Wastewater

Environ Pollut, 2001, 114(2), 177 - 85
Methane emissions from wastewater management; El-Fadel M et al.; Greenhouse gas emissions in the form of methane and carbon dioxide are produced when municipal and industrial wastewater and their residual solid by-product (sludge) are handled under or subject to anaerobic conditions, thus contributing to the global warming potential or the greenhouse effect . This paper presents estimation methods used for determining methane emissions from the management of wastewater . Applications for estimating countrywide methane gas emissions from wastewater management are presented with the country of Lebanon as an example . The relative significance of these emissions is assessed in comparison with methane emissions from developing and developed countries . Uncertainty associated with the estimation process and mitigation measures to reduce potential impacts of methane emissions from wastewater management are also discussed.

Arch Environ Contam Toxicol, 2001 Oct, 41(3), 274 - 81
Nitrogen, phosphorous, and organic carbon removal in simulated wetland treatment systems; Hunter RG et al.; Effects of vegetation, wastewater drawdown, hydraulic retention time (HRT), and media depth on removal of nitrogen, phosphorous, and organic carbon in microcosms were investigated . Synthetic wastewater was added daily to 28 microcosms, and effluent was sampled every 12 days for 132 days . Effluent was analyzed for ammonium (NH(4)(+)-N), nitrate (NO(3)(-)-N), orthophosphate (PO(4)(3-)-P), and total organic carbon (TOC) . Average percent removal of NH(4)(+)-N was significantly greater in microcosms containing plants (67%) than in those without plants (29%) . Percent removal of PO(4)(3-)-P was also significantly greater in microcosms with plants (42%) than in microcosms without plants (20%), but no significant difference was found for TOC removal between microcosms with plants (67%) and those without plants (74%) . Average removal was significantly lower in microcosms with wastewater drawdown than in those without wastewater fluctuation for both NH(4)(+)-N (51% versus 83%) and PO(4)(3-)-P (14% versus 71%) . Percent NH(4)(+)-N removal was significantly greater in microcosms with a 6-day retention time (80%) than in those with a 2-day retention (53%), and PO(4)(3-)-P removal was also significantly greater with a 6-day retention time (55%) than a 2-day retention (29%) . No differences were seen in TOC removal due to any of the treatments but HRT, where removal was greater microcosms with a 2-day HRT (76%) than in those with a 6-day HRT (60%) . Media depth did not have a significant effect on nutrient removal . Results of this study demonstrate that required design parameters are different depending on the nutrient being removed in systems simulated by these microcosms.

Folia Microbiol (Praha), 2001, 46(2), 133 - 6
Industrial and agricultural wastes as substrates for laccase production by white-rot fungi; Kahraman S et al.; White-rot fungi, Coriolus versicolor and Funalia trogii, produced laccase on media with diluted olive-oil mill wastewater and vinasse . Addition of spent cotton stalks enhanced the laccase activity with a maximum after 12 d of cultivation.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2001, 36(6), 957 - 70
Environmental assessment of a site contaminated by organic compounds; Riccardi C et al.; This paper presents a study on environmental assessment of an abandoned industrial area located in central Italy . Main production was refractory materials and compounds for treatment of industrial wastewater . The present work deals with a methodology for development of a sound sampling design, chemical characterization of soil samples, definition of the degree of site contamination according to law limits and evaluation of the fate and transport of contaminants by EPA simulation model (VLEACH 2.2a) . Results indicate that toxic compounds (polycyclic aromatic hydrocarbons and plasticizers) are uniformly distributed in the contaminated site and only in one sampling point their concentrations exceed law limits . Modeling results confirm that contaminants migration to groundwater can be excluded, addressing for a site remediation limited to the surface layer.

Bioresour Technol, 2001 Sep, 79(3), 251 - 62
Fungal decolorization of dye wastewaters: a review; Fu Y et al.; In recent years, there has been an intensive research on fungal decolorization of dye wastewater . It is becoming a promising alternative to replace or supplement present treatment processes . This paper examines various fungi, living or dead cells, which are capable of decolorizing dye wastewaters; discusses various mechanisms involved; reports some elution and regeneration methods for fungal biomass; summarizes the present pretreatment methods for increasing the biosorption capacity of fungal biomass; discusses the effect of various factors on decolorization.

Water Sci Technol, 2001, 44(1), 41 - 8
Reducing phosphate discharges: the role of the 1991 EC urban wastewater treatment directive; Farmer AM; This paper reviews the status of implementation of the 1991 EC urban wastewater treatment Directive in relation to its requirements for phosphate removal from wastewater discharges . Transposition of the Directive is satisfactory in most Member States as is implementation of requirements regarding collection and secondary treatment of sewage, with the notable exceptions of Belgium and Italy . A range of approaches has been adopted for the designation of sensitive areas under the Directive and designation is still not complete . It is likely that most Member States will have met the treatment requirements for sensitive areas by the end of 1998 . Exceptions will include France and Spain (where implementation will be incomplete), the UK (which designated more sensitive areas in 1998 and will meet requirements for these at a later date) and Greece and Italy (for which sensitive area designation is lacking or uncertain) . The Commission has indicated that it will examine compliance for both designation and treatment closely . This may place further pressure on Member States to designate further sensitive areas . It is estimated that currently in ten EU Member States, containing 90% of the EU population, about 375,000 tonnes of phosphorus are produced in domestic wastewater each year . In 1994 39-45% of this was removed in wastewater treatment works.

Water Sci Technol, 2001, 44(1), 173 - 80
Surface runoff pollution by cattle slurry and inorganic fertilizer spreading: chemical oxygen demand, ortho-phosphates, and electrical conductivity levels for different buffer strip lengths; Nunez-Delgado A et al.; As a way of dealing with the removal of pollutants from farming practices generated wastewater in the EU, we investigate the effect of spreading cattle slurry and inorganic fertiliser on 8 x 5 m2 and 8 x 3 m2 areas, referred to surface runoff chemical oxygen demand (COD), ortho-phosphates (o-P) and electrical conductivity (EC) levels, and the efficiency of grass buffer strips of various lengths in removing pollutants from runoff . The experimental plot was a 15% sloped Lolium perenne pasture . Surface runoff was generated by means of a rainfall simulator working at 47 mm h-1 rainfall intensity . Runoff was sampled by using Gerlach-type troughs situated 2, 4, 6 and 8 m downslope from the amended areas . During the first rainfall simulation, COD, o-P and EC levels were consistently higher in the slurry zone, more evidently in the larger amended area . During the second and third rainfall simulations, concentration and mass levels show a downslope drift into the buffer zones, with no clear buffer strip length attenuation . Correlation between runoff and mass drift is clearly higher in the slurry zone . Percentage attenuation in COD and o-P levels, referred to initial slurry concentrations--including rainfall dilution--were higher than 98%, and higher than 90% for EC.

Water Sci Technol, 2001, 44(1), 121 - 8
Retrofitting SBR systems to nutrient removal in sensitive tourist areas; Tasli R et al.; Retrofitting of existing SBR systems for nutrient removal is evaluated and defined for small communities in sensitive coastal areas, with seasonal fluctuations in wastewater quantity and quality . The proposed approach is developed by means of basic process stoichiometry and verified using ASM2d . The efficiency of retrofitting is found to rely on the delicate balance between the overall sludge age, the initial settled sludge volume in the reactor, and the ratio of the initial volume to the feed volume in each cycle, a parameter corresponding to the recycle ratio in continuous systems.

Environ Manage, 2001 Oct, 28(4), 483 - 96
Surface water pollution in three urban territories of Nepal, India, and Bangladesh; Karn SK et al.; In South Asian countries such as Nepal, India, and Bangladesh, pollution of rivers is more severe and critical near urban stretches due to huge amounts of pollution load discharged by urban activities . The Bagmati River in the Kathmandu valley, the Yamuna River at Delhi, and peripheral rivers (mainly Buriganga River) of Dhaka suffer from severe pollution these days . The observed dry season average of biochemical oxygen demand (BOD) in all these rivers is in the range of 20-30 mg/liter and total coliform are as high as 104-105 MPN/100 ml . Per capita pollution load discharge of urban areas has been estimated to be about 31, 19, and 25 g BOD/capita/day in Bagmati, Yamuna, and the rivers of Dhaka, respectively . Regression analysis reveals pollution loads steadily increasing nearly in step with the trend in urbanization . The dissolved oxygen (DO) level of the Bagmati and Buriganga rivers is declining at an average annual rate of nearly 0.3 mg/liter/year . Unplanned urbanization and industrialization occurring in these cities may be largely responsible for this grave situation . Inadequate sewerage, on-site sanitation, and wastewater treatment facilities in one hand, and lack of effective pollution control measures and their strict enforcement on the other are the major causes of rampant discharge of pollutants in the aquatic systems.

J Hazard Mater, 2001 Aug 17, 85(3), 301 - 15
Production of granular activated carbon from waste walnut shell and its adsorption characteristics for Cu(2+) ion; Kim JW et al.; Production of granular activated carbon by chemical activation has been attempted employing walnut shells as the raw material . The thermal characteristics of walnut shell were investigated by TG/DTA and the adsorption capacity of the produced activated carbon was evaluated using the titration method . As the activation temperature increased, the iodine value increased . However, a temperature higher than 400 degrees C resulted in a thermal degradation, which was substantiated by scanning electron microscopy (SEM) analysis, and the adsorption capacity decreased . Activation longer than 1h at 375 degrees C resulted in the destruction of the microporous structure of activated carbon . The iodine value increased with the increase in the concentration of ZnCl2 solution . However, excessive ZnCl2 in the solution decreased the iodine value . The extent of activation by ZnCl2 was compared with that by CaCl2 activation . Enhanced activation was achieved when walnut shell was activated by ZnCl2 . Applicability of the activated carbon as adsorbent was examined for synthetic copper wastewater . Adsorption of copper ion followed the Freundlich model . Thermodynamic aspects of adsorption have been discussed based on experimental results . The adsorption capacity of the produced activated carbon met the conditions for commercialization and was found to be superior to that made from coconut shell.

Water Res, 2001 Sep, 35(13), 3190 - 6
Stability of enhanced biological phosphorus removal and composition of polyphosphate granules; Schonborn C et al.; The influence of varying Ca- and Mg-concentration of the influent wastewater on the enhanced biological phosphorus removal was investigated in an anaerobic-aerobic bench-scale plant . The artificial enhancement of the Mg-concentration in the influent from 15 to 24 mg l(-1) and 31 mg l(-1), respectively, caused a raise of the mean P-removal efficiency from 85 to 97% . The P-elimination was very stable in time . A chemical precipitation of magnesium ammonium phosphate could be excluded . The elemental composition of polyphosphate granules was investigated by electron microscopy and energy dispersive X-ray spectroscopy . The elements Ca, Mg and K were the principal metal components of polyphosphate granules . Concerning the metal composition, different types of granules could be distinguished . The quantitative ratios of Ca, Mg and K varied in dependence on the influent concentration of these metals . A relation between the Mg/Ca-ratio of the granules and the efficiency of enhanced biological phosphorus removal can be supposed.

Water Res, 2001 Sep, 35(13), 3147 - 52
Dye removal from textile dye wastewater using recycled alum sludge; Chu W; The removal of dyes from textile dying wastewater by recycled alum sludge (RAS) generated by the coagulation process itself was studied and optimized . One hydrophobic and one hydrophilic dye were used as probes to examine the performance of this process . It was found that RAS is a good way of removing hydrophobic dye in wastewater, while simultaneously reducing the fresh alum dosage, of which one third of the fresh alum can be saved . The back-diffusion of residued dye from the recycling sludge is detected but is easily controlled as long as a small amount of fresh alum is added to the system . The use of RAS is not recommended for the removal of hydrophilic dyes, since the high solubility characteristics of such dyes can cause deterioration in the water quality during recycling.

Water Res, 2001 Sep, 35(13), 3137 - 46
Hydraulic effects on sludge accumulation on membrane surface in crossflow filtration; Ozaki N et al.; Membrane filtration technology for application of wastewater treatment has been developing recently . In the application to wastewater treatment, it is major concern to remove cake layer on membrane surface effectively with crossflow shear stress . Hydraulic effect of sludge accumulation process on membrane surface in bubble and non-bubble driven crossflow filtration was studied . Maximum sludge accumulation . sludge accumulation rate, and lag phase were introduced to describe sludge accumulation process, and the effects of hydraulic conditions were clarified experimentally . Maximum sludge accumulation and sludge accumulation rate were dependent on aeration intensity, and were less depend on flow channel width and MLSS concentration . Their tendencies were explained by shear stress . Shear stress was thought to be the major hydraulic factor that influences them . Lag phase was dependent on aeration intensity, flow channel width, and MLSS concentration . A non-dimensional equation was proposed to explain dependencies of flow channel width based on consideration of hydraulic behavior of MLSS particles and shear stress.

Water Res, 2001 Sep, 35(13), 3041 - 8
Effects of impurities on oxygen transfer rates in diffused aeration systems; Chern JM et al.; A series of unsteady-state reaeration tests were performed in a 500-L tank at 0.81-4.58 m3/h diffused-air flow rate and 288-302 K water temperature . Three different types of impurities: soybean oil, surfactant, and diatomaceous earth were doped to simulate the impurities in wastewaters and the effects of the impurities on the oxygen transfer rate were investigated . The ASCE and the two-zone oxygen mass-transfer models were used to analyze the unsteady-state reaeration data and the volumetric mass-transfer coefficients determined from the unsteady-state reaeration data were correlated as a function of the diffused-air flow rate, water temperature, and impurity concentration . The results showed that the alpha factors based on the ASCE model are less sensitive to the impurity concentration while the presence of the impurities significantly reduces the alpha factors in the gas bubble zone . The saturation DO concentration and volumetric oxygen mass-transfer rate can be predicted by the two-zone model along with the correlation obtained in this study.

Biotechnol Prog, 2001 Jul-Aug, 17(4), 664 - 8
Adsorption step in the biological degradation of a textile dye; Aretxaga A et al.; This research documents the removal of the dye Gris Lanaset G from aqueous solutions by fungal pellets . Adsorption of the dye by dead biomass pellets of Trametes versicolor was determined and compared with dye removal by enzymatic degradation . Six kinetic equations were fitted to the experimental adsorption data obtained . The results indicate that kinetics such as the Elovich equation, which considers that the rate-controlling step is the diffusion of the dye molecules, show the best fit . Nonlinear Langmuir and Freundlich equations were also fitted into the adsorption data, and it can be concluded that the adsorption equilibrium can be interpreted by the Langmuir isotherm . Adsorption plays an important role in the process of the elimination of color from textile wastewater, although not all of the elimination is due to this physical process when the microorganism is active . The removal of color (around 90%) with active microorganisms is greater than that obtained with the adsorption process.

Environ Technol, 2001 Jun, 22(6), 647 - 51
Phonological studies of the new gas-induced agitated reactor using computational fluid dynamics; Yang TC et al.; An ozone-induced agitated reactor has been found to be very effective in degrading industrial wastewater . However, the cost of the ozone generation as well as its short residence time in reactors has restricted its application in a commercial scale . An innovated gas-induced draft tube installed inside a conventional agitated reactor was proved to effectively retain the ozone in a reactor . The setup was demonstrated to significantly promote the ozone utilization rate up to 96% from the conventional rate of 60% above the onset speed . This work investigates the mixing mechanism of an innovated gas-induced reactor for the future scale-up design by using the technique of computational fluid dynamics . A three-dimensional flow model was proposed to compute the liquid-gas free surface as well as the flow patterns inside the reactor . The turbulent effects generated by two 45 degrees pitch-blade turbines were considered and the two phases mixing phenomena were also manipulated by the Eulerian-Eulerian techniques . The consistency of the free surface profiles and the fluid flow patterns proved a good agreement between computational results and the experimental observation.

Bioresour Technol, 2001 Sep, 79(2), 171 - 7
Decolorization of an anthraquinone-type dye using a laccase formulation; Soares GM et al.; Decolorization of the dye Remazol Brilliant Blue R (RBBR) was studied, as it is representative of an important class of recalcitrant anthraquinone-type dyes . For this purpose a commercial laccase formulation (CLF) containing laccase, a redox mediator and a non-ionic surfactant was used . Small molecular weight components were removed from the CLF by gel filtration, which made it possible to compare the effect of its laccase alone . Apart from slightly better thermostability of the CLF as compared with the laccase alone, the pH and temperature profiles were similar regardless of the presence of the small molecular weight components . The laccase alone did not decolorize RBBR . A small molecular weight redox mediator (HBT) was necessary for decolorization to occur . A comparison of the kinetics of RBBR decolorization using the CLF and its laccase alone is reported . Provided that a redox mediator is included, it is suggested that laccase may be suitable for the wastewater treatment of similar anthraquinone dyes.

J Environ Biol, 2001 Jan, 22(1), 59 - 66
Effect of textile industrial effluent on tree plantation and soil chemistry; Singh G et al.; A field study was conducted at Arid Forest Research Institute to study the effect of textile industrial effluent on the growth of forest trees and associated soil properties . The effluent has high pH, electrical conductivity (EC), sodium adsorption ratio (SAR) and residual sodium carbonate (RSC) whereas the bivalent cations were in traces . Eight months old seedlings of Acacia nilotica, Acacia tortilis, Albizia lebbeck, Azadirachta indica, Parkinsonia aculeata and Prosopis juliflora were planted in July 1993 . Various treatment regimes followed were; irrigation with effluent only (W1), effluent mixed with canal water in 1:1 ratio (W2), irrigation with gypsum treated effluent (W3), gypsum treated soil irrigated with effluent (W4) and wood ash treated soil irrigated with effluent (W5) . Treatment regime W5 was found the best where plants attained (mean of six species) 173 cm height, 138 cm crown diameter and 9.2 cm collar girth at the age of 28 months . The poorest growth was observed under treatment regime of W3 . The growth of the species varied significantly and the maximum growth was recorded for P . juliflora (188 cm height, 198 cm crown diameter and 10.0 cm collar girth) . The minimum growth was recorded for A . lebbeck . Irrigation with effluent resulted in increase in percent organic matter as well as in EC . In most of the cases there were no changes in soil pH except in W5 where it was due to the effect of wood ash . Addition of wood ash influenced plant growth . These results suggest that tree species studied (except A . lebbeck) can be established successfully using textile industrial wastewater in arid region.

Waste Manag, 2001, 21(6), 535 - 42
Effect of aluminum sulfate and cationic polyelectrolytes on the destabilization of emulsified wastes; Pinotti A et al.; Emulsified oil in wastewater constitutes a severe problem in the different treatment stages . Aluminum salts have been traditionally used as coagulants in wastewater treatments . Polyelectrolytes are used to coagulate and flocculate colloidal systems . The performance of aluminum sulfate in comparison to polyelectrolytes (chitosan and polyacrylamide) as conditioning chemicals for an emulsion waste was tested, and the predominant mechanisms acting in each case were analyzed . Turbidimetry, jar test, colloidal titration and microscopy were used to test emulsion destabilization . Both charge neutralization and bridge formation were identified and confirmed as mechanisms of interaction of polyelectrolytes with waste constitutents . Charge neutralization would be more important for chitosan than for polyacrylamide treatment . A coincidence between the doses necessary to reach zero colloidal charge and minimum turbidity was observed for polyelectrolytes . The time necessary to produce system clarification was larger for aluminum sulfate than for polyelectrolytes; this time was shortened for higher aluminum sulfate concentration . The pH showed a marked effect on aluminum sulfate performance with the optimum at pH 6; polyelectrolyte action was practically not affected by pH . Polyelectrolyte addition produced the minimum turbidity for the same doses that zero colloidal charge; at higher doses, emulsion was restabilized and became turbid again . However, aluminum sulfate treatment did not produce emulsion restabilization.

Environ Sci Technol, 2001 Jul 15, 35(14), 3040 - 7
Studies on the interfacial characterization of O/W emulsion for the optimization of its treatment; Shin SH et al.; Wastewater produced in the form of an o/w emulsion is difficult to treat properly because of its complex behavior . To acquire information for the optimization of emulsion controlling processes, the interfacial features of emulsion systems have been investigated in this work . The surface tension is found to decrease as the oil content is increased, and contact angle is influenced by the hydrophobicity of the substrate . The work of adhesion for substrates with different degrees of hydrophobicity has been estimated from the contact angle and surface tension . Temperature and pH have a significant influence on the turbidity and surface tension, and it is observed that electrophoretic characteristics of oil droplets are closely related with turbidity . Also, effects of inorganic salts and surfactants on the electrokinetic properties of emulsions have been considered, and the influence of coagulant on the stability is discussed through the calculation of potential energy of interaction between oil droplets . Adsorption and electrocoagulation processes have been attempted under various conditions in order to examine the practical treatment efficiencies of emulsion in relation to its interfacial characteristics.

Water Res, 2001 Aug, 35(12), 3018 - 24
Ferric chloride and lime conditioning of activated sludges: an electron microscopic study on resin-embedded samples; Deneux-Mustin S et al.; Ferric chloride and lime conditioning of sewage sludge is usually interpreted in terms of enhanced aggregation of sludge components . In this study, transmission electron microscopy was used to investigate the conditioning mechanism at a submicronic scale . Samples were collected from two municipal wastewater treatment plants at different stages of the process, embedded in an epoxy resin, and sectioned with an ultramicrotome . Transmission electron microscopy examination of thin sections revealed that clumps of crystalloids develop on external surfaces of flocs after the application of both conditioners . This precipitate creates a rigid structure around the flocs which, upon mechanical dewatering, transmits the stresses applied to the inner parts of flocs . The porous structure of the precipitate may also participate to the withdrawal of water as a draining media . Energy dispersive X-ray spectroscopy revealed that Fe, P, and Ca are the dominant elements in the precipitate with Fe/P and Fe/Ca elemental ratios close to 2.8-3 and 1.1-3, respectively.

Water Res, 2001 Aug, 35(12), 2935 - 42
Stabilized landfill leachate treatment by combined physicochemical-nanofiltration processes; Trebouet D et al.; Landfill leachate is a complex wastewater which the composition and concentration of contaminants are influenced by the type of waste deposited and the age of landfill . In the last years, several processes or process combinations were developed and tested to reach requirements for the discharge of leachate . Among the new processes, membrane processes are considered as promising: reverse osmosis is one of the most widely used treatment in the Northwestern European countries and nanofiltration is gained in popularity during the last 5 years . Successful application of membrane technology for the treatment of landfill leachates, requires efficient control of membrane fouling . Two organic membranes of nanofiltration were used for pilot-scale testing . Leachates were subject to several pretreatments (pH modification, prefiltration and coagulation with FeCl3) to remove potential foulants including dissolved organic and inorganic substances, colloidal and suspended particles . These pretreatments do not enhance the performances (retention and permeation flux) of membranes because the pH range and the presence of Fe3+ ions contribute greatly to change the characteristics of organic matter and the surface charges of membranes . However, the results show that nanofiltration is sufficient to eliminate refractory COD, the permeates have a COD lower than the requirements for discharge.

Mar Pollut Bull, 2001 Jun, 42(6), 513 - 21
Livestock wastewater treatment by a mangrove pot-cultivation system and the effect of salinity on the nutrient removal efficiency; Ye Y et al.; The present investigation compared the capacity of greenhouse pot-cultivation systems under two salinity conditions (freshwater and saline water) with two mangrove species (Bruguiera gymnorrhiza and Kandelia candel) to remove nutrients from livestock wastewater . During the whole treatment period there were relatively stable leachate TOC concentrations for wastewater-treated pots . Leachate NH4(+)-N concentration of B . gymnorrhiza pots was generally lower than that of K . candel pots . Leachate PO4(3-)-P concentration of pots receiving wastewater under freshwater condition was higher than that under saline water condition . Soil inorganic N content was more than two times higher for the wastewater treatments than that for the controls under low salinity condition and slower rate of increase under saline water condition . Soil P nutrients of both total and extractable inorganic forms significantly increased for both systems due to the discharges of livestock wastewater under both salinity conditions . The rate of increase in P contents for plants receiving livestock wastewater was 1-4 times that of the controls, much more than that in N contents (0.04-1.30 times) . N nutrient removal efficiencies were 84.3% (65.6% by soil and 18.7% by plant) and 95.5% (32.2% by soil and 63.4% by plant), respectively by Kandelia candel and B . gymnorrhiza pot-cultivation systems under freshwater condition . Under saline water condition, N nutrient removal efficiencies by K . candel and B . gymnorrhiza pot-cultivation systems were 92.7% (80.7% by soil and 12.0% by plant) and 98.0% (67.6% by soil and 30.3% by plant), respectively . P nutrient removal efficiencies by K . candel and B . gymnorrhiza systems under freshwater condition were 79.2% (76.6% by soil and 2.6% by plant) and 91.8% (88.2% by soil and 3.6% by plant), respectively . The corresponding values were 88.0% (84.2% by soil and 3.8% by plant) and 97.8% (95.9% by soil and 1.9% by plant) under saline water condition.

Water Sci Technol, 2001, 43(12), 93 - 8
Helicobacter pylori in water systems for human use in Mexico City; Mazari-Hiriart M et al.; Helicobacter pylori infection is associated with peptic ulcers and gastric cancer in humans . Transmission of H . pylori is still not certain with some epidemiological data suggesting water as a possible transmission route . The objective of this study was to detect H . pylori 16S rRNA gene in five water systems in the Mexico City area . Samples were taken between 1997 and 2000 from extraction wells (system 1), from dams used as water sources, both pre- and post-treatment (systems 2 and 3), treated wastewater (system 4) and non-treated wastewater (system 5) . Detection of the H . pylori 16S rRNA gene in water samples was carried out using nested PCR in 139 water samples and confirmed by using cagA gene detection by PCR-hybridisation . The results showed the presence of H . pylori in 58 (42%) of the water samples in total with a prevalence of 68% in system 1, 100% in system 2, 0% in system 3, 17% in system 4 and 20% in system 5 . This first stage showed the presence of H . pylori in the tested water systems; nevertheless, viability of the microorganism in water and vegetables needs to be confirmed as well as demonstration of a relationship between human and environmental strains.

Water Sci Technol, 2001, 43(12), 73 - 6
Astrovirus detection in wastewater samples; Pinto RM et al.; Procedures for the detection of astroviruses in wastewater samples have been developed and evaluated . Following these methodologies, we investigated the occurrence of astroviruses in wastewater samples from three different sewage treatments plants located in Southern France and two in the Barcelona area . Some positive samples were genotyped by analysis of a fragment of the ORF1a by restriction fragment length polymorphism (RFLP) with endonuclease DdeI . The amplimers generated contain several sites for the DdeI restriction endonuclease, being the number and location of sites different between strains.

Water Sci Technol, 2001, 43(12), 31 - 8
HACCP (Hazard Analysis and Critical Control Points) to guarantee safe water reuse and drinking water production--a case study; Dewettinck T et al.; To obtain a sustainable water catchment in the dune area of the Flemish west coast, the integration of treated domestic wastewater in the existing potable water production process is planned . The hygienic hazards associated with the introduction of treated domestic wastewater into the water cycle are well recognised . Therefore, the concept of HACCP (Hazard Analysis and Critical Control Points) was used to guarantee hygienically safe drinking water production . Taking into account the literature data on the removal efficiencies of the proposed advanced treatment steps with regard to enteric viruses and protozoa and after setting high quality limits based on the recent progress in quantitative risk assessment, the critical control points (CCPs) and points of attention (POAs) were identified . Based on the HACCP analysis a specific monitoring strategy was developed which focused on the control of these CCPs and POAs.

Water Sci Technol, 2001, 43(12), 23 - 6
Viral risks associated with wastewater reuse: modeling virus persistence on wastewater irrigated salad crops; Petterson SR et al.; A model for virus decay on lettuce and carrot crops has been derived as part of a comprehensive wastewater irrigation microbial risk assessment model under development . Results from the decay modeling indicated the presence of a very persistent sub-population of viruses evidenced by an initial rapid phase of decay followed by a very slow phase . In addition, virus counts fitted a negative binomial rather than Poisson distribution indicating over-dispersion . Hence the data indicated that viruses were not uniformly distributed over the surfaces of both crops . The aim of this paper was to investigate the implications of over-dispersion and the presence of a very persistent sub-population of viruses for assessing viral illness from the consumption of lettuces and carrots irrigated with secondary treated effluent . When over-dispersion or clumping of viruses was accounted for, a significant increase in the heterogeneity in the risk estimates arose . In addition, predicted infection rates were significantly underestimated if the presence of a persistent sub-population of viruses was not considered in the decay kinetics of the risk model . Hence, both viral clumping and persistence sub-populations should be accounted for in future risk assessments of enteric viruses associated with wastewater reuse.

J Hazard Mater, 2001 Jul 30, 85(1-2), 91 - 109
Analysis of electrokinetic sedimentation of dredged Welland River sediment; Mohamedelhassan E et al.; The Welland River is a tributary of the Niagara River . In the late 1980s it was discovered that a section of the Welland River was contaminated with heavy metals as a results of two sewer outfalls that has been used by a steel plant and local industrial and municipal operations for the last 50-60 years . One of the major problems encountered in the treatment of the dredged Welland River sediment is a slow rate of sedimentation due to the large proportion of fine solids in the sediment . In this study, the results of electrokinetic sedimentation of the Welland River sediment are analyzed based on the principles of gravitational and electrokinetic sedimentation . It was found that the effects of electric field intensity and the initial solid concentration of the suspension are the dominating factors governing the average particle settling velocity, the coefficient of free settling in the free settling stage and the coefficient of sedimentation in the hindered settling stage . The electrokinetic treatment is proven to be effective in terms of increasing the free and hindered settling velocities, reducing the overall sedimentation time and increasing the final solid concentration of the sediment . Thus, electrokinetics can be used to accelerate sedimentation of dilute solid suspensions, such as dredged sediment, wastewater and mine tailings.

Arch Environ Contam Toxicol, 2001 Aug, 41(2), 129 - 41
Toxic effects of wastewaters collected at upstream and downstream sites of a purification station in cultures of rainbow trout hepatocytes; Risso-de Faverney C et al.; The toxic effects of wastewater samples, collected in December 1998, from upstream (U) and downstream (D) sites of the purification station of the town of Nice (South-East France on the coast of the Mediterranean Sea) were assessed undiluted and at various dilutions (75%, 50%, and 25% of collected water sample), on trout hepatocyte cultures treated for 48 or 72 h . Chemical contamination (PCBs, PAHs, Cd, Cu, Pb, and Zn) was also evaluated by chemical analysis . The water samples from the upstream site were more cytotoxic than those from the downstream site . The induction of CYP1A enzyme and metallothioneins (MTs) were selected as specific indicators of exposure to organic contaminants and metals, respectively . CYP1A-related EROD activity as well as protein expression were found to be greatly induced after 72 h exposure of the hepatocytes to the undiluted water samples (U(100%) and D(100%)), but CYP1A1 mRNA was significantly overexpressed only by samples from the upstream site . Maximal MT levels were reached after 48 h of treatment with the least concentrated water samples (U(25%) and D(25%)) . Glutathione S-transferase (GST) activities were similarly increased under the same conditions . On the other hand, there was no significant glutathione peroxidase (GPx) activity response . Induction of apoptosis was analyzed by using as markers both the fragmentation of the nuclear DNA into oligonucleosomal-length fragments recognized as a "DNA ladder" and the activation of DEVD (Asp-Glu-Val-Asp)-dependent protease considered as the central mediator of programmed cell death . Significant DNA cleavage was only detectable after 72-h exposure to the most concentrated water samples from upstream sites (U(75%) and U(100%)) . DEVD-dependent protease activities were significantly increased, mainly in cells exposed to U(75%) and D(25%) for 72 h . In addition, pollution-related DNA damage assessed by using the Comet assay was approximatively 1.5 times greater than that of the control level with the undiluted water samples U(100%) and D(100%), after 72-h and 48-h exposure, respectively . The present study shows that such a multibiomarker-based approach could provide complementary information, for aquatic pollution monitoring, about the early biochemical effects in cells exposed to complex chemical pollution and could be considered as early warning systems to aquatic pollution.

