewater from textile wet processes using the Metrohm NIO-electrode . Titration and sampling were successfully performed with standard equipment . The software used for the process control of a lab-scale anaerobic treatment plant was also used to evaluate the obtained titration curves . This allowed performing the titrations without using a more expensive titrator.

Water Sci Technol, 2002, 45(4-5), 503 - 10
Implementation of a wastewater treatment plant operation support tool based on on-line simulation; Jumar U et al.; The operators of modern wastewater treatment plants (WWTPs) are faced with increasing demands . Beyond the requirement to consistently meet discharge limits for pollutant loads, the cost efficiency of plant operation is becoming more and more important . This results in new challenges for automatic control and human control action . On-line simulation opens up interesting perspectives to provide comprehensive process information, serving as a base for optimised operation of WWTPs . This paper describes the development and application of a computer analysis and support tool for the large-scale municipal WWTP of the city of Magdeburg, Germany . It will show that by linking a simulation server to the Distributed Control System (DCS) relevant additional features for plant control arise . A good cost-benefit ratio of the system is achieved by using web techniques for implementing the software.

Water Sci Technol, 2002, 45(4-5), 495 - 502
Evaluation of a four year experience with a fully instrumented anaerobic digestion process; Steyer JP et al.; For several years, a 1 m3 fixed bed anaerobic digestion process has been operated for the treatment of distillery vinasses . This reactor has been fully instrumented with the following variables available on-line: pH, temperature, liquid and gas flow rates, gas composition (i.e., CH4, CO2 and H2), concentration of bicarbonate, chemical oxygen demand, total organic carbon, volatile fatty acids and partial and total alkalinity, these last four variables being measured twice by different techniques (i.e., using a TOC analyzer, a titrimetric sensor and an infrared spectrometer) . The purpose of this paper is to compare the respective benefits of advanced instrumentation for the monitoring of wastewater treatment processes in general, and for anaerobic digestion in particular . It will also provide some statistical analysis of the time required to operate a fully instrumented wastewater treatment process . It is indeed well admitted in the literature that instrumentation is usually the main limitation step for using closed-loop control . However, it is our opinion that, in the near future, this situation will change . This point is discussed based on our four years practical experience.

Water Sci Technol, 2002, 45(4-5), 485 - 94
Status and future trends of ICA in wastewater treatment--a European perspective; Jeppsson U et al.; The status of instrumentation, control and automation (ICA) within the European wastewater community is reviewed and some major incentives and bottlenecks are defined . Future trends of ICA are also discussed . The information is based on a COST 624 workshop and a non-exhaustive survey with regard to ICA carried out in 13 European countries during March 2001 . The level of instrumentation (type of sensors, usage frequency, etc.) and how these instruments are used for on-line control purposes are presented for each individual country (Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Netherlands, Romania, Slovenia, Spain, Sweden and Switzerland) . The most common types of applied real-time control in wastewater treatment plants are given . One conclusion of the paper is that sensors no longer represent the main bottleneck for on-line control, rather the lack of plant flexibility is more troublesome . Moreover, the current transitional phase of the wastewater industry in Europe represents a unique opportunity to apply ICA on a large scale . The driving forces are simply too strong to ignore.

Water Sci Technol, 2002, 45(4-5), 477 - 83
International online support to process optimisation and operation decisions; Onnerth TB et al.; The information level at all technical facilities has developed from almost nothing 30-40 years ago to advanced IT--Information Technology--systems based on both chemical and mechanical on-line sensors for process and equipment . Still the basic part of information is to get the right data at the right time for the decision to be made . Today a large amount of operational data is available at almost any European wastewater treatment plant, from laboratory and SCADA . The difficult part is to determine which data to keep, which to use in calculations and how and where to make data available . With the STARcontrol system it is possible to separate only process relevant data to use for on-line control and reporting at engineering level, to optimise operation . Furthermore, the use of IT makes it possible to communicate internationally, with full access to the whole amount of data on the single plant . In this way, expert supervision can be both very local in local language e.g . Polish and at the same time very professional with Danish experts advising on Danish processes in Poland or Sweden where some of the 12 STARcontrol systems are running.

Water Sci Technol, 2002, 45(4-5), 469 - 76
On-line instrument confirmation: how can we check that our instruments are working?
Lumley D.
As on-line instrumentation becomes increasingly important for operating modern wastewater treatment plants it is necessary to have diagnostic methods that can indicate sensor deviation at an early stage . Examples of on-line diagnosis methods used at the Rya WWTP (Goteborg, Sweden) are presented . These include on-line mass balance calculations and soft sensors, which make indirect parameter estimates . By comparing the estimates with the corresponding on-line sensors it is possible to make control decisions and to chose alternative strategies . These comparative methods are often useful for process monitoring and diagnosis as well . Some other soft sensor applications using exponential filters are also presented.

Water Sci Technol, 2002, 45(4-5), 461 - 7
Remote control system for the operation of 65 WWTPs; Teichgraber B et al.; The present report discusses the monitoring system for approximately 340 facilities for water management of the Emschergenossenschaft and Lippeverband . It is based on the operation control system of the wastewater treatment plants (currently 61) and the pumping stations of the Lippeverband, which has been created since 1985 . For the near future, the integration of the plants of the Emschergenossenschaft including storm-water tanks is scheduled . The current connection ratios of the WWTPs which are to be monitored vary between 500 and 1,940,000 Population Equivalents . The data recorded at each plant are transmitted to the allocated catchment area centre and then to the district centres . The encompassing monitoring centre serves the integrated control of all plants . The comprehensive remote control is managed through the presentation of relevant plant-type-specific system parameters . The investment costs of approximately 33,000 Euros/plant and annual costs of 9,400 Euros/plant stand against a considerable increase of the operation safety and the reduction of manpower.

Water Sci Technol, 2002, 45(4-5), 373 - 81
Model reduction through boundary relocation to facilitate real-time control optimisation in the integrated urban wastewater system; Meirlaen J et al.; Real time control is one of the possibilities to minimise the impact of the integrated urban wastewater system (sewer system and treatment plant) on the receiving water quality . Integrated control uses information about the river state to act in the sewer system or in treatment plant . In order to test and tune these integrated controllers, a simplified integrated model is needed . Even with these simplified models, the simulation times may be too long and further model reduction is needed . In this paper, dependency-structure based model reduction is proposed as a technique to further reduce model complexity . Three steps are proposed: relocation of the upstream system boundaries to just upstream of the first control point, relocation of the downstream boundaries to just downstream of the last measurement point, and third, a further model simplification based on an analysis of the sensitivity of the control actions on submodel elimination . The effect of applying the different reduction approaches on the control strategy and on the resulting river water quality is discussed on the basis of a case study of the catchment of Tielt.

Water Sci Technol, 2002, 45(4-5), 365 - 72
Improved design and optimization of aeration control for WWTPs by dynamic simulation; Alex J et al.; This paper introduces a model library based on the simulation environment MATLAB/SIMULINK which allows the simulation of the aeration system of an wastewater treatment plant (WWTP) . The model library presented covers all parts of an aeration system starting with the compressor set over the common air rail, flow resistances through pipes, controllable valves, aeration membranes and ending last not least with the controllers involved . The main objective of the development of the simulation system is the design, test and the support of the installation of more predictable and efficient control concepts for the aeration system in WWTPs . An example is given to demonstrate the application of the simulation system and to promote a control scheme with a flexible reference value for the pressure at the common air rail based on a most open valve (MOV) concept.

Water Sci Technol, 2002, 45(4-5), 355 - 63
Dynamic simulation of chemical industry wastewater treatment plants; Bury SJ et al.; High variability, stringent effluent permits, and often extreme operating conditions define the practice of wastewater treatment in the chemical industry . This paper reviews the benefits and challenges of applying dynamic simulation to chemical-industry wastewater treatment plants by describing case studies at full-scale wastewater treatment plants (WWTP) . The applications range from process troubleshooting to optimization and control . The applications have been valuable and useful in developing a deeper understanding of the plants as integrated systems . However there still remains substantial work to implement the dynamic simulations for daily real-time use by plant engineers and operators . This opportunity to improve plant operations is still largely untapped and will remain so until dynamic state estimation and data reconciliation are incorporated into simulation packages for use in developing the on-line simulations.

Water Sci Technol, 2002, 45(4-5), 299 - 308
A framework for extreme-event control in wastewater treatment; Rosen C et al.; In this paper an approach to extreme event control in wastewater treatment plant operation by use of automatic supervisory control is discussed . The framework presented is based on the fact that different operational conditions manifest themselves as clusters in a multivariate measurement space . These clusters are identified and linked to specific and corresponding events by use of principal component analysis and fuzzy c-means clustering . A reduced system model is assigned to each type of extreme event and used to calculate appropriate local controller set points . In earlier work we have shown that this approach is applicable to wastewater treatment control using look-up tables to determine current set points . In this work we focus on the automatic determination of appropriate set points by use of steady state and dynamic predictions . The performance of a relatively simple steady-state supervisory controller is compared with that of a model predictive supervisory controller . Also, a look-up table approach is included in the comparison, as it provides a simple and robust alternative to the steady-state and model predictive controllers . The methodology is illustrated in a simulation study.

Water Sci Technol, 2002, 45(4-5), 289 - 97
A hybrid supervisory system to support WWTP operation: implementation and validation; Rodriguez-Roda I et al.; Integrated operation of Wastewater Treatment Plants is still far from being solved . A reasonable proposal should link advanced and robust control algorithms to some knowledge-based techniques, allocating the detailed engineering to numerical computations, while delegating the logical analysis and reasoning to supervisory intelligent systems . This paper describes the development and implementation of a knowledge-based Hybrid Supervisory System to support the operation of a real Wastewater Treatment Plant . The system integrates different reasoning modules, overcoming the limitations in the use of each single technique, while providing an agent based architecture with additional modularity and independence . It is structured into three separated levels: data gathering, diagnosis, and decision support . The different tasks of the system are performed in a seven-step cycle: data gathering and update, diagnosis, supervision, prediction, communication, actuation, and evaluation phase . In spite of certain reservations of the scientific community about the use of these techniques, the system is successfully performing real-time support to the operation of the Granollers facility since September 1999 . Results of the first four-month validation period are shown and discussed . An example of the system behavior is also shown in the paper . The conclusions indicate the key steps which are necessary to transfer the system to another facility.

Water Sci Technol, 2002, 45(4-5), 227 - 35
Adaptive multiscale principal components analysis for online monitoring of wastewater treatment; Lennox J et al.; Fault detection and isolation (FDI) are important steps in the monitoring and supervision of industrial processes . Biological wastewater treatment (WWT) plants are difficult to model, and hence to monitor, because of the complexity of the biological reactions and because plant influent and disturbances are highly variable and/or unmeasured . Multivariate statistical models have been developed for a wide variety of situations over the past few decades, proving successful in many applications . In this paper we develop a new monitoring algorithm based on Principal Components Analysis (PCA) . It can be seen equivalently as making Multiscale PCA (MSPCA) adaptive, or as a multiscale decomposition of adaptive PCA . Adaptive Multiscale PCA (AdMSPCA) exploits the changing multivariate relationships between variables at different time-scales . Adaptation of scale PCA models over time permits them to follow the evolution of the process, inputs or disturbances . Performance of AdMSPCA and adaptive PCA on a real WWT data set compared and contrasted . The most significant difference observed was the ability of AdMSPCA to adapt to a much wider range of changes . This was mainly due to the flexibility afforded by allowing each scale model to adapt whenever it did not signal an abnormal event at that scale . Relative detection speeds were examined only summarily, but seemed to depend on the characteristics of the faults/disturbances . The results of the algorithms were similar for sudden changes, but AdMSPCA appeared more sensitive to slower changes.

Water Sci Technol, 2002, 45(4-5), 151 - 8
Evaluation of control strategies using an oxidation ditch benchmark; Abusam A et al.; This paper presents validation and implementation results of a benchmark developed for a specific full-scale oxidation ditch wastewater treatment plant . A benchmark is a standard simulation procedure that can be used as a tool in evaluating various control strategies proposed for wastewater treatment plants . It is based on model and performance criteria development . Testing of this benchmark, by comparing benchmark predictions to real measurements of the electrical energy consumptions and amounts of disposed sludge for a specific oxidation ditch WWTP, has shown that it can (reasonably) be used for evaluating the performance of this WWTP . Subsequently, the validated benchmark was then used in evaluating some basic and advanced control strategies . Some of the interesting results obtained are the following: (i) influent flow splitting ratio, between the first and the fourth aerated compartments of the ditch, has no significant effect on the TN concentrations in the effluent, and (ii) for evaluation of long-term control strategies, future benchmarks need to be able to assess settlers' performance.

Water Sci Technol, 2002, 45(4-5), 127 - 34
Wastewater treatment benchmark: what can be achieved with simple control?
Vrecko D, Hvala N, Kocijan J.
In this paper a simple control strategy is applied to and assessed on the wastewater treatment benchmark . The controllers used in the presented control strategy are PI controllers, feedforward control and a step-feed procedure . The controlled variables are not directly the effluent concentrations but other process variables which have an effect on the effluent . The setting of set-points is also analyzed to select the values with the best performance . Set-point analysis has shown that with an optimal setting of set-points under stormy influent conditions, the achieved plant performance is also retained for rainy and dry influent conditions . The evaluation of plant performance indicates that with the proposed control strategy, a lower number of effluent violations has been achieved, as well as lower energy consumption and lower sludge production, when compared to results published up to now . Only the effluent quality criterion deteriorated.

Water Sci Technol, 2002, 45(4-5), 109 - 16
On the use of fluorescence measurements to characterize wastewater; Vasel JL et al.; This paper examines the correlations between some water quality parameters and fluorescence intensities and spectra in filtered wastewater using a 280 nm excitation wavelength . We did not obtain satisfying linear relationships between fluorescence and COD or TOC (r2 approximately 0.4) for any of the emission wavelengths used between 320 and 400 nm (especially at 355 nm, the average emission lambda(max.)) . The relationships with NK were better (r2 approximately 0.7); leading us to suggest that one evaluates mainly the organic nitrogen content at lambda(ex.) = 280 nm . Whole spectra processing did not improve the correlations . Gel permeation chromatography yielded markedly different TOC and fluorescence chromatograms, which explains the difficulty of correlating organic content and fluorescence . Other investigations are necessary before spectrofluorimetry can be used as a reliable technique for on-line wastewater pollution estimation.

Water Sci Technol, 2002, 45(4-5), 1 - 8
Lessons learnt at ICA2001 . IWA Conference on Instrumentation, Control and Automation; Olsson G; This paper gives an introduction as well as some general experiences and conclusions from the 1st IWA Conference on Instrumentation, Control and Automation (ICA2001), June 3-7, 2001, Malmo, Sweden . The highlights from the different sessions of the conference are summarised and some challenges for the coming years, with regard to ICA within the field of wastewater treatment, are also discussed.

Aquat Toxicol, 2002 Jun, 57(4), 267 - 80
Heat shock protein Hsp70 expression and DNA damage in Baikalian sponges exposed to model pollutants and wastewater from Baikalsk Pulp and Paper Plant; Efremova SM et al.; Lake Baikal, a unique habitat for a great number of endemic species, is the largest freshwater reservoir in the world which is still largely unaffected by anthropogenic pollution, except for some shore regions with industrial activity . The expressions of a biomarker of exposure (heat shock protein Hsp70) and a biomarker of effect (DNA single-strand breaks) were measured for the first time in endemic Baikalian sponge species (Baikalospongia intermedia, Lubomirskia fusifera, and Lubomirskia abietina) . Tissue cubes of B . intermedia and dissociated cells of L . fusifera and L . abietina reacted to temperature stress (10-16 degrees C above ambient temperature) with a time-dependent increase in expression of Hsp70 . In B . intermedia, the effects of model pollutants (lead, copper, and zinc, and the organochlorines tetrachloroguaiacol, TCG, and pentachlorophenol, PCP) and of the wastewater from the final refinement and aeration reservoirs of the Baikalsk Pulp and Paper Plant (BPPP), located at the shore of the southern basin of Lake Baikal, on the expression of Hsp70 and the extent of DNA damage were investigated . It was found that lead and zinc but not copper cause a strong induction of Hsp70 in this sponge, while the frequency of DNA single-strand breaks increased after exposure to all these heavy metals tested . Induction of DNA single-strand breaks was also observed after exposure to TCG and PCP, but these compounds did not (consistently) enhance Hsp70 expression . Wastewater taken from the final water aeration pond of BPPP caused a concentration-dependent increase in Hsp70 expression in B . intermedia . However, there was no difference in the basal levels of Hsp70 between sponges collected in the shallow water at an unpolluted site near Baikalsk City and at a polluted site where the wastewaters of BPPP are discharged into the lake . There was also no clear difference in the wastewater concentration-dependent induction of Hsp70 expression between sponges collected at these sites, indicating no adaptation to continuous stress exposure.

J Environ Qual, 2002 Mar-Apr, 31(2), 690 - 6
Microcosm wetlands for wastewater treatment with different hydraulic loading rates and macrophytes; Jing SR et al.; Constructed wetlands (CW) usually require large land areas for treating wastewater . This study evaluated the feasibility of applying CW with less land requirement by operating a group of microcosm wetlands at a hydraulic retention time (HRT) of less than 4 d in southern Taiwan . An artificial wastewater, simulating municipal wastewater containing 200 mg L(-1) of chemical oxygen demand (COD), 20 mg L(-1) of NH4+-N (AN), and 20 mg L(-1) of PO4(3-)-P (OP), was the inflow source . Three emergent plants {reed, Phragmites australis (Cav.) Trin . ex Steud.; water primrose, Ludwigia octovalvis (Jacq.) P.H . Raven; and dayflower, Commelina communis L.} and two floating plants {water spinach, Ipomoea aquatica Forssk.; and water lettuce, Pistia stratiotes L.} plants were tested . The planted systems showed more nutrient removal than unplanted systems; however, the type of macrophytes in CW did not make a major difference in treatment . At the HRTs of 2 to 4 d, the planted system maintained greater than 72,80, and 46% removal for COD, AN, and OP, respectively . For AN and OP removal, the highest efficiencies occurred at the HRT of 3 d, whereas maximum removal rates for AN and OP occurred at the HRT of 2 d . Both removal rates and efficiencies were reduced drastically at the HRT of 1 d . Removals of COD, OP, and AN followed first-order reactions within the HRTs of 1 to 4 d . The efficient removals of these constituents obtained with HRT between 2 and 4 d indicated the possibility of using a CW system for wastewater treatment with less land requirement.