Mar Environ Res, 2000 Jul-Dec, 50(1-5), 257 - 61
In vivo and in vitro effects of benzothiazole on sheepshead minnow (Cyprinodon variegatus); Evans JJ et al.; Benzothiazole, a common chemical associated with tire manufacturing and industrial wastewater, is a principal component of both fresh water and estuarine tire leachate, a neurotoxicant to larval sheepshead minnows (Cyprinodon variegatus) in in vivo estuarine studies . The neurotoxic potential of benzothiazole was investigated following in vivo and in vitro exposure of sheepshead minnows to 3.75, 7.5, 15, 30 and 60 mg/l benzothiazole . Following benzothiazole exposure, fish were evaluated for survival, growth and histological alterations . Fish mortality occurred after 5 days of exposure to 60 mg/l (LC50 = 41.9) . Significant decreases in larval growth were noted at all concentrations . Histologically, gills had cellular alterations but the central nervous system lacked the severe cellular damage seen in previous tire leachate exposure studies . Benzothiazole cytotoxicity to primary cultures of brain cells from sheepshead minnow and tilapia (Oreochromis niloticus) and two epithelial cell lines was evaluated using a tetrazolium salt assay (MTT) at 1 and 4 days . In vitro results indicate primary cultures of brain cells are less sensitive to benzothiazole than epithelial cell lines . Significant cytotoxicity to the epithelial cell lines was noted at 30 and 60 mg/l concentrations . Histologically and cytotoxicologically, the present study indicates that benzothiazole is a gill toxicant and not a neurotoxicant.

Mar Environ Res, 2000 Jul-Dec, 50(1-5), 185 - 9
Comparative vitellogenic responses in three teleost species: extrapolation to in situ field studies; Thompson S et al.; Induction of vitellogenin (VTG) was compared among three teleostean species to determine their relative sensitivity of exposure to 17 beta-estradiol (E2) . Japanese medaka (Oryzias latipes), sunshine bass (Morone saxatalis x Morone chrysops) and channel catfish (Ictalurus punctatus) were exposed to aqueous concentrations of E2 ranging from 10 to 100,000 ng/l for 21 days . Respective EC50 values for plasma VTG detected by western blot in medaka, catfish and bass were 200, 170 and 1560 ng E2/l . Since these EC50 values are based on VTG induction curves calculated relative to control values, they indicate differences in species' sensitivity to E2 exposure . Catfish and bass VTG responses obtained in laboratory exposures were compared to VTG responses previously observed with 21-day wastewater treatment plant effluent exposures . Plasma VTG induction in effluent-exposed fish ranged from 14 to 82% above reference values depending on species . Extrapolation of field responses with laboratory-exposed fish indicate catfish and bass were exposed to the equivalent of 27-240 ng E2/l in sewage effluent.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2001 May, 36(5), 727 - 34
Removal of fluoride ion from aqueous solution by a cerium-poly(hydroxamic acid) resin complex; Haron MJ et al.; A cerium-loaded poly(hydroxamic acid) chelating ion exchanger was used for fluoride ion removal from aqueous solution . The resin was effective in decreasing the fluoride concentration from 5 mM down to 0.001 mM in acidic pH between 3 and 6 . The sorption followed a Langmuir model with a maximum capacity of 0.5 mmol/g . The removal is accomplished by an anion exchange mechanism . The rate constant for the sorption was found to be 9.6 x 10(-2) min-1 . A column test shows that the fluoride ion was retained on the column until breakthrough point and the fluoride sorbed in the column can be eluted with 0.1 M NaOH . The column can be reused after being condition with hydrochloric acid at pH 4 . The resin was tested and found to be effective for removal of fluoride from actual industrial wastewater.

J Chromatogr A, 2001 Jun 1, 919(1), 59 - 65
On-line dialysis as a sample preparation technique for ion chromatography; De Borba BM et al.; The use of on-line dialysis as a sample preparation technique for ion chromatography is described . A fully automated sample preparation device coupled to an ion chromatographic system for the determination of anions and cations in various matrices is presented . The method was based on stopped-flow dialysis, where the samples were continuously dialyzed for 10 min while the acceptor solution was stationary within the recipient channel . The matrices examined, without additional sample treatment, included milk, untreated wastewater, fruit juice, engine coolant, and a multivitamin tablet . The analyte recoveries for anions and cations in various matrices ranged from 87 to 106% . In addition, multiple sample injections were performed and repeatabilities were found in the range of 0.2 to 4%.

Water Res, 2001 Aug, 35(11), 2711 - 23
Metabolic modelling of full-scale biological nitrogen and phosphorus removing wwtp's; Meijer SC et al.; This paper evaluates the experiences with modelling full-scale biological phosphorus and nitrogen removing wastewater treatment plants . For the simulation, we used a metabolic phosphorus model integrated in ASM2d, further referred to as TUDP-model . It was found that the metabolic model for bio-P removal can be applied for modelling full-scale wwtp's, without extensive parameter adjustments . A stepwise modelling approach was proposed . Only three specific parameters were calibrated . Two parameters, the inert fraction in the influent and the actual anoxic sludge fraction will need calibration for all systems . Parameter sensitivity analyses showed that the sensitivity of operational data, often considered as known input data, is high . The model kinetics were found less sensitive . This will in general be the case for all low-loaded wwtp's recorded in their pseudo-steady state . Based on mass balance calculations, operational data and measurements were evaluated . Since all terms on a phosphorus balance can be measured, errors in operational data (e.g . SRT and flow rates) become very apparent in P-removal models (ASM2d, TUDP) . We suggest using the P-balance in general for wwtp modelling, as a check on data consistency . This study showed that considering operational data per definition as known input data is not justified . Therefore, operational data should be evaluated, or considered in model calibration over the use of kinetic and stoichiometric parameters.

Water Res, 2001 Aug, 35(11), 2595 - 606
Naphthenic acids and surrogate naphthenic acids in methanogenic microcosms; Holowenko FM et al.; Naphthenic acids (NAs) are a complex mixture of naturally occurring acyclic and cyclic aliphatic carboxylic acids in petroleum . In the Athabasca oil sands . NAs have been identified as the largest component of dissolved organic matter in the tailings waters from oils sands extraction processes . They are the major contributor to the acute toxicity of the fine tailings wastewaters at the oil sands extraction plants in northeastern Alberta, Canada . In this study, three sources of NAs were studied, including commercially available NAs, those extracted from oil sands process-affected waters, and individual naphthenic-like surrogate compounds . Analysis by gas chromatography-mass spectrometry demonstrated differences between the commercial and extracted NAs . The NAs derived from the process-affected waters showed a short-term inhibition of methanogenesis from H2 or acetate, but with time the populations resumed methane production . It has been postulated that microbial metabolism of the carboxylated side chains of NAs would lead to methane production . The two NA mixtures failed to stimulate methanogenesis in microcosms that contained either oil sands fine tailings or domestic sewage sludge . However, in microcosms with sewage sludge, methanogenesis was stimulated by some surrogate NAs including 3-cyclohexylpropanoic acid at 400-800 mg/L, 5-cyclohexylpentanoic acid at 200 mg/L or 6-phenylhexanoic acid at 200 and 400 mg/L . When added at 200 mg/L to methanogenic microcosms containing fine tailings, 3-cyclohexylpropanoic and 4-cyclohexylbutanoic acids produced methane yields that suggested mineralization of the side chain and the ring.

Water Res, 2001 Aug, 35(11), 2583 - 8
Cofermentation of rutin and hesperidin during two-stage anaerobic pre-treatment of high-loaded brewery wastewater; Herrmann AP et al.; In a lab-scale two-stage digester (consisting of an acidification and a methane reactor) operated continuously with high-loaded brewers wastewater (psiCOD 9.000 mg1(-1)) as the primary substrate, the cofermentation of two commonly found flavonoids (rutin and hesperidin) was studied . At overall hydraulic retention times of 48-50 h and organic loading rates in the methane reactor ranging from 8 to 10 g COD 1R(-1) d(-1) the addition of up to (0.71 g 1R(-1) d(-1) of either rutin or hesperidin did not cause adverse effects on the reactor performance, in terms of VFA pattern, COD removal efficiency, and specific biogas production . The added flavonoid glycosides were rapidly converted in the acidification reactor yielding several hydroxyaromatic metabolites . With hesperidin as the cosubstrate, all of the formed metabolites were completely removed during passage through the methane reactor whereas in case of rutin, substantial amounts of m-cresol and 4-hydroxyphenylacetate were built up in the medium and remained in the effluent of the methane reactor.

Environ Sci Technol, 2001 Jul 1, 35(13), 2698 - 703
Partial degradation of phenol by advanced electrochemical oxidation process; Wu Z et al.; The partial electrocatalytic degradation of phenol to organic acids has been investigated using an undivided electrolytic reactor with a beta-PbO2 anode containing fluorine resin . It was found that the decrease of benzoquinone (BQ) formed during phenol degradation and the acceleration of the process from phenol to organic acids are possible under an optimized operating condition . A possible pathway for phenol degradation was proposed, and a mathematical model for phenol and BQ evolution was developed . Operating parameters such as initial pH, current density, and temperature of the reaction were found to greatly impact the degradation rate of the phenol and even the pathway . Higher removal rate of phenol and BQ can be achieved at an appropriate temperature and higher current density in acidic medium preferably at pH 4 . Under these conditions, phenol would be more likely degraded in the pathway from phenol to organic acids rather than through the BQ . When phenol is completely removed, the toxicity of the wastewater would be lessened suitable for biological process treatment . Accounting for the decrease of instantaneous current efficiency (ICE) during degradation, partial degradation would be highly economical for wastewater treatment, which would be an alternative process in practical application.

Water Sci Technol, 2001, 43(11), 91 - 8
Direct influent filtration as a pretreatment step for more sustainable wastewater treatment systems; van Nieuwenhuijzen AF et al.; Within the scope of a research programme into wastewater treatment scenarios based on physical-chemical pretreatment, the application of direct influent filtration (DIF) as a first treatment step in a wastewater treatment system was investigated . The aim of the experimental research was to investigate the feasibility of DIF as a pretreatment step for advanced particle removal . With a large scale pilot-plant filter at WWTP Leiden-Noord, The Netherlands the removal characteristics for suspended and colloidal material were investigated as well as operational conditions of eight different filter configurations . From the experimental research it was concluded that filtration of raw wastewater is possible, notwithstanding the relatively short run-times due to clogging . In general, the filters produced a filtrate with a constant quality with low concentrations of solids and low turbidity . Without addition of chemicals hardly any colloids and solubles were retained, but only suspended particulates were removed . After dosage of iron or polymer, it was possible to remove more suspended matter and a high proportion of colloidal material . Finally it was concluded that DIF could be applied as a compact treatment system to produce a high quality primary effluent with a constant composition, but for practical application further research has to be done.

Water Sci Technol, 2001, 43(11), 83 - 90
Flotation with polyelectrolytes as a first step of a more sustainable wastewater treatment system; Mels AR et al.; Within the framework of a research programme into more sustainable wastewater treatment systems based on physical-chemical pretreatment the application of dissolved air flotation (DAF) with polyelectrolytes as a primary treatment was investigated . Experiments with municipal wastewater were carried out in 2.5 I flotation batches and in a 100 I DAF pilot reactor . Two cationic polyelectrolytes (PEs) with molecular weights of 4 x 10(6) g/mol and 8 x 10(6) g/mol, were tested . The higher weight PE was more effective in removing turbidity and was used in the pilot experiments for coagulation/flocculation . Within the pilot system experiments the dry solids concentration of the float layer as well as the removal efficiencies of turbidity, CODparticulate, CODdissolved and nutrients, were studied . Typical results were that the obtained dry solids concentration of the floated sludge was 10%, when the float layer was removed after several hours . By using polyelectrolytes it was possible to remove more than 80% of CODparticulate and turbidity at dosages of 7-8 mg/g influent COD (i.e . 5 mg PE/100 NTU) . The removal efficiency of CODdissolved was low . There was a proportional relationship between CODparticulate and turbidity . This led to the conclusions that by introducing a dosing control strategy based on continuous turbidity measurements a constant CODparticulate removal efficiency can be obtained.

Water Sci Technol, 2001, 43(11), 67 - 74
Evaluation of refractory organic removal in combined biological powdered activated carbon--microfiltration for advanced wastewater treatment; Seo GT et al.; Biological powdered activated carbon (BPAC) was incorporated with a microfiltration (MF, 0.2 micron pore size) system to remove the refractory organic matter contained in secondary sewage effluent . A synthetic secondary sewage effluent was used as influent in this study, containing both non-biodegradable organic substances (such as humic acid, lignin sulfonate, tannic acid and arabic gum powder) and biodegradable ones . These refractory organic materials were possibly degraded in contact with microorganisms for 20-27 days . Although humic acid and arabic gum were weakly adsorbed on the activated carbon, they could be effectively removed in the BPAC reactor . The TOC removal at a powdered activated carbon (PAC) concentration of 20 g/L was higher than at 0.5-2 g PAC/L (83% and 66-68%, respectively) . The higher removal efficiency was due to the increased rejection at the membrane module in which most of the PAC was accumulated . More than 90% of non-biodegradable compounds removal (detected as E280, UV absorption at 280 nm) occurred in the BPAC reactor . The biological growth parameter b/Y, used in system design, was estimated to be 0.017 d-1 . Relatively high permeate flux of 1.88 m/d could be obtained even at higher PAC concentration of 20 g/L.

Water Sci Technol, 2001, 43(11), 345 - 50
Constructed wetland technology transfer to Nepal; Shrestha RR et al.; Constructed Wetland (CW) technology is still not wide spread in developing countries despite having great potential . This paper describes an approach carried out in Nepal to transfer CW technology for wastewater treatment . Three CWs (hospital wastewater treatment--20 m3/d, greywater treatment of a single household, septage treatment--40 m3/d) were built and two have been investigated so far . All systems are subsurface flow systems with at least one vertical flow stage . Their treatment efficiency turned out to be very high . Median load elimination rates of the hospital wastewater and greywater treatment plants were for TSS: 97 to 99%; BOD5: 97 to 99%; COD: 94 to 97%; NH4-N 80 to 99%; PO4-P: 5 to 69%; Total Coliforms: 99.87 to 99.999% (3-5 log steps) . Beside the treatment task the plants play an important role as demonstration sites to make common people and especially decision makers aware of the existing environmental problems and one possible solution . Several recommendations are pointed out to promote the technology in developing countries.

Water Sci Technol, 2001, 43(11), 329 - 36
Wastewater collection and treatment technologies for semi-urban areas of India: a case study; Sundaravadivel M et al.; Sanitation and wastewater management problems in small and medium towns in India (referred to as "semi-urban areas"--SUAs) are distinctly different from those of large cities or rural villages . There is an apparent lack of choices of appropriate sanitation options for these semi-urban areas, leading them to adopt on-site sanitation technologies . A field study of four such small towns in India was conducted to evaluate the suitability of available low-cost wastewater collection and treatment technologies, in light of their current practice . Based on the field study, this paper suggests a system comprising "combined surface sewers" and "reed-bed channel" for collection and treatment of wastewater for semi-urban areas, that can utilize all the existing infrastructure to effect better sanitation at lower costs . The suggested system involves converting the existing open wastewater collection drains on the road sides, as "decentralized" networks of covered drains with simple structural modifications to collect both wastewater and stormwater; and, converting the large open drains on the outskirts of SUAs that carry wastewater to agricultural fields, as gravel media filled beds planted with local reeds . Cost estimates for the towns studied indicate this system to be over 70% cheaper compared to conventional collection and treatment systems.

Water Sci Technol, 2001, 43(11), 301 - 7
Comparison of operational design criteria for subsurface flow constructed wetlands for wastewater treatment; Leonard KM et al.; Many communities are investigating the use of constructed wetlands as a simple, viable alternative to poorly operating on-site wastewater treatment . Currently, the most popular design models in the U.S.A . for subsurface flow units are the US Environmental Protection Agency (EPA) and the Tennessee Valley Authority (TVA) methods . However, there has been limited data verifying if the operating performance is up to design standards . In order to address this problem, this paper documents the performance of such treatment systems over a broad range of conditions in North Alabama . The operational data is used to determine a best-fit value of reaction rate constant and proposes improved input parameters for both design models . According to this data, the average plug-flow reaction rate constant was calculated to be 0.70 d-1 for the EPA method, while the recommended organic loading criterion is 11.4 m2/kg BOD5 per day into the wetland for the TVA method.

Water Sci Technol, 2001, 43(11), 291 - 9
Duckweed based wastewater treatment (DWWT): design guidelines for hot climates; Smith MD et al.; Conventional wastewater treatment systems are expensive in either investment or running costs . On the other hand, waste stabilisation ponds may be unable to meet effluent standards for nutrients . Wastewater treatment using duckweed therefore becomes more significant as an option capable of achieving effluent standards and generating revenue from selling the duckweed . However existing duckweed based wastewater treatment (DWWT) systems have high land requirements despite being able to reduce concentrations of organic compounds and pathogens to acceptable levels . Improved guidelines for the design of DWWT are necessary to obtain a reliable and cost-effective wastewater treatment plant using duckweed . This guideline provides a DWWT design program using spreadsheets for different configurations of wastewater treatment units using duckweed . The design program developed suggests that a combination of anaerobic ponds, DWWT systems and maturation ponds can minimise land requirements and capital costs while achieving specified effluent standards . In order to achieve effluent standards, the land required is typically from 1.5 to 1.8 m2/capita (excluding associated facilities), capital costs are in the range from 7.9 to 9.7 USD/capita, with a retention time from 15 to 18 days . Income generation is dependent mainly on the social and cultural acceptability of duckweed use within the community.

Water Sci Technol, 2001, 43(11), 223 - 31
A scientific approach to wastewater recovery and reuse in the textile industry; Orhon D et al.; Wastewater recovery and reuse in industries requires all the basic steps of quality management . It should involve a comprehensive in plant survey of processes with wastewater generation, identification of recoverable streams, and treatment requirements for reuse . It should equally undertake evaluation of wastewater quality remaining after segregation of the recovered portion, with specific emphasis on technological implications of appropriate treatment and compliance with effluent limitations . In this study, all these factors were experimentally assessed and evaluated for a knit fabric processing textile plant.

Water Sci Technol, 2001, 43(11), 189 - 96
Improving the efficiency of a wastewater treatment plant by fuzzy control and neural network; Bongards M; One of the main problems in operating a wastewater treatment plant is the purification of the excess water from dewatering and pressing of sludge . Because of a high load of organic material and of nitrogen it has to be buffered and treated together with the inflowing wastewater . Different control strategies are discussed . A combination of neural network for predicting outflow values one hour in advance and fuzzy controller for dosing the sludge water are presented . This design allows the construction of a highly non-linear predictive controller adapted to the behaviour of the controlled system with a relatively simple and easy to optimise fuzzy controller . Measurement results of its operation on a municipal wastewater treatment plant of 60,000 inhabitant equivalents are presented and discussed . In several months of operation the system has proved very reliable and robust tool for improving the system's efficiency.

Water Sci Technol, 2001, 43(11), 119 - 26
Experimental validation of a single-OUR method for wastewater RBCOD characterisation; Ziglio G et al.; Wastewater characterisation is of primary importance for the correct design and management of a treatment plant . The aim of this work was the evaluation of a new rapid and easy to use respirometric technique for the characterisation of readily biodegradable COD (RBCOD) . When the necessary calibration curve is obtained, the RBCOD assessment procedure needs less than 30 minutes . On the contrary, conventional techniques require some hours . The first step consists in calculating a calibration curve in order to point out the correlation between oxygen consumed and known amount of added Sodium Acetate . To a well aerated biomass (in order to remove residual readily biodegradable substrate) a known amount of Sodium Acetate is added and the related OUR is measured . The oxygen consumed (delta DO) is related to the added COD (as Sodium Acetate) . Therefore, the RBCOD concentration in wastewater samples can be obtained according to the following steps: (1) measure delta DO; (2) multiply delta DO by the Volume of aerated mixed liquor used in the test; (3) from the calibration curve, calculate the readily biodegradable COD equivalent to Acetate; (4) estimate RBCOD concentration multiplying the wastewater sample volume tested in the reactor . Some advantages of this technique are described in the paper.

Water Sci Technol, 2001, 43(11), 1 - 7
A new economical method to remove humic substances in water: adsorption onto a recycled polymeric material with surfactant addition; Adou AF et al.; Cationic surfactants were used to enhance the adsorption of dissolved organic matter (DOM), contained in the effluent of municipal wastewater, onto polypropylene (PPL), a polymeric synthetic adsorbent made from recycled plastics . Both batch and continuous up-flow column experiments were carried out . The DOM, in the form of humic acid, was treated with a range of cationic surfactants, then, adsorption experiments were conducted to evaluate the adsorption of the mixture onto PPL in both its soluble and precipitated forms . This research validated the feasibility of the proposed system in which anionic humic acid is removed from the aqueous phase by forming neutral hydrophobic molecules with cationic surfactants and subsequently by adsorbing them on the hydrophobic surface of PPL.

Environ Manage, 2001 Aug, 28(2), 149 - 63
Industrial development versus environmental conservation at local scale: a case study from southeastern Spain; Maestre Gil FT; Local scale has an important role in environmental management . In Spain, rapid industrialization has occurred in the last three decades, leading to substantial changes in socioeconomic relations and resulting in significant environmental degradation . This paper describes the environmental status of the township of Sax (Alicante, in southeast Spain), which has passed from agriculture to industrial manufacturing in 50 years . The human population has grown exponentially during the second half of the 20th century, with a 91% increase from 1955 to 1995, coinciding with strong growth in manufacturing (factories increased fivefold in the period 1955-1976) and important changes in the working population and land use . Illegal rubbish dumps, water pollution, forest fires, erosion, and degradation of wildlife habitats are the main outcomes of these dramatic socioeconomic and demographic changes . The administration has focused on the control of water pollution and waste management, while nongovernmental organizations have concentrated on the prevention of forest fires and the development of environmental education programs . These measures are insufficient to manage current environmental degradation, and an environmental management plan for the study area is discussed . Increasing effort in waste management and industrial wastewater control, changes in land-use policy, and the creation of an advisory committee to increase public participation in decision-making have been identified as environmental target objectives for the coming years.

J Chromatogr A, 2001 Jun 15, 919(2), 289 - 97
Analysis of sulfophthalimide and some of its derivatives by liquid chromatography-electrospray ionization tandem mass spectrometry; Reemtsma T; A system was developed for the separation of sulfophthalimide (SPI), sulfophthalamide (SPAM), sulfophthalamic acid (SPAA) and sulfophthalic acid (SPA) by ion-pair liquid chromatography and their detection by electrospray ionization tandem mass spectrometry (ESI-MS-MS) . Except for SPAM, the 3- and 4-sulfo-isomers of the analytes were separated by HPLC using volatile tributylamine as ion-pairing agent . Initial fragmentations of the analytes in the negative mode involve losses of CO2 or HNCO or condensation via H2O or NH3 elimination . ortho-Effects of the sulfonate group were recognized in the fragmentation of the respective 3-sulfo-isomers and allowed us to assign the order of elution of the SPAA isomers . Quantitative analysis of these sulfonated aromatic compounds with MRM detection was elaborated and resulted in detection limits ranging from 1 pg for SPA to 13 pg for SPAA isomers and in limits of quantification of 2-10 microg/L for 5 microL volumes of injected tap water, municipal wastewater or industrial effluents up to salt contents of 0.5-1 g/L . The method was applied to study the isomer-specific chemical and microbial transformations of SPI, which was previously shown to be formed by white-rot fungi from sulfophthalocyanine textile dyes.

Water Sci Technol, 2001, 43(10), 91 - 9
A methodology to evaluate water and wastewater treatment plant reliability; Eisenberg D et al.; Evaluating the reliability of treatment processes and treatment facilities should be an important part of the planning and design process for water resource, wastewater treatment, and particularly wastewater reuse projects . With the recent developments in technology, particularly the development of membrane processes and alternative disinfection processes for water and wastewater treatment, there is an increasing need for a common methodology to evaluate the reliability of alternative processes and treatment facilities that utilize different combinations of those processes . To assess the reliability of a treatment facility, several aspects of treatment must be considered including a methodical evaluation of both mechanical reliability and plant performance . A straightforward method for conducting these types of analyses is described herein along with a description of applications of this methodology . A discussion is provided highlighting the value of such a methodology for both the water quality engineer and the risk manager.

Water Sci Technol, 2001, 43(10), 9 - 16
Prospects, problems and pitfalls of urban water reuse: a case study; Hermanowicz SW et al.; This paper presents a successful water reclamation and reuse project in the San Francisco Bay area . The project, which includes a water reclamation facility and a separate distribution system, is operated by a wastewater utility and reclaims approximately 4% of its dry-weather flow . Project history, its design and implementation are further discussed . Planning, and especially demand analysis, was critical for project development . Earlier attempts of water reuse were not successful because reclaimed water quality did not match the requirements of potential large industrial customers . Current customers are a mix of public, commercial and residential users who apply the reclaimed water solely for landscape irrigation . In addition, a large fraction of the reclaimed water is used internally in the main wastewater treatment plant . Early connection of largest customers, innovative collaboration with a neighboring reclamation project and cooperation of the local water supplier were very important for project success . Distribution of internal process water consumes most energy . The second major energy use is for the treatment of reclaimed water while distribution of reclaimed water to external customers requires least energy.

Water Sci Technol, 2001, 43(10), 75 - 81
Some economic considerations on wastewater reclamation for irrigation, with reference to the Italian situation; Nurizzo C et al.; The purpose of this work is to check construction and operation costs for simplified post-treatment trains able to produce water displaying a quality suitable for different agricultural uses . Having in mind the quality of most of surface waters in Italy, the main parameters to control for a general purpose reclaimed water supply are microbial quality and TSS content . Therefore a contact filtration followed by disinfection is to be considered the minimum option, while the use of polishing ponds can be strictly limited in many Italian regions due to the area requirements and to the need to provide a full lining of bottom and levees . Some data referring to surface waters quality and to the Italian epidemiological situation are given . On the basis of the current Italian situation, the construction and operation cost increases due to a polishing section, downstream a standard municipal WWTP, are evaluated and the impact of different technical choices is shortly discussed (disinfection options, chemicals, etc.) . Some considerations about the link existing in Italy between the cost of water for irrigation and the agricultural economy are made.

Water Sci Technol, 2001, 43(10), 59 - 66
Strategies for development of industrial wastewater reuse in Thailand; Visvanathan C et al.; Majority of the industrial activities in Thailand are concentrated around Bangkok Metropolitan Area . The ever increasing industrial activities have led to over exploitation of water resources and discharge of significant pollution load . Therefore, it is important to identify the wastewater reuse potentials and develop strategies for its promotion within the industrial sector . Although technological advances have made it possible to treat effluents for industrial re-use, in practice, the Thai industries do lack in implementation of such technologies . Promotion of cleaner production concepts and advanced new technologies such as membrane technologies could assist the industry for the implementation of wastewater reuse projects in Thailand . This paper discusses various technical, institutional and management related issues to promote industrial wastewater reuse, with few case studies.

Water Sci Technol, 2001, 43(10), 51 - 8
Reclaimed municipal wastewater--a potential water resource in China; He P et al.; Due to water resource shortage and socio-economic development within twenty years, China faces serious problems of water supply and water pollution . Several criteria and suitable reclamation processes related to water reuse have been created in China, which are helpful to improve the situation of water scarcity . In the future, reclaimed municipal wastewater reuse will mainly be developed for urban and industrial use . Potential supply quantity of reclaimed water, quality of reclaimed water, and reclamation cost are favorable to potential reuses . Based on further public environmental education, on a relevant development of national and local standards for reclaimed water quality, and on an increase of sanitary rate, more and more planned reclaimed water reuse projects would be expected in China.

Water Sci Technol, 2001, 43(10), 43 - 50
Wastewater reuse in Italy; Barbagallo S et al.; In many parts of Italy, particularly in the South, it has become ever more difficult to meet the water demand . The recent years of drought and the constant increase of water demand for the civil sector have made irrigation supply more problematic . Wastewater reuse could represent a viable solution to meet water demand . The focus of this paper is on the regulation problems, hampering the development of wastewater reuse for irrigation, and on the potentials for reuse, particularly in Southern Italy . Planned exploitation of municipal wastewater could help meeting the irrigation water demand particularly in Southern Italy, where farmers have been practising uncontrolled wastewater reuse for a long time . In Northern and Central Italy, where available water resources generally meet water needs for different purposes, wastewater reuse could play an important role in controlling the pollution of water bodies . Despite the fact that Italian legislation is extremely strict and outdated, for several years in some regions, such as Sicily, wastewater reuse systems have been in operation; furthermore, several projects of wastewater reuse are currently in progress.

Water Sci Technol, 2001, 43(10), 35 - 42
The Virginia Pipeline: Australia's largest water recycling project; Kracman B et al.; The need to conserve, reuse and recycle water is becoming increasingly important for both environmental and economic reasons . The Virginia Pipeline is Australia's largest water recycling project . More than half the output from (the capital of South Australia) Adelaide's largest wastewater treatment plant is further treated to achieve a product water quality fit for irrigation of vegetable crops with minimal public health restrictions . The project partners have a vision to achieve total reuse . To achieve this vision, recycled water will need to be stored during cool weather periods when the demand for water is low . Temporary storage of this water in poor quality aquifers is the subject of a major research project.

Water Sci Technol, 2001, 43(10), 311 - 8
Improved O3/H2O2 oxidation process for wastewater reclamation; Yang M et al.; A continuous two step O3/H2O2 oxidation system, in which the waste gas from the former reactor was reused in the latter step with an ejector, was established for the purpose of wastewater reclamation in electronics industries . ORP monitor was combined into the system to obtain the optimum ratio of H2O2 to O3 by automatically adjusting the dosage of H2O2, and ion exchange resin was used for removing organic acids formed during oxidation . The effectiveness of the O3/H2O2 oxidation system for TOC removal was investigated under various conditions by using IPA, DMSO, and NMP as model substances . The optimum H2O2/O3 for oxidizing IPA was in a range above 0.15, and it increased with the increase of O3 dose . A sudden drop of ORP from ca . 800 mV to a little more than 200 mV was observed when H2O2/O3 was approaching the optimum point from the lower end . An ORP between 250 mV and 300 mV or 800 mV and 900 mV was proper for H2O2/O3 control . The treatability of the model substances was in an order of IPA << DMSO < NMP, being consistent with the magnitude of the energy of the highest occupied molecular orbital (epsilon HOMO) . The two step treatment system developed in this study was found to be more efficient than the conventional single step system . With the help of H2O2 dosing control and two step treatment using waste O3, the system could save about 40% O3 in comparison with the conventional O3/H2O2 oxidation process.