J Agric Food Chem, 2002 Apr 10, 50(8), 2392 - 9
Effects of natural phenolic compounds on the antioxidant activity of lactoferrin in liposomes and oil-in-water emulsions; Medina I et al.; The effect of natural phenolic compounds on the antioxidant and prooxidant activity of lactoferrin was studied in liposomes and oil-in-water emulsions containing iron . The antioxidants tested with lactoferrin were alpha-tocopherol, ferulic acid, coumaric acid, tyrosol, and natural phenolic extracts obtained from three different extra-virgin olive oils and olive mill wastewater . The natural extracts of olive oils and mill wastewaters were composed mainly of polyphenols and simple phenolics, respectively . Lipid oxidation at 30 degrees C was determined by the formation of hydroperoxides and fluorescent compounds resulting from oxidized lipid interactions . All phenolic compounds showed synergistic properties in reinforcing the antioxidant activity of lactoferrin in lipid systems containing iron . The highest synergistic effects were observed for the phenolic extracts rich in polyphenols of extra-virgin olive oils and lactoferrin . This synergistic effect was higher in liposomes than in emulsions.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2002 Mar, 37(3), 321 - 30
Improved method for concentration of Giardia, Cryptosporidium, and poliovirus from water; Watt PM et al.; Methods for the concentration of enteric viruses and the protozoan parasites, Giardia and Cryptosporidium, from drinking water currently require the use of two different types of filters . Electropositive or electronegative microporous filters (0.2-0.45 microm nominal porosity) are used for the collection of enteroviruses, while polypropylene spun-fiber filters (1 microm porosity) and small pleated cartridge filters are used for the collection of protozoan parasites from water . Since the filter mechanically traps the protozoa by size exclusion, a microporous filter with an appropriately small nominal porosity could possibly be used for co-collection of both protozoa and enteroviruses . This study compared the concentration efficiencies of a polypropylene fiber cartridge (DPPPY) filter and two different microporous filters (Filterite and IMDS) with poliovirus (type 1), with respect to their ability to concentrate Giardia and Cryptosporidium from water . Giardia cysts and Cryptosporidium oocysts were added to 4001 of either tap water or tertiary treated wastewater and passed through the test filter . The protozoa were eluted from the polypropylene filter by hand-washing in a detergent solution . Viruses and protozoa were eluted from the microporous filter by two consecutive back-washes with a 1.5% beef extract, 0.1% Tween 80 solution . The eluent was then centrifuged to remove the parasites and the supernatant assayed for viruses . The overall efficiency was greater for the Filterite filter (40.4% for Giardia; 36.6% for Cryptosporidium) when compared to the spun fiber filter (10.1% for Giardia; 16.0% for Cryptosporidium) . The Filterite filters were easier and faster to process than the polypropylene spun fiber filters . There was no significant difference in the recovery of protozoa from 1MDS and DPPPY filters . Co-collection of viruses and protozoan parasites from water onto the same filter is possible and can reduce the time and cost of routine water monitoring.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2002 Mar, 37(3), 297 - 308
The removal of NH3-N from primary treated wastewater in subsurface reed beds using different substrates; Manios T et al.; Subsurface flow experimental reed beds, were designed and built based on a combination of two design methodologies, that of the WRc and Severn Trent Water plc (3) and that of the USA, EPA (17) . Four different growing media were used with a combination of top soil, gravel, river sand and mature sewage sludge compost, aiming to determine the best substrate for ammonia removal . Eight units were constructed, two for each material . One bed for each pair was planted with Typha latifolia plants commonly known as cattails . Primary treated domestic wastewater, was continuously fed in to the bed for more than six months . The best results were achieved by the gravel reed beds with an almost constant removal rate of NH3-N above 80% . There was no significance difference on the performance of planted and unplanted reed beds.

Anal Chem, 2002 Mar 1, 74(5), 1054 - 60
Gas-phase analysis of trimethylamine, propionic and butyric acids, and sulfur compounds using solid-phase microextraction; Kim H et al.; Complaints due to odors are an important problem for the wastewater, composting, and animal agriculture industries . Accurate, objective measurement techniques are needed to monitor emissions, to develop new waste handling procedures, and to reduce the production of these volatile gases . Solid-phase microextraction was investigated as a technique for the determination of representative odorous gases . A flow-through Teflon chamber was used to expose the fibers to certified gas standards . A 75-microm carboxen-poly(dimethylsiloxane) (Car-PDMS) coating was used for trimethylamine (TMA), carbon disulfide (CS2), dimethylsulfide (DMS), and dimethyl disulfide (DMDS), and an 85-microm polyacrylate coating was used for propionic acid (PA) and butyric acid (BA) . Using a 1-h fiber exposure time and a flow rate through the chamber of 72 mL/min, method detection limits were 2.38, 0.074, 0.150, 0.063, 1.85, and 1.32 ppbv for TMA, DMS, CS2, DMDS, PA, and BA, respectively . Enhanced detector signal was observed for all analytes under flow conditions, as compared to static conditions, and the porous nature of the Car-PDMS coating appears to increase the time needed for analytes to reach equilibrium under flow conditions.

Anal Chem, 2002 Mar 15, 74(6), 1275 - 80
Accelerated solvent extraction followed by on-line solid-phase extraction coupled to ion trap LC/MS/MS for analysis of benzalkonium chlorides in sediment samples; Ferrer I et al.; Benzalkonium chlorides (BACs) were successfully extracted from sediment samples using a new methodology based on accelerated solvent extraction (ASE) followed by an on-line cleanup step . The BACs were detected by liquid chromatography/ion trap mass spectrometry (LC/MS) or tandem mass spectrometry (MS/MS) using an electrospray interface operated in the positive ion mode . This methodology combines the high efficiency of extraction provided by a pressurized fluid and the high sensitivity offered by the ion trap MS/MS . The effects of solvent type and ASE operational variables, such as temperature and pressure, were evaluated . After optimization, a mixture of acetonitrile/water (6:4 or 7:3) was found to be most efficient for extracting BACs from the sediment samples . Extraction recoveries ranged from 95 to 105% for C12 and C14 homologues, respectively . Total method recoveries from fortified sediment samples, using a cleanup step followed byASE, were 85% for C12BAC and 79% for C14BAC . The methodology developed in this work provides detection limits in the subnanogram per gram range . Concentrations of BAC homologues ranged from 22 to 206 microg/kg in sediment samples from different river sites downstream from wastewater treatment plants . The high affinity of BACs for soil suggests that BACs preferentially concentrate in sediment rather than in water.

Chemosphere, 2002 Feb, 46(6), 937 - 44
Investigation of retardation effects on the titanium dioxide photodegradation system; Epling GA et al.; The photocatalytic bleaching of dyes using TiO2 has appeared promising in laboratory studies, but little attention has been focused on whether other species such as might be found in wastewater have a deleterious effect on the photobleaching . This study describes the effects that result from the presence of ionic species, organic solvents and humic substances on the photobleaching of several dyes . The manner in which the photobleaching was affected by the presence of adventitious materials was carefully examined with an eye toward elucidating the mechanistic origin of the loss of the photochemical efficiency in the reaction . The overall retardation effects can be attributed to the combination of light attenuation, inhibition and competition effects.

Chemosphere, 2002 Feb, 46(6), 923 - 8
Pre-oxidation and coagulation of textile wastewater by the Fenton process; Kang SF et al.; This paper evaluates the Fenton process, involving oxidation and coagulation, for the removal of color and chemical oxygen demand (COD) from synthetic textile wastewater containing polyvinyl alcohol and a reactive dyestuff, R94H . The experimental variables studied include dosages of iron salts and hydrogen peroxide, oxidation time, mixing speed and organic content . The results show that color was removed mainly by Fenton oxidation . The color removal reached a maximum of 90% at a reaction time of 5 min under low dosages of H2O2 and Fe2+ . In contrast, the COD was removed primarily by Fenton coagulation, rather than by Fenton oxidation . The ratio of removal efficiency between Fenton process and ferric coagulation was 5.6 for color removal and 1.2 for COD removal . It is concluded that Fenton process for the treatment of textile wastewater favors the removal of color rather than COD.

Environ Pollut, 2002, 117(2), 315 - 21
Extractable soil heavy metals following the cessation of biosolids application to agricultural soil; Walter I et al.; Changes in soil heavy metal extractability following the cessation of biosolids applications were studied in a long-term field experiment . Two anaerobically digested biosolids from wastewater treatment plants in Madrid (Sur and Viveros) were applied to cropland from 1983 to 1990 . Soil samples were collected in the 1st, 5th and 9th year after the last biosolids application . Soil pH did not vary significantly after biosolids applications . Organic matter and total heavy metals (Zn, Pb, Cd, Ni, Cr and Cu) concentrations initially increased but then declined over time, mostly after the first 5 years following biosolids application . Metal extracted with DPTA increased in Sur treatments during the 1st year and diminished thereafter . However, in Viveros treatments, heavy metals extracted increased during the 1st year, declined in 1995, and showed a slight increase in 1999 . These changes in heavy metal extractability were widely observed in the percentage of extractable metal recovery (EMR) . The differences observed in the pattern of the two sources of biosolids applied could be due to the different rates of decomposition of their organic matter.

Water Sci Technol, 2002, 45(3), 45 - 52
Increasing wastewater system performance--the importance of interactions between sewerage and wastewater treatment; Langeveld JG et al.; The necessity to assess sewer systems and wastewater treatment plants (WWTPs) as integral parts of the wastewater system has been well known for several years and discussed in many conferences . Until recently, sewer systems and WWTPs were improved (or optimised) separately or independently, which resulted in suboptimal solutions . Nowadays, in The Netherlands as well as in other European countries, a trend can be recognised towards more integral solutions . Nevertheless, due to a lack of knowledge on the interactions between the sewer systems and the WWTPs the implementation of this way of thinking in practice takes a long time . This paper describes the results of two cases in which the interactions between sewerage and wastewater treatment are incorporated within the optimisation of a wastewater system . The first case illustrates the importance of taking the interactions into account, while the second case shows how to deal with the interactions within a wastewater system optimisation study . It is concluded that the combination of total wastewater system analysis, incorporating the interactions within the wastewater system, with efficient search algorithms is expected to be very valuable in future wastewater system optimisation studies.

Water Res, 2002 Mar, 36(5), 1375 - 8
A molecular typing approach for evaluating bioaerosol exposure in wastewater treatment plant workers; Orsini M et al.; Bioaerosols associated with wastewater treatment process may represent a health risk for occupationally exposed personnel . To evaluate microbial contamination in plant workers, we compared oral cavity isolates against isolates collected from aerosol surrounding the aeration basin . Typing was performed by metabolic profile and arbitrarily primed-polymerase chain reaction . The latter is more sensitive and rapid than conventional tests . After comparison, isolates from the air samples were not related to those obtained from the exposed workers . This molecular approach can support bioaerosol risk evaluation .

Water Res, 2002 Mar, 36(5), 1224 - 36
Studies on enhancement of Cr(VI) biosorption by chemically modified biomass of Rhizopus nigricans; Bai RS et al.; This study reports the biosorption of Cr(VI) by chemically modified biomass of Rhizopus nigricans and the possible mechanism of Cr complexation to the adsorbent . The cell wall of this fungus possesses strong complexing property to effectively remove Cr(VI) anions from solution and wastewater . The mechanism of Cr adsorption by R . nigricans was ascertained by chemical modifications of the dead biomass followed by FTIR spectroscopic analysis of the cell wall constituents . Treatment of the biosorbent with mild alkalies (0.01 N NaOH and ammonia solution) and formaldehyde (10%, w/v) deteriorated the biosorption efficiency . However, extraction of the biomass powder in acids (0.1 N HCl and H2SO4), alcohols (50% v/v, CH3OH and C2H5OH) and acetone (50%, v/v) improved the Cr uptake capacity . Reaction of the cell wall amino groups with acetic anhydride reduced the biosorption potential drastically . Blocking of the-COOH groups by treatment with water soluble carbodiimide also resulted in initial lag in Cr binding . Biomass modification experiments conducted using Cetyl Trimethyl Ammonium Bromide (CTAB), Polyethylenimine (PEI), and Amino Propyl Trimethoxy Silane (APTS) improved the biosorption efficiency to exceptionally high levels . The FTIR spectroscopic analysis of the native, Cr bound and the other types of chemically modified biomass indicated the involvement of amino groups of Rhizopus cell wall in Cr binding . The adsorption data of the native and the most effectively modified biomass were evaluated by the Freundlich and the Langmuir adsorption isotherms and the possible adsorption phenomena are also discussed.

Water Res, 2002 Mar, 36(5), 1203 - 12
The efficiency of oxidation ponds at the Kraft pulp and paper mill at Webuye in Kenya; Achoka JD; Two streams of wastewater from the Kraft Pulp and Paper Mills at Webuye are released from the pulping, bleaching and paper pressing departments . One stream is made up of clear wastewater and the second is made up of turbid wastewater . The wastewaters from the mills are treated using oxidation ponds, after which the treated wastewater is discharged into the River Nzoia . The wastewater was analysed for Cd, Cr, Cu, Ni, Pb . Zn, Ca, K, Mg and Na . The results are that the concentrations of Ca and Na significantly increased in the treated wastewater . The concentrations of Cd, Pb, Zn, K and Mg also increased in the treated wastewater, though not significantly . The concentrations of Cr, Cu and Ni decreased in the treated wastewater but not significantly . Mass loadings of the metals discharged into River Nzoia were calculated . It was found that the mean mass loading of two metals (Ca and Na) significantly increased in the treated wastewater . Five metals (Cd, Pb, Zn, K and Mg) increased in the treated wastewater although not significantly . Three metals (Cr, Cu and Ni) decreased in the treated wastewater but the decrease was not significant . The concentrations of Cd, Cu, Ni, Pb and Zn were all above the limits set by EC for drinking water . These findings pose serious questions of the effectiveness of oxidation ponds system to safeguard the receptor against pollutants from the pulp and paper industry at Webuye.

Water Res, 2002 Mar, 36(5), 1143 - 54
Advanced oxidation of a reactive dyebath effluent: comparison of O3, H2O2/UV-C and TiO2/UV-A processes; Alaton IA et al.; In the present study the treatment efficiency of different AOPs (O3/OH- H2O2/UV-C and TiO2/UV-A) were compared for the oxidation of simulated reactive dyebath effluent containing a mixture of monochlorotriazine type reactive dyes and various dye auxiliary chemicals at typical concentrations encountered in exhausted reactive dyebath liquors . A525 (color), UV280 (aromaticity) and TOC removal rates were assessed to screen the most appropriate oxidative process in terms of reactive dyebath effluent treatment . Special emphasis was laid on the effect of reaction pH and applied oxidant (O3, H2O2) dose on the observed reaction kinetics . It was established that the investigated AOPs were negatively affected by the Na2CO3 content (= 867 mg/L) which is always present at high concentrations in dychouse effluents since it is applied as a pH buffer and dye fixation agent during the reactive dyeing process . The ozonation reaction exhibited almost instantaneous decolorization kinetics and a reasonable TOC reduction rate . It appeared to be stable under the investigated advanced oxidation conditions and outranked the other studied AOPs based on the above mentioned criteria . Besides, the electrical energy requirements based on the EE/O parameter (the electrical energy required per order of pollutant removal in 1 m3 wastewater) was calculated for the homogenous AOPs in terms of decolorization kinetics . In view of the electrical energy efficiency, ozonation and H2O2/UV-C oxidation at the selected treatment conditions appear to be promising candidates for full-scale dyehouse effluent decolorization.

Water Res, 2002 Mar, 36(5), 1115 - 26
A neural network model to predict the wastewater inflow incorporating rainfall events; El-Din AG et al.; Under steady-state conditions, a wastewater treatment plant usually has a satisfactory performance because these conditions are similar to design conditions . However, load variations constitute a large portion of the operating life of a treatment facility and most of the observed problems in complying with permit requirements occur during these load transients . During storm events upsets to the different physical and biological processes may take place in a wastewater treatment plant, and therefore, the ability to predict the hydraulic load to a treatment facility during such events is very beneficial for the optimization of the treatment process . Most of the hydrologic and hydraulic models describing sewage collection systems are deterministic . Such models require detailed knowledge of the system and usually rely on a large number of parameters, some of which are uncertain or difficult to determine . Presented in this paper, an artificial neural network (ANN) model that is used to make short-term predictions of wastewater inflow rate that enters the Gold Bar Wastewater Treatment Plant (GBWWTP), the largest plant in the Edmonton area (Alberta, Canada) . The neural model uses rainfall data, observed in the collection system discharging to the plant, as inputs . The building process of the model was conducted in a systematic way that allowed the identification of a parsimonious model that is able to learn (and not memorize) from past data and generalize very well to unseen data that was used to validate the model . The neural network model gave excellent results . The potential of using the model as part of a real-time process control system is also discussed.

Water Res, 2002 Mar, 36(5), 1107 - 14
Removal of phenol from water by adsorption-flocculation using organobentonite; Shen YH; Bentonite modified with short chain cationic surfactant might be the basis of a new approach to removing organic pollutants from water . The treatment process involves dispersing bentonite to the contaminated water and then adding a small cationic surfactant so as to result in flocs which are agglomerates of organobentonite and bound organic pollutants . The flocs are then removed from the solution by sedimentation . Experimental results indicate that BTMA-bentonite displays a high affinity for phenol, possibly because phenol molecules interact favorably with the benzene ring in BTMA ion through increased pi-pi type interactions . Under appropriate operating conditions, 90% phenol removal and nearly 100% bentonite recovery could be achieved by the adsorption flocculation process using BTMA-bentonite . Additionally, the insensitivity of the process to the changing ionic strength of the solution and rapid adsorption kinetics made adsorption-flocculation with BTMA-bentonite attractive for continuous treatment of large volumes of industrial wastewater . The bentonite may function as a recyclable surfactant support for the adsorption and subsequent combustion of organic pollutants.

Water Sci Technol, 2002, 45(3), 95 - 100
Analysis of scenarios for sewerage, wastewater treatment and prioritised load on environment from the Greater City of Copenhagen; Harremoes P et al.; The sewer system for the Greater Copenhagen area covers an area of 4460 ha contributing to the runoff . The total area serves in total 8 municipalities, however it is dominated by the areas in the City of Copenhagen proper . The catchments merge into interceptors, which feed two large treatment plants . The effluent from the two treatment plants discharges during dry weather to Oresund, the sound between Denmark and Sweden . This large system has been analysed for selected scenarios with respect to handling runoff in an optimal way in order to minimise the loads on the most sensitive receiving waters and optimising treatment plant performance.

Water Sci Technol, 2002, 45(3), 71 - 9
Anaerobic transformations of wastewater organic matter and sulfide production--investigations in a pilot plant pressure sewer; Tanaka N et al.; Anaerobic transformations of wastewater organic matter and sulfide production rate were studied using a pilot plant pressure sewer (inner diameter: 102 mm, length: 47 m) . Furthermore, a process model description including carbon and sulfur cycle was presented . Wastewater characterization based on oxygen utilization rate (OUR) measurement and VFA analysis was employed . Under anaerobic conditions, a net production of readily biodegradable substrate was observed, which fact is important for biological removal of nitrogen and phosphorus at subsequent wastewater treatment plants . Model parameters were determined on the basis of experimental findings . The model simulation of transformations of organic matter in sewers can be used as input to the model simulation and evaluation of the processes in wastewater treatment plants . The model is also useful to evaluate the problems in both sewers themselves and treatment plants caused by hydrogen sulfide.

Water Sci Technol, 2002, 45(3), 265 - 72
Managing sewer solids for the reduction of foul flush effects--Forfar WTP; Fraser AG et al.; In times of high sewer flow, conditions can exist which enable previously deposited material to be re-entrained back into the body of the flow column . Pulses of this highly polluted flow have been recorded in many instances at the recently constructed wastewater treatment plant (WTP) in Forfar, Scotland . Investigations have been undertaken to characterise the incoming flows and to suggest remedial measures to manage the quality fluctuations . Initial visits to the works and incoming pipes indicated a high degree of sediment deposition in the two inlet pipes . Analyses were carried out and consequently, changes to the hydraulic regime were made . Measurements of sediment level, sediment quality, wall slime and bulk water quality were monitored in the period following the remedial works to observe any improvements . Dramatic alterations in each of the determinands measured were recorded . Analyses were then undertaken to determine long term sediment behaviour and to assess the future usefulness of existing upstream sediment traps . It was concluded that with proper maintenance of the traps, the new hydraulic regime is sufficient to prevent further significant build up of sediment deposits and reduce impacts on the WTP . Further investigations made by North of Scotland Water Authority highlighted trade inputs to the system which may also have contributed to the now managed foul flush problem.

Water Sci Technol, 2002, 45(3), 25 - 34
Biodegradability of wastewater--a method for COD-fractionation; Vollertsen J et al.; Characterization of wastewater for simulation of in-sewer transformations can be carried out by interpretation of oxygen uptake rate measurements in combination with a conceptual model of the microbial transformations involved . This interpretation can be done by iterative procedures by solving the differential equations constituting the model or by the application of a more "manual" method--the latter being the topic of this paper . Examples where different wastewaters are characterized illustrate the method.

Water Sci Technol, 2002, 45(3), 239 - 46
The effect of extended in-sewer storage on wastewater treatment plant performance; Ashley RM et al.; A project funded by UKWIR is under way in the UK to develop a relatively simple methodology whereby the effects of the introduction of extended in-sewer storage at CSOs on downstream sewerage and treatment can be assessed . Recent legislation (UK and European) has compelled many sewer system operators to introduce systems which increase in-sewer retention times, and also retain more flow and load within sewer networks . The project has reviewed existing knowledge about the interaction between in-sewer flow and treatment plants, together with available models . The study is utilising a "benchmark" of 3 configurations of treatment plant and dynamic simulation using the WRc STOAT software, with minor modifications to ensure that effects on odour generation and nutrient removal processes are adequately modelled . As no existing sewer flow quality model can represent the range of conditions possible in sewer networks, a combined application of the Hydroworks model and a new model developed at Aalborg University is being used for this part of the study.

Water Sci Technol, 2002, 45(3), 229 - 37
Effects of real time control of sewer systems on treatment plant performance and receiving water quality; Frehmann T et al.; Four individual mathematical submodels simulating different subsystems of urban drainage were intercoupled to an integral model . The submodels (for surface runoff, flow in sewer system, wastewater treatment plant and receiving water) were calibrated on the basis of field data measured in an existing urban catchment investigation . Three different strategies for controlling the discharge in the sewer network were defined and implemented in the integral model . The impact of these control measures was quantified by representative immission state-parameters of the receiving water . The results reveal that the effect of a control measure may be ambivalent, depending on the referred component of a complex drainage system . Furthermore, it is demonstrated that the drainage system in the catchment investigation can be considerably optimised towards environmental protection and operation efficiency if an appropriate real time control on the integral scale is applied.

Water Sci Technol, 2002, 45(3), 211 - 8
Effective environmental regulation to maximise the benefits of integrated wastewater management; Crabtree B et al.; On the 25 November 1999, the Secretary of State for the Environment in England and Wales announced the outcome of the water companies' third Periodic Review . As a result, a major environmental investment programme will be completed during the period 2000/2005 . Overall in England and Wales, it is planned that almost 3,600 km of rivers will be protected or improved and 3,800 unsatisfactory CSOs will be improved to allow receiving water objectives to be met . This means that over the next 5-year period an average of nearly 18 discharges will be improved every week . The implementation of the programme will involve a large workload for the Environment Agency in planning and authorising the individual schemes for delivery by the water companies . The paper illustrates how the Urban Pollution Management procedure and associated environmental standards are to be used to underpin the Environment Agency's policy, to encourage the use of integrated wastewater planning and, as a result, ensure that the anticipated environmental improvements will be delivered.

Water Sci Technol, 2002, 45(3), 185 - 93
Cost benefit risk--a concept for management of integrated urban wastewater systems?
Hauger MB, Rauch W, Linde JJ, Mikkelsen PS.
Urban wastewater systems should be evaluated and analysed from an integrated point of view, taking all parts of the system, that is sewer system, wastewater treatment plant and receiving waters into consideration . Risk and parameter uncertainties are aspects that hardly ever have been addressed in the evaluation and design of urban wastewater systems . In this paper we present and discuss a probabilistic approach for evaluation of the performance of urban wastewater systems . Risk analysis together with the traditional cost-benefit analysis is a special variant of multi-criteria analysis that seeks to find the most feasible improvement alternative for an urban wastewater system . The most feasible alternative in this context is the alternative that has the best performance, meaning that the alternative has the lowest sum of costs, benefits and risks . The sum is expressed as the Net Present Cost (NPC) . To use NPC as a decision variable has the problematic effect, that two alternatives performing completely differently when focusing on environmental cost can have the same NPC . The extreme example is one alternative with high risk and low cost and another with low risk and high cost . In this example it is up to the decision-maker to decide whether she wants to spend the budget on preventive installations or cleaning up after failures in the environment.

Water Sci Technol, 2002, 45(3), 167 - 74
The influence of stormwater treatment on the hydraulic and pollution load--balance for an entire river basin; Bode H et al.; The installation of about 500 stormwater detention facilities (SDFs) led to a significant drop of the pollution originating from stormwater runoff in the river basin of the Ruhr which covers 4,488 km2 . The German technical directives on the design of SDFs are briefly outlined and the specific costs for such plants are given . The average costs for one kilogram COD held back by SDFs in combined systems amount to Euro 3.73 (calculated without consideration of the subsequent removal in the municipal wastewater treatment plant (WWTP)) . The tank volume for stormwater storage can be minimised by application of real-time management systems which allow a dynamic operation of all SDFs in a catchment area.

Water Sci Technol, 2002, 45(3), 159 - 66
Sustainable rainwater management in the Emscher river catchment area; Becker M et al.; The wastewater management system of the Emscher region is currently being radically restructured . The receiving waters currently surviving as open sewers are to be freed of their wastewater burden and reconstituted to a state as natural as possible, while the wastewater is to be routed underground to the treatment plants . Great importance is attached to the most natural possible rainwater management, in order to buffer extreme run-off situations in the watercourses and to minimize the costs for residential-area water management engineering . Rethinking, which in many cases percolates through only slowly, is necessary in many respects for this purpose . A contest has been set up in the Emscher catchment area in order to accelerate this in the existing residential areas . Seepage, decentralized retention, disconnection and discharge into bodies of water and watercourses have been financially supported . The results are presented and the further procedure deriving from them discussed.

Water Sci Technol, 2002, 45(3), 141 - 8
Criteria for assessment of the operational potential of the urban wastewater system; Schutze M et al.; Application of real-time control (RTC) is one possible measure to increase the performance of the urban wastewater system . However, the potential and the benefits of control depend strongly on the characteristics of the individual site under question . Conventionally, to evaluate this potential, a detailed feasibility study had to be carried out . In some cases, such a study may well conclude that, for the given site, real-time control does not have any significant potential, thus resulting in unnecessarily having spent precious resources for a detailed study . It would be desirable to have a methodology that allows simple, and cost-effective, screening of sites for which the analysis of real-time control may be beneficial . Earlier research led to the provision of an easy-to-apply scoring system which allows a quick assessment of the RTC potential of controlling flow in sewer systems . However, since this procedure does not take into account water quality aspects, or the treatment plant or the receiving water body, it cannot be used for assessing the potential of RTC of the complete system, let alone for integrated RTC . This paper describes the first part of an on-going project which aims at establishing an enhanced procedure for assessing the real-time control potential for the entire urban wastewater system . After providing a definition of the term "RTC potential", a large number of (partly hypothetical) case studies (varying a number of key parameters of the wastewater system) is simulated, using the simulation tool SYNOPSIS . For each of these sites, a number of real-time control algorithms are developed and optimised, following a general procedure, which allows for local, global and integrated scenarios to be considered . Analysis of the results reveals those system parameters which are of particular significance to the RTC potential of urban wastewater systems . These are discussed and assessed in this paper . Furthermore, the results of a simulation study are provided which indicate a clear potential of integrated control even for many case studies for which local control provides hardly any benefits . Subsequent studies will complement the simulation study by comparison with a number of real case studies in various countries.

Water Sci Technol, 2002, 45(3), 109 - 16
Real time control of the integrated urban wastewater system using simultaneously simulating surrogate models; Meirlaen J et al.; The urban wastewater system (sewer and treatment plant) has a major impact on the river water quality of urban streams . To minimise this impact, real time control is a valuable option . Since the ultimate goal of any control strategy is to optimise the quality of the river system, it is useful to take pollutant immissions into account when determining the control strategy and/or the setpoints of the controller . However, a simultaneously simulating model of the complete system is needed in order to allow design and evaluation of such control strategies . In this work an integrated model of the urban wastewater system is created . This has been accomplished by implementing surrogate models of the three subsystems within a single software platform . The coupled submodels are subsequently used in a semi-hypothetical case study to optimise the resulting river water quality . An ammonia sensor in the river has been used to control the amount of water treated biologically in the treatment plant . It was shown that this integrated control could lower the peak ammonia concentration in the part of the river downstream of the treatment plant . Hence, a proof of principle has been given that the use of measurements in the river to perform control actions in the sewer system and the treatment plant is a promising option.

J Hazard Mater, 2002 Apr 26, 91(1-3), 221 - 38
An investigation into the sorption of heavy metals from wastewaters by polyacrylamide-grafted iron(III) oxide; Manju GN et al.; An adsorbent for heavy metals was synthesized by introducing carboxylate functional group into polyacrylamide-grafted hydrous iron(III) oxide . The product exhibits a very high adsorption potential for Pb(II), Hg(II) and Cd(II) . The removal of metal ions by adsorption on adsorbent has been found to be contact time, concentration, pH and temperature dependent . The process follows first-order reversible kinetics . The intraparticle diffusion of metal ions through pores in the adsorbent was shown to be the main rate-limiting step . The optimum pH range for the removal of metal ions was found to be 5.0-6.0 . The thermodynamic parameters such as free energy change, enthalpy change and entropy change have been calculated to predict the nature of adsorption . The adsorption data were fitted using the Langmuir equation and maximum adsorption for each metal was estimated using their respective Langmuir equation constants . The method was applied for synthetic wastewaters . NaCl regeneration has been tried for several cycles with a view to recover the adsorbed metal ions and also to restore the sorbent to its original state.

J Food Prot, 2002 Mar, 65(3), 471 - 5
Prevalence of Escherichia coli associated with a cabbage crop inadvertently irrigated with partially treated sewage wastewater; Wachtel MR et al.; Preharvest contamination of field crops may have many sources, including feces, soil, and irrigation water . In March 2000, a sewage spill released unchlorinated tertiary-treated effluent into a creek used to irrigate commercial produce . A field of young cabbage transplants was irrigated with creek water as the contaminated water flowed past this land . Cabbage samples were taken from plots within this field, and Escherichia coli was isolated from the roots of these plants but not from the edible portion of the cabbage . No E . coli was isolated from water samples or from control samples taken from a nearby cabbage field watered with chlorinated municipal water . The cabbage field under study had not been fertilized with manure for at least 2 years prior to the contamination incident . Six different E . coli serotypes were identified, although none of them proved to be pathogenic . These serotypes were separated into five groups by a RiboPrinter; the resulting groups correlated well with the serotypes and the locations in the field from which these strains were isolated . We previously found that certain nonpathogenic E . coli strains displayed lower levels of adherence to lettuce seedling roots in a hydroponic adherence assay . The E . coli field strains displayed variable patterns of adherence to lettuce seedlings: strain MW421 showed significantly lower root and shoot adherence levels than did the other field strains, while strains MW423 and MW425 showed significantly higher root and shoot adherence levels . These data suggest that water quality is of paramount importance for the food safety of growing crops.

J Hazard Mater, 2002 Mar 29, 90(3), 237 - 49
Destruction of carbon disulfide in aqueous solutions by sonochemical oxidation; Appaw C et al.; Carbon disulfide (CS(2)) is toxic to animals and aquatic organisms, and can also decompose to carbonyl sulfide (OCS) and hydrogen sulfide (H(2)S) in aqueous environment . The kinetics of the sonochemical degradation of aqueous CS(2) was studied in a batch reactor at 20kHz and 20 degrees C, and the effects of process parameters (e.g . concentration, ultrasonic intensity, irradiating gas) investigated . The concentrations of unbuffered CS(2) solutions used were (6.4-7.0) x 10(-4), 10.5 x 10(-4) and (13.2-13.6) x 10(-4)M and the intensities were varied from 14 to 50W . The reaction rate was found to be zero-order and the rate constant for the degradation at 20 degrees C and 14W in air was 21.1 microM/min using the largest initial concentration range studied . At the same initial concentration range but at 50W (39.47W/m(2)) the degradation rate of CS(2) was 46.7 microM/min, more than two times that at 14W (11.04W/m(2)) . The rate of CS(2) sonochemical degradation in the presence of the different gases was in the order of He>air> or =N(2)O>Ar; the rate with helium was found to be about three times that of argon . The formation of sulfate (SO(4)(2-)) as reaction product with air as the irradiating gas was enhanced in the presence of hydrogen peroxide (H(2)O(2)) and inhibited in the presence of 1-butanol . The sonochemical oxidation of CS(2) may prove to be an efficient and environmentally benign way for the removal of this hazardous pollutant from natural water and wastewater.

Environ Monit Assess, 2002 Feb, 74(1), 11 - 25
Assessment of treatment alternatives for laboratory cod wastewater: a practical comparison with emphasis on cost and performance; Leong ST et al.; This study focused on investigation of treatment alternatives for COD wastewater from academic laboratories, using a number of technologies including chemical reduction/precipitation, ion exchange and adsorption by chitosan . Results showed that high concentrations of 375 mg l(-1) chromium, 1,740 mg l(-1) mercury and 993 mg l(-1) silver in COD wastewater can be reduced to 2.34 mg l(-1), 3.65 mg l(-1) and 1.89 mg l(-1) respectively, by the chemical reduction/precipitation process . Results from ion exchange at a flowrate of 20 ml min(-1) showed breakthrough effluent concentrations obtained at 0.59 mg l(-1) chromium, 3.92 microg l(-1) mercury and 0.65 mg l(-1) silver corresponding to 75.6 l at 63 hr, 40.8 l at 34 hr and 33.6 l at 28 hr respectively . Kinetic and isotherm studies revealed that chitosan can adsorb Cr6+, Hg2+ and Ag+ ions most effectively at a flowrate of 20 ml min(-1) and the optimum pH for feed solution is 4 . Chitosan column experiments indicated that average effluent concentrations at breakthrough point for chromium, mercury and silver are 0.76 mg l(-1), 6.04 mg l(-1) and 0.51 mg l(-1) respectively with throughput volumes and retention times of 120 l at 100 hr, 60 l at 50 hr and 48 l at 40 hr . Results of solidification experiments for chemical sludge and residual chitosan based on compressive strength and metal leachability tests showed, that the acceptable ranges of the solidification parameters were: sludge/cement = 0.1-1.0 (weight/weight), water/cement = 0.5-0.6 (weight/weight) and sand/cement = 0.5-3.0 (weight/weight) . Operating cost per litre of COD wastewater treated, based on the current prices in Thailand was found to be Baht 19.95 for the chemical reduction/precipitation process, Baht 96.35 for ion exchange treatment and Baht 18.29 for chitosan adsorption.