Water Sci Technol, 2001, 43(10), 303 - 10
Particle size analysis as a tool for performance measurements in high rate effluent filtration; van der Graaf JH et al.; In the Netherlands almost all wastewater treatment plants have been redesigned and adapted in order to remove nitrogen, phosphorus and suspended solids to a very low level . The improved effluent quality leads to a growing interest in the reuse of effluent of the modernised wastewater treatment plants . This again results in investigations on filtration techniques as deep bed filtration and membrane filtration . At the wastewater treatment plant Ede research was done on deep bed filtration in order to develop relations between particle removal and filter performance and to explore ways of optimization . The results of the experiments are rather typical for effluent of modern Dutch wastewater treatment plants . The very low concentrations of suspended solids and precipitable substances result in poor flocculating properties . From turbidity measurements it may be concluded that the best results were obtained with a dosage of flocculant . However, the particle size measurements indicated the opposite . Suspended solids calculations, based on the particle volume distributions, showed a better removal without a dosage of flocculant . From this it is concluded that a dosage of coagulant (Fe3+ or Al3+) has an adverse effect on the removal efficiencies even at low dosages (1 mg/l).

Water Sci Technol, 2001, 43(10), 295 - 302
Chemical oxidation of organic matter in secondary-treated municipal wastewater by using methods involving ozone, ultraviolet radiation and TiO2 catalyst; Tanaka T et al.; The efficiencies of chemical oxidation of organic matter in genuine secondary-treated municipal wastewater by using O3, O3/UV, O3/TiO2, UV/TiO2 and O3/UV/TiO2 methods were compared experimentally . Effects of carbonates on these efficiencies were also investigated . Elimination of carbonates from the water increased TOC reduction efficiency of all the methods . The effect of the carbonates on the O3 method was less significant than that on the other methods . The O3/UV method was the most effective for reducing TOC under both carbonate-present and decarbonated conditions . The catalytic ozone process (O3/TiO2) showed a tendency to increase the ozonation efficiency at the beginning of the reaction under the decarbonated condition, but the addition of the TiO2 catalyst inhibited the ozonation under the carbonate-present condition . The photocatalytic oxidation process (UV/TiO2) did not reduce TOC as much as the other methods, but it could reduce TOC over a long time . And the O3/UV/TiO2 method did not show a synergistic effect of ozonation and photocatalytic oxidation . Furthermore, zonation prior to coagulation increased TOC reduction efficiency of coagulation, but this effect was also affected by the carbonates in water.

Water Sci Technol, 2001, 43(10), 277 - 85
Reuse of heat energy in wastewater: implementation examples in Japan; Funamizu N et al.; Sewage and treated water can be a heat source in urban area due to large heat capacity, thus recovery and reuse of its energy is one of the most desirable plans for the sewerage system . In this paper, characteristics of heat energy in wastewater, reuse plans, and some experiences in Japan are presented . Full-scale reuse projects for heating and cooling in the Tokyo Metropolitan Districts and project for melting snow in Sapporo City are discussed . The key factors found in experience of Tokyo were setting the heat pumps near the demand points and the technical developments of equipment to prevent system from clogging, corrosion, and decrease in the heat transfer efficiency . It was also found through the project for melting snow in Sapporo that the key factor in public acceptance was the multi-purpose use of the sewerage system both for melting snow in winter and retaining rain water in summer.

Water Sci Technol, 2001, 43(10), 267 - 75
Source water impact model (SWIM)--a watershed guided approach as a new planing tool for indirect potable water reuse; Drewes JE et al.; The scope of this study was to develop a model to assess the impact of source water quality on reclaimed water used for indirect potable reuse . The source water impact model (SWIM) considered source water qualities, water supply distribution data, water use and the impact of wastewater treatment to calculate reclaimed water quality . It was applied for sulfate, chloride, and dissolved organic carbon (DOC) at four water reuse sites in Arizona and California . SWIM was able to differentiate between the amount of salts derived by drinking water sources and the amount added by consumers . At all sites, the magnitude of organic residuals in reclaimed water was strongly effected by the concentration of organics in corresponding water sources and effluent-derived organic matter . SWIM can be used as a tool to predict reclaimed water quality in existing or planned water reuse systems.

Water Sci Technol, 2001, 43(10), 25 - 33
Role of water reuse for enhancing integrated water management in Europe and Mediterranean countries; Lazarova V et al.; Recycling water is an important aspect of water resource and environment management policies, ensuring reliable alternative water resources, reducing environmental pollution and achieving a more sustainable form of development . This paper focuses on wastewater reuse as a strategy for integrated water management . Key economic, financial, regulatory, social and technical factors that help to make water reuse projects successful are reviewed . Selected examples from Northern and Western Europe and arid and semi-arid Mediterranean regions illustrate the contribution of wastewater reuse to integrated management of water resources.

Water Sci Technol, 2001, 43(10), 249 - 57
Water quality assessment for indirect potable reuse: a new methodology for controlling trace organic compounds at the West Basin Water Recycling Plant (California, USA); Levine B et al.; The West Basin Water Recycling plant (California; USA) was built to increase the region's water resource availability . The plant influent is produced at Los Angeles Hyperion wastewater treatment plant and is treated through two parallel treatment processes depending on the end use: (1) Title 22 water for industrial and urban use, and (2) barrier treatment for groundwater recharge . A new methodology was applied to monitor the fate of base neutral compounds in the water barrier treatment train . The methodology included large sample volumes coupled with integrated chromatographic analysis (ICA) . Data indicated a 25% increase in concentration of base neutral compounds after RO pretreatment, followed by a 70% removal efficiency after RO . The increase in concentration after RO pretreatment appears to be linked to the use of lime clarification.

Water Sci Technol, 2001, 43(10), 233 - 40
Pilot scale nanofiltration membrane separation for waste management in textile industry; Koyuncu I et al.; This paper presents the pilot scale membrane separation studies on dyehouse effluents of textile industry . Nanofiltration (NF) membranes which have 2 m2 of surface area were evaluated for membrane fouling on permeate flux and their suitability in separating COD, color and conductivity in relation to operating pressure and feed concentration from textile industry dyehouse effluents . Successive batch runs demonstrated that any serious membrane fouling was not experienced for NF membrane tested in treating this type of wastewater . The permeate flux was found to increase significantly with operating pressure . Flux decreased with increasing recovery rate . The overall removal efficiencies of COD, color and conductivity were found as greater than 97% . COD was lower than 10 mg/l at 12 bar pressures . Permeate COD was also increased with increasing recovery and COD was 30 mg/l with recovery of 80% . Almost complete color removal was achieved with nanofiltration membrane . Color value was also decreased from 500 Pt-Co to 10 Pt-Co unit . This significant reduction in color and COD makes possible the recycle of the permeate in the dyehouse . Permeate conductivity was decreasing with increasing pressure and retention of conductivity increases with increasing pressures . This phenomenon is expected from the analysis of conductivity mass transport model . Economical analysis have been done and the total estimated cost will be 0.81$/m3 based on 1000 m3/day of and this value is very economical for Istanbul City due to increasing industrial water supply tariffs.

Water Sci Technol, 2001, 43(10), 225 - 32
Membrane filtration of wastewater effluents for reuse: effluent organic matter rejection and fouling; Jarusutthirak C et al.; The reuse of treated wastewater to augment natural drinking water supplies is receiving serious consideration . Treatment of secondary and tertiary effluent by membrane filtration was investigated by assessing nanofiltration (NF) membrane and ultrafiltration (UF) membranes in bench-scale experiments . It was found that secondary and tertiary effluent contained high concentration of effluent organic matter (EfOM), contributing EfOM-related fouling . Flux decline and EfOM rejection tests were evaluated, using a dead-end stirred cell filtration unit . Surface charge and molecular weight cut-off (MWCO) of membranes were significant factors in membrane performance including permeability and EfOM-rejection.

Water Sci Technol, 2001, 43(10), 195 - 201
Biological control tools for wastewater reclamation and reuse . A critical review; Salgot M et al.; The health related risk of wastewater reclamation and reuse is usually defined by laws, rules or regulations by using only biological tools; i.e . bacteria, viruses, or other pathogens or indicators determination . Those determinations exert some influence in the costs of the mentioned practices, and it seems probable that in the near future more determinations will be required . Nevertheless, a total indication of wastewater biological quality is not given by such organisms; in fact, long-term toxicity is not detected by such means . The future of biological control of reclamation and reuse systems and the price associated to such determinations is examined through a practical application case.

Water Sci Technol, 2001, 43(10), 173 - 8
UV disinfection for reuse applications in North America; Sakamoto G et al.; In an effort to conserve and protect limited water resources, the States of Florida and California have actively promoted wastewater reclamation and have implemented comprehensive regulations covering a range of reuse applications . Florida has a semi-tropical climate with heavy summer rains that are lost due to run off and evaporation . Much of California is arid and suffers periodic droughts, low annual rainfall and depleted ground water supplies . The high population density combined with heavy irrigation demands has depleted ground water supplies resulting in salt-water intrusion . During the past decade, Florida reuse sites have increased dramatically from 118 to 444 plants representing a total flow capacity of 826 MGD . California presently has over 250 plants producing 1 BGD with a projected increase of 160 sites over the next 20 years . To prevent the transmission of waterborne diseases, disinfection of reclaimed water is controlled by stringent regulations . Many states regulate wastewater treatment processes, nutrient removal, final effluent quality and disinfection criteria based upon the specific reuse application . As a rule, the resulting effluents have low turbidity and suspended solids . For such effluents, UV technology can economically achieve the most stringent disinfection targets that are required by the States of California and Florida for restricted and unrestricted reuse . This paper compares UV disinfection for wastewater reuse sites in California and Florida and discusses the effect of effluent quality on UV disinfection.

Water Sci Technol, 2001, 43(10), 17 - 23
Water reuse in Japan; Ogoshi M et al.; Even though Japan has mean annual precipitation of 1,714 mm and hundreds of dams and reservoirs constructed, frequent and severe droughts have occurred in wide regions of the country . Because of rapid economic growth and concentrations of population in urban areas, water demands in large cities have stressed reliability of water supply systems and necessitated the development of new water resources with considerable economic and environmental costs . To alleviate these situations, wastewater reclamation and reuse have been implemented widely in major cities . This paper summarizes the current status of water reuse in Japan and discusses dominant uses of reclaimed water, emphasizing non-potable urban applications such as toilet flushing, industrial reuse, and environmental water.

Water Sci Technol, 2001, 43(10), 163 - 71
Wastewater disinfection by low-pressure UV and ozone: a design approach based on water quality; Savoye P et al.; Disinfection processes are known to be very sensitive to wastewater quality . This paper discusses the parameters that impact the UV light (UV) and ozone disinfection processes and the related mechanisms based on literature review . Low-pressure UV and ozone technologies were investigated on effluents that covered a wide range of water quality . The results are given in terms of design doses required to meet three major disinfection standards . Both processes were found eligible for the majority of effluents tested . Although cost-effectiveness is usually considered more favourable to UV, the ozone alternative should be examined in cases such as the disinfection of low-quality effluents or large treatment plants . Ozonation was also found capable of meeting the stringent Title 22 standard with no coagulation at a dose of 10 mg/l.

Water Sci Technol, 2001, 43(10), 117 - 24
Reuse of reclaimed wastewater for golf course irrigation in Tunisia; Bahri A et al.; In Tunisia, golf courses are irrigated with secondary treated effluent stored in landscape impoundments . The impact of the conveyance and storage steps on the physical-chemical and biological quality of irrigation water was evaluated on three golf courses over two years . It was found that the water quality varies all along the water route, from the wastewater treatment plant up to the irrigation site: nutrient and bacteria contents decreased along the route in the three cases . This variation depends on the wastewater quality, the length of the pipes conveying water, the number of regulation reservoirs and ponds, the water residence time in pipes, reservoirs and ponds, and the operation of the ponds . The bacteriological quality of irrigation water deteriorates during the irrigation period in the three golf courses as the ponds are operated as continuous flow reactors . The results obtained in this study indicate the inability of golf water supplies, as currently managed, to properly sanitize reclaimed wastewater and meet target quality criteria recommended by WHO (1989) for water intended for recreational use . For a safe reuse of reclaimed wastewater for golf course irrigation, changes in the design and operation of the ponds should be planned or additional treatment steps provided.

Water Sci Technol, 2001, 43(10), 109 - 16
Cultural eutrophication control through water reuse; Sala L et al.; The increasing use of mineral fertilisers over the last decades has contributed to the appearance of numerous cases of water eutrophication, a new form of water pollution . The starting point of eutrophication is the increase of nutrient concentration (nitrogen and phosphorus) in a water mass, which is subsequently followed by an uncontrolled growth of primary producers and episodes of oxygen depletion due to microbial decomposition of algal organic matter . The excess nutrient loads reaching surface waters are usually associated to discharges from anthropogenic activities, which normally involve direct water usage instead of reuse of reclaimed effluents . Agriculture activities and livestock breeding are two of the main nutrient sources responsible for water eutrophication, as well as human--urban and industrial--wastewater discharges . Wastewater reclamation and reuse can be a suitable strategy for preserving the quality of natural waters, by suppressing effluent discharges and the associated nutrient contributions to receiving waters . Reuse of reclaimed water for agricultural and landscape irrigation as well as for environmental enhancement offers an adequate strategy for preserving natural water systems from eutrophication.

Environ Sci Technol, 2001 Jun 15, 35(12), 2583 - 8
Identification of alkyl dimethylbenzylammonium surfactants in water samples by solid-phase extraction followed by ion trap LC/MS and LC/MS/MS; Ferrer I et al.; A novel methodology was developed for the determination of alkyl (C12, C14, and C16) dimethylbenzylammonium chloride (benzalkonium chloride or BAC, Chemical Abstract Service number: 8001-54-5) in water samples . This method is based on solid-phase extraction (SPE) using polymeric cartridges, followed by high-performance liquid chromatography/ion trap mass spectrometry (LC/MS) and tandem mass spectrometry(MS/MS) detection, equipped with an electrospray interface in positive ion mode . Chromatographic separation was achieved for three BAC homologues by using a C18 column and a gradient of acetonitrile/10 millimolar aqueous ammonium formate . Total method recoveries were higher than 71% in different water matrices . The main ions observed by LC/MS were at mass-to-charge ratios (m/z) of 304, 332, and 360, which correspond to the molecular ions of the C12, C14, and C16 alkyl BAC, respectively . The unequivocal structural identification of these compounds in water samples was performed by LC/MS/MS after isolation and subsequent fragmentation of each molecular ion . The main fragmentation observed for the three different homologues corresponded to the loss of the toluyl group in the chemical structure, which leads to the fragment ions at m/z 212, 240, and 268 and a tropylium ion, characteristic of all homologues, at m/z 91 . Detection limits for the methodology developed in this work were in the low nanogram-per-liter range . Concentration levels of BAC--ranging from 1.2 to 36.6 micrograms per liter--were found in surface-water samples collected downstream from different wastewater-treatment discharges, thus indicating its input and persistence through the wastewater-treatment process.

Environ Sci Technol, 2001 Jun 15, 35(12), 2428 - 35
Distribution and fate of neutral alkylphenol ethoxylate metabolites in a sewage-impacted urban estuary; Ferguson PL et al.; The distribution and fate of neutral metabolites of the alkylphenol ethoxylate (APEO) surfactants in an urbanized estuarine environment were examined utilizing a recently developed, highly sensitive LC-MS method . Results indicated that short ethoxyl-chain APEOs and alkylphenols (APs) were present in surficial sediments throughout the estuary at concentrations roughly correlated to the organic carbon content of the sediment and that the APEO mixture was dominated by nonylphenol ethoxylate (NPEOs) metabolites (0.05-30 microg/g), with lesser amounts of octylphenol ethoxylate metabolites (OPEOs)(<0.005-0.09 microg/ g) and halogenated nonylphenols (<0.001-0.03 microg/g) . NPEO metabolites in surface water (0.22-1.05 microg/L) were also present at higher concentrations than OPEO metabolites (0.007-0.040 microg/L) . APEO metabolite concentrations in both sediment and water showed a strong correlation with conventional sewage tracers, affirming a wastewater source of these contaminants . APEO distributions in surface waters within the estuary could be explained by a combination of post-discharge degradation and mixing with a seawater end-member enriched in OPEO metabolites . Measured in situ Koc values of APEO metabolites were comparable to previously reported values derived from field experiments but higher than Kow and Koc values derived from laboratory experiments . Results from the present work indicate that the fate of APEO metabolites entering the estuarine environment through discharge of wastewater is directed primarily by scavenging onto particles and subsequent burial in sediments, degradation during residence in the water column, and transport out of the estuary through advective and dispersive processes.

Huan Jing Ke Xue, 2001 Mar, 22(2), 87 - 90
{Aerobic sludge granulation and biological phosphorus removal in different operating conditions of SBR}; Lou IC et al.; This paper investigate the effect of the different operating conditions on the aerobic sludge granulation and biological P removal characteristics in SBR by using synthetic domestic wastewater as feed . Different ratios of COD/TN (11.79, 18.85, 20.72, 24.66), COD/TP (27.85, 44.53, 48.93, 58.25), TN/TP (4.00, 2.36, 1.54), temperature(22 degrees C, 15 degrees C, 8 degrees C) and sludge retention time(16d, 10d, 5d) are tested in this process . It is found that the high ratios of COD/TN (24.66), COD/TP (58.25), temperature (22 degrees C) and low SRT (10d) are beneficial to the phosphorus removal and the cultivation of the aerobic granular sludge . The proper TN/TP rate (2.36), dissolved oxygen and selection of anaerobic seed sludge are basic requirement and most important factors to guarantee such aerobic granules in the process.

Environ Pollut, 2001, 113(3), 373 - 84
Polychlorinated biphenyl congeners and organochlorine insecticides in the water column and sediments of Daya Bay, China; Zhou JL et al.; Samples of sub-surface water, suspended particulate matter (SPM) and surface sediments collected from Daya Bay, China have been analysed for 12 polychlorinated biphenyl (PCB) congeners and 18 organochlorine insecticides, using gas chromatography electron capture detection . Total PCB levels varied from 91.1 to 1355.3 ng l-1 in water and from 0.85 to 27.37 ng g-1 dry weight in sediments . The levels of total organochlorine insecticides were in the range 143.3-5104.8 ng l-1 in water and 2.43-86.25 ng g-1 dry weight in sediment . None of the target compounds were detected in SPM . The levels of total hexachlorocyclohexanes in water varied from 35.5 to 1228.6 ng l-1, whilst in sediments they ranged from 0.32 to 4.16 ng g-1 dry weight . For the sum of dichlorodiphenyltrichloroethanes (DDTs), their levels were in the range 26.8-975.9 ng l-1 in water, and 0.14-20.27 ng g-1 dry weight in sediments . The distribution profiles of these contaminants in water and sediments suggest that there are a number of sources contributing to total contaminant burden in the bay, including soil runoffs, wastewater discharges, sewage outfalls and shipping activites . Ratios of DDT/(DDE + DDD) in the water and sediments indicate recent inputs of such chemicals into the day . The results, therefore, provide important information on the current contamination status of a key aquacultural area in China, and point to the need for urgent actions to stop the use of persistent agrochemicals such as DDT and lindane.

Appl Environ Microbiol, 2001 Jul, 67(7), 3322 - 4
Effect of high-rate algal ponds on viability of Cryptosporidium parvum oocysts; Araki S et al.; The physicochemical conditions of high-rate algal ponds were responsible for a more than 97% reduction in the infectivity of Cryptosporidium parvum oocysts in neonatal mice . The use of semipermeable bags of cellulose showed that pH, ammonia, and/or light seems to be a major factor for the inactivation of oocysts in wastewater, supporting the importance of alga-based systems for safer reuse of treated wastewater.

Environ Technol, 2001 May, 22(5), 523 - 32
Pre-evaporative fenton remediation of treated municipal wastewater for reuse purposes; Van Hege K et al.; The present study explored the application of evaporative technology as an alternative desalination technique for wastewater treatment plant effluent . In the experiments carried out, it was shown that evaporation allowed for extensive decontamination of wastewater treatment plant effluent as most inorganic and organic contaminants were completely removed . Ammonia could be retained in the concentrate when pH was adjusted to values lower than 4; however this led to increased nitrite volatility due to the formation of nitric oxide . Using an electronic nose, it was observed that evaporation gave rise to a change in odour quality and quantity due to volatilisation of the volatile organic compounds present in the effluent . Remediation of these components was carried out by Fenton oxidation prior to evaporation . A high removal was observed under the applied conditions of Fe2+ = 25 mg l-1, H2O2 = 50 mg l-1, pH = 3 and a reaction time of 2 hours.

Chemosphere, 2001 Jul, 44(1), 1 - 8
Biological control of leachate from municipal landfills; Ding A et al.; Landfilling is still a popular way for municipal solid waste (MSW) treatment . Leachate generated from landfills is becoming a great threat to the surroundings as it contains high concentrations of toxic substances . How to control leachate migration and to protect environmental pollution is now a concern for many environmentalists . In this work, eight effective microorganisms (EMs) were isolated from wastewater, sludge and soil samples by enrichment culturing techniques and used for leachate migration control in columns and pilot experiments . The preliminary experiments reveal that the EMs could remove 25% and 40% of chemical oxygen demand (COD) from leachate in fine sand and sabulous clay columns, respectively . An aquifer system was designed to simulate in-situ control for leachate migration with EMs . The EMs were injected into the simulated aquifer and formed a permeable biological barrier . The experimental results show that the barrier removed 95% of COD and approximately 100% inorganic nitrogen, that is, nitrate-N plus nitrite-N plus ammonia-N, from the migrating leachate . CO2 production, redox potential and microbial number were monitored simultaneously in the aquifer during the experiment to assess the EMs' activities and the effect of the bio-barrier . The data indicate that the EMs isolated in this work had high activities and were effective for organic and nitrogenous contaminant removal throughout the experiment.

Sci Total Environ, 2001 Jun 12, 273(1-3), 147 - 61
Nutrient fluxes in the Po basin; de Wit M et al.; The nutrient load of the river Po needs to be reduced in order to bring the eutrophication problems in the Northwest Adriatic Sea under lasting control . In this paper we analyse the contribution of the different pollution sources to the nitrogen and phosphorus loads of the river Po (source apportionment) . We also estimate the effects of measures that aim to reduce nitrogen and phosphorus pollution in the Po basin (scenario analyses) . Using a model (PolFlow) that was previously applied to the Rhine and Elbe basins, we found that more than half of the nitrogen and phosphorus loads in the river Po originates from diffuse sources . The results of the scenario analyses indicate that the measures imposed by the EU Nitrates Directive and the EU Wastewater Treatment Directive may not be stringent enough to achieve a large reduction in the N and P loads in the river Po.

Appl Microbiol Biotechnol, 2001 May, 55(5), 644 - 51
Enhancing the start-up of a UASB reactor treating domestic wastewater by adding a water extract of Moringa oleifera seeds; Kalogo Y et al.; Water extract of Moringa oleifera seeds (WEMOS) was used to enhance the start-up of a self-inoculated upflow anaerobic sludge blanket (UASB) reactor treating raw domestic wastewater . Two reactors labelled control (RC) and WEMOS addition (RM) were started without special inoculum . Both reactors were fed continuously for 22 weeks with domestic wastewater containing an average total chemical oxygen demand (COD) of 320 mg O2/l and suspended solid (SS) of 165 mg/l . The reactors operated during the entire experimental period at 29 degrees C and at a hydraulic retention time (HRT) of 4 h . The RM reactor received 2 ml WEMOS per litre of influent . WEMOS solution was prepared on the basis of 2.5% (w/v) ground M . oleifera seeds in water . The results of 22 weeks' operation showed an improvement in the performance of the RM compared to that of the RC . The dosage of WEMOS in the feed (1) shortened the biological start-up period by 20%, (2) increased acidogenic and methanogenic activity by a factor of 2.4 and 2.2 respectively, (3) increased the specific biogas production by a factor of 1.6, (4) favoured fast growth of the sludge bed, and (5) allowed the aggregation of coccoid bacteria and growth of microbial nuclei, which are precursors of anaerobic granulation.

Environ Sci Technol, 2001 Jun 1, 35(11), 2381 - 7
Study of Au/Au(3+)-TiO2 photocatalysts toward visible photooxidation for water and wastewater treatment; Li XZ et al.; With an attempt to extend light absorption of TiO2-based photocatalyst toward the visible light range and eliminate the rapid recombination of excited electrons/holes during photoreaction, a new type of photocatalysts (Au/Au(3+)-TiO2) powder was prepared by a photoreduction/sol-gel process . The crystal phase composition, surface structure, and light absorption of the new photocatalysts were comprehensively examined by X-ray differential detection (XRD), UV-visible absorption spectra, X-ray photoelectron emission spectroscopy (XPS), and photoluminescence (PL) spectra . The photooxidation efficiencies of the photocatalysts were also evaluated in the photodegradation of methylene blue (MB) in aqueous solutions under visible light irradiation from a high-pressure sodium lamp (lambda > 400 nm) . The results of PL analyses in this study indicated that the gold/gold ion-doping on the surface of TiO2 could eliminate the electron/holes recombination and also increase the light absorption in the visible range . The analytical results of UV-visible diffuse reflection spectra (DRS) and optical absorption spectra indicated that a new energy level below 3.2 eV generated in the Au/Au(3+)-TiO2 promoted the optical absorption in the visible region and made it possible to be excited by visible light (E < 3.2 eV) . The experiment demonstrated that the photooxidation efficiency of MB using the Au/Au(3+)-TiO2 powder were significantly higher than that using conventional TiO2 powder and an optimum molar content of gold doping/deposition in the TiO2 was 0.5% . The development of such photocatalysts may be considered a breakthrough in large-scale utilization of solar energy to address environmental needs.

Environ Sci Technol, 2001 Jun 1, 35(11), 2258 - 63
Reduction of haloacetic acids by Fe0: implications for treatment and fate; Hozalski RM et al.; To predict the fate of haloacetic acids (HAAs) in natural or engineered systems, information is needed concerning the types of reactions that these compounds undergo, the rates of those reactions, and the products that are formed . Given that many drinking water distribution systems consist of unlined cast iron pipe, reactions of HAAs with elemental iron (Fe0) may play a role in determining the fate of HAAs in these systems . In addition, zerovalent iron may prove to be an effective treatment technology for the removal of HAAs from chlorinated drinking water and wastewater . Thus, batch experiments were used to investigate reactions of four trihaloacetic acids, trichloroacetic acid (TCAA), tribromoacetic acid (TBAA), chlorodibromoacetic acid (CDBAA), and bromodichloroacetic acid (BDCAA), with Fe0 . All compounds readily reacted with Fe0, and investigation of product formation and subsequent disappearance revealed that the reactions proceeded via sequential hydrogenolysis . Bromine was preferentially removed over chlorine, and TBAA was the only compound completely dehalogenated to acetic acid . In compounds containing chlorine, the final product of reactions with Fe0 was monochloroacetic acid . Halogen mass balances were 95-112%, and carbon mass balances were 62.6-112% . The pseudo-first-order rate constants for trihaloacetic acid degradation were as follows: BDCAA (10.6 +/- 3.1 h-1) > CDBAA (1.43 +/- 0.32 h-1) approximately TBAA (1.41 +/- 0.28 h-1) >> TCAA (0.08 +/- 0.02 h-1).

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2001, 36(4), 587 - 98
Step feeding strategy for enhancing nitrogen and phosphorus removal in AOAO process; Chang HY et al.; This study describes a biological process containing anaerobic/oxide/anoxic/oxide (AOAO) stages, which incorporates a stepwise feeding strategy to enhance nitrogen and phosphorus removal efficiencies . In the experimental reactors, synthetic wastewater was fed into the anaerobic stage and anoxic stage separately, while the substrates and nutrients were successfully consumed without recycling either nitrified effluent or external carbon sources . Experimental results demonstrated that the anoxic stage was provided an intrinsic sufficient carbon source and caused NOx (NO2-N + NO3-N) concentration to reduce from 11.85 mg/l to 5.65 mg/l . The total Kjeldahl nitrogen (TKN) removal rate was between 81.81% and 93.96%, while the PO4-P removal ratio was between 93% and 100% . The substrate fed into the anaerobic at flow rate Q1 and into the anoxic at flow rate Q2 . In addition, three different ratios were performed with Q1/Q2 varied from 7/3, 8/2 to 9/1 . The AOAO process clearly saves nearly one-third of the energy compared to the typical Biological nutrient removal (BNR) system A2O process.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2001, 36(4), 575 - 85
Effects of hydraulic backwash load on effluent quality of upflow BAF; Yoo IK et al.; Using an upflow biological aerated filter (BAF) with treatment capacity of 100 ton/day, various hydraulic loads of backwashing water and influent were investigated to determine how they affect effluent quality of BAF during normal operation . The BAF packed with expanded polypropylene media of 3-5 mm diameter was operated over a five-month period for paper wastewater treatment . The average removal efficiencies of 78% for chemical oxygen demand (COD) and 88% for suspended solids (SS) were maintained, but the effluent CODs varied between 5-60 mg/l depending on the biodegradable fraction of influent wastewater . During normal BAF operation with cyclic backwash, the effluent SS concentrations showed initial peaks after backwash and gradually decreased to a steady state, while the soluble CODs of effluent did not significantly changed . The effluent SS concentrations and the required time intervals to reach steady state after backwash were related with hydraulic loads of backwashing water and influent wastewater applied to the BAF . A higher load of backwashing water gave larger deviation of initial SS peaks from the steady state, the extent of which was more significant under the higher load of influent wastewater.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2001, 36(4), 565 - 73
The use of Mg/Al layered double hydroxide for color removal of textile wastewater; Hussein MZ et al.; Layered double hydroxide of Mg-Al-carbonate system (MACH) was prepared and its heat-treated product (MACHT) was obtained by calcination at 500 degrees C . The resulting materials were used as an adsorbent for removal of color from synthetic textile wastewater (STW) and textile wastewater (TWW) . Batch kinetic study showed that these materials are an efficient adsorbent for textile dye . The maximum adsorption capacities between 16 to 32 mg of dyes per g of adsorbent was obtained by fitting the adsorption data to the Langmuir adsorption Isotherm . It was found that the adsorption capacity of MACHT is higher than MACH.

J Environ Sci Health B, 2001 Mar, 36(2), 189 - 207
Swine wastewater treatment using attached-growth and suspended-growth two stage sequencing batch reactors with real-time control; Cheng N et al.; Two two-stage sequencing batch reactors (TSSBR), one attached-growth and one suspended-growth, were operated under three levels of wastewater concentration (approximately 4,000, 2,000 and 500 TOC mg/L), respectively, to compare the pH and ORP (oxidation-reduction potential) patterns and system performance . In both TSSBR systems, the pH and ORP profiles varied with organic loading yet exhibited consistent patterns with distinctive features suitable for real-time control . For all runs at the three levels of influent, both systems achieved similar levels of treatment for BOD5, TOC and TSS of over 97.5, 93.4, and 97.3%, respectively . The attached-growth system out performed the suspended-growth system in achieving the same levels of treatment at much shorter aeration cycle times . The treatment efficiency for NO3(-)-N and PO4(-3) was greatly affected by the carbon content in the wastewater, and the best treatment was achieved during the TOC approximately 4,000 mg/L runs with final effluent at 4.0 and 21.3 mg/L, respectively.

Environ Toxicol, 2001 Jun, 16(3), 217 - 24
Toxicity tests to assess pollutants removal during wastewater treatment and the quality of receiving waters in Argentina; Gomez CE et al.; In Argentina, legislation to control adverse impacts of effluent discharges and the quality of receiving waters is scant and relies mainly on the physicochemical characteristics of the effluents and receiving waters . Objectives of this study were to use standardized acute toxicity tests to assess treatment of petrochemical industry effluents and the toxicity of various treated industrial effluents in the Buenos Aires metropolitan area and their receiving waters . Tests for the first objective used Daphnia magna and Ceriodaphnia dubia; those for the second used D . magna, Spirillum volutans, and Scenedesmus spinosus . Chemical analyses demonstrated that the removal of aromatic hydrocarbon compounds (benzene, toluene, ethylbenzene, xylene, styrene, and naphthalene) from the petrochemical effluents ranged between 77 and 93%, but toxicity removal was significantly lower: untreated effluents were very toxic and treated effluents were very toxic to toxic {acute toxicity units (TUa) > 3} . Physicochemical parameters measured according to current Argentinian regulations indicated that industrial effluents (e.g., from textile and paper industries) were within established guidelines, but 25% of the samples were moderately to highly toxic (TUa > 1.33) . However, for the receiving waters, toxicity tests were moderate to very toxic . The results show the need of including tests for toxicity of discharged effluents, and their effects on receiving waters of Argentina, especially for regulatory purposes.

J Environ Sci Health B, 2001 May, 36(3), 341 - 53
Treatment of greenhouse wastewater using constructed wetlands; Prystay W et al.; Five wetland designs, based on conventional surface flow (SF) and subsurface flow (SSF) approaches, were assessed for nitrogen and phosphorus removal from greenhouse wastewater . Results indicated none of the individual designs assessed was capable of providing the highest treatment effect for all nutrients of concern; however, the SF wetland emerged as the most appropriate design for the treatment of greenhouse wastewater . The highest mean phosphorus reduction of 65% was observed in the unplanted SF wetlands . Peak nitrate reductions of 54% were observed in the 15-cm deep SF wetlands and ammonia removal of 74% was achieved in the unplanted SF wetlands . Nitrate concentration in the greenhouse effluent can be reduced to acceptable levels for the protection of freshwater aquatic life (i.e., less then 40 ppm) using a loading rate of 1.65 g NO3-N/m2/day and a design water depth of 30 cm or greater . Based on available literature and the results of this research project, a multistage design, consisting of an unplanted pre-treatment basin followed by a 25 to 35 cm deep surface flow marsh with open water components, is recommended.

Mol Cell Endocrinol, 2001 Jun 10, 178(1-2), 99 - 105
Environmental xenoestrogens, antiandrogens and disorders of male sexual differentiation; Sultan C et al.; Over the past 20 years, the documented increase in the disorders of male sexual differentiation, such as hypospadias, cryptorchidism, and micropenis, has led to the suspicion that environmental chemicals are detrimental to normal male genital development in utero . Male sexual differentiation is critically dependent on the normal action of androgens, and unbalanced androgen/estrogen ratios can disturb it . Environmental xenoestrogens (such as herbicides, pesticides, PCBs, plasticizers, and polystyrenes) that mimic estrogens or environmental antiandrogens (such as polyaromatic hydrocarbons, linuron, vinclozolin, and pp'DDE) that disturb endocrine balance, cause demasculinizing effects in the male foetus . These environmental chemicals are often referred to as endocrine disruptors: they are thought to mimic endogenous estrogens by entering the cell, binding to the receptor and activating transcription, they may also antagonize normal androgen action . We have established numerous cell lines to assess the estrogenicity and antiandrogenicity of compounds found in the environment and to identify new products present in wastewater effluents that are able to disrupt endocrine functions . Several cell lines responding to estrogens have been obtained in our group, including cells with different enzymatic equipment and cells expressing chimeric receptor or natural estrogen receptors alpha and beta . These cell lines have proved to be useful for assessing the biological activity of pesticides, fungicides, and chemicals found in plastic or discarded in the environment . In order to generate a powerful tool for the investigation of androgen action and the rapid screening of potential antagonists, we developed a new stable prostatic cell line . The PALM cell line is an original cellular model to characterize the response of hAR, and it provides an easy and rapid bioluminescent test to identify new antagonists . We also developed a model based on a fusion protein between the androgen receptor (AR) and the green fluorescent protein (GFP) to study the intracellular dynamics of AR . The GFP-AR model was applied to define the ability of several xenoestrogens and antiandrogens to inhibit the nuclear transfer of AR . The ubiquitous presence of endocrine disruptors in the environment and the increased incidence of neonatal genital malformation support the hypothesis that disturbed male sexual differentiation may in some cases be caused by increased exposure to environmental xenoestrogens and/or antiandrogens.

J Chromatogr A, 2001 May 25, 918(2), 277 - 91
High-performance liquid chromatography--ToxPrint: chromatographic analysis with a novel (geno)toxicity detection; Bobeldijk I et al.; In order to aid the monitoring of the overall quality of (surface) waters a new analytical approach has been developed, combining on-line solid-phase extraction, HPLC separation and effect-related detection . Compounds present in surface water or wastewater samples are extracted on-line with Oasis {poly(divinylbenzene-co-N-vinylpyrrolidone)} material and directly fractionated by reversed-phase HPLC . The eluent of the total chromatogram is collected on a microtitre plate in fractions of 1 min each . After evaporation and re-dissolvation in a suitable solvent, the (geno)toxicity of the individual fractions before and after enzymatic activation with S9, is determined with the umu test . In this way, harmful compounds can be detected and localized in the HPLC-diode array detection trace even without their identity and exact concentration being known at that moment . The method was developed using two test compounds, 4-nitroquinoline-N-oxide and 2-aminoanthracene . Compounds with mutagenic properties comparable to those of the test compounds can be detected from 0.1 microg/l, which is a concentration relevant for surface waters . The new analytical approach was successfully applied to various types of model samples, as well as real wastewater.

Anal Chem, 2001 Jun 1, 73(11), 2429 - 36
Solid-phase microextraction using fused-silica fibers coated with sol-gel-derived hydroxy-crown ether; Zeng Z et al.; A novel solid-phase microextraction (SPME) fiber containing hydroxydibenzo-14-crown-4 (OH-DB14C4)/hydroxy-terminated silicone oil (OH-TSO) was first prepared by a sol-gel method and investigated for the determination of phenols . The possible mechanism is discussed and confirmed by IR spectra . The coating has stable performance in high temperature (to 350 degrees C) and solvents (organic and inorganic) due to the chemical binding between the coating and the fiber surface . The addition of crown ether enhances the polarity of the coating compared with that of the sol-gel OH-terminated silicone oil fiber and, accordingly, provides higher extraction efficiency for polar phenolic compounds . On the other hand, OH-terminated silicone oil in the coating can not only increase the length of network but also help to spread the stationary phase on the silica surface uniformly . The fluorescence microscopy experiment suggests the benefit the more uniform surface of the sol-gel-derived OHDB14C4/OH-TSO fiber in comparison with sol-gelderived OH-DB14C4 fiber . Some parameters of the SPME fiber for the determination of phenols were investigated . Limits of detection of the phenols are below 1.0 ng/mL, and the precisions are from 2.9 to 4.6% (n = 6) . Linear ranges were found to be 0.1-10 microg/mL The sensitivity of the method is enhanced at a low-pH level (pH approximately 1) and with the addition of salt . The method was applied to the analysis of wastewater sample from a paper mill.

Bioresour Technol, 2001 Aug, 79(1), 35 - 9
Potential utilisation of sewage sludge and paper mill waste for biosorption of metals from polluted waterways; Lister SK et al.; The adsorption of cadmium, copper(II), lead and zinc ions from aqueous solution by sewage sludge, paper mill waste (PMW) and composted PMW was investigated along with the influence of pre-treatment on composted PMW . Langmuir adsorption isotherms were fitted where appropriate . Sewage sludge was the most effective biosorbent of the waste products for all metal ions examined, adsorbing, for example, up to 39.3 mg/g of Pb at an initial concentration of 77.8 mg/l . PMW was a less effective biosorbent than sewage sludge . However, it was found that composting the PMW resulted in an increase in metal uptake capacity and both sewage sludge and composted PMW have potential for low-cost remediation of high leachate wastewaters . The desorption of metal ions from PMW compost was most effective using 0.1 N H2SO4 and 1 mM nitrilotriacetic acid (NTA).

Bioresour Technol, 2001 Aug, 79(1), 1 - 14
State observers for a biological wastewater nitrogen removal process in a sequential batch reactor; Boaventura KM et al.; Biological removal of nitrogen is a two-step process: aerobic autotrophic microorganisms oxidize ammoniacal nitrogen to nitrate, and the nitrate is further reduced to elementary nitrogen by heterotrophic microorganisms under anoxic condition with concomitant organic carbon removal . Several state variables are involved which render process monitoring a demanding task, as in most biotechnological processes, measurement of primary variables such as microorganism, carbon and nitrogen concentrations is either difficult or expensive . An alternative is to use a process model of reduced order for on-line inference of state variables based on secondary process measurements, e.g . pH and redox potential . In this work, two modeling approaches were investigated: a generic reduced order model based on the generally accepted IAWQ No . 1 Model {M . Henze, C.P.L., Grady, W., Gujer, G.V.R., Marais, T., Matsuo, Water Res . 21 (5) (1987) 505-515}-generic model (GM), and a reduced order model specially validated with the data acquired from a benchscale sequential batch reactor (SBR) specific model (SM) . Model inaccuracies and measurement errors were compensated for with a Kalman filter structure to develop two state observers: one built with GM, the generic observer (GO), and another based on SM, the specific observer (SO) . State variables estimated by GM, SM, GO and SO were compared to experimental data from the SBR unit . GM gave the worst performance while SM predictions presented some model to data mismatch . GO and SO, on the other hand, were both in very good agreement with experimental data showing that filters add robustness against model errors, which reduces the modeling effort while assuring adequate inference of process variables.

Water Res, 2001 Jul, 35(10), 2514 - 22
The effects of media size on the performance of biological aerated filters; Moore R et al.; Biological aerated filters (BAFs) are an attractive process option, particularly when low land usage is required . They can combine BOD, solids and ammoniacal nitrogen removal and can be utilised at both secondary and tertiary stages of wastewater treatment . Media selection is critical in the design and operation of BAFs to achieve effluent quality requirements . Two size ranges, 1.5-3.5 and 2.5-4.5 mm, of a foamed clay called StarLight C were used in pilot-scale reactors . Both performed well as BAF media, with reactor loads up to 12 kg COD m(-3) d and 4 kg suspended solids m(-3) d (based on working volumes) . The most consistent effluent was obtained using the smaller medium since, at flow rates above 0.41 min(-1), the BAF using the larger medium produced an effluent containing more than 20 mg l(-1) of suspended solids for over 30 min after backwashing . Up to 70% longer run times, as determined by reaching a set head loss, were recorded for the BAF containing the larger rather than the smaller medium . Additionally, the development of pressure above the smaller medium filter bed tended to be logarithmic rather than linear . Reactor profiles indicated that suspended solids removal did not occur over the full 2.3 m depth of the columns . The BAF containing the smaller medium utilised a mean depth of 1.7 +/- 0.3 m, whereas a mean depth of 2.1 +/- 0.3 m was used by the larger medium BAF . Both the head loss development data and the suspended solids removal profiles indicated that the smaller medium BAF was underperforming as a filter.

Water Res, 2001 Jul, 35(10), 2475 - 83
The electronic nose as a rapid sensor for volatile compounds in treated domestic wastewater; Dewettinck T et al.; An electronic nose consisting of 12 metal oxide sensors was used to monitor volatile compounds in effluent of a domestic wastewater treatment plant . Effluent and reference (deionized water) samples were heated to 60 and 90 degrees C to promote the volatilization and to increase the sensitivity . An effluent measuring campaign of 12 weeks was conducted and the repeatability and reproducibility of the procedure and the apparatus were determined . Processing the obtained fingerprints with principal component analysis (PCA) allowed interpretation and differentiation of the samples in terms of origin and quality, relative to the reference . To minimize the variance due to sensitivity fluctuations of the apparatus and to detect effluents with deviating qualities, two new concepts were defined, i.e . the relative sensorial odour perception (in short: rSOP) and the relative fingerprint . Correlations between the relative overall electronic nose output, expressed as rSOP, and selected routine parameters were weak except for the parameter "volatile suspended solids" (VSS), indicating adsorption of volatile organic compounds (VOCs) onto the organic particles . The results clearly demonstrate the possibility to use the electronic nose as a rapid alarm generator towards volatile compounds, e.g . in specific advanced treatment processes to produce reclaimed water from effluent of the domestic wastewater treatment plant under scrutiny.

Water Res, 2001 Jul, 35(10), 2353 - 62
Characteristics of nitrogen and phosphorus loads in peat mining wastewater; Klove B; Runoff water quality from a peat mine was studied during 1995 and 1996 in Central Finland . Water samples from three drained sub-catchments and groundwater were analysed for all the standard physio-chemical parametres including different forms of nitrogen and phosphorus . The annual leaching of phosphorus, nitrogen and suspended solids was estimated to be 16-38 kgkm(-2), 1,073-1,500 kgkm(-2), and 2-8 tkm(-2), respectively . The variation in nutrient concentrations could be best explained by the relative volumes of new water (5-day sum of rainfall), ditchwater temperature and conductivity . Heavy rainfall caused new water to infiltrate washing nitrate out of the unsaturated peat layer resulting in high concentrations in ground- and ditchwater . Ditchwater phosphorus concentrations always decreased with increased runoff and peaked, as did COD and colour, after dry spells when old groundwater dominated runoff . A large part of the suspended solids load occurred during snowmelt, whereas dissolved solids and nitrogen loads peaked during summer flows.

Analyst, 2001 May, 126(5), 669 - 72
Determination of sulfur dioxide in vitriol plant wastewater by using a polyNiMe4TAA electrochemically modified Pt microelectrode; Li H et al.; A Pt microelectrode modified with nickel(II) polytetramethyldibenzo{b,i}tetraaza{14}annulene was prepared by electropolymerization of nickel(II) tetramethyldibenzo{b,i}tetraaza{14}annulene monomers and applied to determine sulfur dioxide in vitriol plant wastewater . For determination of SO2 with this electrochemically modified Pt microelectrode, the linear range was from 9.6 x 10(-6) to 2.4 x 10(-4) mol L-1, the sensitivity was 1.8 x 10(-4) A L mol-1, the detection limit was calculated to be 4.8 x 10(-6) mol L-1 (S/N = 3), the response time was less than 20 s and the relative standard deviation was found to be 2.1% on analyzing 4.8 x 10(-5) mol L-1 SO2 solution repeatedly (n = 7) . These results demonstrated good accuracy compared with those obtained by the conventional iodimetric method.

Water Sci Technol, 2001, 43(8), 131 - 7
Pretreatment of bakery wastewater by coagulation-flocculation and dissolved air flotation; Liu JC et al.; The pretreatment of wastewater from a large-scale bakery was studied . In the coagulation-flocculation reaction, it was found that both alum and FeCl3 were effective in the jar tests . When at coagulant dosage of 90 to 100 mg/l, 55% of COD and 95 to 100% of SS could be removed . The optimum pH was at 6.0 . In addition, the removal of SS was affected by pH more significantly, while the removal of COD was not affected in the pH range of 6.0 to 8.0 . In the DAF experiments, 48.6% of COD and 69.8% of SS were removed in 10 min at a pressure of 4 kg/cm2, recycle ratio of 0.3 l/min, and pH of 6.0 . Upon the addition of 100 mg/l of alum, the removal efficiency of COD did not increase while SS removal increased to 82.1% . It was found that 5-min flocculation time did improve the COD removal while it had little effect on SS removal . Flocculation for longer than 5 min did not enhance the flotation performance . Similar phenomena were observed when FeCl3 was used as the coagulant, except that flocculation had an insignificant effect on COD and SS removal . It was also found that FeCl3 was relatively more effective than alum . In summary, both coagulation-flocculation and DAF were efficient for the pretreatment . The advantages and disadvantages were discussed.

Water Sci Technol, 2001, 43(8), 115 - 21
Dissolved air flotation treatment of concentrated fish farming wastewaters; Jokela P et al.; Fish farming wastewaters contain nutrients, phosphorus and nitrogen, which promote eutrophication in the typically shallow farming sites in Finland . Fish farming wastewater treatment is problematic because of large quantities of very dilute wastewater (200-600 m3/kg fish produced) . In practice wastewater treatment is concentrated on suspended solids removal . Treatment can be done in two steps: concentration of the very dilute wastewater and subsequent treatment of the concentrated wastewater . Dissolved air flotation pilot trials were conducted using two types of concentrated wastewaters: settled solids from a sludge hopper of a cultivation basin and swirl separator concentrate . Two different pilot plants were used and performances compared . Both mechanical treatment and precipitation by ferric salts were applied . Depending on the influent quality, 70 to 90% phosphorus reductions were achieved without chemicals . Chemical precipitation and flotation produced 90% phosphorus reductions and effluent concentrations at the level of 0.05 mgP/l when 13 m3/(m2h) hydraulic loading was used.

Water Sci Technol, 2001, 43(8), 1 - 7
Development of dissolved air flotation technology from the first generation to the newest (third) one (DAF in turbulent flow conditions); Kiuru HJ; This paper gives a brief description of the development of dissolved air flotation DAF (or so-called high pressure flotation) as an unit operation for removal of solids in water and wastewater treatment during the last 80 years up to this time . The first DAF-systems used in the water industry were the ADKA and Sveen-Pedersen ones from the 1920s . Some of these are still in use . The tanks in which the flotation phenomenon takes place in these systems are very shallow and narrow as well as rather long . The flow rate of water is some 2-3 m/h (at most less than 5 m/h only) and there is a very thin micro-bubble blanket below the water surface between the dry sludge blanket on that and the clarified water which flows almost horizontally below the bubble blanket toward the end of the tanks to be taken out there from near the bottom . The second generation of DAF was introduced in the 1960s and these units are widely in use today . Their tanks are almost square ones having usually a little bit more length than breadth . They are rather deep, too . There is an under-flow wall in front of the back wall of the units having a narrow horizontal gap on the bottom of the tanks for letting out the clarified water from the flotation space . The flow rate of water is usually 5-7 m/h or at most less than 10 m/h . The direction of flow is 30-45 degrees below the horizontal . There is a rather thick micro-bubble bed at the beginning of the tank below the dry sludge blanket . This bubble-bed becomes clearly thinner, when going toward the end of the tank . There are also round DAF tanks which are based on the same hydraulic principles as the rectangular ones presented above . A special application of DAF called the flotation filter was invented at the very end of the 1960s . It is a combination of flotation and rapid sand filtration, both of those being placed in the same tank . Flotation takes place in the upper part of the tank and the filter has been placed in the lower part of it . The direction of water flow is now vertically down from the free surface of water in the tank toward the deep-bed filter . This controls the direction of flow in the flotation space of the tank above the filter bed . The flow rate of water in flotation filters may be 10-15 m/h, but the flow conditions are still laminar . It is the threat that the head-loss of filters would grow too rapidly which in practice is limiting the hydraulic flow rate of flotation filters in this area . The third generation of DAF has been developed at the end of the 1990s . The operational idea is based on that of the flotation filter . The filter bed on the bottom of the tank has been replaced by a thin stiff plate with plenty of round orifices throughout the plate . This plate, having a very much lower flowing resistance than a sand filter can have, controls the vertical flow of water in the flotation space above the plate and distributes it evenly throughout the horizontal cross-section of the tank . The flotation tank is almost square seen from above and its depth is clearly more than the length and breadth of it . This kind of flotation unit can be operated with flow rates of water in the range 25-40 m/l . Even a flow rate of more than 60 m/h has been reported from this kind of DAF-units . There is no risk of clogging of the plate by suspended solids which could limit the flow rate . This is to say that it is possible to operate DAF also in turbulent flow conditions . The depth of the micro-bubble bed below the surface of water can be 1.5-2.5 m . There actually is a continuously regenerated micro-bubble bed in the tank filtering water which is going through this bed . The lower surface of the micro-bubble bed is really a horizontal one a little bit above the plate controlling the flow in the flotation space . The clarified water below the micro-bubble bed is totally clear . It can be said that in this case the removal of suspended solids takes place much more by filtering water by a deep-bed micro-bubble filter than by attaching micro-bubbles onto solids, when both of these are mixed with each other in the inlet shaft of the flotation unit, because the retention time of water in the inlet shaft is very short indeed.

Environ Sci Technol, 2001 May 15, 35(10), 2084 - 8
Selective trace level analysis of phenolic compounds in water by flow injection analysis--membrane introduction mass spectrometry; Alberici RM et al.; Flow injection analysis coupled with membrane introduction mass spectrometry (FIA-MIMS) with on-line derivatization is shown to allow fast, accurate, nearly interference-free, and sensitive (low microgram/L) quantitation of phenolic compounds in water . On-line FIA derivatization of the phenolic compounds is performed by acetic anhydride acetylation in a K2CO3-buffered alkaline medium . The phenol acetates so formed efficiently permeate a silicone membrane and are directly transferred to the mass spectrometer, in which they are analyzed with selectivity and high sensitivity via selected ion monitoring . FIA-MIMS analysis was performed for aqueous solutions of phenol, 2-methylphenol, 4-chlorophenol, 4-chloro-3-methylphenol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol, and detection limits in the 0.5-20 micrograms/L (ppb) range were observed for an analytical frequency of six samples/h . FIA-MIMS for phenolic compound analysis is considerably less time-consuming and labor intensive than most chromatographic methods based on liquid-liquid extraction and preconcentration procedures and is therefore applicable for on-line and in-situ monitoring of phenols in wastewaters and in the environment . FIA-MIMS employing acetic anhydride derivatization is also virtually free of interferences since it combines chemical, membrane, and enhanced MS selectivity; hence quantitation of phenolic compounds can be performed in the presence of congeners.

Environ Int, 2001 May, 26(5-6), 425 - 31
Oxygen demand, nitrogen and copper removal by free-water-surface and subsurface-flow constructed wetlands under tropical conditions; Lim PE et al.; This study was conducted to: (1) assess the role of wetland vegetation in the removal of oxygen demand and nitrogen under tropical conditions, (2) estimate the uptake of nitrogen and copper by wetland plants and (3) investigate the speciation of Cu in wetland media among four operationally defined host fractions, namely exchangeable, carbonate, reducible and organically bound . Four laboratory-scale wetland units, two free-water-surface (FWS) and two subsurface-flow (SF) with one of each planted with cattails (Typha augustifolia), were fed with primary-treated sewage and operated at nominal retention times of 0.6-7 days . The influent and effluent BOD/COD and nitrogen concentrations were monitored to assess the performance of the wetland units for various mass loading rates . At the end of the study, all cattail plants were harvested and analyzed for total Kjeldahl nitrogen (TKN) . Four other wetland units, which were identical to the first four, were fed with domestic wastewater spiked with copper in increasing concentrations . Copper speciation patterns in the sand layer were determined at the end of the study . The results showed that wetland vegetation did not play an important role in oxygen demand removal but were capable of removing about 22% and 26% of the nitrogen input in the FWS and SF wetland units, respectively . Mass balance analysis indicated that less than 1% of copper introduced was taken up by the cattails . Copper speciation patterns in the sand media showed that the exchangeable fraction contributed 30-57% and 63-80% of the nonresidual copper in the planted and unplanted FWS wetlands, respectively . For SF units, the percentages were 52-62% and 59-67%, respectively . This indicates that large amount of copper in the media were potentially remobilizable.

Environ Int, 2001 May, 26(5-6), 395 - 9
Removal of copper from water using limestone filtration technique . Determination of mechanism of removal; Aziz HA et al.; This paper discusses heavy metal removal from wastewater by batch study and filtration technique through low-cost coarse media . Batch study has indicated that more than 90% copper (Cu) with concentration up to 50 mg/l could be removed from the solution with limestone quantity above 20 ml (equivalent to 56 g), which indicates the importance of limestone media in the removal process . This indicates that the removal of Cu is influenced by the media and not solely by the pH . Batch experiments using limestone and activated carbon indicate that both limestone and activated carbon had similar metal-removal efficiency (about 95%) . Results of the laboratory-scale filtration technique using limestone particles indicated that above 90% removal of Cu was achieved at retention time of 2.31 h, surface-loading rate of 4.07 m3/m2 per day and Cu loading of 0.02 kg/m3 per day . Analyses of the limestone media after filtration indicated that adsorption and absorption processes were among the mechanisms involved in the removal processes . This study indicated that limestone can be used as an alternative to replace activated carbon.

Water Sci Technol, 2001, 43(7), 73 - 81
Modeling of a reactive primary clarifier; Gernaey K et al.; Even though many models have been proposed for primary clarification, none is directly compatible with the ASM1 . The objective of this paper is to present the development of a reactive primary clarifier model to be used in a wastewater treatment plant simulator (WEST) . A model simulating COD behavior has been developed based on the Takacs model, and was tested with full-scale data . Particulate effluent COD was well described but problems occurred predicting the underflow suspended solids concentration . The model had to be upgraded with a residence time and a flocculation term to simulate the behavior of soluble COD . An ammonification term was added to the model, resulting in an improved model fit on effluent ammonium.

Water Sci Technol, 2001, 43(7), 377 - 80
An overview of the posters presented at Watermatex 2000 . I . New models/integrated urban wastewater systems/time series analysis; De Clercq B et al.; This paper presents an overview of the posters presented in the sessions 1, 6 and 9 of the Watermatex 2000 conference . The first session focused on the development of new models in different areas of environmental technology, e.g . wastewater, ground pollution, sewers, etc . The sixth session dealt with integrated urban wastewater systems . Session 9 focused on the application of neural network modeling and principal component analysis in time series analysis . Rewarded posters are mentioned and selected for full paper publication in this issue of Wat . Sci . Tech.

Water Sci Technol, 2001, 43(7), 311 - 20
Ranking stormwater control strategies under uncertainty: the River Cam case study; Duchesne S et al.; Monte Carlo simulations taking uncertainty in model parameters into account were performed on a river water quality model . The simulation results were used to rank wastewater treatment plant control strategies according to their impacts on river water quality . This impact is estimated by the maximum ammonium concentration and by the duration of dissolved oxygen concentration below 4 g/m3 at the downstream boundary of the system . The strategies were classified according to the previous criteria using 4 ranking methods, one of them being based on the concept of stochastic dominance . Results are presented for a case study based on a 10 km stretch of the River Cam as it passes through the city of Cambridge in Eastern England . It was found that ranking was robust in face of uncertainty in the parameter values for the control strategies considered as being superior in terms of river water quality impacts.

Water Sci Technol, 2001, 43(7), 301 - 9
Fast, simultaneous simulation of the integrated urban wastewater system using mechanistic surrogate models; Meirlaen J et al.; The urban wastewater system components (sewer, treatment plant, and river) are often modelled using complex mechanistic models . Mechanistic surrogate models are introduced here as simplified models that still contain some physical knowledge . Surrogate models are faster, but are less but still sufficiently accurate, and require more data to be calibrated . The possibilities of replacing actual field data by virtual data generated with a complex mechanistic model for calibration of the surrogate model are examined . As an example, a series of tanks with variable volume is shown to approximate sufficiently well the flow propagation in the river Zwalm (Belgium) as predicted by the "de Saint-Venant" equations . The three surrogate models can be implemented in the WEST simulator, which makes a simultaneous simulation of the system possible . In this work a connection is made between the ASM1 and the new IWA River Model No . 1 (RWOM1) by using a translator between the models in such a way that both mass and elemental balances remain closed for the overall system . This approach is illustrated with a case study on the river Lambro (Italy) . The dispersion process in this river with steady flow could be modelled by using a tanks in series model, while the water quality in the river was predicted to improve substantially with an increase in hydraulic capacity of the treatment plant . The simulation results with the upgraded plant still need to be checked by field data.

Water Sci Technol, 2001, 43(7), 265 - 70
Developing a model based decision support tool for the identification of sustainable treatment options for domestic wastewater; Balkema AJ et al.; To enable decision makers to select sustainable wastewater treatment systems, insight into the sustainability of a wide variety of systems should be provided in a transparent way leaving room for adaptation and interpretation according to the local situation . To provide this insight a structured methodology comparing wastewater treatment systems with respect to sustainability is defined . Similar to life cycle assessment (LCA) three phases can be distinguished: (1) goal and scope definition, (2) inventory analysis, and (3) optimisation and results . In the goal and scope definition we set the system boundaries to include most of the water cycle and part of the food cycle . Furthermore, we defined a multi-disciplinary set of sustainability indicators including technical, economic, environmental, and socio-cultural aspects . In the inventory analysis these sustainability indicators are quantified using simple static models of wastewater unit operations . Selection of unit operations results in a model of a complete wastewater treatment system . In the optimisation phase the decision maker can weigh the different sustainability indicators and select sustainable options through integer programming.

Water Sci Technol, 2001, 43(7), 207 - 14
Closed-loop identification and control application for dissolved oxygen concentration in a full-scale coke wastewater treatment plant; Yoo CK et al.; The objective of this paper is to apply a closed-loop identification to actual dissolved oxygen control system in the coke wastewater treatment plant . It approximates the dissolved oxygen dynamics to a high order model using the integral transform method and reduces it to the first-order plus time delay (FOPTD) or second-order plus time delay (SOPTD) for the PID controller tuning . To experiment the process identification on the real plant, a simple set-point change of the speed of surface aerator under the closed-loop control without any mode change was used as an activation signal of the identification . The full-scale experimental results show a good identification performance and a good tracking ability for set-point change . As a result of improved control performance, the fluctuation of dissolved oxygen concentration variation has been decreased and the electric power saving has been accomplished.

Water Sci Technol, 2001, 43(7), 199 - 206
System analysis for optimal control of a wastewater treatment benchmark; Vrecko D et al.; The paper presents an analysis and optimisation of a wastewater treatment benchmark . The benchmark is a simulation environment defining a plant layout, simulation model, influent data, test procedures and evaluating criteria that should be used for comparing different control strategies . In this paper an analysis of the benchmark which addresses the influences of potential manipulated variables on control performance under different operating conditions is presented . In the study optimisation is used to define the optimal values of the manipulated variables under constant as well as dynamic influent conditions . The results indicate that such an analysis and optimisation give important information about the manipulated variables under varying influent conditions and consequently about possible control strategies.