Water Sci Technol, 2002, 45(2), 27 - 33
Comparison of rain gauge and radar data as input to an urban rainfall-runoff model; Quirmbach M et al.; This paper presents an application of radar data (DX-product of the German Weather Service) with a high resolution in space (1 degree x 1 km) and time (delta t = 5 minutes) in urban hydrology . The radar data and data of rain gauges with different locations in the test catchment were compared concerning their suitability as input into an urban rainfall-runoff model . In order to evaluate the accuracy of model simulation results, five evaluation criteria have been specified which are relevant for an efficient management of sewer systems and wastewater treatment plants . The results demonstrate that radar data should be used in urban hydrology if distances > 4 km between rain gauge and catchment exist and for catchments with a density of rain gauges smaller than 1 rain gauge per 16 km2.

J Environ Sci (China), 2002 Jan, 14(1), 39 - 43
Seed yeast cultivation for salad oil manufacturing wastewater treatment; Zheng SK et al.; The mixture of five yeast strains obtained from soil could remove about 85% TOC of oil-rich wastewater in batch test . While the highest MLSS was obtained at an N:C of 1:5, the oil removal decreased with the increase of N:C during yeast sludge cultivation . Ammonium chloride was the best nitrogen source for yeast cultivation from the viewpoint of yeast growth and oil utilization . An ammonia concentration of over 1300 mg/L led to mass death of yeast at a pH of 5 . The ammonia concentration should be controlled at a level of 1000 mg/L or lower.

J Environ Sci (China), 2002 Jan, 14(1), 34 - 8
Cobalt in alluvial Egyptian soils as affected by industrial activities; Zohny EA; Twenty-five surface (0-20 cm) soil samples were collected from different locations in Egypt representing non-polluted, moderately and highly polluted soils . The aim of this study was to evaluate total Co content in alluvial soils of Delta in Egypt using the delayed neturen activation analysis technique (DNAA) . The two prominent gamma ray lines at 1173.2 and 1332.5 keV was efficiently used for 60Co determination . Co content in non-polluted soil samples ranged between 13.12 to 23.20 ppm Co with an average of 18.16 +/- 4.38 ppm . Cobalt content in moderately polluted soils ranged between 26.5 to 30.00 ppm with an average of 28.3 +/- 1.3 ppm . The highest Co levels (ranged from 36 to 64.69 ppm with an average of 51.9 +/- 9.5); were observed in soil samples collected from, either highly polluted agricultural soils due to prolonged irrigation with industrial wastewater or surface soil samples from industrial sites.

J Environ Sci (China), 2002 Jan, 14(1), 1 - 6
Removal of organic contaminants from water or wastewater with liquefied gases; Yang C et al.; This study utilized liquefied gases (LG) as extractant to remove various organic contaminants including halogenated hydrocarbons and phenols as well as aromatic compounds from aqueous matrices . Orthogonal experiments were performed to optimize the operating conditions such as temperature, co-solvents and so on . Under favorable conditions, high removal efficiencies can be readily achieved for a great number of representative model organic contaminants, the removal efficiencies for most of the hydrophobic contaminants were greater than 90% in a single extraction stage . Tentative effort was also done for the removal of extracted contaminants from recycled liquefied gases.

J Chromatogr A, 2002 Feb 22, 947(2), 217 - 25
Determination of the amount of wash amines and ammonium ion in desulfurization products of process gases and results of related studies; Kaminski M et al.; This paper describes a method for the determination of the so-called wash amines and their degradation products, including ammonium ions, in process liquids and wastewater generated during the desulfurization of hydrogen sulfide gas in the process of crude oil refining and also reports the results of related studies . Ion-exchange liquid chromatography employing an inexpensive cation-exchange HPLC column and refractometric detection was used . The results obtained were compared with those obtained by potentiometric titration . Analytical characteristics and a description of the developed procedure are provided . Examples of the results of routine determinations of amines, their degradation products and ammonium ions in process liquids and wastewater are given.

Aquat Toxicol, 2002 Apr, 57(1-2), 39 - 49
Symptoms and implications of selenium toxicity in fish: the Belews Lake case example; Lemly AD; Belews Lake, North Carolina was contaminated by selenium in wastewater from a coal-fired power plant during the mid-1970s, and toxic impacts to the resident fish community (20 species) were studied for over two decades . Symptoms of chronic selenium poisoning in Belews Lake fish included, (1) telangiectasia (swelling) of gill lamellae; (2) elevated lymphocytes; (3) reduced hematocrit and hemoglobin (anemia); (4) corneal cataracts; (5) exopthalmus (popeye); (6) pathological alterations in liver, kidney, heart, and ovary (e.g . vacuolization of parenchymal hepatocytes, intracapillary proliferative glomerulonephritis, severe pericarditis and myocarditis, necrotic and ruptured mature egg follicles); (7) reproductive failure (reduced production of viable eggs due to ovarian pathology, and post-hatch mortality due to bioaccumulation of selenium in eggs); and (8) teratogenic deformities of the spine, head, mouth, and fins . Important principles of selenium cycling and toxicity were documented in the Belews Lake studies . Selenium poisoning in fish can be 'invisible', because, the primary point of impact is the egg, which receives selenium from the female's diet (whether consumed in organic or inorganic forms), and stores it until hatching, whereupon it is metabolized by the developing fish . If concentrations in eggs are great enough (about 10 microg/g or greater) biochemical functions may be disrupted, and teratogenic deformity and death may occur . Adult fish can survive and appear healthy despite the fact that extensive reproductive failure is occurring--19 of the 20 species in Belews Lake were eliminated as a result of this insidious mode of toxicity . Bioaccumulation in aquatic food chains causes otherwise harmless concentrations of selenium to reach toxic levels, and the selenium in contaminated sediments can be cycled into food chains for decades . The lessons learned from Belews Lake provide information useful for protecting aquatic ecosystems as new selenium issues emerge.

Environ Monit Assess, 2002 Mar, 74(2), 167 - 92
Using mussel isotope ratios to assess anthropogenic nitrogen inputs to freshwater ecosystems; McKinney RA et al.; Stable nitrogen isotope ratios (delta15N) of freshwater mussels from a series of lakes and ponds were related to watershed land use characteristics to assess their utility in determining the source of nitrogen inputs to inland water bodies . Nitrogen isotope ratios measured in freshwater mussels from 19 lakes and ponds in Rhode Island, U.S.A., ranged from 4.9-12.6 per thousand and were found to significantly correlate with the fraction of residential development in 100 and 200 m buffer zones around the ponds . Mussel delta15N values in 12 of the 19 ponds also showed significant correlation with average dissolved nitrate concentrations, which ranged from 23-327 microg L(-1) . These observations, in light of previous studies which link elevated delta15N values of nitrogen derived from septic wastewater with those seen in biota, suggest that mussel isotope ratios may reflect nitrogen source in freshwater ecosystems . We followed an iterative approach using multiple regression analysis to assess the relationship between mussel delta15N and the land use categories fraction residential development, fraction feedlot agriculture, fraction row-crop agriculture, and fraction natural vegetation in 100 and 200 m buffer zones and pond watersheds . From this we developed a simple regression model to predict mussel delta15N from the fraction of residential development in the 200 m buffer zone around the pond . Subsequent testing with data from 16 additional sites in the same ecoregion led us to refine the model by incorporating the fraction of natural vegetation . The overall average absolute difference between measured and predicted delta15N values using the two-parameter model was 1.6 per thousand . Potential sources of error in the model include differences in the scale and categorization of land-use data used to generate and test the model, differences in physical characteristics, such as retention time and range of residential development, and exclusion of sources of enriched nitrogen such as runoff from feedlot operations or increased nitrogen loading from inefficient or failed septic systems.

Environ Monit Assess, 2002 Jan, 73(1), 41 - 66
Necessity of toxicity assessment in Turkish industrial discharges (examples from metal and textile industry effluents); Sponza DT; Toxicity of some organic and inorganic chemicals to microorganisms is an important consideration in assessing their environmental impact against their economic benefits . Microorganisms play an important role in several environmental processes, both natural and engineered . Some organic and inorganics at toxic levels have been detected in industrial discharges resulting in plant upsets and discharge permit violations . In addition to this, even though in some cases the effluent wastewater does not exceed the discharge limits, the results of toxicity tests show potential toxicity . Toxicity knowledge of effluents can benefit treatment plant operators in optimising plant operation, setting pre-treatment standards, and protecting receiving water quality and in establishing sewer discharge permits to safeguard the plant . In the Turkish regulations only toxicity dilution factor (TDF) with fish is part of the toxicity monitoring program of permissible wastewater discharge . In various countries, laboratory studies involving the use of different organisms and protocol for toxicity assessment was conducted involving a number of discharges . In this study, it was aimed to investigate the acute toxicity of textile and metal industry wastewaters by traditional and enrichment toxicity tests and emphasize the importance of toxicity tests in wastewater discharge regulations . The enrichment toxicity tests are novel applications and give an idea whether there is potential toxicity or growth limiting and stimulation conditions . Different organisms were used such as bacteria (Floc and Coliform bacteria) algae (Chlorella sp.) . fish (Lepistes sp.) and protozoan (Vorticella sp.) to represent four tropic levels . The textile industry results showed acute toxicity for at least one organism in 8 out of 23 effluent samples . Acute toxicity for at least two organisms in 7 out of 23 effluent sampling was observed for the metal industry . The toxicity test results were assessed with chemical analyses such as COD, BOD, color and heavy metals . It was observed that the toxicity of the effluents could not be explained by using physicochemical analyses in 5 cases for metal and 4 cases for the textile industries . The results clearly showed that the use of bioassay tests produce additional information about the toxicity potential of industrial discharges and effluents.

J AOAC Int, 2002 Jan-Feb, 85(1), 173 - 81
Evaluation of the mixed aggregate method as an alternative to the bismuth active substances and cobalt thiocyanate active substances procedures for the determination of nonionic surfactants in raw and treated sewage; Borrego E et al.; The mixed aggregate (MA) method was evaluated for the routine determination of total ethoxylated nonionic surfactants in municipal raw and treated sewage . Nonionics in wastewater samples were enriched with a C8 solid-phase extraction cartridge, eluted with ethyl acetate-methanol, and separated from interferences with stacked strong anionic (quaternary ammonium form) and cationic (benzenesulfonic acid form) exchange columns . Sample extracts were evaporated to dryness and redissolved in distilled water . The total amount of ethoxylates, on a weight basis, was determined by measuring the critical micelle concentration of a mixed micelle made up of ethoxylates and the anionic surfactant sodium dodecyl sulfate, used as the reagent . The dye Coomassie Brilliant Blue G was used as a photometric probe . The minimum amount of ethoxylate required for a single determination was 1 microg . For raw sewage samples, mean recoveries and standard deviations were 98 +/- 6 and 98 +/- 4% at fortification levels of 0.3 and 0.6 microg/mL, respectively . For treated sewage samples, mean recoveries and standard deviations were 95 +/- 2 and 100 +/- 2% at fortification levels of 0.03 and 0.06 microg/mL, respectively . The MA method and the classical bismuth active substances and cobalt thiocyanate active substances procedures were compared . The former offers some significant advantages over the classical procedures in terms of sensitivity, selectivity, precision, simplicity, and rapidity; the type of response is independent of both the molecular weight and the chain length of the surfactant.

Environ Sci Technol, 2002 Feb 15, 36(4), 778 - 83
Novel electrode system for electroflotation of wastewater; Chen X et al.; Electroflotation (EF) is an attractive method in wastewater treatment . The heart of EF is the dimensionally stable oxygen evolution anode that is usually expensive . In this paper, we present a stable anode by coating IrOx-Sb2O5-SnO2 onto titanium . Accelerated life test showed that the electrochemical stability of the Ti/IrOx-Sb2O5-SnO2 anode containing only 2.5 mol % of IrOx nominally in the activated coating was even higher than that of the conventional Ti/IrOx anode . Its service life for electroflotation application is predicted to be about 20 yr . Voltammetric investigation demonstrated that the Ti/IrOx-Sb2O5-SnO2 anode could provide fast electron transfer . Moreover, the present anode was designed to be fork-like and arranged interlockingly at the same level as the cathode with a similar shape . Such an innovation in electrode configuration and arrangement allows bubbles produced at both electrodes to be dispersed into wastewater flow quickly and, therefore, enhances the effective contact between bubbles and particles, favorable for high flotation efficiency . In addition, the novel electrode system reduces the interelectrode gap to 2 mm, a spacing that is technically difficult for a conventional electrode system . This small gap results in a significant energy saving . Easy maintenance is found to be another advantage of this novel electrode system.

Environ Sci Technol, 2002 Feb 15, 36(4), 588 - 95
Formation of N-nitrosodimethylamine (NDMA) from dimethylamine during chlorination; Mitch WA et al.; Chlorine disinfection of secondary wastewater effluent and drinking water can result in the production of the potent carcinogen N-nitrosodimethylamine (NDMA) at concentrations of approximately 100 and 10 parts per trillion (ng/L), respectively . Laboratory experiments with potential NDMA precursors indicate that NDMA formation can form during the chlorination of dimethylamine and other secondary amines . The formation of NDMA during chlorination may involve the slow formation of 1,1-dimethylhydrazine by the reaction of monochloramine and dimethylamine followed by its rapid oxidation to NDMA and other products including dimethylcyanamide and dimethylformamide . Other pathways also lead to NDMA formation during chlorination such as the reaction of sodium hypochlorite with dimethylamine . However, the rate of NDMA formation is approximately an order of magnitude slower than that observed when monochloramine reacts with dimethylamine . The reaction exhibits a strong pH dependence due to competing reactions . It may be possible to reduce NDMA formation during chlorination by removing ammonia prior to chlorination, by breakpoint chlorination, or by avoidance of the use of monochloramine for drinking water disinfection.

Appl Microbiol Biotechnol, 2002 Feb, 58(2), 224 - 8
Acid-base enrichment enhances anaerobic hydrogen production process; Chen CC et al.; This study offers a novel and quick enrichment technology that can be used as a preliminary method to obtain a hydrogen-producing species from the biological sludge produced by wastewater treatment . The influences of acid-base enrichment (by sludge pH adjustment) on the anaerobic hydrogen-producing micro-organisms were investigated using serum bottle assays . The enrichment pH values were controlled at 3, 4, 5, 7, 10, 11 and 12 with 1 N hydrochloric acid and 1 N sodium hydroxide . For each enrichment pH, the cultivation pH values were controlled at 5, 6 and 7 . Based on the experimental results, hydrogen accumulation from sludge with acid or base enrichment is higher than that of the control . The hydrogen-production potential of the sludge with acid or base enrichment is 200 and 333 times enhanced, compared with the control, when the enrichment pH is 10 and 3, respectively . The enhancement is due to a shortening of the micro-organisms' lag-time which occurs at a proper cultivation-pH level.

Life Support Biosph Sci, 1998, 5(3), 357 - 69
Wetland systems for bioregenerative reclamation of wastewater: from closed systems to developing countries; Nelson M; Results are presented from constructed wetland systems designed to treat wastewater in Akumal, Quintana Roo, Mexico, which was developed after prior experience with the Biosphere 2 closed ecological system wetland systems . These systems illustrate the congruity of needs in advanced life support systems and in solving social and environmental problems in developing countries . For sustainable food production for life support, closed ecological systems need to bioregenerate and recycle nutrient-rich wastewater . Developing countries need low-tech ecologically engineered systems that minimize requirements for capital, nonrenewable energy, and technical expertise . Biosphere 2's surface flow wetlands covered 41 m2 and treated the wastewater from eight inhabitants, laboratories, and domestic animals during the 1991-1993 closure experiment . The Mexican wetlands are subsurface flow wetlands using limestone gravel as substrate . Two wetland systems treat sewage from 40 people and cover 131 m2 . During the initial year of operation, the wetlands in Akumal reduced BOD 86%, TSS 39%, total P 80%, total N 75%, and coliform bacteria 99.85% . Phosphorus uptake in the limestone gravel was around 6 mg/kg . High biodiversity, with 70 plant species, was maintained in the Akumal constructed wetlands 1.5 years after planting . The Shannon diversity index was 4.7 (base 2) . Plant diversity was slightly less than tropical forest ecosystems of the region, but far greater than biodiversity in natural mangrove wetlands.