Water Sci Technol, 2001, 43(7), 191 - 8
Advanced monitoring and control of anaerobic wastewater treatment plants: diagnosis and supervision by a fuzzy-based expert system; Punal A et al.; A fuzzy-based expert system (ES) for the diagnosis and supervision for anaerobic digesters is presented . The system was developed in a Microsoft Windows support using fuzzy logic inference together with a rule base for the implementation of expert knowledge . The ES runs on-line through three main modules, which determine the state and trend of the process, and the best set points for the actuation on the final control elements of the plant . Two further modules run in parallel, when they are required by the operator, using off-line and on-line information for the detection of inhibition due to toxic compounds in the process and for the validation of the on-line diagnosis . The diagnosis and supervision ES was tuned up in order to adjust the membership functions describing the process, and lately tested, running on-line, to study the response of the rule base.

Water Sci Technol, 2001, 43(7), 183 - 90
Advanced monitoring and control of anaerobic wastewater treatment plants: fault detection and isolation; Steyer JP et al.; In this paper, a fault detection and isolation approach using fuzzy logic is described for on-line analysis of problems occurring in anaerobic digestion processes . The measurements available on the process are preprocessed to build a vector of fault residuals indicating the magnitude of the problems . This vector is classified into a prespecified category (i.e., a class) which is a state of the system, according to discrimination fuzzy rules . Three different types of classes were defined in a hierarchical structure: sensors faults, sub-process faults and process faults . This approach was developed to handle in real time both technical and biological problems . Demonstration of the practical interest of this study was made using real life experiments and large improvement of the reliability and safety of the process was obtained, thus optimizing the overall wastewater treatment.

Water Sci Technol, 2001, 43(7), 175 - 82
Advanced monitoring and control of anaerobic wastewater treatment plants: software sensors and controllers for an anaerobic digester; Bernard O et al.; A mass balanced based model representing the dynamical behaviour of anaerobic digester has served as a basis for the design of software sensors for the concentration of inorganic carbon, alkalinity and volatile fatty acids . The predictions of the sensors are close to the actual off-line measurements . The model has also been used to design a model-based adaptive linearizing controller and a fuzzy controller whose objective is to regulate the ratio of the intermediate alkalinity over the total alkalinity below some desired value (0.3) under which the process is assumed to remain in stable conditions and avoid VFA accumulation . Both controllers were calibrated via extensive numerical simulations and implemented . The controllers proved successful in maintaining the ratio of TA over PA below 0.3, even in presence of large variations of the organic load.

Water Sci Technol, 2001, 43(7), 147 - 56
Supervisory control of wastewater treatment plants by combining principal component analysis and fuzzy c-means clustering; Rosen C et al.; In this paper a methodology for integrated multivariate monitoring and control of biological wastewater treatment plants during extreme events is presented . To monitor the process, on-line dynamic principal component analysis (PCA) is performed on the process data to extract the principal components that represent the underlying mechanisms of the process . Fuzzy o-means (FCM) clustering is used to classify the operational state . Performing clustering on scores from PCA solves computational problems as well as increases robustness due to noise attenuation . The class-membership information from FCM is used to derive adequate control set points for the local control loops . The methodology is illustrated by a simulation study of a biological wastewater treatment plant, on which disturbances of various types are imposed . The results show that the methodology can be used to determine and co-ordinate control actions in order to shift the control objective and improve the effluent quality.

Water Sci Technol, 2001, 43(7), 139 - 46
Parameter optimisation of real-time control strategies for urban wastewater systems; Schutze M et al.; Real-time control (RTC) of wastewater systems has been a topic of research and application for over two decades . Attempts so far have mainly focused on one of the parts of the urban wastewater system: either the sewer system, or the treatment plant or the river . Approaches to integrate these subsystems and considering them jointly for control purposes have been pursued only recently . Control of the systems aims at pursuing one (or several concomitant) objectives, which are expressed, for example, in terms of overflow volumes, loads, effluent concentrations, receiving water quality or monetary costs, to name just a few . This paper provides a general and formal definition of the problem to define a real time control algorithm for a given urban wastewater system . A general mathematical optimization problem is formulated, which describes the task of finding an (in some sense) optimum control algorithm . Since this optimization problem is, in the general case, highly non-linear with only limited information available about the objective function itself, optimization methods appropriate for this type of problem are identified . Here, the similarity of the problem to find a control algorithm and of the parameter estimation problem common in mathematical modelling becomes apparent . Hence, methods (and problems encountered) in parameter estimation can be transferred to the problem of determining optimum RTC algorithms . This parallelism is outlined in the paper . As an application of the parameterisation and optimization of control strategies, integrated control of an urban wastewater system is discussed . Since the analysis of integrated control as just described poses certain requirements on a simulation engine, a novel modelling tool, called SYNOPSIS, is utilized here . This simulation tool, comprising of modules simulating water quantity and quality processes in all parts of the urban wastewater system, is embedded into a suite of optimization procedures . An integrated RTC algorithm for the urban wastewater system is formulated, the parameters of which are optimized using various global optimization routines . Comparison of their efficiency indicates good performance for the Controlled Random Search and for the genetic algorithms . The findings suggest that integrated control can indeed lead to an increase in performance of the urban wastewater system . These results appear to be encouraging and justify further work . Areas for further development are identified in the final section of the paper.

Water Sci Technol, 2001, 43(7), 123 - 30
Global predictive real-time control of Quebec Urban Community's westerly sewer network; Pleau M et al.; Quebec Urban Community (QUC) has selected Global Predictive Real-Time Control (GP-RTC) as the most efficient approach to achieve environmental objectives defined by the Ministry of Environment . QUC wants to reduce combined sewer overflows (CSOs) frequency to the St Lawrence river to two events per summer period in order to reclaim the use of Jacques-Cartier Beach for recreational activities and sports of primary contact . QUC's control scheme is based on the Certainty Equivalent Control Open Loop Feedback (CEOLF) strategy which permits one to introduce, at each control period, updated measurements and meteorological predictions . A non-linear programming package is used to find the flow set points that minimise a multi-objective (cost) function, subjected to linear equality and inequality constraints representing the physical and operational constraints on the sewer network . Implementation of GP-RTC on QUC's westerly network was performed in the summer of 1999 and was operational by mid-August . Reductions in overflow volumes with GP-RTC compared to static control are attributed to the optimal use of two existing tunnels as retention facilities as well as the maximal use of the wastewater treatment plant (WWTP) capacity.

Environ Pollut, 2001, 113(2), 121 - 8
Modelling the sorption of metals from aqueous solutions on goethite fixed-beds; Lehmann M et al.; The research on separation methods of toxic metals from wastewater streams is continuous and intensive and, among them, sorption processes are considered of particular importance, mainly due to their effectiveness . The sorption of chromate anions and zinc cations from dilute aqueous solutions using a packed-bed (column configuration) of synthesised granulated goethite was investigated in the present study . The examined parameters during this investigation were the following: (1) the initial pH value of metal-laden aqueous solution (two representative values at acidic pH, 3.5 and 5.0, were tested); (2) the quantity of sorbent in the column, corresponding to bed height; and (3) the influence of ethylene diamine tetra acetic acid (EDTA) addition, a common, strong chelating agent . The Bed Depth-Service Time model has been applied to the sorption results in order to model the column operation . The removal efficiency of Cr(VI) anions by the sorptive column was found to be higher than that of Zn(II) cations . The presence of EDTA caused a certain decrease of removal efficiency for the case of hexavalent chromium, due to competition for the same sorption sites, while the removal of divalent zinc was increased, due to variation of cation speciation.

J Environ Manage, 2001 Apr, 61(4), 319 - 28
Sustainable wastewater management for small communities in the Middle East and North Africa; Bakir HA; Accelerated expansion of wastewater services to small communities in the Middle East and North Africa (MENA) is essential in order to address serious concerns over water scarcity and pollution in addition to meeting the demand for convenience and protecting public health . Centralized and conventional wastewater systems are currently the preferred choice of planners and decision-makers in MENA . Water and funding are not available to provide these centralized conventional services to small communities . This paper presents an integrated approach to sustainable wastewater management for small communities in MENA under the severe water resources crisis . The approach calls for a paradigm shift from centralized conventional wastewater systems to decentralized wastewater systems . Management of wastewater in MENA should start at home . Wastewater generation should be reduced through a combination of domestic water conservation measures . On-site systems must be improved and monitored to control pollution and to recover water for non-potable water uses . Should the circumstances not allow the use of on-site systems, wastewater should be transported and managed through a community system applying the principles of decentralized wastewater management and using the settled sewers for wastewater transportation where appropriate . This approach will facilitate the accelerated and sustainable extension of environmentally responsible wastewater services to MENA's small communities . It offers great potential for cost reduction, accommodates the necessary domestic water conservation efforts, reduces freshwater inputs in wastewater transportation thus eliminating unnecessary demand on freshwater, reduces associated environmental risks and increases wastewater reuse opportunities.

Mar Pollut Bull, 2001 Jan, 42(1), 59 - 70
Changes in macroalgal communities in the vicinity of a Mediterranean sewage outfall after the setting up of a treatment plant; Soltan D et al.; Benthic macroalgal communities of the upper rocky sublittoral were studied in 1995-1996 in the vicinity of the Marseille (Mediterranean, France) sewage outfall, 8 years after the setting up of a wastewater treatment plant and compared to a previous study carried out in 1972-1974 . The number of taxa has increased, a clear stational and seasonal gradient of differentiation of the vegetation appeared, and a turf of ephemeral species is taking place of Corallina elongata at sites close to the outfall . These changes may be due to a decrease in pollutant load, the discharge of ferric chlorates used in the treatment process . However, the overall change is much less conspicuous than that described for deeper soft bottom communities, in particular the Cystoseira amantacea community is not still restored . Biological traits of this species (short distance dispersal) and the nature of most pollutants removed from the effluent (solids and organic matter) may explain this phenomenon.

Huan Jing Ke Xue, 2001 Jan, 22(1), 71 - 4
{Treatment of dilute solution anilines-containing with displacement by extraction}; Feng X et al.; It was found that the biodegradability (indicated by BOD5/CODCr value of water solution containing anilire or chloroaniline declined with the increasing of their concentration . In order to bio-treat such water, decrease of the solute's concentration was necessary . Based on the research of organic solvents' and complexing agent's biodegradability, a series of extraction experiments were conducted for aniline and m-chloroaniline with complexing agent or physical solvent . The factors influencing the distribution ratio were discussed . The BOD5/CODCr value of raffinates showed that the raffinate can be treated by biological degradation without dilution if suitable solvent was choosed . It was proved that displacement by extraction had great potentiality for treating wastewater containing non-biodegradable organic contaminant.

Huan Jing Ke Xue, 2001 Jan, 22(1), 45 - 8
{Comparison between porous polymer carrier and activated carbon carrier used for treating organic wastewater in anaerobic fluidized-bed reactor}; Yang P et al.; A comparative performance between porous polymer carriers (HP) and granular activated carbon carriers (GAC) in anaerobic fluidied-bed reactors was undertaken to evaluate their characters . The results showed that the COD removal and the biogas volume yield rate were 84% and 16.5 m3/(m3.d) respectively when HP was used as carrier to treat synthetic wastewater, at the top COD organic load rate of 65.5 kg/(m3.d), however those were 74.2% and 14.5% respectively for GAC carrier at the top load rate of 63.25 kg/(m3.d) . The COD removal and biogas volume yield rate were 64.7%-54.5% and 1.89-2.7 m3/(m3.d) respectively when HP was used as carriers to treat straw pulping wastewater, at the load rate of 14.5-36.15 kg/(m3.d), and those were 61.0%-52.1% and 0.73-2.0 m3/(m3.d) respectively for GAC carriers at the load rate 9.16-19.06 kg/(m3.d) . The study revealed that the HP carriers reactor is more efficient than the GAC carriers reactor in microbial immobilization and the wastewater treatment.

Huan Jing Ke Xue, 2001 Jan, 22(1), 109 - 13
{Analysis of toxic organic compounds in MGP-Wastewater and investigation of Wastewater's general characteristics}; Shen Y et al.; A full-scale investigation and analysis of MGP(Manufacture Gas from Petroleum)-Wastewater was carried out in this study . It's the first time that this paper publicizes the wastewater's general data, pretreatment method of GC/MS analysis and compositions of toxic organic compounds . The concentrtion of wastewater's CODCg, BOD5, phenolic, N-NH4+ and extractive-organic is: 400 mg.L(-1)-600 mg.L-1, 60 mg.L(-1)-80 mg.L-1, 20 mg.L(-1)-30 mg.L-1, 60 mg.L(-1)-80 mg.L-1 and 170 mg.L(-1)-200 mg.L-1 respectively . There are 79 kinds of aromatic compounds were detected by GC/MS, the total concentration of influent and effluent is 140.79 mg.L-1 and 129.11 mg.L-1 respectively . The data approved that MGP-wastewater is toxic and difficult for bio-treatment.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2001, 36(2), 203 - 13
Kinetics of photocatalytic degradation of reactive yellow 17 dye in aqueous solution using UV irradiation; Neppolian B et al.; In this paper photoinduced degradation of reactive yellow 17 (RY 17) dye has been studied employing TiO2 in the form of slurry in a batch reactor . UV lamps were used as the source for irradiation . The disappearance of the dye in the solution follows approximately pseudo-first order kinetics . The apparent rate constant decreases with increase in initial concentration of the dye . The addition of oxygen, hydrogen peroxide and persulphate ion influences the degradation rate of the dye . The formation of CO2, SO4(2-), NO3- and NH4+ ions have been identified in the mineralisation process . The decolourisation and mineralisation were followed by UV-Visible spectrophotometer and high performance liquid chromatography respectively . The results reveal that photocatalytic degradation may be a useful technique in the removal of reactive dyes in wastewater from textile industries.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2001, 36(2), 177 - 89
The comparative selection between spiral wound and disc tube membranes to treat steel industry wastewater; Kim DI et al.; To select the most suitable membrane process to treat the final effluent discharged from the S wastewater treatment facility at P Steel Works, the effluent was passed through two types of membrane (spiral wound and disc tube) in a pilot-scale study . The permeate flux and regeneration of each membrane were comparatively observed and the removal efficiency of contaminants determined . The experimental results from employing the disc tube membrane revealed that the fouling was comparably limited by operating the plant at 34 bar recovery and was highly sustained at permeate flux of 75% which equals to 32.9 l/hr.m2 . In contrast, the fouling was significantly greater when applying the spiral would membrane with the recovery correspondingly diminished at 72% . The disc-tube membrane was chosen to treat the effluent to be recycled for process water as the water quality satisfied the industry water standards.

J Environ Radioact, 2001, 54(3), 361 - 76
Sorption and transport of radionuclides by tumbleweeds from two plastic-lined radioactive waste ponds; Warren RW; Previous research has examined the uptake of radionuclides by tumbleweeds growing in contaminated soils, but none has heretofore examined the sorption of radionuclides to tumbleweeds blowing into radioactively contaminated water . Three tumbleweed species; Russian thistle (Salsola kali), Jim Hill mustard (Sisymbrium altissimum) and summer cypress (Kochia scoparia) blow in, and out of, two plastic-lined radioactive wastewater ponds, constructed in 1993 on the US Department of Energy's Idaho National Engineering and Environmental Laboratory in southeast Idaho . This research quantified radionuclide sorption to tumbleweeds, tumbleweed movement from the ponds, and determined radionuclide transport from the ponds . Average plant/water concentration factors associated with tumbleweeds taken from the ponds ranged from 5 for 152Eu to over 9000 for 54Mn . Based on changes in tumbleweed numbers and average concentrations associated with them, 66.2 MBq were estimated to have been transported from the ponds via tumbleweeds between 18 October 1994 and 8 November 1996 . This amounts to about 0.01% of the non-tritium and 0.0002% of the tritium activity released to the ponds through 8 November 1996 . A power function best described the radionuclide buildup curve for tumbleweeds submerged in the ponds . Visually marked tumbleweeds traveled from the ponds in the predominant wind direction a maximum of 737 m . Management practices which may reduce the number of tumbleweeds blowing both into and out of contaminated ponds are discussed.

Water Sci Technol, 2001, 43(3), 45 - 52
Comparative investigations on COD-removal in sequencing batch reactors and continuous flow plants; Dockhorn T et al.; Investigations on enhanced COD removal from municipal wastewater were performed over a period of 2.5 years, comparing three different types of reactor . The main idea was to determine the influence of the mixing characteristics of the reactor on the treatment processes and the effluent quality . Therefore three pilot plants (a completely mixed reactor, a cascade of three reactors and a SBR) were operated under equal conditions (wastewater, hydraulic load, temperature, sludge age) in parallel to each other . Investigations were carried out at different sludge ages . It could be shown that within one sludge age the CODf removal efficiency increased, when mixing characteristics came closer to the plug flow and it also increased with higher temperatures . A significant correlation was observed between the COD removal efficiency and the sludge load . The higher the sludge load was the greater the CODf concentration in the effluent . Especially the SBR reactor showed an excellent performance under the given operating conditions . Dynamic simulation calculations were carried out, to investigate whether the influence of the type of reactor on the COD-elimination could be described theoretically by combining growth kinetics and the mixing characteristics of the individual reactors . The results showed that performance was better when mixing characteristics came closer to plug flow.

Water Sci Technol, 2001, 43(3), 373 - 80
The SBR process: an efficient and economic solution for the treatment of wastewater at small cheesemaking dairies in the Jura mountains; Torrijos M et al.; The small cheesemaking plants in the Jura Mountains (N.E . France) need self-contained solutions for treating their wastewater . Any solution must suit the characteristics of the effluent produced by these small production units and be simple, robust and financially feasible in regard to both capital and running costs . Given this context, a technique based on an SBR was recommended and the operations of the first treatment plant established on an industrial scale, monitored for the first year, with particular attention paid to operating constraints . The results obtained show that the SBR is, from a technical point of view, perfectly adapted to treating cheese production wastewater, with purification levels at 97.7% for total COD and 99.8% for BOD5 . In the course of this study, it has been shown that the SBR process, thanks to its simple design and operation, can easily be run by the cheesemaker who will need to devote a minimum of time to it . Furthermore, with treatment costs of around 2 centimes (0.33 US cent) per litre of milk delivered, the SBR process meets perfectly both the technical and financial conditions for treatment as laid down by the Federation of Cooperatives of the Doubs and Jura departements.

Water Sci Technol, 2001, 43(3), 363 - 71
Biological nutrient removal in a full-scale SBR treating piggery wastewater: results and modelling; Tilche A et al.; Research activities carried out at ENEA during the last few years allowed development of a Sequencing Batch Reactor (SBR) that is able to remove biologically organic waste, nitrogen and phosphorus and that showed to be particularly suited to obtain low effluent nutrient concentrations even starting from concentrated wastes . This plant, in more than one year of operation, is quite steadily obtaining more than 98% removal of nitrogen, phosphorus and COD . On the basis of the experimental results, a simulation model has been built and calibrated . The model showed the potential to be used for forecasting the behaviour of the process, being able to reproduce a process imbalance that followed the tentative reduction of aeration time.

Water Sci Technol, 2001, 43(3), 347 - 54
From the lab to full-scale SBR operation: treating high strength and variable industrial wastewaters; Flapper TG et al.; This paper describes the path taken from client objectives through laboratory studies and detailed design to full-scale SBR operation and current research . Conventional municipal design principles have often been used to develop treatment processes for industrial wastewaters . The use of scientific trials to test design criteria offers the client a "tailor made" design fir for their particular wastewater character . In this project, a waste management company wished to upgrade their physical-chemical treatment plant to incorporate a biological reactor for treating a range of industrial wastewaters . Laboratory-scale trials were undertaken to determine appropriate design criteria for a full-scale biological process . These laboratory studies indicated that conventional design criteria were not appropriate and that a SBR configuration was optimal compared with an IDAR configuration . It was also found that a novel fungal:bacterial mixed liquor consortium developed, resulting in good effluent quality and settling properties . The treatment plant was able to be constructed and operational within a tight timeframe and budget, allowing the client to take advantage of a commercial opportunity . The plant has been operating since 1997 and meets its discharge conditions . By combining scientific studies with engineering principles, the end-user obtained a complete treatment plant to meet their specific needs . A further benefit of the laboratory trials is current research into the development of a fungal:bacterial SBR to treat industrial wastewaters . This offers ongoing knowledge to the operational full-scale SBR.

Water Sci Technol, 2001, 43(3), 339 - 46
Sequencing batch reactor technology: the key to a BP refinery (Bulwer Island) upgraded environmental protection system--a low cost lagoon based retro-fit; Hudson N et al.; BP Refinery (Bulwer Island) Ltd (BP) located on the eastern Australian coast is currently undergoing a major expansion as a part of the Queensland Clean Fuels Project . The associated wastewater treatment plant upgrade will provide a better quality of treated effluent than is currently possible with the existing infrastructure, and which will be of a sufficiently high standard to meet not only the requirements of imposed environmental legislation but also BP's environmental objectives . A number of challenges were faced when considering the upgrade, particularly; cost constraints and limited plot space, highly variable wastewater, toxicity issues, and limited hydraulic head . Sequencing Batch Reactor (SBR) Technology was chosen for the lagoon upgrade based on the following; SBR technology allowed a retro-fit of the existing earthen lagoon without the need for any additional substantial concrete structures, a dual lagoon system allowed partial treatment of wastewaters during construction, SBRs give substantial process flexibility, SBRs have the ability to easily modify process parameters without any physical modifications, and significant cost benefits . This paper presents the background to this application, an outline of laboratory studies carried out on the wastewater and details the full scale design issues and methods for providing a cost effective, efficient treatment system using the existing lagoon system.

Water Sci Technol, 2001, 43(3), 201 - 8
The anaerobic SBR process: basic principles for design and automation; Ruiz C et al.; This study has determined the purification performance and the basic principles for the design of an anaerobic SBR (ASBR) to be used to treat wastewater generated in the food industries . Two ASBR's were set up and one fed with a slaughterhouse effluent at low concentration, the other with concentrated dairy wastewater . The maximum loading rate applied should not exceed 4.5 g of COD/L/day for the dilute effluent and 6 g of COD/L/day for the concentrated effluent . At higher loading rates, the reactors become difficult to operate, mainly because of sludge removal problems, and purification efficiency declines . A detailed study of the kinetics (TOC, VFA, rate of biogas production) throughout one treatment cycle led to the development of a simple control strategy based on the monitoring of the biogas production rate which was then applied to the reactor treating the dairy wastewater . After automation, the reactor worked free of problems at an average pollution load of 5.4 g of COD/L/day.

Water Sci Technol, 2001, 43(3), 19 - 26
Generation and properties of aerobic granular sludge; Etterer T et al.; A sequencing batch reactor (SBR) was used to investigate the generation of different granules cultured under aerobic and alternating anaerobic/aerobic conditions . The reactor was fed with synthetic wastewater . A substrate loading rate of 3.6 kg COD/(m3 day) was applied . Granules of heterotrophic microorganisms were formed . After the first experimental period of 8 weeks the average granule diameter was 3.2 mm . In the second period, alternating anaerobic/aerobic conditions were applied to form granular sludge with an average diameter of 3.0 mm . An isopycnic centrifugation procedure was used to determine the characteristic density of the aerobic granular sludge . The average density of the granular sludge was 1.044 g/ml and 1.048 g/ml, respectively . In free-settling tests the final settling velocity of single aggregates was examined to estimate porosity . Settling velocities up to 2.0 cm/s could be measured . Calculations based on the experimental results showed an average granula porosity of 72% for the first run and 65% average porosity for the second run . This paper indicates the validity of general assumptions in free-settling tests.

Water Sci Technol, 2001, 43(3), 107 - 14
Dynamic control of a continuous-inflow SBR with time-varying influent loading; Yu RF et al.; The conventional sequential control of Sequencing Batch Reactor (SBR) is designed with fixed time periods for various operation phases . However, both of the flow rates and qualities of influent vary over time, therefore, a big capacity of wastewater equalization unit is required to cope with influent variability . Such an equalization unit increases the total treatment costs of the system, especially in a small-scale wastewater treatment system . Moreover, in using a SBR treating a time-varying influent loading with conventional sequential control, the system performance cannot be optimized . This paper presents the application of on-line ORP and pH monitoring to dynamically control a continuous-inflow SBR with time-varying loading of influent flow rates and water qualities . Experiential results show that the dynamic controlled SBR revealed not only achieved better substrate removal efficiencies, but also reduced treatment costs.

Mar Pollut Bull, 2001 Mar, 42(3), 202 - 14
Recovery of the macrozoobenthic community after severe dystrophic crises in a Mediterranean coastal Lagoon (Orbetello, Italy); Lardicci C et al.; The Orbetello lagoon, one of the largest Western Mediterranean lagoons, was affected by high algal blooms and severe anoxic crises in 1992 and 1993, with fish mortality throughout most of the lagoon and a drastic reduction of benthic species . Many measures were undertaken between 1994 and 1996 to remove the severe eutrophication of this lagoon . Such measures included harvesting of the floating seaweed biomass, removal of all wastewater and sea channel enlargement by dredging activity . The aim of the present research was to study the macrozoobenthic assemblage in 1999 and to compare it with previous research in order to assess the recovery of the lagoon . A total of 106 taxa and 45,175 individuals were collected in three areas (sea inlets, western and eastern lagoon) having different organic matter loading during winter and summer . The results of multivariate and correlation analyses indicated that trophic status and its seasonal dynamics were crucial in determining species distribution among the different areas . Moreover, comparison of the macrozoobenthic structure between winter 1995 and 1999 showed differences in species composition and structural parameters in the western and eastern lagoon, where a clear recovery of benthic assemblages was observed in 1999 . However, the dominance of opportunistic species in most of the lagoon and the decrease in some structural parameters during summer suggested that this basin still presented signs of disturbance in 1999, six years after the last extended anoxic crises and even after completion of the restoration measures carried out in the environment . It was hypothesized that a secondary disturbance, sustained by a high seasonal release of nutrients from the sediments, could create considerable deviations from the expected improvement in benthic conditions.

Ann Chim, 2001 Mar-Apr, 91(3-4), 169 - 74
Electrochemical treatment of olive oil mill wastewater; Longhi P et al.; The possibility of oxidizing at a PbO2 anode the phenols and polyphenols, present in the olive oil mill wastewater, has been studied as a pretreatment for the submission of such wastewater to the traditional biological treatments . The results obtained operating at current densities ranging 500 to 2000 A/m2 show that it is possible to reduce the concentration of the phenolic components, which interfere with the biological treatments, down to low values without decreasing too much the total organic content of the wastewater.

Ann Chim, 2001 Mar-Apr, 91(3-4), 145 - 9
Innovative methods for removing phosphorus from wastewaters; Di Palma L et al.; Wastewater containing a mixture of hypophosphites and phosphites was treated in order to assess the possibility of attaining high levels of phosphorus oxidation to phosphate . An initial series of tests based on chemical oxidation by means of Fenton's reagent demonstrated the feasibility of this process for solutions containing 250-750 mg/l of phosphorus . Removal yields of up to 98% were attained at pH 3.5 by using variable ratios of {H2O2}/{Fe2+} . The second series involved the electrolytic generation of Fenton's reagent at pH 2-2.5 through cathodic oxygen reduction . This demonstrated the possibility of obtaining quantitative yields for solutions containing 80-160 mg/l P with a constant {H2O2}/{Fe2+} ratio of 3.94 . Economic comparison of the two processes showed that the operative cost of the electrochemical treatment is comparable to that of the chemical process.

J Environ Manage, 2001 Jan, 61(1), 93 - 111
A system dynamics approach for regional environmental planning and management: a study for the Lake Erhai Basin; Guo HC et al.; In recent years, water-quality deterioration associated with rapid socio-economic development in the Lake Erhai Basin, China, has acquired more and more attention from the public and the government . An effective planning for the basin's environmental management system is desired for sustainable regional development . In this study, an environmental system dynamics model, named ErhaiSD, is developed for supporting this planning task . The ErhaiSD consists of dynamic simulation models that explicitly consider information feedback that governs interactions in the system . Such models are capable of synthesizing component-level knowledge into system behaviour simulation at an integrated level . This capability is very useful in analyzing and recommending policy decisions . For the study case, interactions among a umber of system components within a time frame of 15 years are examined dynamically . Four planning alternatives are considered . The base run is based on an assumption that the existing pattern of human activities will prevail in the entire planning horizon, and the other alternatives are based on previous planning studies . The contributions of various nonpoint pollution sources to the lake's eutrophication problems, and the effects of industrial activities and wastewater treatment processes on pollution problems in the Xier River are analyzed through the developed modeling system . The exercise draws attention to the implications of different alternatives to the system's environmental and socio-economic objectives . The modeling results are directly useful for simulating and evaluating a variety of decision actions and their dynamic consequences, and answering questions such as 'What should I do?', 'What if I do?' and 'What are the expected consequences?'.

J Environ Manage, 2001 Jan, 61(1), 37 - 49
Total waste-load control and allocation based on input-output analysis for Shenzhen, south China; Ni JR et al.; The general objective for this paper is to reveal the dynamic relationships between the rapid economic development, water pollution and the subsequent waste-load allocation in different economic sectors through a case-study in Shenzhen City, South China . Two-objective analysis model was employed based on the input-output table for Shenzhen with the full consideration of various constraints in local area . The improved Tchebycheff procedure was used for obtaining the solutions . The predictions were made on economic development and pollutants from wastewater in different sectors and different planning years . The present study allows for the consideration of the economic structural adjustment . It is found that the current situation of economic structure is generally good and is subject to further adjustment in Shenzhen, although it has undergone the rapid development in the past 18 years . When the maximum Gross Domestic Production and the minimum Chemical Oxygen Demand are chosen as the two objectives subject to other constraints, the harmonized results indicated a scheme that claims substantial reduction of polluting effluences in Shenzhen while closely keeping the economic growth rate as planned.

J Environ Manage, 2001 Jan, 61(1), 25 - 36
Integrating water-quality management and land-use planning in a watershed context; Wang X; The spatial relationships between land uses and river-water quality measured with biological, water chemistry, and habitat indicators were analyzed in the Little Miami River watershed, OH, USA . Data obtained from various federal and state agencies were integrated with Geographic Information System spatial analysis functions . After statistically analyzing the spatial patterns of the water quality in receiving rivers and land uses and other point pollution sources in the watershed, the results showed that the water biotic quality did not degrade significantly below wastewater treatment plants . However, significantly lower water quality was found in areas downstream from high human impact areas where urban land was dominated or near point pollution sources . The study exhibits the importance of integrating water-quality management and land-use planning . Planners and policy-makers at different levels should bring stakeholders together, based on the understanding of land-water relationship in a watershed, to prevent pollution from happening and to plan for a sustainable future.

Water Sci Technol, 2001, 43(2), 91 - 9
Possible impact of treated wastewater discharge on incidence of antibiotic resistant bacteria in river water; Iwane T et al.; Escherichia coli and coliform group bacteria resistant to seven antibiotics were investigated in the Tama River, a typical urbanized river in Tokyo, Japan, and at a wastewater treatment plant located on the river . The percentages of antibiotic resistance in the wastewater effluent were, in most cases, higher than the percentages in the river water, which were observed increasing downstream . Since the possible increase in the percentages in the river was associated with treated wastewater discharges, it was concluded that the river, which is contaminated by treated wastewater with many kinds of pollutants, is also contaminated with antibiotic resistant coliform group bacteria and E . coli . The percentages of resistant bacteria in the wastewater treatment plant were mostly observed decreasing during the treatment process . It was also demonstrated that the percentages of resistance in raw sewage are significantly higher than those in the river water and that the wastewater treatment process investigated in this study works against most of resistant bacteria in sewage.

Water Sci Technol, 2001, 43(2), 75 - 82
Enhanced virus recovery from municipal sewage sludge with a combination of enzyme and cation exchange resin; Sano D et al.; There is a great difficulty in virus enumeration in sewage sludge because viruses in sludge are firmly captured by sludge solids . In order to determine the precise number of viruses in sludge, an enhanced virus recovery method with a combination of an enzyme and a cation exchange resin (CER) was developed . Test viruses were seeded to a sample sludge obtained from a municipal wastewater treatment plant, and the sludge were incubated with various eluents . The quantity of eluted viruses in the liquid phase was then measured by the plaque assay technique . Using the eluent containing only water, CER, and CER with enzyme exhibited 0%, 19% and 39% of virus recovery, respectively . While the conventional USEPA method exhibited a virus recovery of 21% . Furthermore, viruses eluted by the eluent containing the CER and the lysozyme included not only surface-attached viruses but also solids-embedded viruses.

Water Sci Technol, 2001, 43(2), 349 - 54
Acrylonitrile removal from synthetic wastewater and actual industrial wastewater with high strength nitrogen using a pure bacteria culture; Wang CC et al.; A gram-negative rod-shaped bacteria (strain AAS6), capable of utilizing acrylonitrile as the sole source of both carbon and nitrogen, was utilized to investigate the removal of acrylonitrile in ABS resin manufacturing wastewater . Both synthetic wastewater, containing a high concentration of acrylonitrile, and actual wastewater obtained from an ABS manufacturing factory were used . The result indicated that strain AAS6 was capable of completely removing acrylonitrile from synthetic wastewater containing less than 889 mg/l acrylonitrile and from actual industrial wastewater containing less than 400 mg/l acrylonitrile . Whether in synthetic wastewater or actual industrial wastewater, strain AAS6 showed approximately the same ability for acrylonitrile removal and used acrylic acid, a metabolic by-product of acrylonitrile, as the carbon source and ammonium as the nitrogen source . The bacteria could not directly metabolize other chemicals found in the actual industrial wastewater . However, its metabolic activities were not inhibited by the presence of compounds such as butadiene, styrene or acrylonitrile-styrene polymer . Thus, this strain is expected to play an important role in aeration tanks for treating ABS resin manufacturing wastewater.

Water Sci Technol, 2001, 43(2), 341 - 8
Removal and recovery of heavy metals from wastewaters by supported liquid membranes; Yang XJ et al.; The removal and recovery of Cu, Cr and Zn from plating rinse wastewater using supported liquid membranes (SLM) are investigated . SLMs with specific organic extractants as the liquid membrane carriers in series are able to remove and concentrate heavy metals with very high purity, which is very promising for recycling of heavy metals in the electroplating industry . A technical comparison between the membrane process and the conventional chemical precipitation process was made.

Water Sci Technol, 2001, 43(2), 305 - 12
Removal of hydrophobic dyestuff from dyeing wastewater by photo-sensitization process; Tsui SM et al.; Recently, photochemical reaction became more important in view of using UV in textile dyeing wastewater treatment processes, in which neither chemical sludges nor toxic residues are left in the treated effluent . The photodegradation of hydrophobic dye (Palanil Yellow 5R, PY-5R) in the presence of acetone, which performs as a solvent and/or a photo-sensitizer, was investigated in this study . The results demonstrated that photochemical reaction in the presence of acetone could rapidly and effectively enhance color removal at a wavelength of 253.7 nm . The photodegradation follows pseudo first-order decay . The rate constants and decay quantum yields of dye degradation by UV depend on the solution pH and solvent system, (i.e., acetone to water ratio) . The photosensitization of the disperse dye was found to be optimized at pH 9 and in 0.5 (v:v) acetone-water ratio.

Water Sci Technol, 2001, 43(2), 271 - 6
Biotreatability studies of pharmaceutical wastewater using an anaerobic suspended film contact reactor; Mohan SV et al.; The pharmaceutical industrial effluents, which include several organic solvents and other toxic chemicals, are generally treated by aerobic process, which is cost intensive in nature . The alternative anaerobic route to degrade the toxic effluents is attractive due to the lower cost of treatment and the generation of gas, which can supplement the energy requirements . There are few reports on the anaerobic treatment of the pharmaceutical effluents . In the present investigation, the effluents from a bulk drug industry, which utilizes several organic chemicals, have been taken to assess their applicability for anaerobic treatment . The organic loading rates were varied from 0.25 kg/m3/day to 2.5 kg/m3/day and the COD reduction was found to be in the range of 60 to 80% . Long term operation of an anaerobic suspended film contact reactor carried out with 1.25 kg/m3/day was found to be optimum . The biogas generated during the degradation process was monitored and the methane content was found to be 60-70%.

Water Sci Technol, 2001, 43(2), 253 - 60
Peroxidase-catalyzed removal of phenols from a petroleum refinery wastewater; Wagner M et al.; The phenol content of a petroleum refinery wastewater was reduced below the discharge limit following treatment with horseradish peroxidase and H2O2 . Approximately 58% of COD, 78% of BOD5, and 95% of toxicity were removed along with the phenols . As a result of treatment, phenols were transformed into less biodegradable compounds which could be removed by subsequent coagulation and precipitation . Optimization of the peroxide concentration led to 20% enzyme savings . The use of PEG and chitosan as protective additives resulted in 4 and 25-fold reductions in enzyme requirements, respectively . Phenol removal did not appear to be adversely affected by the presence of other hydrocarbons that are frequently present in refinery wastewaters.

Water Sci Technol, 2001, 43(2), 221 - 8
Partial oxidation of reactive dyestuffs and synthetic textile dye-bath by the O3 and O3/H2O2 processes; Balcioglu IA et al.; Ozonation and O3/H2O2 oxidation of reactive dyestuffs and simulated textile dye-bath were investigated . Effects of reaction pH, initial dye concentration, H2O2 concentration and assisting chemicals on treatment efficiency were examined . We found considerable improvement in COD and colour removal rates at pH = 11, that was almost the actual pH of the prepared textile wastewater, whereas in particular increasing the initial dyestuff concentration had an adverse effect upon oxidation rates . Removal of colour, COD and TOC were found to be fairly sensitive to the introduction of soda that is frequently applied as an auxiliary chemical during the reactive dyeing process . The addition of H2O2 had negligible effect on COD removal efficiency and decolorization rate compared to ozonation alone at different pH values . Accordingly it can be inferred that the theoretically expected effect of OH radical scavengers (e.g . carbonate, chloride) present in the synthetic dye-bath as well as introduced radical formation promoters (e.g . H2O2, OH-) were probably hidden due to the complexity of the synthetic wastewater matrix . Biodegradability of the ozonated dye-bath was accelerated by a factor of three corresponding to a 233% relative enhancement . The inhibition of the oxygen uptake rate decreased from 91% to 75% within only 5 min treatment time.

Water Sci Technol, 2001, 43(2), 17 - 24
Comparison of a novel electro-Fenton method with Fenton's reagent in treating a highly contaminated wastewater; Huang YH et al.; This study applied a novel electrochemical process called the Fered-Fenton method to treat a highly concentrated wastewater . By combining electrochemical reduction and chemical oxidation, the process can remove organic compounds and heavy metals in a batch reactor . A PVC-stabilizer processing wastewater was treated in this investigation owing to its high heavy metal concentration (Pb = 7,500 mg/l) and high organic concentration (COD = 11,000 mg/l) . The major organic component was acetate . Direct anodic oxidation showed no effect on COD removal . Fenton's method only removed 36% of COD using 4,000 mg-Fe2+/l and 28,000 mg-H2O2/l dosage . In the Fered-Fenton process, about 89% of COD was removed with 2,000 mg-Fe3+/l and 28,000 mg-H2O2/l . Furthermore, the COD removal attained an efficiency of about 98% for 56,000 mg-H2O2/l used . Results presented herein demonstrate that the Fered-Fenton method is superior to direct anodic oxidation and Fenton's method in this case . Furthermore, the changes of the intermediate compounds including acetate, oxadate, and formate during the reaction were analyzed, which provided us with the information to propose degradation reactions of the wastewater in this system.

Water Sci Technol, 2001, 43(2), 147 - 54
Monitoring and classification of toxicity using recombinant bioluminescent bacteria; Gu MB et al.; Recombinant bioluminescent biosensing cells were used to detect and classify toxicity caused by various chemicals in water environments . Classification of the toxicity was realized based upon the chemicals' actions of toxicity by using DNA-, oxidative- and membrane-damage sensitive strains . Tested samples contained a single chemical or mixture of chemicals in media, wastewater, or river water . Finally, it is suggested that this method for classification of toxic chemicals in wastewater or other aqueous systems may be adopted for primary screening steps of the samples and can give useful information about the samples' characteristics.

Water Sci Technol, 2001, 43(2), 101 - 8
Study on endocrine disrupting chemicals in wastewater treatment plants; Nasu M et al.; From July 1998 to March 1999, a study was made of a total of 27 treatment plants for the principal purpose of understanding the actual condition of endocrine disrupting chemicals (EDCs) in sewage, and the behavior of EDCs in wastewater treatment plants . The results showed actual levels of influent and effluent concentrations of EDCs in sewage . Substances detected above the minimum limit of determination were 15 for wastewater influent and 6 for effluent . Similarly, nonyl phenol ethoxylate and 17 beta-estradiol, which are highlighted as pertinent substances, were detected . It was confirmed that the reduction ratio of EDCs in treatment plants was 90% or more for almost all substances . The behavior of EDCs in general in treatment plants was also studied . As a result, the EDCs reduction effect was recognized in both the primary setting tank and biological reaction tank, though the trend varies among substances.

Water Sci Technol, 2001, 43(2), 1 - 8
Increased toxicity of textile effluents by a chlorination process using sodium hypochlorite; Chen CM et al.; Chlorinated textile effluents were tested for their toxicity using different bioassays . These assays were the Microtox assay, daphnia (Daphnia similis) 48-hr survival test, medaka embryo 14-day and juvenile 96-hr survival tests, and tilapia (Oreochromis mossambicus) juvenile 96-hr survival test . By comparing the results of toxicity tests on water samples collected at the instream prior to the chlorination process and at the outlet of the wastewater treatment facility, we found that wastewater toxicity was obviously increased by chlorination using NaOCl as the oxidant, as evidenced by the different bioassays used . Because no significant difference was observed in water chemistry, such as pH, DO, and conductivity, the induced-toxicity may be partially attributable to residue chlorine or other chlorinated compounds generated by chlorination . Future studies are warranted to identify the cause of the increase in the textile wastewater toxicity.

Water Sci Technol, 2001, 43(5), 61 - 8
Urban drainage redefined: from stormwater removal to integrated management; Chocat B et al.; Even though urban drainage has been practised for more than 5000 years, many challenges arising from growing demands on drainage still remain with respect to runoff quantity and quality; landscape aesthetics, ecology and beneficial uses; and operation of existing urban wastewater systems . Further advances can be achieved by adopting an integrated approach, optimal operation of the existing infrastructure, advanced pollution and runoff source controls, improved resilience of receiving waters, and adaptive water management . The specific research needs include new technologies and strategies for stormwater management, advanced treatment of urban wet-weather effluents, and tools for analysis and operation of drainage systems . High diversity of demands on, and region/site specific conditions of, urban drainage shapes the role of urban drainage experts--as mediators among the many stakeholders and fields involved.

Water Sci Technol, 2001, 43(5), 41 - 9
River Water Quality Model no . 1 (RWQM1): case study . I . Compartmentalisation approach applied to oxygen balances in the River Lahn (Germany); Borchardt D et al.; A case study on the application of the River Water Quality Model No . 1 (RWQM1) is presented in order to illustrate the importance of modelling a sediment compartment for an ecologically meaningful assessment of the impact of wastewater effluents and combined sewer overflows . The focus of this case study is on the compartmentalisation approach of the RWQM1 that makes such a description possible . In contrast to this, a strongly simplified biochemical submodel is used that considers only oxygen and dissolved substrate . The object of the case study is the River Lahn, a moderately polluted 5th order stream in Germany, for which the connectivity of surface/subsurface flows and mass fluxes within river sediments have been intensively investigated . The hyporheic flow between a downwelling and upwelling zone of a riffle-pool sequence has been studied with the aid of tracer experiments and continuous records of water constituents . High diurnal fluctuations of oxygen travelled to considerable depth of the sediment and oxygen in the interstitial water decreased considerably while travelling through the riffle . Starting with the implementation of a strongly simplified version of the biochemical part of the RWQM1, but with the consideration of a sediment pore water compartment in addition to the water column compartment, a calibration procedure is performed using tracer data from the water column and the sediment . The calibrated model is then used to study the system response to wastewater treatment plant effluent and combined sewer overflow emissions . The modelling approach makes it possible to quantify the sediment oxygen demand and the spatial and temporal extent of sediment zones with oxygen depletion . However, the spatially averaged approach does not account for inhomogeneities in the sediment . It is shown that for this river with its alluvial coarse sediments even moderate emissions from sewerage systems may be high enough to drop sediment oxygen concentrations to low levels while those in the surface flow remain close to saturation . Similarly, it is demonstrated that combined sewer overflows may cause anoxic sediment oxygen conditions for extended time periods . The implications for ecologically sound river water quality modelling and for specific quality objectives are discussed.

Water Sci Technol, 2001, 43(5), 309 - 17
Waste design and source control lead to flexibility in wastewater management; Larsen TA et al.; The concepts of waste design and source control are introduced as contracts between wastewater handling agencies and consumers and consumers and industry respectively . Waste design serves to produce waste streams that are optimized in composition and time sequence for easy transport and treatment . Source control makes services and installations available, which allow the consumer to adhere to the specification of waste design . Increased delegation of responsibility to the consumer is expected to result in more flexible wastewater handling systems.

Water Sci Technol, 2001, 43(5), 223 - 9
Impact of atmospheric deposition on the headworks of a wastewater treatment plant--a case study; Atasi KZ et al.; Specialized sampling equipment and ultra-clean analytical methodology were employed to quantify the concentrations or fluxes of mercury (Hg), cadmium (Cd) and polychlorinated biphenyl (PCBs) in ambient air, precipitation, runoff, sanitary sewer, and wastewater treatment plant (WWTP) influent . The relationship between the atmospheric deposition and runoff on controlled surfaces were explored for the three pollutants . The impact of the atmospheric deposition and runoff to the headwork loading of the WWTP were investigated . Atmospheric deposition was found to be the primary source of the mass of Cd, Hg, and PCBs in runoff from the controlled surfaces . Neither atmospheric deposition nor the runoff was the main sources of the three pollutants to the Detroit Wastewater Treatment Plant (WWTP) . Wet weather flow contributes the main portion of the Cd, Hg, and PCBs loading to the WWTP.

Water Sci Technol, 2001, 43(5), 153 - 62
Dynamic phosphorus mass balance modeling of large watersheds: long-term implications of management strategies; Cassell EA et al.; The principles of mass balance, compartment-flux diagramming, and dynamic simulation modeling are integrated to create computer models that estimate phosphorus (P) export from large-scale watersheds over long-term futures . These Watershed Ecosystem Nutrient Dynamics (WEND) models are applied to a 275,000 ha dairy-documented watershed and a 77,000 ha poultry-dominated watershed in northeastern USA . Model predictions of present-day P export loads are consistent with monitoring data and estimates made using P export coefficients . For both watersheds P import exceeds P export and P is accumulating in the agricultural soils . Agricultural and urban activities are major contributors to P export from both watersheds . Continued urban growth will increase P export over time unless wastewater management is substantially enhanced and/or rates of urban growth are controlled . Agriculture cannot rely solely on the implementation of increasingly stringent conservation practices to reduce long-term P export but must consider options that promote P input/output balance . The WEND modeling process is a powerful tool to integrate the diversity of activities in watersheds into a holistic framework . Model outputs are suited to assist managers to explore long-term effects of overall watershed management strategies on P export in comparison to environmental and economic goals.

Water Sci Technol, 2001, 43(5), 137 - 44
New challenges for the management of plant nutrients and pathogens in the Waikato River, New Zealand; Vant WN; The water quality of the Waikato River is currently much better than it was in the 1950s . Major improvements in the treatment of the sewage and industrial wastewaters which are discharged to the river mean that levels of indicator bacteria in the lower reaches of the river are now many times lower than in the past . Eve so, conditions are still not suitable for swimming, and blue-green algal blooms occur at times . Non-point or diffuse sources of contaminants now dominate the nutrient and pathogens budgets . Progressively-intensifying farming, particularly in lowland areas, is thought to contribute the majority of the contaminants found in the river . Future improvements in water quality will therefore depend more on activities like changes to farming practice--such as retiring the riparian margins of lowland tributaries of the river--than on further advances in wastewater treatment.

Water Sci Technol, 2001, 43(5), 111 - 8
Small diameter gravity sewers: self-cleansing conditions and aspects of wastewater quality; Dias SP et al.; The construction of conventional sewerage systems in small communities, with pipes laid on a uniform slope and manholes regularly spaced, is sometimes not economically feasible, because of the high costs of sewer installation . Under those circumstances, the small diameter gravity sewers (SDGS) have often proven to be substantially less costly than conventional sewers . Typically, in SDGS systems the wastewater from one or more households is discharged into an interceptor tank (or a single compartment septic tank) . The settled effluent is discharged afterwards into small diameter sewers operating under gravity . In this paper, special emphasis is given to the analysis of self-cleansing conditions and to the analysis of risks of sulphide generation and occurrence of septic conditions in SDGS systems . For the evaluation of the self-cleansing conditions, the critical velocity and the critical shear stress were computed according to the Shields equation . The forecasting of dissolved oxygen concentrations and sulphide build-up along the lines, for different flow conditions, was done running an established wastewater quality model.

Water Sci Technol, 2001, 43(5), 11 - 30
River Water Quality Model no . 1 (RWQM1): II . Biochemical process equations; Reichert P et al.; In this paper, biochemical process equations are presented as a basis for water quality modelling in rivers under aerobic and anoxic conditions . These equations are not new, but they summarise parts of the development over the past 75 years . The primary goals of the presentation are to stimulate communication among modellers and field-oriented researchers of river water quality and of wastewater treatment, to facilitate practical application of river water quality modelling, and to encourage the use of elemental mass balances for the derivation of stoichiometric coefficients of biochemical transformation processes . This paper is part of a series of three papers . In the first paper, the general modelling approach is described; in the present paper, the biochemical process equations of a complex model are presented; and in the third paper, recommendations are given for the selection of a reasonable submodel for a specific application.

Water Sci Technol, 2001, 43(1), 43 - 50
Hybrid modelling of anaerobic wastewater treatment processes; Karama A et al.; This paper presents a hybrid approach for the modelling of an anaerobic digestion process . The hybrid model combines a feed-forward network, describing the bacterial kinetics, and the a priori knowledge based on the mass balances of the process components . We have considered an architecture which incorporates the neural network as a static model of unmeasured process parameters (kinetic growth rate) and an integrator for the dynamic representation of the process using a set of dynamic differential equations . The paper contains a description of the neural network component training procedure . The performance of this approach is illustrated with experimental data.

Water Sci Technol, 2001, 43(1), 225 - 32
Wastewater treatment and nitrogen removal using submerged filter systems; Chui PC et al.; The performance of two submerged filter systems: a two filters-in-series system and a single combined filter system, in treating a strong nitrogenous wastewater with nitrogen concentration of 480 mg/L was evaluated . Both systems were equally effective in removing up to 90% of nitrogen and 98% of COD from the wastewater for loading rates up to 5 kg COD/m3.d and 0.5 kg N/m3.d . The second system in which anaerobic, anoxic, and aerobic zones were incorporated in a single filter offers a greater flexibility in treatment in that by repositioning the locations of the aeration point and effluent recycling inlet, the zonal volumes can be altered easily to treat wastewaters with different COD and nitrogen concentrations.

Water Sci Technol, 2001, 43(1), 181 - 90
Application of COD fractionation by a new combined technique: comparison of various wastewaters and sources of variability; Sperandio M et al.; A new respirometric method for COD fractionation was applied to various wastewaters collected on French treatment plants . Great variations were observed especially in the readily biodegradable fraction (RBCOD) ranging from 1 to 16% of total COD . Variability of the results among the origin can be explained by the reactions occurring in the sewers . In one of the towns studied, the wastewater samples collected directly in the sewer show COD characteristics very different from the sewage which reaches the treatment plant . By analysing the same wastewater after aerobic and anaerobic storage, it was proved that RBCOD respectively decreased or increased significantly . Seasonal fluctuations were also quantified, showing that RBCOD fraction decreased from 75 mg/L to -15 mg/L during the summer whereas the variation of soluble fraction was less important.

Water Sci Technol, 2001, 43(1), 107 - 14
Comparison of enumeration methods for ammonia-oxidizing bacteria; Konuma S et al.; MPN, antibody, fluorescent in situ hybridization (FISH) and dot blot hybridization methods for enumeration of ammonia-oxidizing bacteria were applied to various samples from suspended systems . As for FISH, reoptimization of an oligonucleotide probe Nso 190 was attempted . The advantages and disadvantages of these methods were discussed . MPN appeared to have disadvantages of underestimation . Dot blot hybridization had lower detection limit and higher reliability than other methods . It could be applied to mixed liquors and effluents of municipal wastewater treatment plant (WWTPs), lab-scale reactor and enrichment cultures of ammonia-oxidizing bacteria . FISH could be successfully applied to high ammonium loading system such as enrichment cultures, but weak signal, auto-fluorescence and non-specific binding could cause problems when applied to low ammonium loading systems such as effluents of WWTPs and river water . Mixed liquor of municipal WWTP seemed to be a critical case for FISH.

J Hazard Mater, 2001 Jun 1, 84(1), 57 - 71
Chemical oxidation of methylene blue using a Fenton-like reaction; Dutta K et al.; Oxidation by Fenton-like reactions is proven and economically feasible process for destruction of a variety of hazardous pollutants in wastewater . We report herein the oxidation of methylene blue, a basic dye of thiazine series using a Fenton-like reaction at normal laboratory temperature and at atmospheric pressure . The effects of different parameters like the initial concentrations of dye, Fe2+, and H2O2, pH of the solution, reaction temperature, and added electrolytes on the oxidation of the dye present in dilute aqueous solution in the concentration range (3.13-9.39)x10(-5)mol dm(-3) (10-30 mg l(-1)) have been assessed . The results indicate that the dye can be most effectively oxidized in aqueous solution at dye:Fe(2+):H2O2 molar ratio of 1:1.15:14.1 . More than 98% removal of the dye could be achieved in 1h in the pH range 2.2-2.6 at 299 K which corresponds to about 81% reduction of the initial COD . The results will be useful for designing the treatment systems of various dye-containing wastewaters.

J Hazard Mater, 2001 Jun 1, 84(1), 29 - 41
Electrocoagulation (EC)--science and applications; Mollah MY et al.; Although electrocoagulation is an evolving technology that is being effectively applied today for wastewater treatment, the paucity of scientific understanding of the complex chemical and physical processes involved is limiting future design and hindering progress . The objective of this review through a survey of the literature is to bring the chemistry and physical processes involved into perspective and to focus attention on those areas critically needing research.

Chemosphere, 2001 May-Jun, 43(4-7), 449 - 54
Application of the new C18 speedisks to the analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans in water and effluent samples; Pujadas E et al.; A recently introduced disk for solid-phase extraction of pollutants from water (C18 Speedisk) has been tested for the analysis of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) . The complete procedure of analysis has been validated with spiked deionized water . The accuracy, expressed as recovery for the sum of 2,3,7,8-substituted congeners . is 92% and the precision, expressed as the RSD of reproducibility, is 5.8% . The limit of detection (LOD), using 2 l of water, is 4.2 pg/l (0.6 pg ITEQ/l) for the sum of 2,3,7,8-substituted congeners . Actually, the C18 Speedisks have substituted the use of other C18 membrane disks in our laboratory because they allow the fast and efficient analysis of samples with high content of suspended material and reduce the time of elution of free-particulate samples . These disks have been successfully applied to the analysis of water from different sources and with very different physical and chemical characteristics: seawater, rain water, an industrial effluent, a landfill leachate and the inlet and chlorinated and non-chlorinated outlet water from a wastewater treatment plant.

Fresenius J Anal Chem, 2001 Apr, 369(7-8), 620 - 8
Identification of photocatalytic degradation products of non-ionic polyethoxylated surfactants in wastewaters by solid-phase extraction followed by liquid chromatography-mass spectrometric detection; Castillo M et al.; The photodegradation of non-ionic surfactants (nonylphenol- and alcohol-polyethoxylates, NPEOx and CnEOx) was investigated in different waters with and without a photoinducter (Fe(III)) . Deionized water and industrial effluent spiked at 0.5 mg/L with C10EO6 and NPEO9 were irradiated using a xenon arc lamp . Aliquots of the test solutions were taken at different time intervals and were preconcentrated using solid phase extraction (SPE) with C18 cartridges . Liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) was used to identify the chemical species generated from phototransformation of non-ionic surfactants . The intermediates detected included nonylphenol diethoxylate (NPEO2) and nonylphenol ethoxy acetic acid (NPE2C) . Much smaller amounts of degradation products of NPEO9 having only the alkyl chain carboxylated were also formed in the photocatalysis experiment . The identified C10EO6 photoproducts included fatty alcohols and acids . Polyethylene glycols (PEGs) were also formed as the consequence of the central scission of C10EO6 and the deethoxylation of NPEO9 . The photodegradation in wastewater samples was more efficient than in deionized water being the half-life (t(1/2)) of C10EO6, 48 h and 29 h in deionized water and wastewater, respectively, and for NPEO9, 17 h and 14 h in deionized water and wastewater, respectively . When induced photodegradation was undertaken, the t(1/2) for NPEO9 was 21 min and 29 min in deionized water and wastewater, respectively . Disappearance of parent compounds was observed after 120 h from the beginning of the photodegradation experiment, or after 210 min of irradiation for the photocatalysis.

Environ Sci Pollut Res Int, 2001, 8(1), 27 - 34
Use of semipermeable membrane devices (SPMDs) . Determination of bioavailable, organic, waterborne contaminants in the industrial region of Bitterfeld, Saxony-Anhalt, Germany; Vrana B et al.; Triolein-containing semipermeable membrane devices (SPMDs) were employed as passive samplers to provide data on the bioavailable fraction of organic, waterborne, organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polynuclear aromatic hydrocarbons (PAHs) in streams flowing through a highly polluted industrial area of Bitterfeld in Saxony-Anhalt, Germany . The contamination of the region with organic pollutants originates in wastewater effluents from the chemical industry, from over one-hundred years of lignite exploitation, and from chemical waste dumps . The main objective was to characterise time-integrated levels of dissolved contaminants, to use them for identification of spatial trends of contamination, and their relationship to potential pollution sources . SPMDs were deployed for 43 days in the summer of 1998 at four sampling sites . The total concentration of pollutants at sampling sites was found to range from a low of 0.8 microgram/SPMD to 25 micrograms/SPMD for PAHs, and from 0.4 microgram/SPMD to 22 micrograms/SPMD for OCPs, respectively . None of the selected PCB congeners was present at quantifiable levels at any sampling site . A point source of water pollution with OCPs and PAHs was identified in the river system considering the total contaminant concentrations and the distribution of individual compounds accumulated by SPMDs at different sampling sites . SPMD-data was also used to estimate average ambient water concentrations of the contaminants at each field site and compared with concentrations measured in bulk water extracts . The truly dissolved or bioavailable portion of contaminants at different sampling sites ranged from 4% to 86% for the PAHs, and from 8% to 18% for the OCPs included in the estimation . The fraction of individual compounds found in the freely dissolved form can be attributed to the range of their hydrophobicity . In comparison with liquid/liquid extraction of water samples, the SPMD method is more suitable for an assessment of the background concentrations of hydrophobic organic contaminants because of substantially lower method quantification limits . Moreover, contaminant residues sequestered by the SPMDs represent an estimation of the dissolved or readily bioavailable concentration of hydrophobic contaminants in water, which is not provided by most analytical approaches.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2001, 36(3), 383 - 93
The biotoxicity and color formation results from ozonation of wastewaters containing phenol and aniline; Shang NC et al.; This study was undertaken to investigate the color forming phenomena and biotoxicity related problems during the initial stage of ozonation in the wastewater containing phenol or aniline . Experimental results indicate that the phenol under alkaline condition and aniline in all pH conditions cause a serious color problem during the period of early initial ozonation . In addition, the ozonated aniline exhibited more severe color formation than the ozonated phenol did . Both of these compounds revealed that either a high compound concentration or low ozone dosage applied incurred a strong color forming phenomena . Moreover, according to the Microtox test, both ozonated byproducts increased the toxicity during early ozonation when the color formation occurred . The EC50-value as COD decreased from 0.72 (for phenol, pH = 7) to 1.38 (for aniline, pH = 4) orders-of-magnitude . This observation implies that the ozonated color formation would generate new toxicity problems if these colored matters were not further oxidized.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2001, 36(3), 321 - 31
Approach to a two-step process of dye wastewater containing acid red B; Xiong Y et al.; The treatment of simulated wastewater containing Acid Scarlet BS was tested with a two-step process that the pretreatment of Fe(II)-mediated decolorization was followed by the electrochemical oxidation with a three-phase three-dimensional electrodes . The experimental results showed that the decolorization mechanism was reductive destruction for the azo group of the dye molecular rather than flocculation or absorption and that the three-phase three-dimensional electrode can effectively reduce COD in the decolorized wastewater simultaneously by several mechanisms such as absorption, air-oxidation, anodic oxidation, cathodic electrogenerated H2O2 and so on . It was also observed that COD for the decolorized wastewater was easier removed as compared with the original dye wastewater, implying that the first and second stage act synergistically to destroy the organic pollutants.