Environ Technol, 2001 Dec, 22(12), 1487 - 95
Effect of applying Hong Kong biosolids and lime on nutrient availability and plant growth in an acidic loamy soil; Wong JW et al.; A greenhouse experiment was conducted to evaluate the growth of Brassica chinensis L . in an acidic loamy soil amended with municipal biosolids with or without lime treatment (750 mg kg(-1)) . The soil was amended with one of two municipal biosolids from Tai Po (TP) or Yuen Long (YL) wastewater treatment plants at application rates of 0, 5, 10, 25 and 50% (v/v) . Initial NH(+)4-N and PO(3-)4-P concentrations in the amended soil increased with an increase in municipal biosolids loading rates and those with biosolids from TP had a greater increase in nutrients than those from YL . However, initial NO(-)3-N contents in both municipal biosolids amended soils decreased with an increase in biosolids loading rates, particularly for the soil amended with YL . Soluble K, Mg, Na and Ca concentrations in the soil increased with application rates . Municipal biosolids amended soil without lime treatment had higher NH(+)4-N, NO(-)3-N and major cation contents than those with lime . Addition of Tai Po municipal biosolids and lime significantly increased the dry weight yields of B . chinensis L., while YL municipal biosolids increased yields only at the 5% rate with lime amendment . The maximum growth was obtained at municipal biosolids application rates of 5 and 10% for TP and 5% for YL for limed soil . Addition of municipal biosolids increased the total N, P, Zn, Cr and major cation concentrations in the shoot tissue, while lime treatment reduced Zn and Cr contents . The high salt and metal concentrations would likely be factors inhibiting plant growth at high application rates, especially for YL biosolids . Further studies to determine the long-term effects of biosolid application on soil and crop quality are warranted.

Environ Technol, 2001 Dec, 22(12), 1459 - 65
Inhibition on acidogenesis of dairy wastewater by zinc and copper; Yu HQ et al.; Acidogenesis of dairy wastewater produced volatile fatty acids, mainly acetate and propionate, plus hydrogen as by-product . Zinc (Zn) inhibited acidogenesis at concentrations over 10 mg l(-1); but at 10 mg l(-1), or less, it enhanced acidogenesis slightly . On the other hand, copper (Cu) inhibited acidogenesis at all tested concentrations ranging 5-400 mg l(-1) . Production of acetate was inhibited by both metals at all concentrations; but production of propionate and hydrogen was favored at low concentrations of Zn (up to 80 mg l(-1)) and Cu (up to 40 mg l(-1)) . Production of hydrogen corresponded with the degradation of carbohydrate and the production of propionate . Overall, Cu was 1.4-4.3 folds more toxic than Zn, according to the overall production patterns of fatty acids and hydrogen as well as degradation patterns of carbohydrate and protein.

Environ Technol, 2001 Dec, 22(12), 1439 - 46
Effect of different operational parameters in the enhanced biological phosphorus removal process . Experimental design and results; Carrera J et al.; The uncontrolled dumping of phosphorus into a water environment creates serious problems of eutrophication, affecting water quality and causing grave problems in the aquatic ecosystem . European legislation demands drastic reduction of phosphorus dissolved in wastewater . Enhanced Biological Phosphorus Removal (EBPR) is the current tendency in wastewater treatment . This biological process depends on a multiplicity of variables, but its three main factors are: influent COD/P ratio, anaerobic fraction and sludge retention time (SRT) . The aim of this work is to statistically determine the effect of these three parameters in EBPR through a response surface methodology . The objective function that has been chosen is phosphorus removed per unit biomass formed . This function provides ample information on BPR, since the quantity of phosphorus removed depends on the accumulative capacity of the microorganisms present . Two levels were chosen for the SRT (5 and 10 days), two for the anaerobic fraction (0.1 and 0.2), and six for levels of the influent COD/P ratio (between 16 and 87) . The experiments were undertaken at pilot scale (100 litres) with an A2/O configuration, with simultaneous nitrogen and phosphorous removaL The wastewater used is a synthetic mixture of complex sources of carbon and nitrogenwithout volatile fatty acids . The empirical model obtained indicates that the factor most influencing the EBPR process is the influent COD/P ratio, whilst the anaerobic fraction is that which has least influence . Additionally, there is an optimum in the influent COD/P ratio that is to be found between 41 and 48.

Appl Environ Microbiol, 2002 Mar, 68(3), 1436 - 9
Isolation and genotyping of Helicobacter pylori from untreated municipal wastewater; Lu Y et al.; For this study, we isolated Helicobacter pylori from wastewater by a series of steps beginning with immunomagnetic separation and cell culture . After Gram staining and three standard microbial tests, the 16S rRNA sequences of a total of 23 out of 37 putative H . pylori isolates were verified by PCR . Eleven H . pylori isolates were genotyped and fell into four vacA classes: those with the vacA allelic variants s1a and m1, s1b and m1, s2 and m2, or s2 and m1 . Most H . pylori isolates were of the vacA s1a/m1 type, which has been shown to be associated with advanced diseases based on genotyping of H . pylori from gastric cancer patients . These results demonstrated that H . pylori survives in water and may be a potential source of H . pylori transmission, especially where water is not adequately treated.

Appl Environ Microbiol, 2002 Mar, 68(3), 1358 - 66
Novel psbA1 gene from a naturally occurring atrazine-resistant cyanobacterial isolate; Sajjaphan K et al.; A naturally occurring atrazine-resistant cyanobacterial isolate, strain SG2, was isolated from an atrazine-containing wastewater treatment system at the Syngenta atrazine production facility in St . Gabriel, La . Strain SG2 was resistant to 1,000 microg of atrazine per ml but showed relatively low resistance to diuron {3-(3,4-dichlorophenyl)-1,1-dimethyl urea} . Analyses of 16S ribosomal DNA indicated that strain SG2 falls into the Synechocystis/Pleurocapsa/Microcystis group . Photosynthetically driven oxygen evolution in strain SG2 was only slightly inhibited (about 10%) by 2,000 microg of atrazine per ml, whereas in the control strain Synechocystis 6803, oxygen evolution was inhibited 90% by 1,000 microg of atrazine per ml . No atrazine accretion, mineralization, or metabolites were detected when strain SG2 was grown with {(14)C}atrazine . Strain SG2 contained three copies of the psbA gene, which encodes the D(1) protein of the photosystem II reaction center . Nucleotide sequence analyses indicated that the psbA2 and psbA3 genes encoded predicted proteins with the same amino acid sequence . However, the psbA1 gene product contained five extra amino acids, which were not found in PsbA proteins from five other cyanobacteria . Moreover, the PsbA1 protein from strain SG2 had an additional 13 amino acid changes compared to the PsbA2/PsbA3 proteins and contained 10 amino acid alterations compared to conserved residues found in other cyanobacteria . Reverse transcriptase PCR analysis indicated that the psbA1 gene and the psbA2/psbA3 gene(s) were expressed in photosynthetically grown cells in the presence of atrazine . These results suggest that strong selection pressure conferred by the continual input of atrazine has contributed to the evolution of a herbicide-resistant, yet photosynthetically efficient, psbA gene in a cyanobacterium.

Life Support Biosph Sci, 1998, 5(4), 415 - 21
An evaluation of the vapor phase catalytic ammonia removal process for use in a Mars transit vehicle; Flynn M et al.; This article describes the design specification of the Vapor Phase Catalytic Ammonia Removal (VPCAR) process and the relative benefits of its utilization in a Mars Transit Vehicle application . The VPCAR process is a wastewater treatment technology that combines distillation with high-temperature catalytic oxidation of volatile impurities such as ammonia and organic compounds.

Biotechnol Bioeng, 2002 Apr 20, 78(2), 147 - 56
Biokinetics in acidogenesis of highly suspended organic wastewater by adenosine 5' triphosphate analysis; Yu Y et al.; In this paper, we pointed out the problems of using conventional volatile suspended solids (VSS) and chemical oxygen demand (COD) to evaluate biokinetic coefficients, especially for the treatment of highly suspended organic wastewater . We also introduced a novel approach to evaluate biokinetic coefficients by measurement of adenosine 5'-triphosphate (ATP) of microorganisms . The concept of using ATP analysis in biokinetic evaluations with highly suspended wastewater was shown to be effective . This study also showed that the conventional VSS and COD methods were strongly affected by incoming suspended organics in the wastewater and by biokinetics of microorganisms . A cheese-processing wastewater was used in evaluating the biokinetics of mesophilic acidogens . The concentration of COD and total suspended solids in the wastewater was 63.3 g/L and 12.4 g/L, respectively . The TSS was 23.6% of total solids concentration . A high ratio of VSS to total suspended solids of 96.7% indicated that most of the suspended particles were organic materials . Lactose and protein were the major organic components contributing COD in the wastewater, and a total of 94.2% of the COD in the wastewater was due to the presence of lactose and protein . Two different physiological conditions where the maximum rates of acetate and butyrate production occurred were tested . These were pH 7 (condition A for acetate production) and pH 7.3 (condition B for butyrate production) at 36.2C, respectively . Based on the molecular structures of the major organic substances and microbial ATP analysis, the residual substrate and microbial concentrations were stoichiometrically converted to substrate COD (SuCOD) and microbial VSS (MVSS), respectively, using correlation coefficients reported previously . These SuCOD and MVSS were simultaneously used to evaluate the biokinetic coefficients using Monod-based mathematical equations . The nonlinear least squares method with 95% confidence interval was used to evaluate biokinetic coefficients . The maximum microbial growth rate, mu(max) and half saturation coefficient, K(s), for conditions A and B were determined to be 9.9 +/- 0.3 and 9.3 +/- 1.0 day(-1) and 134.0 +/- 58.3 and 482.5 +/- 156.5 mg SuCOD/L, respectively . The microbial yield coefficient, Y, and microbial decay rate coefficient, k(d) for conditions A and B were determined to be 0.29 +/- 0.03 and 0.20 +/- 0.05 mg MVSS/mg SuCOD, and 0.14 +/- 0.05 and 0.25 +/- 0.05 day(-1), respectively . Specific substrate utilization rate at condition B was 43.8 +/- 20.6 mg SuCOD/mg MVSS/day, which was 31% higher than that at condition A .

J Microbiol Methods, 2002 May, 49(3), 209 - 24
Cryptosporidium parvum and Cyclospora cayetanensis: a review of laboratory methods for detection of these waterborne parasites; Quintero-Betancourt W et al.; Cryptosporidium and Cyclospora are obligate, intracellular, coccidian protozoan parasites that infest the gastrointestinal tract of humans and animals causing severe diarrhea illness . In this paper, we present an overview of the conventional and more novel techniques that are currently available to detect Cryptosporidium and Cyclospora in water . Conventional techniques and new immunological and genetic/molecular methods make it possible to assess the occurrence, prevalence, virulence (to a lesser extent), viability, levels, and sources of waterborne protozoa . Concentration, purification, and detection are the three key steps in all methods that have been approved for routine monitoring of waterborne oocysts . These steps have been optimized to such an extent that low levels of naturally occurring Cryptosporidium oocysts can be efficiently recovered from water . The filtration systems developed in the US and Europe trap oocysts more effectively and are part of the standard methodologies for environmental monitoring of Cryptosporidium oocysts in source and treated water . Purification techniques such as immunomagnetic separation and flow cytometry with fluorescent activated cell sorting impart high capture efficiency and selective separation of oocysts from sample debris . Monoclonal antibodies with higher avidity and specificity to oocysts in water concentrates have significantly improved the detection and enumeration steps.To date, PCR-based detection methods allow us to differentiate the human pathogenic Cryptosporidium parasites from those that do not infect humans, and to track the source of oocyst contamination in the environment . Cell culture techniques are now used to examine oocyst viability . While fewer studies have focused on Cyclospora cayetanensis, the parasite has been successfully detected in drinking water and wastewater using current methods to recover Cryptosporidium oocysts . More research is needed for monitoring of Cyclospora in the environment . Meanwhile, molecular methods (e.g . molecular markers such as intervening transcribed spacer regions), which can identify different genotypes of C . cayetanensis, show good promise for detection of this emerging coccidian parasite in water.

Environ Int, 2002 Feb, 27(7), 541 - 53
Environmental geochemistry and pollution studies of Aliaga metal industry district; Sponza D et al.; The Aliaga metal industry district located 50 km northwest of Izmir City, in Turkey, includes many metal factories . The geology of the area is represented by Mesozoic flysch deposits and Cenozoic volcano sedimentary rocks . Tectonic elements are NE-SW and NW-SE trending faults and a W-NW trending fault direction that is important for water supply . Rock, soil, stream sediment, and water samples taken at various distances from the industrial area were analyzed for Fe, Ti, Mn, Cr, Pb, Cu, Ni, Zn, and Mo . According to the results, the elements in rocks are reasonable for the range of "Clarke" values, but in the soils and stream sediment, they comprise higher values than are acceptable for agricultural activities . Toxicity analyses were carried out in the drinking artesian water of Cakmakli village and wastewater samples of the factories and river water both of which are used for irrigation of the agricultural areas in and around the investigated area . The people should, however be made aware that this waste and river water is unacceptable for agriculture . Additionally, the contamination of seawater in Nemrut Bay is probably caused by contaminated river and underground water running to the sea . The chemical and toxicity analysis of drinking water samples show that they are above accepted standards and harmful . Previous air pollution studies (funnel gas emission analyses) also show that gas emission contains high amount of dust particles with high Fe, Zn, Pb, and Cu concentrations . As a result, all elements analyzed are of great importance relative to problems concerning contamination of the soil, stream sediment, ground surface water, and air by individual metals from uncontrolled processing of some metal factories.

J Chromatogr A, 2002 Feb 1, 945(1-2), 195 - 209
Development of a static headspace gas chromatographic procedure for the routine analysis of volatile fatty acids in wastewaters; Cruwys JA et al.; An optimised procedure has been developed for the routine analysis of volatile fatty acids in wastewater matrices, using static headspace gas chromatography with flame ionisation detection . Factors such as sample volume, sample pre-treatment and the time and temperature of sample equilibration have been included in an optimisation model designed to provide maximum detector response for acetic, propionic, iso- and n-butyric and iso- and n-valeric acids in the concentration range 0-1000 mg/l . Optimal headspace conditions were observed when equilibrating at 85 degrees C for 30 min, using a 2.0 ml sample volume with the addition of 1.0 ml of NaHSO4 (62%, w/v) into standard 22.3 ml vials . 2-Ethylbutyric acid was used as an internal standard . The suitability of ordinary least squares regression and weighted least squares regression models for the purposes of calibration and quantification were investigated . A weighted least squares linear regression model applied to the heteroscedastic data provided lower detection limits, e.g . 3.7 and 3.3 mg/l for acetic and propionic acids.

Biotechnol Bioeng, 2002 Apr 5, 78(1), 89 - 103
Quantitative analyses of anaerobic wastewater treatment processes: identifiability and parameter estimation; Noykova N et al.; We investigated the problem of identifying the parameters of a nonlinear fifth order model describing the population dynamics of two main bacterial groups in an anaerobic wastewater treatment process . In addition to addressing problems concerning structural and practical identifiability, we also analyzed how mathematical descriptions of bacterial population dynamics can model real data . Using three data sets recorded under different experimental conditions, we estimated important biochemical parameters and demonstrated that our model could describe the data successfully . Parameters, which are simultaneously determined using information from all three experiments, have more reliable estimates . We conclude that, after appropriate estimation, this model can be used for optimization and the control of continuous processes .

Huan Jing Ke Xue, 2001 Nov, 22(6), 57 - 60
{Extraction and stripping of H acid and DSD acid wastewater}; Li Z et al.; H acid and DSD acid are two important substrate of dyes, which wastewater is treated more difficulty because of containing multi-component, with high chroma value and nonbiodegradability . A treatment way of this wastewater by extraction based on chemical association was carried out . Trialkylamine (Alamine 336) and chlorinated quaternary ammonium salt (Aliquat 336) were used as reacting agent with n-octanol, kerosene as modifier and diluent respectively . Results showed that the extraction efficiency depended on solution pH . Alamine 336 could be used to treat waste water with low pH while Aliquat 336 was high efficiency for waste water with pH > 6 . Recovery yield of H acid and DSD acid was greater than 99% and the chroma value of wastewater was reduced effectively by simulating multi-stages cross-flow extraction . Back-extraction is quite easy and the solvent could be regenerated.

Huan Jing Ke Xue, 2001 Nov, 22(6), 53 - 6
{Treatment of 2-naphtholwastewater using air oxidation and ion exchange}; Li Z et al.; The properties of 2-naphtholwastewater were studied in details in this paper, the wastewater was characterized by the strong acidity, high buffer capability and concentrated salt . Air oxidation and anion exchange were employed for the treatment of the wastewater . Under formal pH, room temperature and 1 BV/h rate, the result showed that the removal of COD reached to 97% and the recovery of sodium naphthalensulfonate to 98% . Besides, wastewater treated can be reused for washing the sodium naphthalensulfonate.

Water Res, 2002 Feb, 36(4), 933 - 43
The effect of polymer addition on granulation in an anaerobic baffled reactor (ABR) . Part I: process performance; Uyanik S et al.; The stability and performance of an anaerobic baffled reactor (ABR) treating an ice-cream wastewater at several organic loading rates have been investigated . Specifically, it was determined whether an ABR would promote phase separation and if a polymer additive was capable of enhancing granule formation in an ABR . In order to achieve these goals, two ABRs, having identical dimensions and configurations, were used to study the above objectives using a synthetic ice-cream wastewater . The ABR proved to be an efficient reactor configuration for the treatment of a high-strength synthetic ice-cream wastewater . An organic loading rate of around 15 kg CODm(-3) d(-1) was treated with a 99% COD removal efficiency . From the jar test and inhibition assay, it was concluded that Kymene SLX-2 was the most effective and least inhibitory polymer tested . The methane yield was higher in the polymer-amended reactor compared to the control reactor . In addition, polymer addition resulted in a considerably higher degree of biomass retention and lower solids washout from the ABR . Consequently, it demonstrated that there was a considerable potential for sludge conditioning in ABRs by facilitating better biomass retention within the reactor which in turn led to better process performance . Granulation was achieved in both ABRs within 3 months . However, the granules from the polymer-amended reactor appeared earlier and were generally larger and more compact, although this was not quantified in detail during the present study . The main advantage of using an ABR comes from its compartmentalised structure . The first compartment of an ABR may act as a buffer zone to all toxic and inhibitory material in the feed thus allowing the later compartments to be loaded with a relatively harmless, balanced and mostly acidified influent . In this respect, the latter compartments would be more likely to support active populations of the relatively sensitive methanogenic bacteria and partly explains why the best granules and the highest methane yield were obtained in Compartment 2 . It is unlikely that a complete separation of phases (acidogenic and methanogenic) occurred within the ABRs since methane production was observed in all compartments, although this was low (approximately 40% of all gas composition) in Compartment 1, becoming higher (approximately 70%) in the following compartments.