J Environ Sci Health A Tox Hazard Subst Environ Eng, 2001, 36(3), 307 - 20
Industrial wastewater treatment by an advanced oxidation process; Gunukula RV et al.; The overall objective of this study was to evaluate an advanced oxidation process (AOP) used to treat oil and grease (O&G), total petroleum hydrocarbons (TPH), and chemical oxygen demand (COD) of industrial wastewaters generated during barge cleaning operations . This wastewater generally contains appreciable concentrations of O&G, TPH, COD, biochemical oxygen demand (BOD) and benzene, toluene, ethylbenzene and xylene (BTEX) compounds . A bench scale AOP test unit was designed and built for the treatment of the barge cleaning industrial wastewater . The AOP test unit was a 0.33 gpm mobile, modular unit consisting of two contact chambers, two counter current columns and two catalytic chambers . Six experiments were performed using the AOP unit to determine its effectiveness on the reduction of O&G, TPH, and COD . The wastewater was delivered to the AOP from a storage tank . The unit was run for a total of 120 minutes at various gas delivery rates of ozone for each treatment run . Influent and effluent samples were collected at 30 minutes intervals and analyzed for O&G, TPH, and COD . Significant reductions in O&G and TPH concentrations were observed . Oxygen alone indicated a 50% removal efficiency for O&G and TPH . The ozone treatment efficiency was 86% for O&G and TPH at a dosage rate of 12 SCFH and 82% for a dosage rate of 6 SCFH.

Water Res, 2001 Jun, 35(9), 2336 - 40
Characterization and lime treatment of olive mill wastewater; Aktas ES et al.; Seventeen olive mill wastewater (OMW) samples were characterized . For characterization of the samples, amount of total, fixed, volatile, suspended, volatile-suspended solids, COD, oil-grease, polyphenol, volatile phenol, nitrogen and reducing sugar were determined . Effects of lime treatment on the waste samples were investigated . Reduction of contents of the samples treated with the lime was described . The effect of the addition of lime on an artificial phenolic mixture was also examined.

Water Res, 2001 Jun, 35(9), 2179 - 90
Techno-economic evaluation of soil-aquifer treatment using primary effluent at Ahmedabad, India; Nema P et al.; A pilot study was carried out in Sabarmati River bed at Ahmedabad, India for renovation of primary treated municipal wastewater through soil aquifer treatment (SAT) system . The infrastructure for the pilot SAT system comprised of two primary settling basins, two infiltration basins and two production wells located in the centre of infiltration basins for pumping out renovated wastewater . The performance data indicated that SAT has a very good potential for removal of organic pollutants, nutrients as well as bacteria and viruses . The SAT system was found to be more efficient and economical than the conventional wastewater treatment systems and hence recommended for adoption . A salient feature of the study is the introduction of biomat concept and its contribution in the overall treatment process.

Water Res, 2001 Jun, 35(9), 2113 - 20
Nitrogen removal from wastewater by a catalytic oxidation method; Huang TL et al.; The ammonia-containing waste produced in industries is usually characterized by high concentration and high temperature, and is not treatable by biological methods directly . In this study, a hydrophobic Pt/SDB catalyst was first used in a trickle-bed reactor to remove ammonia from wastewater . In the reactor, both stripping and catalytic oxidation occur simultaneously . It was found that higher temperature and higher oxygen partial pressure enhanced the ammonia removal . A reaction pathway, which involves oxidizing ammonia to nitric oxide, which then further reacts with ammonia to produce nitrogen and water, was confirmed . Small amounts of by-products, nitrites and nitrates were also detected in the resultant reaction solution . These compounds came from the absorption of nitrogen oxides . Both the minimum NO2- selectivity and maximum ammonia removal were achieved when the resultant pH of treated water was near 7.5 for a feed of unbuffered ammonia solution.

Can J Microbiol, 2001 Apr, 47(4), 341 - 7
Detection of Legionella pneumophila in bioaerosols by polymerase chain reaction; Pascual L et al.; Most studies focusing on detecting microorganisms in air by polymerase chain reaction (PCR) have used a liquid impinger to sample bioaerosols, mainly because a liquid sample is easy to be processed by PCR analysis . Nevertheless, the use of multiple-hole impactors for the analysis of bioaerosols by PCR has not been reported despite its great utility in culture analysis . In this study we have modified the impaction onto an agar surface sampling method to impaction onto a liquid medium using the MAS-100 air sampler (Merck) (single-stage multiple-hole impactor) . To evaluate the recovery of airborne microorganisms of both sampling methods, a suspension containing Escherichia coli was artificially aerosolized and bioaerosols were collected onto Tergitol-7 agar and phosphate-buffered saline (PBS) with the MAS-100 . A linear regression analysis of the results showed a strong positive correlation between both sampling methods (r = 0.99, slope 0.99, and y intercept 0.07) . Afterwards, the method of impingement into a liquid medium was used to study airborne Legionella pneumophila by PCR . A total of 64 samples were taken at a wastewater treatment plant, a chemical plant, and an office building and analyzed by culture and PCR . Results showed that three samples were positive both by PCR and plate culture, and that nine samples negative by plate culture were positive by PCR, proving that L . pneumophila was present in bioaerosols from these three different environments . The results demonstrate the utility of this single-stage multiple-hole impactor for sampling bioaerosols, both by culture and by PCR.

Environ Sci Technol, 2001 May 1, 35(9), 1798 - 805
Pathogen filtration, heterogeneity, and the potable reuse of wastewater; Redman JA et al.; Filtration is commonly employed in water and wastewater treatment to remove particles and reduce the concentration of microbial pathogens . All physical models of packed-bed filtration are based on a proportional relationship between particle removal per unit depth of bed and the local particle concentration, dC/dz = -C/l, where l is the filtration length scale . Although l is known to vary with time and filter depth for heterogeneous suspensions or "dirty" beds, this paper demonstrates that the filtration rates of even seemingly monodisperse particle suspensions under clean-bed filtration conditions cannot be described with a single filtration length scale . A new model is derived for particle filtration that accounts for heterogeneity at two different spatial scales . Heterogeneity at the scale of the pathogen and/or collector (microscale heterogeneity) leads to a slow power-law decay of contaminant concentration with distance, instead of the fast exponential decay predicted by the standard model . Heterogeneity at the filter scale (macroscale heterogeneity) provides another level of complexity that can be evaluated once microscale heterogeneity effects are characterized . This model for microscale and macroscale heterogeneous particle filtration is verified by filtration experiments on a recombinant analogue of the waterborne pathogen Norwalk virus.

J Environ Monit, 2001 Feb, 3(2), 232 - 7
Identification of surfactant degradation products as toxic organic compounds present in sewage sludge; la Farre M et al.; A cost-effective strategy combining chemical analysis and bioassays for the identification of polar toxic compounds in sewage sludge is reported . ToxAlert 100 bioluminescence inhibition assay was used in combination with chemical analysis involving extraction, clean-up, chromatographic separation and mass spectrometry detection . This methodology was applied to real samples of sludge from three wastewater treatment plants (WWTP) located in Catalonia (Spain) during a 3 month period . In the first step, sewage sludge was lyophilized, treated by sonication with a mixture of methanol and chloroform and finally cleaned up using a sequential solid phase extraction (SSPE) with an octadecylsilica cartridge (C18) in series with a polymeric Lichrolut EN cartridge (Lic EN) . In the second step, the toxicity of each fraction of the sludge sample was investigated using the ToxAlert 100 . The unequivocal identification and quantification of polar organic cytotoxic substances present in the fractionated extracts were determined by liquid chromatography-mass spectrometry (LC-MS) . Major toxic compounds identified were: non-ionic polyethoxylated surfactants (nonylphenol polyethoxylates, alcohol polyethoxylates), their intermediates (polyethylene glycol polyethoxylated, nonylphenol carboxylates and polyethoxylated alcohol carboxylates), linear alkylbenzenesulfonates and heavy metals . The toxic response (in terms of bioluminescence inhibition using ToxAlert 100), defined by the 50% effective concentration (EC50), and the toxicity units (TU) for every standard non-ionic surfactant were calculated . The results provided the identification of polar cytotoxic compounds as well as the evaluation of their contribution to the total toxicity observed in sewage sludge.

Environ Toxicol Chem, 2001 Feb, 20(2), 432 - 41
A probabilistic model for silver bioaccumulation in aquatic systems and assessment of human health risks; Warila J et al.; Silver (Ag) is discharged in wastewater effluents and is also a component in a proposed secondary water disinfectant . A steady-state model was developed to simulate bioaccumulation in aquatic biota and assess ecological and human health risks . Trophic levels included phytoplankton, invertebrates, brown trout, and common carp . Uptake routes included water, food, or sediment . Based on an extensive review of the literature, distributions were derived for most inputs for use in Monte Carlo simulations . Three scenarios represented ranges of dilution and turbidity . Compared with the limited field data available, median estimates of Ag in carp (0.07-2.1 micrograms/g dry weight) were 0.5 to 9 times measured values, and all measurements were within the predicted interquartile range . Median Ag concentrations in biota were ranked invertebrates > phytoplankton > trout > carp . Biotic concentrations were highest for conditions of low dilution and low turbidity . Critical variables included Ag assimilation efficiency, specific feeding rate, and the phytoplankton bioconcentration factor . Bioaccumulation of Ag seems unlikely to result in toxicity to aquatic biota and humans consuming fish . Although the highest predicted Ag concentrations in water (> 200 ng/L) may pose chronic risks to early survival and development of salmonids and risks of argyria to subsistence fishers, these results occur under highly conservative conditions.

Environ Toxicol Chem, 2001 Feb, 20(2), 231 - 8
Linear alkylbenzenes in muscle tissues of white croaker near a large ocean outfall in southern California, USA; Phillips CR et al.; Muscle tissues of a bottom-dwelling marine fish, white croaker (Genyonemus lineatus), collected near a large wastewater outfall in southern California, USA, were analyzed for long-chain linear alkylbenzenes (LABs) . Total LABs (summed concentrations of C11 through C14 isomers) were highest (166-748 ng g-1 wet wt) in individuals collected in the immediate vicinity of the Orange County Sanitation District (OCSD; Fountain Valley, CA, USA) outfall diffuser, whereas relatively lower concentrations occurred in fish from mid-shelf and inshore locations at distances of 2.5 and 5 km, respectively, from the outfall . Fish tissue LAB concentrations were roughly proportional to sediment LAB concentrations at the respective collection sites . The extent of LAB degradation, as determined by ratios of internal to external C12 isomers, did not appear to relate to LAB concentrations or sampling location . Tissue DDT and PCB concentrations were not significantly correlated with LABs and, thus, did not appear to relate to recent exposures to sewage residues from the OCSD discharge . Measurements of LAB concentrations in fish tissues may be widely applicable as a monitoring tool for interpreting exposures to sewage discharges.

Environ Toxicol Chem, 2001 Jan, 20(1), 133 - 9
Analysis of estrogenic hormones in municipal wastewater effluent and surface water using enzyme-linked immunosorbent assay and gas chromatography/tandem mass spectrometry; Huang CH et al.; Although the estrogenic hormones 17 beta-estradiol and 17 alpha-ethinyl estradiol can be quantified in polluted waters by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/tandem mass spectrometry (GC/MS/MS), the compounds often are present at concentrations below detection limits . Enzyme-linked immunosorbent assays (ELISAs) provide a sensitive and robust means of quantifying estrogenic hormones in wastewater effluents and surface waters . Results from ELISA analysis of estrogenic hormones in secondary wastewater effluent indicate concentrations comparable to those that cause vitellogenesis in fish . Confirmatory analyses by GC/MS/MS are consistent with ELISA results . Effluent filtration, using sand filtration or microfiltration, removes approx . 70% of the hormones from secondary effluent, while advanced treatment, using reverse osmosis, removes more than 95% of hormones . The detection limits for estrogenic hormones are approx . 0.1 ng/L in wastewater effluent and 0.05 ng/L in surface water . The ELISA technique provides a relatively simple and practical method of assessing the fate of estrogenic hormones in engineered and natural systems.

J Hazard Mater, 2001 May 30, 83(3), 255 - 64
Oxidation of p-hydroxybenzoic acid by UV radiation and by TiO2/UV radiation: comparison and modelling of reaction kinetic; De Heredia JB et al.; The phenolic compound p-hydroxybenzoic acid is very common in a great variety of agroindustrial wastewaters (olive oil and table olive industries, distilleries) . The objective of this work was to study the photocatalytic activity of TiO2 towards the decomposition of p-hydroxybenzoic acid . In order to demonstrate the greater oxidizing power of the photocatalytic system and to quantify the additional levels of degradation attained, we performed experiments on the oxidation of p-hydroxybenzoic acid by UV radiation alone and by the TiO2/UV radiation combination . A kinetic model is applied for the photooxidation by UV radiation and by the TiO(2)/UV system . Experimental results indicated that the kinetics for both oxidation processes can be fitted well by a pseudo-first-order kinetic model . The second oxidation process can be explained in terms of the Langmuir-Hinshelwood kinetic model . The values of the adsorption equilibrium constant, K(pHB), and the second order kinetic rate constant, k(c), were 0.37 ppm(-1) and 6.99 ppm min(-1), respectively . Finally, a comparison between the kinetic rate constants for two oxidation systems reveals that the constants for the TiO2/UV system are clearly greater (between 220-435%) than those obtained in the direct UV photooxidation.

Environ Sci Technol, 2001 Mar 15, 35(6), 1223 - 30
Derivatization LC/MS for the simultaneous determination of fatty alcohol and alcohol ethoxylate surfactants in water and wastewater samples; Dunphy JC et al.; A new LC/MS method has been developed for the simultaneous measurement, in water and wastewater samples, of all species contained in commercial samples of linear type of alcohol ethoxylate (AE) surfactants including fatty alcohols . The method requires derivatization of the terminal hydroxyl of each surfactant species with 2-fluoro-N-methylpyridinium p-toluenesulfonate, which imparts a permanent cationic charge, allowing all species including the fatty alcohols and those with only one ethoxylate to be effectively detected by electrospray MS . Detection limits of typically <10 ppt for each individual species were attained in treated wastewater, in which total AE concentrations (combination of up to 114 individual species) are not expected to exceed 10 ppb . The method was validated for clean water as well as sewage influent and effluent samples.

Environ Sci Technol, 2001 Jan 15, 35(2), 365 - 73
Chemical equilibria model of strontium-90 adsorption and transport in soil in response to dynamic alkaline conditions; Spalding BP et al.; Strontium-90 is a major hazardous contaminant of radioactive wastewater and its processing sludges at many Department of Energy (DOE) facilities . In the past, such contaminated wastewater and sludge have been disposed in soil seepage pits, lagoons, or cribs often under highly perturbed alkaline conditions (pH > 12) where 90Sr solubility is low and its adsorption to surrounding soil is high . As natural weathering returns these soils to near-neutral or slightly acidic conditions, the adsorbed and precipitated calcium and magnesium phases, in which 90Sr is carried, change significantly in both nature and amounts . No comprehensive computational method has been formulated previously to quantitatively simulate the dynamics of 90Sr in the soil-groundwater environment under such dynamic and wide-ranging conditions . A computational code, the Hydrologic Utility Model for Demonstrating Integrated Nuclear Geochemical Environmental Responses (HUMDINGER), was composed to describe the changing equilibria of 90Sr in soil based on its causative chemical reactions including soil buffering, pH-dependent cation-exchange capacity, cation selectivity, and the precipitation/dissolution of calcium carbonate, calcium hydroxide, and magnesium hydroxide in response to leaching groundwater characteristics including pH, acid-neutralizing capacity, dissolved cations, and inorganic carbonate species . The code includes a simulation of one-dimensional transport of 90Sr through a soil column as a series of soil mixing cells where the equilibrium soluble output from one cell is applied to the next cell . Unamended soil leaching and highly alkaline soil treatments, including potassium hydroxide, sodium silicate, and sodium aluminate, were simulated and compared with experimental findings using large (10 kg) soil columns that were leached with 90Sr-contaminated groundwater after treatment . HUMDINGER's simulations were in good agreement with dynamic experimental observations of soil exchange capacity, exchangeable cations, total 90Sr, and pH values of layers within the soil columns and of column effluents.

Environ Technol, 2001 Mar, 22(3), 331 - 7
A pilot-scale study of tertiary treatment of Jizhuangzi wastewater treatment plant by continuous preozonation-microflocculation-filtration process; Lu SG et al.; A pilot-scale study of tertiary wastewater treatment of the JIZHUANGZI Municipal Wastewater Treatment Plant was carried out by preozonation, coagulation and direct filtration process with the aim of producing wastewater suitable for reuse . The proposed treatment scheme could produce a filtered water with lower turbidity, COD(Cr) and colour at lower ozone and coagulant dosages . Ozone was added into the mixing tank with coagulant simultaneously and postozonation was not cost effective . With the increase of ozone dosage, better COD(Cr) and colour removals were observed especially at the ozone dosage between 0.7-1.0 mg l(-1) . Similarly, increasing ferric sulphate dosage resulted in better removals of turbidity, COD(Cr) and colour in the filtered water . In contrast, increasing polymer T-80 dosage seemed to improve colour removal rather than turbidity and COD(Cr) . To achieve removal efficiency of 70% for turbidity, 45% for COD(Cr) and over 60% for colour, the optimum dosages of ozone, ferric sulphate and polymer T-80 should be 0.7-1.0 mg l(-1), 10.0-12.5 mg l(-1) and 0.7-1.0 mg l(-1), respectively.

Environ Int, 2000 Aug, 26(1-2), 63 - 8
Investigation of a ponding irrigation system to recycle agricultural wastewater; Chen PH et al.; This article presents the results of natural carrying capacity of ponding irrigation system in Taoyuan agricultural zone, Taiwan . Both the systematic water quality and the ponding effects were examined . The ponding irrigation system included a flow channel and storage ponds . The data showed that most water characteristics deteriorated gradually from upper- to down-stream in the flow channel and the flow channel was not attributed to any self-purification in agricultural returning water practically . On the other hand, the results of storage ponds indicated that they can provide a natural treatment (i.e., the outlet water quality of the ponds is more desirable than that of the inlet) . Consequently, the ponding irrigation system offers the natural self-purification in ponds to reuse and recycle the returning agricultural wastewater and to extend the irrigation capacity and efficiency.

Mutat Res, 2001 Feb 20, 490(2), 209 - 14
Detection of DNA damage in haemocytes of zebra mussel using comet assay; Pavlica M et al.; The aim of the study was to use the comet assay on haemocytes of freshwater mussel, Dreissena polymorpha Pallas, for detection of possible DNA damage after exposure to pentachlorophenol (PCP) and to evaluate the potential application of the comet assay on mussel haemocytes for genotoxicity monitoring of freshwater environment . Zebra mussels were exposed for seven days to different concentrations (10, 80, 100, 150 microg/l) of PCP and in the river Sava downstream from Zagreb municipal wastewater outlet . Significant increase in DNA damage was observed after exposure to PCP at doses of 80 microg/l and higher and after in situ exposure in the river Sava as well . This study confirmed that the comet assay applied on zebra mussel haemocytes may be a useful tool in determining the potential genotoxicity of water pollutants.

Environ Int, 2001 Jan, 26(3), 189 - 95
Treatment of wastewater by natural systems; Ayaz SC et al.; Experimental results from a pilot-scale constructed wetland (CW) treatment plant have been described . The study was conducted at two different systems: continuous and batch . In the continuous system, the treatment yields were monitored in different loading conditions in 1-year period . The pilot plant consists of two serially connected tanks settled up with fillers; Cyperus was used as treatment media and wastewater between the two tanks was recycled periodically . Chemical oxygen demand (COD) and suspended solid (SS) removal efficiencies were obtained as 90% and 95%, respectively . The effluent COD concentration at an average loading of 122 g COD/m2 day was satisfactory for the Turkish Water Pollution Control Regulation . This means that a 0.8 m2 of garden area per person is required . Other removal values for the same conditions were as follows: total Kjeldahl nitrogen (TKN) was 77%, total nitrogen (TN) was 61%, and PO4(3-) -P was 39% . The batch experimental systems consist of 12 pairs of serially connected tanks, with each pair having a surface area of 1 m2 . Each set was filled with sewage once a day, and the wastewater between the paired tanks was recycled periodically by the pump . Each pair of tanks was filled with materials such as gravel, peat, and perlite . Seven of them were vegetated with Phragmites, Cyperus, Rush, Iris, Lolium, Canna, and Paspalum, while the other five were not seeded . The best performances were obtained by Iris for COD (% 94), by Canna for ammonia nitrogen (% 98), and by Iris for total nitrogen (% 90) and phosphorus (% 55) removal.

Environ Int, 2001 Jan, 26(3), 157 - 61
Towards a clean Izmit Bay; Morkoc E et al.; The elongated semi-enclosed Bay of Izmit, which receives both domestic and industrial wastes, has been monitored by measuring its physical and biochemical parameters for 2 years, 1994-1995 . It is clear that there are two distinct water masses . The upper layer has been occupied by the less saline (22-26 ppt) waters of the Black Sea origin; whereas the lower layer contains saline (38.5 ppt) Mediterranean waters . The seasonal variations in the biochemical characteristics were dependent on the bay's two-layer flow system . If one considers the distribution of transparency in the upper bay waters, it has been observed that the Secchi disk depth (SDD) decreases from west to east . Furthermore, these depths are limited by the high primary productivity associated with the low concentrations of nutrients observed during the spring . Discharges of wastes into the surface waters significantly affect the biological production and oxygen consumption in the lower layer . Within the last 10 years, 80% of organic matter has been removed from industrial wastewater . However, organic loads from the domestic wastewaters have doubled because of the growth in the surrounding population . Fortunately, as a result, the total organic loads in the bay have not changed significantly within the last 10 years.

Analyst, 2001 Apr, 126(4), 469 - 71
Headspace gas chromatographic determination of 2-alkyl-5,5-dimethyl-1,3-dioxane derivatives in wastewaters of a polyester resin plant; Franchini M et al.; The static headspace gas chromatographic technique can be conveniently employed to check the presence and amount of the odorous side-products, 2-R-1,3-dioxanes (R = H, CH3, C2H5, i-C3H7, n-C3H7), directly from the wastewaters flowing from the reactors during the synthesis of polyester resins . By the optimisation of a simple and direct analytical method, the amounts of these compounds may be continuously monitored and controlled . This method is characterized by good repeatability (3-4%) and does not seem to suffer from matrix effects . The detection limits for the determination of the five dioxanes fall in the range 400-700 micrograms dm-3 (alpha = beta = 0.05).

Environ Toxicol, 2001, 16(2), 158 - 71
Interlaboratory study for the validation of an ecotoxicological procedure to monitor the quality of septic sludge received at a wastewater treatment plant; Robidoux PY et al.; Septic tank sludge is regularly hauled to the Montreal Urban Community (MUC) wastewater treatment plant . It is then discharged and mixed with the wastewater inflow before entering the primary chemical treatment process . An ecotoxicological procedure integrating chemical and toxicological analyses has been recently developed and applied to screen for the illicit discharge of toxic substances in septic sludge . The toxicity tests used were the Microtox, the bacterial-respiration, and the lettuce (Lactuca sativa) root elongation tests . In order to validate the applicability of the proposed procedure, a two-year interlaboratory study was carried out . In general, the results obtained by two independent laboratories (MUC and the Centre d'expertise en analyse environnementale du Quebec) were comparable and reproducible . Some differences were found using the Microtox test . Organic (e.g., phenol and formaldehyde) and inorganic (e.g., nickel and cyanide) spiked septic sludge were detected with good reliability and high efficiency . The relative efficiency to detect spiked substances was > 70% and confirms the results of previous studies . In addition, the respiration test was the most efficient toxicological tool to detect spiked substances, whereas the Microtox was the least efficient (< 15%) . Efficiencies to detect spiked contaminants were also similar for both laboratories . These results support previous data presented earlier and contribute to the validation of the ecotoxicological procedure used by the MUC to screen toxicity in septic sludge.

Water Res, 2001 Jun, 35(8), 2078 - 80
On the degradability of printing and dyeing wastewater by wet air oxidation; Hu X et al.; A modified first-order kinetics model was used to study the wet air oxidation of printing and dyeing wastewater . The model simulations are in good agreement with experimental data . The results indicate that a certain fraction of organic pollutants in the printing and dyeing wastewater could not be removed even at elevated temperature and prolonged reaction time . The ratio of degradable organic matter is found independent of temperature and can be improved by using a catalyst.

Bioresour Technol, 2001 Jun, 78(2), 217 - 9
The adsorption of Congo red and vacuum pump oil by rice hull ash; Chou KS et al.; Rice hull ash (RHA) of large surface area was obtained by acid wash and then calcination at 600 degrees C for 4 h . The white ash was then mixed with kaolin and starch to make pellet adsorbents with reasonable strength to be utilized in a packed column . Both ash and pellet samples showed good adsorption capacities toward the organic substances in wastewater . Furthermore, the surface nature of the white ash and pellet adsorbent could be modified through either hydration or esterification reactions . Corresponding changes in silanol concentrations were successfully correlated to changes in adsorption capacity toward either Congo red or vacuum pump oil molecules.

Bioresour Technol, 2001 Jun, 78(2), 161 - 4
Nitrogen budget in Scenedesmus obliquus cultures with artificial wastewater; Nunez VJ et al.; Semicontinuous cultures of Scenedesmus obliquus in artificial wastewater, recycled into proteins about 33% and 25% of the dissolved nitrogen missing from the medium 24 h after harvesting 50% and 70% of the culture, and replacing the volume harvested with fresh medium . The residual dissolved nitrogen concentrations were 25% and 43% of the initial, respectively, with an imbalance in the mass budget close to 17 and 20 mg N l(-1) d-1 . Most or all the nitrogen missing was found in an ammonia trap located at the air vent of the closed cultures, showing that an important role of microalgae in wastewater treatment is that of favouring NH3 stripping due to the photosynthesis-induced pH increases.

Bioresour Technol, 2001 Jun, 78(2), 155 - 60
A further study of the anaerobic biotreatment of malt whisky distillery pot ale using an UASB system; Goodwin JA et al.; Pot ale from a pilot-scale malt whisky distillery was treated using a mesophilic upflow anaerobic sludge blanket (UASB) digester . Stable operation was observed at organic loading rates (OLRs) of 5.46 kg COD/m3 day or less when the pot ale was diluted with tap water . Digester failure occurred when undiluted pot ale was used, even though OLR was less than 5 kg COD/m3 day . Overall performance was worse than that observed previously when UASB digesters were used to treat pot ale from a different source supplemented with trace elements . A substantial proportion of effluent chemical oxygen demand (COD) was present as volatile fatty acids (VFA), particularly during periods of reactor stress, indicating that overall performance was limited by the rate of VFA conversion . Wastewater alkalinity rose during digestion . The sludge which developed in the reactor was flocculent but did not form compact granules.

Bioresour Technol, 2001 Jun, 78(2), 133 - 9
Removal of selected metal ions from aqueous solution using modified corncobs; Vaughan T et al.; The objective of this study was to convert corncobs to metal ion adsorbents for wastewater treatment . Ground corncobs were modified with either 0.6 M citric acid (CA) or 1.0 M phosphoric acid (PA) to help improve their natural adsorption capacity . The effect of a combination of wash and modification treatment was tested for corncob adsorption efficiency with five different metal ions (cadmium, copper, lead, nickel, zinc) individually or in a mixed solution containing each metal at a 20 mM concentration . Results were compared to those of commercial resins Amberlite IRC-718, Amberlite 200, Duolite GT-73 and carboxymethylcellulose (CMC) . Modified corncobs showed the same adsorption efficiency as Duolite GT-73 for cadmium, copper, nickel and zinc ions and had greater adsorption than CMC for nickel and zinc ions . For mixed metals, the modified corncobs exhibited the same adsorption efficiency as Duolite GT-73 for cadmium and copper ions and the same or higher adsorption than Amberlite IRC-718 for lead ions . Adsorption capacities of modified samples were compared to those of Amberlite IRC-718, Amberlite 200 and Duolite GT-73 . Commercial resins generally had higher adsorption capacities than modified corncobs . However, the adsorption capacity of modified corncobs for copper and lead ions was equivalent to Duolite GT-73, but was lower than for Amberlite IRC-718 or Amberlite 200 . Depending on the specific metal ion and the presence or absence of other metal ions, chemically modified corncobs were at least equivalent in adsorption properties to all of the commercial cation exchange resins examined in this study.

Environ Technol, 2001 Apr, 22(4), 463 - 76
Full scale UASB reactor performance in the brewery industry; Ahn YH et al.; In this paper the 7 year experience of the Oriental Breweries, located in Kumi, Korea utilizing a full-scale upflow anaerobic sludge blanket (UASB) reactor for the anaerobic pretreatment of brewery wastewater is presented . The anaerobic pretreatment system selected has successfully achieved the desired treatment efficiency for the brewery wastewater during that period and it has also continued operation even with low wastewater concentrations (average CODcr 1,400 mg l-1) and lower flow rates than specified by the design parameters . The CODcr removal of the UASB reactor averaged over 80% throughout the entire period, incurring normal running expenses of only $0.20-0.31 m-3 of treated water . In addition a further economical feature of the process was the utilization of the gas digester production as the municipal gas source, reducing total operating expenses around 30 to 45% and costing the plant only $0.1 m-3 . Maintenance of good granule production, which is always a key issue in operating UASB systems, was not possible by this installation, however, so frequent expensive reseeding of the reactor was often necessary due to biomass washout . The full scale and lab scale research revealed that underloading can be as detrimental as overloading, due to excessively long retention time in the UASB system for the overall operating period and to excessive pre-acidification and/or incorrect reactor configuration of the completely mixed type . To enhance the sludge granulation, therefore, the installation of a pre-acidification reactor in the UASB system treating easily biodegradable substrates such as brewery wastewater is not necessary because adequate pre-acidification can occur in the equalization tank.

Environ Technol, 2001 Apr, 22(4), 397 - 408
Effect of operating parameters on anoxic biological phosphorus removal in anaerobic anoxic sequencing batch reactor; Merzouki M et al.; Optimizing anoxic biological phosphorus removal in the anaerobic-anoxic sequencing batch reactor (A2 SBR) was observed to depend greatly on three parameters: the amount of added nitrate, the sludge retention time (SRT) and the phosphorus/carbon feeding ratio (P/C, wt/wt) . The concentration of 120 mg N-NO3 l-1 in the anoxic medium corresponding to 800 mg COD l-1 acetic acid and 60 mg P-PO4 l-1 in the synthetic wastewater, the SRT of 15 days and the P/C feeding ratio of 20/100 were determined as optimal for complete phosphorus removal in the A2 SBR . The acetate uptake, the phosphorus release and the phosphorus removal increased with the P/C feeding ratio and the phosphorus sludge content (Ps) . The polyphosphate-accumulating organisms (PAO) were dominant under operation at all P/C feeding ratios tested except 2/100 . At a P/C feeding ratio of 20/100, PAO could accumulate a high content of polyphosphate compared with other P/C ratios . In contrast, the P/C ratio of 2/100 caused a decrease in the polyphosphate content in PAO, the deterioration of enhanced biological phosphorus removal (EBPR) activity, and the dominance of glycogen-accumulating organisms (GAO) . This study was completed by microscopic observations which revealed three morphological types of PAO . This is the first time that an oval form of PAO could be observed in the A2 SBR.