Water Res, 2002 Feb, 36(4), 859 - 70
Characterization of dissolved organic matter in effluents from wastewater treatment plants; Imai A et al.; Dissolved organic matter (DOM) in effluents from sewage and human-wastes treatment plants (STPEs and HWTPEs) was fractionated using resin adsorbents into six classes: aquatic humic substances (AHS), hydrophobic bases (HoB), hydrophobic neutrals (HoN), hydrophilic acids (HiA), hydrophilic bases (HiB), and hydrophilic neutrals (HiN) . DOM-fraction distribution varied substantially depending on the kind of wastewater and the type of treatment process . AHS and HiA dominated in all effluents, collectively accounting for more than 55% of the DOM measured as dissolved organic carbon (DOC) . In particular, HiA were the most abundant fraction in the effluents, constituting 32-74% of the DOM . AHS appeared to be the second most dominant fraction and varied considerably, accounting for 3-28% of the DOM . The HoN fraction also varied from 0-21% . AHS, HoN, and HiA were the fractions that changed substantially and differed characteristically among the samples studied . The ratios of ultraviolet absorbance to DOC (UV: DOC ratio) in all effluents exhibited a common relationship: AHS> total DOM > HiA . Nevertheless, the ratios were substantially different between STPEs and HWTPEs and among HWTPEs . For HWTPEs, the effluent from the chemical coagulation process had the highest UV: DOC ratios . On the other hand, the effluent from the ultrafiltration and activated carbon adsorption processes had the lowest ratios . Molecular size distribution of the effluents was determined by size exclusion chromatography and found to exhibit a relatively narrow size range and low weight-averaged molecular weights ranging from 380 to 830 g mol(-1) . The weight-averaged molecular weight of DOM increased as the UV: DOC ratio of total DOM increased.

Water Res, 2002 Feb, 36(4), 817 - 24
Formation of N-nitrosodimethylamine (NDMA) from reaction of monochloramine: a new disinfection by-product; Choi J et al.; Studies have been conducted specifically to investigate the hypothesis that N-nitrosodimethylamine (NDMA) can be produced by reactions involving monochloramine . Experiments were conducted using dimethylamine (DMA) as a model precursor . NDMA was formed from the reaction between DMA and monochloramine indicating that it should be considered a potential disinfection by-product . The formation of NDMA increased with increased monochloramine concentration and showed maximum in yield when DMA was varied at fixed monochloramine concentrations . The mass spectra of the NDMA formed from DMA and 15N isotope labeled monochloramine (15NH2Cl) showed that the source of one of the nitrogen atoms in the nitroso group in NDMA was from monochloramine . Addition of 0.05 and 0.5 mM of preformed monochloramine to a secondarily treated wastewater at pH 7.2 also resulted in the formation of 3.6 and 111 ng/L of NDMA, respectively, showing that this is indeed an environmentally relevant NDMA formation pathway . The proposed NDMA formation mechanism consists of (i) the formation of 1,1-dimethylhydrazine (UDMH) intermediate from the reaction of DMA with monochloramine followed by, (ii) the oxidation of UDMH by monochloramine to NDMA, and (iii) the reversible chlorine transfer reaction between monochloramine and DMA which is parallel to (i) . We conclude that reactions involving monochloramine in addition to classical nitrosation reactions are potentially important pathways for NDMA formation.

Water Res, 2002 Feb, 36(4), 1084 - 8
The use of upflow anaerobic filter and AnSBR for wastewater treatment at ambient temperature; Bodik I et al.; This research was carried out in order to study the effect of the temperature and hydraulic retention time (HRT) on the start-up and steady-state performance of upflow anaerobic filter (UAF) and anaerobic sequencing batch reactor (AnSBR) . A mixture of synthetic substrate (glucose and sodium acetate) and real municipal wastewater was used as a laboratory substrate . The temperature (in the range 9-23 degrees C) and HRT (in the range 6-46 h) were selected as the most decisive technological parameters for a practical application . Average removal efficiency of COD found for tested anaerobic reactors were 56-88% (AnSBR) and 46-92% (UAF) depending on used temperature and HRTs . Based on the observed results, the use of AnSBR and UAF in practice seems to be a potential technology for (pre)-treatment of wastewater produced by small communities.

Environ Toxicol, 2002 Feb, 17(1), 63 - 73
Potential genotoxicity of wastewater-contaminated pore waters with comparison to sediment toxicity and macrobenthic community composition; Lewis MA et al.; The objectives of this survey were to determine the genotoxic potential of sediment pore waters above and below 10 wastewater outfalls and to compare the results to sediment chemical quality guidelines, acute toxicity, and macrobenthic community composition . The focus of the study was on genotoxicity since its occurrence in environmental media below wastewater discharges in the Gulf of Mexico region has not been reported in the scientific literature . Pore waters from 43 sediment samples were assayed using a microbial mutagenicity assay before and after activation with a rat liver microsome mix (S-9) . A combination of either direct or activated responses was observed for 40% of the pore waters . Direct, activated, and both direct and activated responses were observed in 5, 26, and 9% of the total samples, respectively . Mutagenic effects were observed below 7 of the 10 outfall areas and in 4 of 6 control areas associated with 6 outfalls . The lowest pore water concentrations causing an activated mutagenic response were statistically similar above and below the outfalls . Mutagenicity occurred more frequently than acute toxicity to estuarine and freshwater invertebrates and there was no consistent relationship between its occurrence and the exceedance of sediment chemical quality guidelines . In contrast, there was some indication that mutagenic activity paralleled low benthic community diversity.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2002, 37(2), 195 - 9
Filtration treatment of dairy processing wastewater; Samkutty PJ et al.; The effectiveness of various filtration agents in the primary treatment of dairy processing wastewater was investigated in laboratory-scale studies . The filtration agents used were: zeolite, crushed coral, charcoal, sand and crushed coral and sand and glass beads . The effectiveness of the filtration media was determined by testing parameters such as chemical oxygen demand (COD), total solids (TS) and total suspended solids (TSS) before and after filtration of wastewater . Percent reduction of the different parameters as a result of filtration was calculated . Sand combined with crushed coral or glass beads was found to be the most effective filtering medium with an average reduction of 99% in TSS, 93% in COD and 51% in TS . Charcoal filtration resulted in an average 85% reduction in TSS, 83% reduction in COD and 46% reduction in TS . Filtration using crushed coral resulted in an average 83% reduction in TSS, 78% reduction in COD and 39% reduction in TS . Zeolite was the least effective of the four media; it resulted in an average reduction of 78% in TSS, 76% in COD and 30% in TS . The differences among mean values of COD, TSS and TS after the different treatments were analyzed statistically using analysis of variance (ANOVA) . When differences among means were found to be statistically significant (p < 0.0001), each mean value was compared with every other mean value using Duncan's multiple range test and least significant difference (LSD) test . Comparison of the mean values indicated the following: No significant difference between means of zeolite and crushed coral treatment . Mean values of COD, TSS, and TS of charcoal treatment were significantly different from the other treatments . Sand combined with crushed coral or glass beads was the most effective filtration agent and the means were significantly different from the means of the other treatments.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2002 Jan, 37(1), 1 - 6
Laundry detergents as a source of heavy metals in Irish domestic wastewater; Aonghusa CN et al.; Concentrations of Cd, Cu and Zn in 175 detergent samples representing twenty-one brands of washing powders were analysed . Mean concentrations of 3.03 (+/- 0.50) microg Cd/g, 2.61 (+/- 1.22) microg Cu/g and 15.23 (+/- 7.26) microg Zn/g were recorded . The concentration of cadmium was much lower than previously reported . The daily contribution of metals from laundry washing are in the order of 54.5 microg Cd/ca/d, 47.0 microg Cu/ca/d and 274.1 microg Zn/ca/d . In Irish municipal wastewater the contribution from detergents of these metals are 31.9% for Cd, 0.24% Cu and 0.30% for Zn . This has important implications for sewage sludge disposal.

Sci Total Environ, 2002 Feb 4, 284(1-3), 249 - 61
Fish tissue quality in near-coastal areas of the Gulf of Mexico receiving point source discharges; Lewi MA et al.; The objective of this study was to determine inorganic and organic contaminant concentrations in edible tissue of fish collected from eight coastal areas receiving wastewater discharges and from two reference locations . Trace metal residues were statistically similar regardless of the collection site . Zinc (100% detection in all samples), total mercury (100%), total arsenic (92%), copper (92%), and selenium (88%) were the more commonly detected trace metals . Mercury concentrations exceeded the Florida health-based standard of 0.5 microg/g for limited fish consumption in 30% of the total samples and averaged 0.40 (+/- 1 S.D . = 0.22, range < or = 0.08 to 0.85) microg/g wet weight . The average total PAH concentrations were 1.79 (+/- 1.60) ng/g (reference areas) and 2.17 (+/- 3.29) ng/g (wastewater-impacted areas) . Pyrene was detected most frequently (63% of the total samples) and averaged 0.74 (+/- 0.35) ng/g wet wt . The average total PCB concentrations were 4.8 (+/- 7.1) ng/g (reference areas) and 31.6 (+/- 31.3) ng/g (wastewater-impacted areas) Concentrations of dieldrin and cis-chlordane were approximately eight times greater, respectively, in fish collected from wastewater receiving waters, whereas total DDT and total pesticide concentrations were not elevated in the same areas . Concentrations of total PCBs and all chlorinated pesticides were below US health-based standards . The lack of a published reference data base for fish tissue quality in near-coastal areas of the Gulf of Mexico restricts an assessment of the environmental significance of results from this and similar studies investigating the fate of point source contaminants.

Sci Total Environ, 2002 Feb 4, 284(1-3), 123 - 34
Incomplete degradation of linear alkylbenzene sulfonate surfactants in Brazilian surface waters and pursuit of their polar metabolites in drinking waters; Eichhorn P et al.; In Brazil more than 90% of the population are not connected to municipal wastewater treatment plants . As a consequence, surface waters receive continuously considerable amounts of untreated domestic sewage containing surfactants as a major constituent . Such polluted waters gave rise to special interest if they are used as a source for the production of drinking water . In this work, the river Rio Macacu (State Rio de Janeiro, Brazil) was monitored for the occurrence of the most widely used anionic surfactant linear alkylbenzene sulfonate (LAS) together with its main degradative product, sulfophenyl carboxylates (SPC) . In order to pursue the fate of both compounds after emission into the river, samples were collected at several locations along the river bank, and analyzed applying liquid chromatography-mass spectrometry after enrichment by solid-phase extraction . The LAS concentrations ranged between 14 and 155 microg l(-1) and the levels of their metabolic intermediates were found from 1.2 to 14 microg l(-1) . The self-purification capacity of the water was impressively demonstrated in the upper course of the river downstream of a town considered as one major discharge point, whereas in the lower course the relative constant concentrations of both analytes were detected which was explained with an overall increasing level of pollution . Furthermore, a series of drinking water samples from Niteroi and Sao Goncalo, supplied by the same waterworks treating surface waters from the Rio Macacu, were taken during two sampling periods and examined for the presence of the strongly polar SPC which is suspected of by-passing the purification processes . The levels detected in the drinking water ranged between 1.6 and 3.3 microg l(-1) . For the analyses of drinking and surface waters the peak pattern of a selected SPC homologue composed by several positional isomers served as an indicator to describe the progression of SPC degradation occurred in the river and could be used to distinguish drinking waters of different origins.

Dis Aquat Organ, 2001 Dec 20, 48(1), 1 - 5
Inactivation of infectious salmon anaemia virus, viral haemorrhagic septicaemia virus and infectious pancreatic necrosis virus in water using UVC irradiation; Oye AK et al.; The UVC irradiation doses necessary for a 99.9% (3-log) inactivation of 3 different fish pathogenic viruses diluted in freshwater/seawater and wastewater from a fish processing plant were determined . The results showed that both infectious salmon anaemia virus (ISAV) and viral haemorrhagic septicaemia virus (VHSV) were very sensitive to UVC irradiation, showing a 3-log reduction of infectivity in freshwater of 33 +/- 3.5 and 7.9 +/- 1.5 J m(-2), respectively, while that of infectious pancreatic necrosis virus (IPNV) was substantially higher, 1188 +/- 57 J m(-2) . Using ISAV as a model, a comparison of the effect of UVC irradiation on virus isolation versus reverse transcription polymerase chain reaction (RT-PCR) showed that considerably higher UVC doses, depending on the length of the amplified product, were necessary to abolish RT-PCR detection of viral RNA.

Water Sci Technol, 2002, 45(1), 33 - 9
Influence of load distribution and recycle rate in step-fed facultative ponds; Sambuco JP et al.; This study presents the results of research on a wastewater treatment system with four identical facultative ponds in series with step-feeding and recirculation (SFFPR) . Four modes of distribution of the influent were studied, which were (in percentages of the inflow per pond): C1 = 25/25/25/25; C2 = 50/20/20/10; C3 = 50/50/0/0; C4 = 100/0/0/0 . The organic loading applied to the four ponds overall was around 200 kg BOD5/ha.d . The distribution C4 = 100/0/0/0 was selected for studying the recycle rate . Three recycling rates were studied: 0.5Q, 1Q and 2Q . COD and BOD5 removal efficiencies were high whatever the step-feed distribution . For the distribution C1 and C2, the four ponds were homogeneous . The equal distribution of organic loading rate in C2 distribution was most beneficial for algal growth . For piston pattern distributions (C3 and C4), the ponds receiving the highest loading showed a bacterial biomass higher than that of the primary production . Increasing the recirculation rate seemed to lead towards homogenisation of the ponds, while a decrease appeared to lead to their individualisation and increased their productivity . The SFFPR constitutes a stage of the treatment process which can replace the facultative stage; it produces a high effluent quality and decreases land area requirements.

J Environ Qual, 2002 Jan-Feb, 31(1), 309 - 18
Point- and nonpoint-source pesticide contamination in the Zwester Ohm catchment, Germany; Muller K et al.; Reducing pesticide loads in surface waters implies identifying the pathways responsible for the pollution . The current study documents the pesticide contamination of the river Zwester Ohm, a 4917-ha catchment in Germany with 41% of the land used for crop production . Discharges and concentrations of 19 pesticides were measured continuously at three locations for 15 mo . The load detected at the outlet of the catchment amounted to 9048 g a.i . The losses represent 0.22% of the pesticides applied by the farmers . The contamination showed a seasonal pattern following the pesticide application times . The wastewater treatment plant system (WWTPS) in the catchment (two wastewater treatment plants {WWTP}, 14 combined sewer overflows (CSO), four CSO tanks) emits during dry weather periods purified sewage and during storm events sewage mixed with stormwater runoff into the river . The contribution by the WWTPS to the pesticide load was defined as point-source pollution (PSP) . The load was dominated by PSP with at least 77% of the total pollution . No significant interdependencies between intrinsic properties of the pesticides, hydrometeorological factors, and the loads occurring in the stream could be found . Therefore, it is not possible to predict PSP for other catchments based on the results from this study . Whereas 65% of the total load entered the river via the WWTP, a portion of 12% was attributed to the CSO . The study points out that the influence of CSO on PSP should be taken into account in future catchment studies in areas with comparable agricultural structure.

Biotechnol Bioeng, 2002 Mar 30, 77(7), 806 - 14
Application of neural network for simulation of upflow anaerobic sludge blanket (UASB) reactor performance; Sinha S et al.; Up-flow anaerobic sludge blanket (UASB) reactors are being used with increasing regularity all over the world, especially in India, for a variety of wastewater treatment operations . Consequently, there is a need to develop methodologies enabling one to determine UASB reactor performance, not only for designing more efficient UASB reactors but also for predicting the performance of existing reactors under various conditions of influent wastewater flows and characteristics . This work explores the feasibility of application of an artificial neural network-based model for simulating the performance of an existing UASB reactor . Accordingly, a neural network model was designed and trained to predict the steady-state performance of a UASB reactor treating high-strength (unrefined sugar based) wastewater . The model inputs were organic loading rate, hydraulic retention time, and influent bicarbonate alkalinity . The output variables were one or more of the following, effluent substrate concentration (Se), reactor bicarbonate alkalinity, reactor pH, reactor volatile fatty acid concentration, average gas production rate, and percent methane content of the gas . Training of the neural network model was achieved using a large amount of experimentally obtained reactor performance data from the reactor mentioned above as the training set . Training was followed by validation using independent sets of performance data obtained from the same UASB reactor . Subsequently, simulations were performed using the validated neural network model to determine the impact of changes in parameters like influent chemical oxygen demand (COD) concentration and hydraulic retention time on the reactor performance . Simulation results thus obtained were carefully analyzed based on qualitative understanding of UASB process and were found to provide important insights into key variables that were responsible for influencing the working of the UASB reactor under varying input conditions .

Biotechnol Appl Biochem, 2002 Feb, 35(Pt 1), 1 - 7
A peroxidase isoenzyme secreted by turnip (Brassica napus) hairy-root cultures: inactivation by hydrogen peroxide and application in diagnostic kits; Agostini E et al.; We have purified various peroxidase isoenzymes from roots and hairy-root cultures of turnip (Brassica napus) which could potentially be used for commercial applications such as an enzyme immunoassays, diagnostic test kits, wastewater treatment and soil remediation . One of them, a basic peroxidase called HR2, was secreted into the medium of turnip hairy-root cultures . HR2 had a pI of 9.6, a molecular mass of 39.3 kDa and showed great thermostability . The inactivation of HR2 by H2O2 in the absence of reductant substrates was studied . Under these conditions H2O2 acted as a suicide substrate . The kinetic constants calculated have been compared with those of a basic isoperoxidase from horseradish (Armoracia sp.) roots (HRP-C), which is commonly used in commercial kits . The results for HR2 indicated that it was more resistant to inactivation because it presented a lower inactivation efficiency and a higher value for the partition ratio (r=1250) than those described for HRP-C . These results make turnip peroxidase HR2 suitable for use in systems in which high H2O2 concentrations are found . Such an application is demonstrated, namely an enzymic diagnostic kit for determination of uric acid in which HR2 was found to be as efficient as the enzyme originally included in standard kits.

Water Environ Res, 2001 Nov-Dec, 73(6), 691 - 703
Responses of Onondaga Lake, New York, to early stages of rehabilitation: unanticipated ecosystem feedbacks; Matthews DA et al.; Responses of polluted Onondaga Lake, New York, to early stages of a phased program to rehabilitate the lake from the effects of domestic waste inputs are documented . The analysis is based on more than 10 years of paired monitoring of the effluent (total ammonia and total phosphorus) of a wastewater treatment plant (WWTP) that discharges to the lake as well as the lake itself (including total ammonia, nitrite, total and dissolved forms of phosphorus, plankton biomass and composition, Secchi disc transparency, and zebra mussel density) . Major reductions in total ammonia and total phosphorus loading relative to the preceding decade are reported for the WWTP for the November 1998 through October 1999 interval . Dramatic and, in some cases, unanticipated changes in the lake's water quality and biota in response to the reductions in loading are documented for the April to October interval of 1999 including: (1) major decreases in total ammonia concentrations and improved status with respect to ammonia toxicity standards, (2) development of dense populations of zebra mussels, (3) decreases in fall concentrations of nitrite and improved status with respect to the related toxicity standard, (4) decreases in total phosphorus and total dissolved phosphorus concentrations, and (5) a severe Microcystis (phytoplankton) bloom that caused nuisance conditions and poor clarity . The zebra mussel invasion is attributed to the reductions in total ammonia concentrations to below toxic levels . The Microcystis bloom was probably related to the abrupt increase in the zebra mussel population . Additional reductions in phosphorus loading from the WWTP will be required to limit phytoplankton production and avoid the potential for continued nuisance conditions . Potential complications in resolving lake responses to future reductions in loading associated with the zebra mussel invasion are considered.

Water Environ Res, 2001 Nov-Dec, 73(6), 667 - 72
Microbial risks from wastewater irrigation of salad crops: a screening-level risk assessment; Petterson SR et al.; The potential health risk from viruses, associated with the consumption of lettuce crops spray irrigated with secondary-treated municipal effluent, has been evaluated in the first level investigation of a tiered microbial risk assessment . The study assessed the impact of two factors on the estimated risk of infection: a suitable probability density function for the occurrence of human enteroviruses in irrigation water and appropriate die-off rates for viruses on lettuce crops . A Monte Carlo simulation using a log-normal and a nonparametric, kernel estimated probability density function indicated that slight changes in the upper tail of the probability density function had a relatively low effect on the estimated infection rates . Predicted infection rates were much more sensitive to the decay rate of viruses than occasional high virus numbers . The median and 99th percentile risks of infection from the overall model were 0.10 and 0.51/10000 lettuce consumers, respectively, indicating possible human health concern, and the justification of a more detailed microbial risk assessment.

Water Sci Technol, 2002, 45(1), 41 - 8
The influence of thermal stratification on the hydraulic behavior of waste stabilization ponds; Kellner E et al.; Thermal stratification, which is characterized by a high vertical thermal gradient, is usually observed in deep lakes . However, although waste stabilization ponds have small depths, their high turbidity provides favorable conditions for the occurrence of this phenomenon, mainly during summer . During that time of the year, the layers nearest to the surface concentrate a larger amount of thermal energy compared to the deeper layers, which results in a temperature difference between the surface and the bottom of the pond . As a consequence a density profile appears, with the less dense layers located at the surface of the pond and the densest ones close to the bottom . This stratification in the water column induces alterations in the flow pattern and a decrease of the useful volume of the pond . This paper presents a mathematical model developed to forecast the conditions of thermal stratification in waste stabilization ponds and the volume actually used for wastewater treatment . With these values it is possible to correct the average residence time of the liquid in the pond . The theoretical results were compared with experimental observations, and maximum differences of 15% between the calculated and observed temperature profiles were found.

Water Sci Technol, 2002, 45(1), 127 - 32
Domestic wastewater treatment in waste stabilization ponds for irrigation in Mendoza, Argentina: policies and challenges; Velez OR et al.; Arid areas call for imaginative water management solutions to avoid the dangers of water shortages . Growing demands of water for domestic and industrial uses decrease the availability of water for agriculture . It therefore becomes necessary to set up a policy for the use of domestic effluents . For the province of Mendoza, Argentina, with 1,500,000 inhabitants, a master plan was designed as of 1991 for the treatment of domestic effluents and subsequent disposal for irrigation . The guidelines set up by WHO for the use of wastewater in agricultural applications were taken into consideration . At present, the Province of Mendoza has available projects which are either complete, in execution or in the bidding process, entailing secondary treatment capacity with reuse of 320,000 cubic metres/day and an estimated possible irrigation area of 10,000 hectares . With this infrastructure, some strategic lines of action are recommended to establish a policy for the agricultural use of wastewater: (a) to program the use of treated wastewater to avoid discharges to irrigation flows; (b) to develop an institutional scheme for the efficient and safe use of these waters; and (c) develop scientific and technologic know-how to accompany the updated policies.

Water Sci Technol, 2002, 45(1), 111 - 6
Comparison of conventional and macrophyte-based systems for the treatment of domestic wastewater; Baldizon ME et al.; Different wetland and stabilisation ponds, comprising of duckweed, reed and algal systems, were compared for the treatment of domestic sewage . Within the large performance variations observed within systems, the differences observed between systems can be considered to be insignificant.

Water Sci Technol, 2002, 45(1), 1 - 8
Feasibility of waste stabilization pond technology for small municipalities in Colombia; Pena MR et al.; The selection of any wastewater treatment technology should take into consideration both "software" and "hardware" aspects . There are contrasting opinions regarding the feasibility of waste stabilisation ponds (WSP): some emphasise their advantages while others are concerned with their high land area requirements . As with any technology, WSP are feasible under specific circumstances related to the context where they are to be implemented . In this study data were collected from three regions in Colombia (Narino, Tolima and Valle del Cauca) in order to assess the feasibility of WSP under real conditions in a tropical country . A feasibility matrix was developed in order to organise and synthesise the information gathered . The results obtained showed that WSP are highly feasible in Tolima and Valle del Cauca due to the fact that these regions have geographical, socio-economic and technical characteristics that enhance the advantages of WSP technology . Narino has a very mountainous topography along with other local limitations that hinder the application of WSP technology . The cost of land was not found to be a real limitation for the technology, whereas the availability of land is . Finally, the feasibility matrix may be a good planning tool at regional or national levels in order to help decision-making regarding cost-effective wastewater treatment alternatives on the basis of local conditions.

J Hazard Mater, 2002 Mar 1, 90(2), 205 - 16
Treatment of high-strength phenolic wastewater by a new two-step method; Lin SH et al.; Treatment of high-strength phenolic wastewater by a novel two-step method was investigated in the present study . The two-step treatment method consisted of chemical coagulation of the wastewater by metal chloride followed by further phenol reduction by resin adsorption . The present combined treatment was found to be highly efficient in removing the phenol concentration from the aqueous solution and was proved capable of lowering the initial phenol concentration from over 10,000 mg/l to below direct discharge level (1mg/l) . In the experimental tests, appropriate conditions were identified for optimum treatment operation . Theoretical investigations were also performed for batch equilibrium adsorption and column adsorption of phenol by macroreticular resin . The empirical Freundlich isotherm was found to represent well the equilibrium phenol adsorption . The column model with appropriately identified model parameters could accurately predict the breakthrough times.

Analyst, 2002 Jan, 127(1), 1 - 4
A prototype industrial sensing system for phosphorus based on micro system technology; Bowden M et al.; Progress in the development of a miniaturised microfluidic instrument for monitoring phosphorus in natural waters and wastewater is presented . The yellow colorimetric method for phosphate analysis has been transferred to a microfluidic chip configuration This simple method employs one reagent mixed in a 1:1 ratio with a sample to produce a yellow colour absorbing strongly below 400 nm . A stopped flow approach is used which, together with the very rapid kinetics and simple reagent stream, enables a very uncomplicated microfluidic manifold design to be adopted . The working wavelength is 380 nm to coincide with the peak output of a recently developed UV-LED narrow bandwidth light source . The limit of detection for the yellow method is 0.2 ppm with a dynamic linear range from 0-50 ppm possible . The reaction time at room temperature is less than 3 min, which means that up to 20 samples per hour can be analysed.

Water Res, 2002 Feb, 36(3), 799 - 804
A modified ceramic sampler and lysimeter design for improved monitoring of soil leachates; Bowman MS et al.; This paper describes the design and use of modified solution samplers and non-weighing lysimeters in a field experiment examining the response of a turf-soil system to landfill leachate irrigation over a 2-year period . The two designs were shown to offer significant performance advantages, were cost effective and overcame many of the reported problems commonly associated with each technique . The quantities of leached chloride detected in the 20%, 50% and undiluted leachate irrigated plots by the modified solution samplers (1,677, 4,319 and 8,021 kg ha(-1), respectively) and microlysimeters (1,759, 4,512 and 8,160 kg ha(-1), respectively) were significantly higher than the conventional sampler design (1,407, 3,767 and 7,052 kg ha(-1), respectively) . Additionally, the microlysimeter design functioned reliably throughout the experiment, achieving solution flow rates analogous to the unconfined plots . Therefore, it was concluded that both the designs appear to be suitable for monitoring changes in soil solution composition associated with sub-surface wastewater irrigation.

Water Res, 2002 Feb, 36(3), 617 - 24
Evaluation of a rapid physical-chemical method for the determination of extant soluble COD; Hu Z et al.; Characterization of total chemical oxygen demand (COD) in wastewater is critical for accurate modeling of constituent biotransformation steps . We evaluated the accuracy and precision of a commonly used soluble COD determination technique (coagulation using ZnSO4 at pH 10.5) in relation to three other physical-chemical separation techniques: destabilization with a non-hydrolyzing trivalent cation (LaCl3), sequential filtration, and ultracentrifugation . Samples of deionized water and domestic wastewater were spiked with aliquots of synthetic soluble COD and recoveries using the different separation methods were compared . Although mechanisms of coagulation using LaCl3 and ZnSO4 are different, the mean COD recoveries using these methods were in close agreement . Further, sorption of soluble COD onto zinc hydroxide precipitate flocs appeared to be negligible . The two coagulation methods yielded statistically different (p = 0.05) soluble COD values when applied to nine independent wastewater samples (obtained on nine different days) . but the difference was less than 10% . The COD quantified by the coagulation techniques corresponded most closely with the < 1,000 Da molecular weight fraction defined as "truly soluble COD" . Centrifugation of wastewater samples amended with mercuric chloride (HgCl2) at 10 mg/L overestimated the soluble COD concentration . Our results confirm that coagulation using either ZnSO4 or LaCI3 is appropriate for the rapid determination of soluble COD fraction in wastewater matrices.

J Chromatogr A, 2002 Jan 4, 942(1-2), 201 - 10
Quantification of sulfur and sulfur-containing compounds in wastewaters by means of a combination of liquid chromatographic methods; Hurse TJ et al.; Low-micromolar concentrations of sulfite, thiosulfate and sulfide, present in synthetic wastewater or anaerobic digester effluent, were quantified by means of derivatization with monobromobimane, followed by HPLC separation with fluorescence detection . The concentration of elemental sulfur was determined, after its extraction with chloroform from the derivatized sample . by HPLC with UV detection . Recoveries of sulfide (both matrices), and of thiosulfate and sulfite (synthetic wastewater) were between 98 and 103% . The in-run RSDs on separate derivatizations were 13 and 19% for sulfite (two tests), between 1.5 and 6.6% for thiosulfate (two tests) and between 4.1 and 7.7% for sulfide (three tests) . Response factors for derivatives of sulfide and thiosulfate, but not sulfite, were steady over a 13-month period during which 730 samples were analysed . Dithionate and tetrathionate did not seem to be detectable with this method . The distinctness of the elemental sulfur and the derivatizing-agent peaks was improved considerably by detecting elution at 297 instead of 263 nm.

J Chromatogr A, 2002 Jan 4, 942(1-2), 185 - 90
Determination of phosphonic acid breakdown products by high-performance liquid chromatography after derivatization; Nowack B; A new HPLC method for the determination of oxidative breakdown products of aminopolyphosphonates is presented . The phosphonate nitrilotrismethylenephosphonic (NTMP) acid undergoes catalytic oxidation by molecular oxygen in the presence of manganese(II) . The two diphosphonates iminodimethylenephosphonic acid (IDMP) and formyliminodimethylenephosphonic acid (FIDMP) are formed . The analytical method employs the derivatization of the aldehyde group in FIDMP by 2,4-dinitrophenylhydrazine and of the imine group in IDMP by 9-fluorenyl methylchloroformate . The two derivatives are quantified in separate runs using the same acidic phosphate-acetonitrile eluent with detection at 370 nm for FIDMP and 260 nm for IDMP . The detection limit for FIDMP is 0.01 microM, for IDMP 0.02 microM . The method is suitable for the determination of the breakdown products in wastewater.

Environ Technol, 2001 Sep, 22(9), 1105 - 11
Indirect electrochemical treatment of saline dyestuff wastewater; Zhan XM et al.; Dyestuff wastewater is always found to contain highly-concentrated sodium chloride . In many cases, biological processes are not available to dispose saline dyestuff wastewater . In this paper, both direct a nd indirect electrochemical oxidation of saline dyestuff wastewater were carried out and the accessibility of indirect electrochemical oxidation by electrochemically generated hypochlorite was investigated . It was found that the indirect electrochemical process removed COD by 87% and color by 100% in 50 minutes while the direct electrochemical process removed COD by 47% and color by 50% in 5 hours.The rate-limiting step for hypochlorite evolution at the anode was found to be diffusion-controlled . For the two processes, COD removal kinetics could be simplified as the pseudo first-order kinetics . The rate constants of COD removal were 0.038 min(-1) and 0.0018 min(-1) for the indirect and direct oxidation respectively . Current efficiency of the indirect process was I while that of the direct process was 0.16; cost efficiency of the two processes was 8,000 mg-COD (kWh)(-1) and 1,000 mg-COD (kWh)(-1) respectively . It can be concluded that the indirect electrochemical process is a promising method for the disposal of saline dyestuff wastewater.

Environ Technol, 2001 Sep, 22(9), 1025 - 33
Application of synthetic poly(DADM) flocculants for dye wastewater treatment; Choi JH et al.; Poly(DADM) flocculants were synthesized and applied for the removal of color, turbidity and organic materials from dye wastewater . The effect of poly(DADM) on color removal was investigated by comparing two treatments: (i) alum alone and (ii) alum/poly(DADM) in combination . The effects of poly(DADM) flocculant, poly(DADM) concentration, poly(DADM) types and pH on the removal efficiency of coloring materials were investigated . Poly(DADM) flocculants were highly efficient in the removal of color and turbidity from dye wastewater . Compared to treatment with alum alone, the addition of a small amount of poly(DADM) (25 mg l(-1)) reduced alum dosage by 50% while improving color removal efficiency . Highly efficient color removal was obtained in wide pH ranges by adding poly(DADM) as a flocculant . Our results indicate that the use of poly(DADM) flocculant is cost effective in dye wastewater treatment by reducing sludge production and the dosage of inorganic coagulant . Effects of zeta potential were also investigated.

Ying Yong Sheng Tai Xue Bao, 2001 Feb, 12(1), 145 - 50
{Discussion on some basic problems in design of wetland ecosystem}; Cui B et al.; The design of wetland ecosystem is the key and fundament in wetland restoration and mitigation . In recent years, it has been frequently applied to the proper construction of wetlands . The paper first reviews the concept of wetland ecosystem design, as well as the basis of ecological engineering, and then presented the basic principles in the design of wetland ecosystem . Some major ecological indicators including hydrology, chemical, substrate, soil and biotic indicators were also discussed, and some reference values for ecological indicators were presented . On the base of the designing purposes, three major types in the wetland design were analysed . They include constructing wetlands for wastewater treatment, for mitigation wetlands, and for controlling flooding and non-point source pollution.

Environ Toxicol Chem, 2002 Jan, 21(1), 16 - 23
Detection of estrogenic potency in wastewater and surface water with three in vitro bioassays; Murk AJ et al.; A study was performed to optimize sample preparation and application of three in vitro assays for measuring estrogenic potency in environmental extracts . The three assays applied were an estrogen receptor (ER)-binding assay and two reporter gene effect assays: a yeast estrogen screen (YES) and the ER-mediated chemically activated luciferase gene expression (ER-CALUX) assay . All assays were able to detect estrogenicity, but the amounts of material needed for the assays differed greatly between the three assays (ER-binding assay >> YES > ER-CALUX) . In addition, in the ER-binding assay, both agonists and antagonists give an estrogenic response, resulting in higher estradiol equivalency (EEQ) levels than both the ER-CALUX and the YES assay for the same samples . The EEQs found in wastewater treatment plants (WTPs) with the ER-CALUX assay were in the range of 4 to 440 and 0.11 to 59 pmol/L for influent and effluent, respectively . Water extracts from four large rivers had levels ranging from 0.25 to 1.72 pmol/L . Extracts from suspended matter and sludge contained estrogenic potency of 0.26 to 2.49 and 1.6 to 41 pmol EEQ/g dry weight, respectively . In WTPs, the average reduction of estrogenic potency in effluent compared to influent was 90 to 95% in municipal WTPs and about 50% in industrial WTPs . In influent, 30% of the ER-CALUX activity could not be explained by the calculated potencies based on chemical analysis of a number of known (xeno)estrogens; in effluent the unexplained fraction was 80% . These first results of analyzing estrogenic potency in WTP water and surface water in The Netherlands indicate that further studies are warranted to investigate the actual risks for aquatic systems.

Bioresour Technol, 2002 Feb, 81(3), 249 - 55
Cadmium removal using Cladophora in batch, semi-batch and flow reactors; Sternberg SP et al.; This study presents the results of using viable algae to remove cadmium from a synthetic wastewater . In batch and semi-batch tests, a local strain of Cladophora algae removed 80-94% of the cadmium introduced . The flow experiments that followed were conducted using non-local Cladophora parriaudii . Results showed that the alga removed only 12.7(+/-6.4)% of the cadmium introduced into the reactor . Limited removal was the result of insufficient algal quantities and poor contact between the algae and cadmium solution.

Anal Chem, 2002 Jan 1, 74(1), 261 - 9
Development of a precolumn derivatization method for the determination of free amines in wastewater by high-performance liquid chromatography via fluorescent detection with 9-(2-hydroxyethyl)acridone; You J et al.; A simple, sensitive, and mild method for the determination of amino compounds based on a condensation reaction with fluorescence detection has been developed . 9-(2-Hydroxyethyl)acridone reacts with coupling agent N,N'-carbonyldiimidazole at ambient temperature to form activated amide intermediate 9-(2-acridone)oxyethylcarbonylimidazole (AOCD) . The amide intermediate (AOCD) preferably reacts with amino compounds under mild reactions in the presence of 4-(dimethylamino)pyridine (base catalyst) in acetonitrile to give the corresponding sensitively fluorescent derivatives with an excitation maximum at lambda(ex) 404 nm and an emission maximum at lambda(em) 440 nm . The labeled derivatives exhibit high stability under reversed-phase conditions . The fluorescence intensities of derivatives in various solvents or at different temperatures were investigated . The method, in conjunction with a gradient elution, offers a baseline resolution of the common amine derivatives on a reversed-phase C18 column . The LC separation for the derivatized amines shows good reproducibility with acetonitrile-water including 2.5% DMF as mobile phase . The relative standard deviations (n = 6) for each amine derivative are <4.5% . The detection limits (at a signal-to-noise ratio of 3) per injection were 0.16-12.8 ng/mL . Further research for the field of application, based on the AOCD amide intermediate as derivatization reagent, for the determination of free amines in real water samples is achieved.

J Agric Food Chem, 2002 Jan 30, 50(3), 596 - 601
Partitioning of olive oil antioxidants between oil and water phases; Rodis PS et al.; The partition coefficient (K(p)) of the natural phenolic antioxidant compounds in the olive fruit between aqueous and olive oil phases was determined . The antioxidants of olive oil are either present in the olive fruit or formed during the olive oil extraction process . The antioxidants impart stability to and determine properties of the oil and are valuable from the nutritional point of view . The olive oil antioxidants are amphiphilic in nature and are more soluble in the water than in the oil phase . Consequently, a large amount of the antioxidants is lost with the wastewater during processing . The determination of antioxidants was performed using HPLC, and the K(p) was estimated to be from as low as 0.0006 for oleuropein to a maximum of 1.5 for 3,4-DHPEA-EA (di-hydroxy-phenyl-ethanol-elenolic acid, oleuropein aglycon) . Henry's law fitted very well to the experimental data . The partition coefficients were also estimated by applying the activity coefficients of the antioxidants in the two phases using a predictive group contribution method, the UNIFAC equation . The K(p) values estimated with UNIFAC method were of the same order of magnitude but varied from the experimental values . Nevertheless, this method may be a rough predictive tool for process optimization or design . Because the K(p) values were very low, some changes in the process are recommended in order to achieve a higher concentration of antioxidants in the oil . A temperature increase may lead to increasing the partition coefficient . Also, limiting the quantity of water during oil extraction could be a basis for designing alternative processes for increasing the antioxidant concentration in the olive oil.

Environ Technol, 2001 Nov, 22(11), 1363 - 71
Excess sludge production and costs due to phosphorus removal; Paul E et al.; Based on data collected from 35 French wastewater treatment plants and on published data, excess sludge production and chemical consumption associated with phosphorus removal is estimated for the three following phosphorus removal processes: chemical precipitation, Enhanced Biological Phosphorus Removal and hybrid process . The influence of wastewater characteristics on excess sludge production are assessed . Chemical costs and costs associated with sludge disposal were calculated and results for the three phosphorus removal processes are compared . The global costs for phosphorus removal are then estimated.

Environ Technol, 2001 Nov, 22(11), 1355 - 61
Technico-economic feasibility of P-recovery from municipal wastewaters; Jeanmaire N et al.; The feasibility of recovering phosphates from municipal wastewater is assessed from literature, targeted interviews of water industry experts and process modeling . It is concluded that it is technically feasible to recover up to 75% of wastewater treatment plant (WwTP) inflow P, but today this is only attractive in WwTPs operating biological nutrient removal . The recovered P-product is likely to be of a better quality than currently available phosphate rock . P-recovery should reduce total wastewater biosolids production by 2-8% dry matter but where biosolids are incinerated ash production should reduce by 12-48% . It will considerably facilitate co-combustion in cement works . The impact of P- recovery on wastewater biosolids management, and in particular the reductions in transport distances where biosolids are used on agricultural land (resulting from lowered P:N ratios) are costed . Savings could be around UK 100 pounds per tonne of P recovered (roughly half of UK dockside prices of imported phosphate rock), giving a total saving of UK 450,000 pounds/year for the UK if 20% of all sewage P were recovered . The size of the savings is related to the capacity of the WwTP and to the % land surface around the WwTP that is available for agricultural spreading . Economic feasibility will depend on the local context, for example possible advantages for WwTP operation (nuisance deposit avoidance, removal of return streams of P to WwTP head), advantages for biosolids management or national decisions to fix P-recycling as environmental objectives.

Environ Technol, 2001 Nov, 22(11), 1347 - 53
Phosphorus availability for beneficial use in biosolids products; Hogan F et al.; It has become necessary to identify accurately the availability of phosphorus in biosolids products applied to land.The fertiliser value of these products must be quantified not only to satisfy the customer but also to ensure the best use of phosphorus when considering the need to avoid excess concentrations in the wider environment, With the advent of chemical phosphorus removal at more wastewater treatment works, the impact of iron and phosphate availability is particularly important . Existing research has indicated that there is a correlation between phosphate availability, and factors such as biosolids pH and iron concentration . However, it has not yet been possible to draw any firm conclusions, which can be used as a tool to manage the availability of phosphate in practice . Through a joint research programme for Anglian Water, involving literature investigation, laboratory tests on biosolid/soil interactions, and benchmarking phosphate availability over time, the study uses the best available input and output data to indicate the parts of the land bank most at risk from over-enrichment.

Environ Technol, 2001 Nov, 22(11), 1325 - 35
The application of calcium phosphate precipitation chemistry to phosphorus recovery: the influence of organic ligands; van der Houwen JA et al.; This paper describes current knowledge of phosphate precipitation chemistry in the context of phosphorus recovery from wastewaters, and presents experimental results on the effect of organic species, as key potential inhibitors, to the precipitation of calcium phosphate . The supersaturation required for precipitation at 25 degrees C, pH 7, 0.1 M ionic strength and near-stoichiometric (for hydroxylapatite) calcium to phosphate molar ratio was determined under spontaneous precipitation conditions . The experiments were carried out in air . The phase precipitating at the critical concentration was allowed to grow under constant supersaturation . The influence of organic ligands on the precipitation was investigated using two small molecular weight organic ligands, acetate and citrate, present at a concentration of 10(-3) M . The precipitate was studied using X-ray diffraction and scanning electron microscopy . Good reproducibility of the experiments, which were carried out in triplicate, was observed . The study assessed the supersaturation necessary for spontaneous precipitation of hydroxylapatite to be 10.93, calculated using a solubility constant of log K= -57.74 . The required supersaturation was not affected by the presence of acetate . However, citrate was found to increase the supersaturation required for precipitation to 11.73 . It is likely that this increase is due to binding of citrate on the active growth sites of newly formed nuclei, thereby inhibiting precipitation . All experiments showed formation of a single phase: micro-crystalline hydroxylapatite.

Environ Technol, 2001 Nov, 22(11), 1313 - 24
Rem nut ion exchange plus struvite precipitation process; Liberti L et al.; Nutrients control technologies from wastewater are based on destructive technologies which defer the problem fromthe diluted liquid-phase (effluent) to a more concentrated waste (sludge) in the case of phosphates, or to nitrogen gas and/or volatile compounds in the case of ammonia . The REM NUT process allows for simultaneous removal of phosphate and ammonium ions by selective ion exchange and recovery by chemical precipitation in the form of struvite (magnesium ammonium phosphate) from the spent exchangers regeneration eluates . In the paper revised versions of the REM NUT process, i.e., P-driven layouts, are presented and cost effectiveness is compared to chemical precipitation based on the use of ferric chloride.

Environ Technol, 2001 Nov, 22(11), 1245 - 52
Development of artificial seed crystal for crystallization of calcium phosphate; Moriyama K et al.; An artifical seed crystal material consisting of calcium silicate hydrate (5CaO x 6SiO2 x 5H2O : tobermorite crystals) applicable for phosphorus removal by crystallization was developed . Card-house shaped tobermorite crystals were developed on the seed material where orthophosphate crystallized as a calcium phosphate . The seed material can be manufactured by mixing siliceous and calcareous raw materials, pelletizing and subsequent autoclaving . Laboratory experiments were conducted to apply the new developed seed crystal material in the phosphorus recovery from sludge sidestreams of a wastewater treatment plant . In this crystallization process, the performance the carbon dioxide degassingprocess usually carried out when applying crystallization was not necessary, the hydroxyapatite was able to crystallize at a pH of 8.0 to 8.5 without precipitation of calcium carbonates . In the treatment of a sidestream with orthophosphate concentrations of 50 mgl(-1) and COD concentrations between 200 to 400 mgl(-1), phosphorus removal efficiencies ranging from 75 to 85% were observed . The seed crystal material was collected after the laboratory experiments and the chemical estimation and the germination test for agricultural reuse were performed . As a result, it was shown that the hydroxyapatite precipitated on the seed material had a 100% fusibility to soil and had characteristics to be a good nutrient source as a fertilizer for plants.

Water Sci Technol, 2001, 44(11-12), 69 - 75
Phosphorus retention capacity of iron-ore and blast furnace slag in subsurface flow constructed wetlands; Gruneberg B et al.; The suitability of iron-ore and blast furnace slag for subsurface flow (SSF) constructed wetlands was studied over a period of four months . Dairy farm wastewater (TP 45 mg l(-1)) was percolated through buckets planted with reed (volume 9.1 l; hydraulic load 151 m(-2) d(-1)) . One group of buckets was kept under aerobic conditions and the other group under anaerobic conditions, monitored by continuous redox potential measurements . Even at high mass loading rates of 0.65 g P m(-1) d(-1) the slag provided 98% removal efficiency and showed no decrease in performance with time . However, phosphorus fractionation data indicate that the high phosphorus retention capacity under aerobic conditions is to a great extent attributable to unstable sorption onto calcium compounds (NH4Cl-P) . Phosphorus sorption of both the slag (200 microg P g(-1)) and the iron-ore (140 microg P g(-1)) was promoted by predominantly anaerobic conditions due to continuous formation of amorphous ferrous hydroxides . None of the substrates had adverse affects on reed growth.

Water Sci Technol, 2001, 44(11-12), 61 - 7
The impact of biomass harvesting on phosphorus uptake by wetland plants; Kim SY et al.; Two species of macrophytes, Baumea articulata and Schoenoplectus mucronatus, were examined for their capacity to remove phosphorus under nutrient-rich conditions . Forty large bucket systems with the two different species growing in two types of substrate received artificial wastewaters for nine months, simulating a constructed wetland (CW) under high loading conditions . Half of the plants growing in the topsoil and gravel substrates were periodically harvested whereas the other half remained intact . Plant tissue and substrate samples were regularly analysed to determine their phosphorus concentrations . With respect to phosphorus uptake and removal, the Schoenoplectus in the topsoil medium performed better than the Baumea . Biomass harvesting enhanced P uptake in the Schoenoplectus, however the effect was not significant enough to make an improvement on the overall P removal, due to the slow recovery of plants and regrowth of biomass after harvesting . From P partitioning, it was found that the topsoil medium was the major P pool, storing most of total P present in the system . Plant parts contributed only minor storage with approximately half of that P stored below ground in the plant roots . The overall net effect of harvesting plant biomass was to only remove less than 5% of total phosphorus present in the system.

Water Sci Technol, 2001, 44(11-12), 585 - 90
Application of a constructed wetland for non-point source pollution control; Kao CM et al.; In Taiwan, non-point source (NPS) pollution is one of the major causes of impairment of surface waters . The main objective of this study was to evaluate the efficacy of using constructed wetlands on NPS pollutant removal and water quality improvements . A field-scale constructed wetland system was built inside the campus of National Sun Yat-Sen University (located in southern Taiwan) to remove (1) NPS pollutants due to the stormwater runoff, and (2) part of the untreated wastewater from school drains . The constructed wetland was 40 m (L) x 30 m (W) x 1 m (D), which received approximately 85 m3 per day of untreated wastewater from school drainage pipes . The plants grown on the wetland included floating (Pistia stratiotes L.) and emergent (Phragmites communis L.) species . One major storm event and baseline water quality samples were analyzed during the monitoring period . Analytical results indicate that the constructed wetland removed a significant amount of NPS pollutants and wastewater constituents . More than 88% of nitrogen, 81% of chemical oxygen demand (COD), 85% of heavy metals, and 60% of the total suspended solids (TSS) caused by the storm runoff were removed by the wetland system before discharging . Results from this study may be applied to the design of constructed wetlands for NPS pollution control and water quality improvement.

Water Sci Technol, 2001, 44(11-12), 565 - 70
Stormwater treatment: do constructed wetlands yield improved pollutant management performance over a detention pond system?
Bavor HJ, Davies CM, Sakadevan K.
Constructed wetland systems have been proposed as representing an improved ecotechnological option over detention basins, in terms of their abilities to reduce stormwater bacterial and nutrient loads to receiving waters . Concentrations of microbial and pollutants were determined in inflow and outflow samples collected from each type of system . Removal efficiencies for the wetland although higher than for the pond, were lower than some previously reported values for the treatment of municipal wastewater by constructed wetlands . Performance of a number of constructed wetland systems for stormwater treatment is evaluated considering the functional components of the systems.

Water Sci Technol, 2001, 44(11-12), 55 - 60
Phosphorus removal from trout farm effluents by constructed wetlands; Comeau Y et al.; Freshwater trout farms need a high and continuous clean water flow to keep fish exposed to a non-toxic ammonium concentration . As a result, the concentration of effluents from these farms are even below standard effluent criteria for municipal wastewater effluent for solids, nitrogen and phosphorus . Nevertheless, the mass of pollutants discharged, originating mostly from excreta and undigested fish food, must be reduced by simple and economical treatment processes . We designed and operated a three-stage system aimed at retaining solids by a 60 pm nylon rotating microscreen followed by treatment with a phosphorus-retaining constructed wetland system . Washwater from the microscreen was pumped to a series of two horizontal flow beds of 100 m3 each (0.6 m deep) . Coarse (2 mm) and finer (< 2 mm) crushed limestone were used in each bed, respectively, with the first one being planted with reeds (Phragmites australis) and the second one designed to remove even more phosphorus by adsorption and precipitation . Preliminary results indicated that the microscreen captured about 60% of the suspended solids and that greater than 95% of the suspended solids and greater than 80% of the total phosphorus mass loads were retained by the beds . The potential of constructed wetlands as an ecologically attractive and economical method for treating fish farm effluents to reduce solids and phosphorus discharge appears promising.

Water Sci Technol, 2001, 44(11-12), 545 - 50
Treatment of swine wastewater in marsh-pond-marsh constructed wetlands; Reddy GB et al.; Swine waste is commonly treated in the USA by flushing into an anaerobic lagoon and subsequently applying to land . This natural system type of application has been part of agricultural practice for many years . However, it is currently under scrutiny by regulators . An alternate natural system technology to treat swine wastewater may be constructed wetland . For this study we used four wetland cells (11 m width x 40 m length) with a marsh-pond-marsh design . The marsh sections were planted to cattail (Typha latifolia, L.) and bulrushes (Scirpus americanus) . Two cells were loaded with 16 kg N ha(-1) day(-1) with a detention of 21 days . They removed 51% of the added N . Two additional cells were loaded with 32 kg ha(-1) day(-1) with 10.5 days detention . These cells removed only 37% of the added N . However, treatment operations included cold months in which treatment was much less efficient . Removal of N was moderately correlated with the temperature . During the warmer periods removal efficiencies were more consistent with the high removal rates reported for continuous marsh systems--often > than 70% . Phosphorus removal ranged from 30 to 45% . Aquatic macrophytes (plants and floating) assimilated about 320 and 35 kg ha(-1), respectively of N and P.

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