Water Res, 2001 May, 35(7), 1739 - 47
Development of anaerobic migrating blanket reactor (AMBR), a novel anaerobic treatment system; Angenent LT et al.; A novel anaerobic treatment system, the anaerobic migrating blanket reactor (AMBR), was developed after completing a parallel study with upflow anaerobic sludge blanket (UASB) and anaerobic sequencing batch reactor (ASBR) processes . Using sucrose as the main component of a synthetic wastewater, the AMBR achieved a maximum chemical oxygen demand (COD) loading rate of 30 g.l-1.day-1 at a 12-h hydraulic retention time (HRT) . This resulted in a standard methane production rate (SMPR) of 6.51.l-1.day-1 and an average methane-based COD (MCOD) removal efficiency of 62.2% . A key element in granular biomass formation was migration of the biomass blanket through the reactor . Although a carbohydrate-rich wastewater was used, no separate pre-acidification was required for the AMBR, because of high mixing intensities and wash out of acidogenic bacteria . In contrast, the absence of pre-acidification created "bulking" problems (caused by abundant acidogenic bacteria at the surface of granules) in a UASB reactor, operated under conditions similar to that of the AMBR . As a result, a maximum COD loading rate and SMPR of 21 g.l-1.day-1 and 4.91.l-1.day-1 were achieved, respectively, for the UASB reactor at a 12-h HRT . These values were 18 g.l-1.day-1 and 3.71.l-1.day-1, respectively, for an ASBR at a 12-h HRT . Hence, the performance of the AMBR in treating a carbohydrate-rich wastewater was found to be superior in terms of maximum loading rate and SMPR.

Water Res, 2001 May, 35(7), 1723 - 9
Variation of bulk properties of anaerobic granules with wastewater type; Batstone DJ et al.; Development of a granular sludge with high strength, high biological activity and a narrow settling distribution is necessary for optimal operation of high-rate upflow anaerobic treatment systems . Several studies have compared granules produced from different wastewaters but these have largely been from laboratory-fed reactors or compared granules from full-scale reactors fed similar wastewater types . Though two authors have commented on the inferiority of granules produced by a protein-based feed, the properties of these granules have not been characterised . In this paper, granules from full-scale reactors treating fruit and vegetable cannery effluent, two brewery effluents and a pig abattoir (slaughterhouse) were compared in terms of basic composition, size distribution, density, settling velocity, shear strength, and EPS content . The results supported previous qualitative observations by other researchers that indicate granule properties depend more on wastewater type rather than reactor design or operating conditions such as pre-acidification level . The cannery-fed granules had excellent shear strength, settling distribution and density . Granules from the two brewery-fed reactors had statistically the same bulk properties, which were still acceptable for upflow applications . The protein-grown granule had poor strength and settling velocity.

Water Res, 2001 May, 35(7), 1649 - 58
Comparison of methods for determination of microbial biomass in wastewater; Vollertsen J et al.; Microbial biomass in wastewater was determined by methods used in environmental microbiology and by a method used in wastewater engineering based on a conceptual model simulating fundamental microbial processes in wastewater from measured oxygen uptake rates . The methods originating from environmental microbiology are based on staining and counting of cells for the determination of total cell biomass (acridine orange and DAPI), physiological state of cells (LIVE/DEAD BacLight) and activity of cells (reduction of the redox dye CTC and microautoradiography) . Depending on the staining method applied, cell biomasses yielded 15-86% of the biomass defined by the model, and good correlations between cell biomass and model biomass were found . Cell biomass, oxygen uptake and acetate uptake were measured in wastewater, where acetate was added . Substrate uptake rates were found not to be proportional to the increases in cell biomass, suggesting that only a small fraction of the cell biomass was responsible for the main part of the substrate uptake . Despite the differences found between cell biomass and model biomass, it was recommended to use the conceptual model as an engineering tool for simulation of microbial processes and wastewater quality changes . However, there should be a clear distinction between the terms 'model biomass', 'cell biomass' and different activity measurements of cells.

J AOAC Int, 2001 Mar-Apr, 84(2), 383 - 91
Determination of phthalates in crude extracts of sewage sludges by high-resolution capillary gas chromatography with mass spectrometric detection; Berset JD et al.; A simple solvent extraction by ethyl acetate without subsequent cleanup was used to determine 16 phthalic acid esters (PAEs), including bis(2-ethylhexyl) phthalate (DEHP), in sewage sludge samples from different catchment areas . The compounds were separated on a gas chromatographic capillary column with a nonpolar HT-8 stationary phase . For most of the PAEs, internal standard quantification with deuterated dibutyl phthalate (DBP) and deuterated DEHP was best achieved by using electron ionization mass spectrometry in the selected-ion monitoring mode . Because of its high concentrations in the sludges, DEHP was quantified in the full-scan acquisition mode . Molecular weight and ester-type information for the PAEs was obtained in the positive chemical ionization mode with methane as the reagent gas . Finally, selected sewage sludges containing different amounts of industrial wastewater were analyzed by the proposed method . DEHP was the most abundant compound found at 21-114 mg/kg x dm, followed by the lower-molecular weight PAEs diethyl phthalate, diisobutyl phthalate, and DBP and the higher-molecular weight compounds butylbenzyl phthalate, dicyclohexyl phthalate, di-n-octyl phthalate, and dinonyl phthalate, which were present mostly at <1 mg/kg x dm.

Anal Chem, 2001 Apr 1, 73(7), 1515 - 20
High-temperature, microwave-assisted UV digestion: a promising sample preparation technique for trace element analysis; Florian D et al.; A novel, microwave-assisted, high-temperature UV digestion procedure was developed for the accelerated decomposition of interfering dissolved organic carbon (DOC) prior to trace element analysis of liquid samples such as, industrial/municipal wastewater, groundwater, and surface water, body fluids, infusions, beverages, and sewage . The technique is based on a closed, pressurized, microwave digestion device . UV irradiation is generated by immersed electrodeless Cd discharge lamps (228 nm) operated by the microwave field in the oven cavity . To enhance excitation efficiency an antenna was fixed on top of the microwave lamp . The established immersion system enables maximum reaction temperatures up to 250-280 degrees C, resulting in a tremendous increase of mineralization efficiency . Compared to open UV digestion devices, decomposition time is reduced by a factor of 5 and the maximum initial concentration of DOC can be raised by at least a factor of 50 . The system's performance on a real-type sample was evaluated for the mineralization of skimmed milk (IRMM, CRM 151) and subsequent determination of trace elements using standard spectroscopic techniques . Recovery for Cd (109%), Cu (112%), Fe (99%), and Pb (96%) showed good agreement with the 95% confidence interval of the certified values.

Water Res, 2001 Apr, 35(6), 1552 - 62
Factors affecting the performance of stormwater treatment wetlands; Carleton JN et al.; Data from 35 studies on 49 wetland systems used to treat stormwater runoff or runoff-impacted surface waters were examined and compared in order to identify any obvious trends that may aid future stormwater treatment wetland design efforts . Despite the intermittent nature of hydrologic and pollutant inputs from stormwater runoff, our analysis demonstrates that steady-state first-order plug-flow models commonly used to analyze wastewater treatment wetlands can be adapted for use with stormwater wetlands . Long-term pollutant removals are analyzed as functions of long-term mean hydraulic loading rate and nominal detention time . First-order removal rate constants for total phosphorus, ammonia, and nitrate generated in this fashion are demonstrated to be similar to values reported in the literature for wastewater treatment wetlands . Constituent removals are also demonstrated via regression analyses to be functions of the ratio of wetland area to watershed area . Resulting equations between these variables can be used as preliminary design tools in the absence of more site-specific details, with the understanding that they should be employed cautiously.

Bioresour Technol, 2001 Jan, 76(1), 67 - 70
Biosorption of cadmium(II), lead (II) and copper(II) with the filamentous fungus Phanerochaete chrysosporium; Say R et al.; The biosorption from artificial wastewaters of heavy metals (Cd(II), Pb(II) and Cu(II)) onto the dry fungal biomass of Phanerochaete chryosporium was studied in the concentration range of 5-500 mg l(-1) . The maximum absorption of different heavy metal ions on the fungal biomass was obtained at pH 6.0 and the biosorption equilibrium was established after about 6 h . The experimental biosorption data for Cd(II), Pb(II) and Cu(II) ions were in good agreement with those calculated by the Langmuir model.

Bioresour Technol, 2001 Jan, 76(1), 63 - 5
Removal of heavy metals from industrial wastewaters by adsorption onto activated carbon prepared from an agricultural solid waste; Kadirvelu K et al.; Activated carbon was prepared from coirpith by a chemical activation method and characterized . The adsorption of toxic heavy metals, Hg(II), Pb(II), Cd(II), Ni(II), and Cu(II) was studied using synthetic solutions and was reported elsewhere . In the present work the adsorption of toxic heavy metals from industrial wastewaters onto coirpith carbon was studied . The percent adsorption increased with increase in pH from 2 to 6 and remained constant up to 10 . As coirpith is discarded as waste from coir processing industries, the resulting carbon is expected to be an economical product for the removal of toxic heavy metals from industrial wastewaters.

Bioresour Technol, 2001 Jan, 76(1), 45 - 52
Performance evaluation of a mesophilic anaerobic fluidized-bed reactor treating wastewater derived from the production of proteins from extracted sunflower flour; Borja R et al.; A study of the anaerobic digestion of wastewater derived from the production of protein isolates from extracted sunflower flour was carried out in a laboratory-scale, mesophilic (35 degrees C) fluidized-bed reactor with saponite as bacterial support . Chemical oxygen demand (COD) removal efficiencies in the range of 98.3-80.0% were achieved in the reactor at organic loading rates (OLR) of between 0.6 and 9.3 g COD/I d, hydraulic retention times (HRT) of between 20.0 and 1.1 d and average feed COD concentration of 10.6 g/l . Eighty percent of feed COD could be removed up to OLR of 9.3 g COD/l d . The yield coefficient of methane production was 0.33 l of methane (at STP) per gram of COD removed and was virtually independent of the OLR applied . Because the buffering capacity of the experimental system was maintained at favorable levels with excess total alkalinity present at all loadings, the rate of methanogenesis was not affected by loading . The experimental data indicated that a total alkalinity in the range of 2,000-2,460 mg/l as CaCO3 was sufficient to prevent the pH from dropping to below 7.0 for OLR of up to 9.3 g COD/l d . The volatile fatty acid (VFA) levels and the VFA/alkalinity ratio were lower than the suggested limits for digester failure (0.3-0.4) for OLR and HRT up to 9.3 g COD/l d and 1.1 d, respectively . For a HRT of 0.87 d (OLR of 12.1 g COD/l d) the start of acidification was observed in the reactor.

J Agric Food Chem, 2001 Mar, 49(3), 1309 - 14
Efficiency of rice bran for removal of organochlorine compounds and benzene from industrial wastewater; Adachi A et al.; Rice bran was found to effectively adsorb several organic compounds, such as dichloromethane, chloroform, carbon tetrachloride, trichloroethylene, tetrachloroethylene, and benzene . Equilibrium adsorption isotherms conformed to the Freundlich type (log-log linear) . The adsorption of dichloromethane and chloroform by rice bran was observed over the range of pH 1-11 . Therefore, rice bran is applicable for treatment of wastewater over a wide pH range . Dichloromethane was successfully removed from water samples with an average removal efficiency of 70% after 60 min when rice bran was added to water samples containing from 0.006 to 100 mg/L dichloromethane . The removal of these organochlorine compounds and benzene by rice bran was attributed to the uptake by intracellular particles called spherosomes . Here, we report the results of a fundamental study of the efficiency of rice bran for removal of organochlorine compounds and benzene using a batch system on the laboratory scale, and describe elucidation of the mechanism of removal of these compounds by rice bran.

J Agric Food Chem, 2001 Apr, 49(4), 1873 - 80
Treatment of olive oil mill wastewater by Fenton's reagent; Rivas FJ et al.; Wastewater from olive oil mills has been treated by means of the Fe(II)/H(2)O(2) system (Fenton's reagent) . Typical operating variables such as reagent concentration (C(H(2)O(2)) = 1.0--0.2 M; C(Fe(II)) = 0.01--0.1 M) and temperature (T = 293--323 K) exerted a positive influence on the chemical oxygen demand and total carbon removal . The optimum working pH was found to be in the range 2.5--3.0 . The exothermic nature of the process involved a significant increase of the temperature of the reaction media . The process was well simulated by a semiempirical reaction mechanism based on the classic Fenton chemistry . From the model, the reaction between ferric iron and hydrogen peroxide {k = 1.8 x 10(15) exp((-12,577 +/- 1248)/T)} was suggested to be the controlling step of the system . Also, the simultaneous inefficient decomposition of hydrogen peroxide {k = 6.3 x 10(12) exp((-11,987 +/- 2414)/T)} into water and oxygen was believed to play an important role in the process . On the basis of stoichiometric calculations for hydrogen peroxide consumption, an estimation of the process economy has been completed.

Appl Biochem Biotechnol, 2001 Feb, 90(2), 107 - 24
One- and two-stage upflow anaerobic sludge-bed reactor pretreatment of winery wastewater at 4-10 degreesC; Kalyuzhnyi SV et al.; The operating performance of a single and two (in series) laboratory upflow anaerobic sludge-bed (UASB) reactors (2.7-L working volume, recycle ratio varied from 1:1 to 1:18) treating diluted wine vinasse was investigated under psychrophilic conditions (4-10 degreesC) . For a single UASB reactor seeded with granular sludge, the average organic loading rates (OLRs) applied were 4.7, 3.7, and 1.7 g of chemical oxygen demand (COD)/(L.d) (hydraulic retention times {HRTs} were about 1 d) at 9-11, 6 to 7, and 4 to 5 degreesC, respectively . The average total COD removal for preacidified vinasse wastewater was about 60% for all the temperature regimes tested . For two UASB reactors in series, the average total COD removal for treatment of non-preacidified wastewater exceeded 70% (the average OLRs for a whole system were 2.2, 1.8, and 1.3 g of COD/{L.d} under HRTs of 2 d at 10, 7, and 4 degreesC, respectively) . In situ determinations of kinetic sludge characteristics (apparent Vm and Km) revealed the existence of substantial mass transfer limitations for the soluble substrates inside the reactor sludge bed . Therefore, application of higher recycle ratios is essential for enhancement of UASB pretreatment under psychrophilic conditions . The produced anaerobic effluents were shown to be efficiently posttreated aerobically: final effluent COD concentrations were about 0.1 g/L . Successful operation of the UASB reactors at quite low temperatures (4-10 degreesC) opens some perspectives for application of high-rate anaerobic pretreatment at ambient temperatures.

J Contam Hydrol, 2001 Jan, 47(1), 85 - 104
Multicomponent simulation of wastewater-derived nitrogen and carbon in shallow unconfined aquifers . II . Model application to a field site; MacQuarrie KT et al.; A multicomponent reactive transport model as presented by MacQuarrie and Sudicky {MacQuarrie, K.T.B., Sudicky, E.A., this volume . Multicomponent simulation of wastewater-derived nitrogen and carbon in shallow unconfined aquifers: I . Model formulation and performance, J . Contam . Hydrol.} is applied to a well-studied wastewater plume in a sandy aquifer near Cambridge, Ontario . Domestic wastewater is released into the unsaturated zone via a drain field at a depth of about 0.8 m . The physical transport parameters for the model are obtained by simulating a non-reactive solute, while kinetic input data for the nitrogen and carbon reaction network are obtained from the literature . The model shows that the wastewater-loading rate has little influence on the moisture content in the unsaturated zone, thus oxygen diffusion in the air phase is an important transport mechanism . The model results are in general agreement with the field-determined moisture and oxygen profiles near the drain field . The simulation results show that oxidation of ammonium and dissolved organic carbon (DOC) goes to completion in the 1.5-m distance between the drain field and the water table, and that calcite dissolution limits the pH reduction to about 0.2 units . The model-predicted nitrate concentrations in the core of the plume are in the range of 20-25 mg N/l and are in good agreement with the field data . Overall, the results for the major reactive species from the model simulation agree well with the geochemical data obtained below the drain field and it is concluded that the major physical and biochemical processes have been correctly captured in the current model formulation.

Environ Technol, 2001 Jan, 22(1), 75 - 82
Effects of pretreatment on physical and ion exchange properties of natural clinoptilolite; Inglezakis VJ et al.; Four pretreatment procedures have been applied to natural clinoptilolite to establish the influence of the pretreatment process on the properties of the material under investigation . Modification of material properties is imposed for its use in wastewater treatment via ion exchange processes . Batch pretreatment procedures as well as continuous flow column have been studied by using sodium chloride, sodium hydroxide and nitric acid solutions in deionized water . Measurements of the effective capacity, the diffusion coefficient in the solid state and examination of the crystal structure have been employed to assess the effect of each specific pretreatment on the material under test . The effective capacity is improved in all cases, by a factor of 2.4 to 3.6, while the diffusion coefficient values depend strongly on the type of pretreatment used and fall in the range of 0.03-1.37 x 10(-8) cm2s-2 at 20 degrees C . The crystal structure remains unaltered as evidenced by XRD measurements.

Bioresour Technol, 2001 Apr, 77(2), 145 - 55
Testing of alkaline and enzymatic hydrolysis pretreatments for fat particles in slaughterhouse wastewater; Masse L et al.; Four pretreatments to hydrolyse and/or reduce the size of fat particles in slaughterhouse wastewater (SHW) were tested: sodium hydroxide and three lipases of plant, bacterial and animal (pancreatic) origin . Hydrolysing agents and SHW containing between 2.5 and 3 g/l of fat particles were mixed at room temperature for 4 h . Additions of 5-400 meq NaOH/l did not increase soluble COD (SCOD) in SHW, but the average particle size was reduced to 73% +/- 7% of the initial average particle size (D(in)) at NaOH concentrations ranging from 150 to 300 meq/l . Pretreatment with pancreatic lipase PL-250 reduced the average particle size to a maximum of 60% +/- 3% of D(in) . As D(in) was decreased from 359 to 68 microns, the enzyme concentration required to obtain the maximum particle size reduction increased from 200 to 1000 mg/l . A 4-h pretreatment with PL-250 also increased the free long-chain fatty acid (LCFA) concentration to a maximum of 15.5 mg/l, indicating some solubilization of the pork fat particles in SHW . SCOD was not significantly increased by the pretreatment, but SCOD was not found to be a good indicator of enzymatic lipolysis because of enzyme adsorption on the fat particle surface . Pancreatic lipase appeared more efficient with beef fat than pork fat, possibly because beef fat contains less polyunsaturated fatty acids than pork fat . The bacterial lipase LG-1000 was also efficient in reducing average fat particle size, but high doses (> 1000 mg/l) were required to obtain a significant reduction after 4 h of pretreatment . SCOD was not increased by pretreatment with LG-1000 . No particle size reduction or changes in SCOD were noted after 4 h of pretreatment with the plant lipase EcoSystem Plus . It was concluded that PL-250 was the best pretreatment to hydrolyse fat particles in SHW . However, its impact on the efficiency of a downstream anaerobic digestion process remains to be tested.

Folia Microbiol (Praha), 2000, 45(3), 275 - 8
Effect of dichromate on population and growth of various protozoa isolated from industrial effluents; Haq RU et al.; Three protozoa belonging to genera Euglena, Vorticella and Stylonychia collected from industrial wastes were cultured in a medium containing inorganic salts, basically meant for the growth of algae . Protozoa showed rapid growth in the medium . Hexavalent chromium (K2Cr2O7) at a concentration of 5 micrograms/L in the medium adversely affected the growth of protozoa . At the end of eight days of Cr administration, the population of Euglena, Vorticella and Stylonychia increased 8-, 4.5- and 10-fold, respectively, as against 30-, 6.75- and 50-fold increase in the control cultures . No apparent death phase and no change in activity or morphology of protozoa was observed at this Cr concentration . The protozoa were also exposed to different metal ions, viz . Pb (2.42 mmol/L), Cr (0.48 mmol/L), Cd (0.36 mmol/L), administered in the culture medium for a period of 2 years . The metal tolerance for S . mytilus and V . microstoma was Pb > Cr > Cd . E . proxima could not tolerate any of the long-term metal treatments . Because of the ability of these protozoa to tolerate high concentrations of heavy metals, their potential role in remediation of heavy metals from industrial wastewater is considered.

Water Res, 2001 Apr, 35(5), 1354 - 7
Cyanobacteria diversity and toxicity in a wastewater treatment plant (Portugal); Vasconcelos VM et al.; Cyanobacteria are common in eutrophic natural waters . Being favoured by warm, stable and nutrient-enriched waters they may constitute an important part of the phytoplankton community in Wastewater Treatment Plants (WWTP) . The phytoplankton communities of two ponds (facultative and maturation) of the WWTP of Esmoriz (North Portugal) were studied, with particular importance given to cyanobacteria . Mouse bioassays were performed with cyanobacteria samples during some of the blooms and ELISA assays specific for hepatotoxic microcystins were carried out . During the study period (January-July 1999) cyanobacteria were frequently dominant in the ponds ranging from 15.2 to 99.8% of the total phytoplankton density . The main species were Planktothrix mougeotii, Microcystis aeruginosa and Pseudanabaena mucicola . Mouse bioassays were performed during Oscillatoria bloom period but the results were negative, in spite of the high cyanobacteria biomass . ELISA assays were performed for both ponds but only in the maturation pond positive values were found . Microcystin concentrations (as MCYST-LR equivalents) varied from 2.3 to 56.0 micrograms/l on the margin of the pond and between 1.7 and 4.6 micrograms/l in the outflow of this pond . These values indicate that WWTP may be a source of contamination of water bodies with cyanobacteria toxins.

Water Res, 2001 Apr, 35(5), 1338 - 43
The role of hydroxyl radicals for the decomposition of p-hydroxy phenylacetic acid in aqueous solutions; Benitez FJ et al.; The chemical decomposition of p-hydroxyphenylacetic acid, a priority phenolic pollutant present in wastewaters from some agro-industrial plants, is studied by means of a single photochemical process produced by a polychromatic UV radiation and by hydroxyl radicals generated by the combination of UV radiation plus hydrogen peroxide and by the Fenton's reagent (hydrogen peroxide plus ferrous salts) . Batch experiments were conducted to establish the degradation levels obtained and the quantum yields in the single photodecomposition process . An improvement in the decomposition of the phenolic acid in the combined UV/H2O2 oxidation is observed, due to the generation of OH radicals, and the contribution of the radical reaction to the global process is determined . In the Fenton's reagent oxidation, the effects of the operating variables (H2O2 and Fe2+ initial concentrations, pH, type of buffer used) are established and the rate constant for the reaction of p-hydroxyphenylacetic acid with OH radicals is evaluated from a kinetic model, its value being 7.02 x 10(8) M-1 s-1 at 20 degrees C.

Water Res, 2001 Apr, 35(5), 1304 - 10
Determination of N-chloramines in As-samra chlorinated wastewater and their effect on the disinfection process; Fayyad MK et al.; Chlorine is the most widely used disinfectant of wastewater due to its capacity to inactivate most pathogenic microorganisms quickly . However, chlorine reacts with natural organic compounds present in wastewater to produce some undesirable organic byproducts . One such class of compounds is the nitrogenous compounds . The reaction between chlorine and compounds containing a nitrogen atom with one or more hydrogen atoms attached to it will form chloramines which have lower disinfection efficiency . Eighty percent of the wastewater generated in Jordan is treated at the Khirbet As-Samra wastewater treatment plant for eventual use in agriculture . In this study efficiency of chlorination was studied by collecting samples from the effluent of the treatment plant . The yield concentration of N-chloramines upon chlorination was determined . Efficiency of disinfection process as a function of contact time, concentration of chlorine dosage, concentration of nitrogenous compound and pH were studied . In this study, it has been found that at a chlorine dosage of 15 mg/L and contact time of 15 min, the percentage total coliform kill in As-samra wastewater sample was 100% . After addition of histidine, glycine and phenylalanine (15 mg/L in each case) to the wastewater sample, the percentage of total coliform kill dropped to 58, 78 and 79% respectively . When chlorine dosage was increased to 24 mg/L the percentage total coliform kill reached 96, 99 and 100% in wastewater samples treated with 5 mg/L histidine, glycine and phenylalanine, respectively . The percentage total coliform kill dropped to zero in wastewater samples treated with histidine, glycine and phenylalanine at a concentration of 30 mg/L each . This work supports the theory that amino acids and ammonia preferentially react with chlorine to form N-chloramine which significantly reduces the disinfection efficiency of the chlorination process.

Water Res, 2001 Apr, 35(5), 1256 - 62
Separation of titanium dioxide from photocatalytically treated water by cross-flow microfiltration; Xi W et al.; This study focuses on the separation of titanium dioxide from water by cross-flow microfiltration (CMF) within wastewater treatment by photocatalysis using slurry reactor systems . The systematic studies have shown that the separation performance of TiO2 particles is strongly affected by cross-flow velocity, transmembrane pressure, feed concentration, pH of the suspension and ionic strength . An extreme sensitivity to pH and electrolyte concentration indicates the importance of interfacial effects in solid-liquid separation of TiO2 particles . Under optimal conditions, permeate fluxes of up to 1250 l m-2 h-1, approaching those of pure water, could be obtained with a polypropylene membrane which is not sensitive to abrasion . The obtained results makes TiO2 separation by cross-flow microfiltration attractive in solar-catalytic detoxification.

Water Res, 2001 Apr, 35(5), 1225 - 39
A chemometric approach to understanding the bioelimination of anionic, water-soluble dyes by a biomass using empirical and semi-empirical molecular descriptors; Greaves AJ et al.; Single correlation and multiple linear regression analyses have been applied to understand the bioelimination of 103 anionic, water-soluble dyes by a biomass at a wastewater treatment works . The chemometric approach highlighted that anionic, water-soluble dyes with larger molecular size/ionic charge ratios and containing more primary aromatic amines and unsulphonated naphthalene nuclei and fewer aliphatic alcohol groups had superior levels of bioelimination.

Water Res, 2001 Apr, 35(5), 1179 - 90
Inhibiting effects of chloroform on anaerobic microbial consortia as monitored by the Rantox biosensor; Pollice A et al.; The Rantox biosensor was designed for anaerobic wastewater treatment process control, and detects modifications of the feed based on the response of the acetoclastic methanogens contained in the sensor to periodic pulses of a concentrated organic substrate . The biosensor was tested under various operating conditions at the laboratory scale, in parallel with a digester under control fed on the same substrate . The aim was to evaluate the response of the biosensor in the presence of an incoming organic toxic compound (CHCl3) . The experimental set-up, i.e . the biosensor and the digester, was connected to an automated control system developed under LabVIEW environment for data acquisition and operational sequence programming (the Rantox Virtual Instrument) . Biomasses with different activities were used as inocula, and inhibition was induced by dosing chloroform according to two different procedures . The results showed good sensitivity and rapid response of the biosensor to feed intoxication . The presence of chloroform was detected by the Rantox with a rapid and visible response, and well in advance with respect to the digester.

Water Res, 2001 Apr, 35(5), 1159 - 68
Phosphorus removal by sands for use as media in subsurface flow constructed reed beds; Arias CA et al.; Sorption of P to the bed sand medium is a major removal mechanism for P in subsurface flow constructed reed beds . Selecting a sand medium with a high P-sorption capacity is therefore important to obtain a sustained P-removal . The objective of this study was to evaluate the P-removal capacities of 13 Danish sands and to relate the removal to their physico-chemical characteristics . The P-removal properties were evaluated in short-term isotherm batch-experiments as well as in 12-week percolation experiments mimicking the P-loading conditions in constructed reed bed systems . The P-removal properties of sands of different geographical origin varied considerably and the suitability of the sands for use as media in constructed reed beds thus differs . The P-removal capacity of some sands would be used up after only a few months in full-scale systems, whereas that of others would persist for a much longer time . The most important characteristic of the sands determining their P-removal capacity was their Ca-content . A high Ca content favours precipitation with P as sparingly soluble calcium phosphates particularly at the slightly alkaline conditions typical of domestic sewage . In situations where the wastewater to be treated is more acid, the contents of Fe and Al may be more important as the precipitation reactions with these ions are favoured at lower pH levels . The maximum P-sorption capacities estimated using the Langmuir-isotherm plots did not correspond to or correlate with the actual amount of P removed in the percolation columns . Hence, the Langmuir-isotherm does not estimate the P-removal capacities of sands . It is suggested that a suitable quick method of screening a selection of potential media for P-removal potential is to perform simple removal isotherm studies using water with a similar chemical composition as the wastewater to be treated . This method will not provide a direct estimate of the P-removal capacity that can be obtained in full-scale systems, but it is a means of comparing the relative performance of potential media.

J Hazard Mater, 2001 May 7, 83(1-2), 11 - 28
Application of a fiber-optic NIR-EFA sensor system for in situ monitoring of aromatic hydrocarbons in contaminated groundwater; Buerck J et al.; Interaction of analyte molecules with the evanescent wave of light guided in optical fibers is among the most promising novel sensing schemes that can be applied for environmental monitoring and on-line process analysis . By combining this measuring principle with the solid-phase extraction of analyte molecules into the polymer cladding of a fiber, it is possible to perform direct absorption measurements in the cladding, if the fiber is adapted to a conventional spectrometer/photometer . A big advantage of this arrangement is that the measurement is scarcely disturbed by matrix effects (background absorption of water in IR measurements, stray light due to turbidity in the sample) . By using near-infrared (NIR) evanescent field absorption (EFA) measurements in quartz glass fibers coated with a hydrophobic silicone membrane it is possible to design and construct sensors for monitoring apolar hydrocarbons (HCs) in aqueous matrices.The paper presents a fiber-optic sensor system for the determination of aromatic HCs in groundwater or industrial wastewater . Generally, this instrument is suitable for quantitative in situ monitoring of pollutants such as aromatic solvents, fuels, mineral oils or chlorinated HCs with relatively low water saturation solubility (typically between 0.01 and 10 g l(-1)) . The sensor probe is connected via all-silica fibers to a filter photometer developed at the IFIA, thus, allowing even remote analysis in a monitoring well . This portable instrument provides a total concentration signal of the organic compounds extracted into the fiber cladding by measuring the integral absorption at the 1st C--H overtone bands in the NIR spectral range.In situ measurements with the sensor system were performed in a groundwater circulation well at the VEGAS research facility of the University of Stuttgart (Germany) . The NIR-EFA sensor system was tested within the frame of an experiment that was carried through in a tank containing sandy gravel with a groundwater-saturated aquifer, where soil and groundwater were contaminated with technical grade xylene . The goal of this experiment was to model and optimize the groundwater circulation well used for the remediation of the aquifer and soil surrounding the well . The sensor proved to trace reliably the total hydrocarbon concentration in the process water pumped from the well to a stripper column . Measurements were performed continuously over 4 months with C8 HC sum concentrations in the process water between 80 mg l(-1) down to the limit of detection, which is around 200 microg l(-1) . It could be demonstrated that the fiber-optic sensor system is a valuable tool for near-real-time control of a remedial action technique and verification and documentation of its success.

Bioresour Technol, 2001 May, 78(1), 99 - 102
Reaction coefficient (K) evaluation for full-scale facultative pond systems; Soares SR et al.; Facultative ponds have found application in wastewater treatment as an economical system where geographical locations are available at reasonable cost . Several design methods have been reported to describe the organic matter removal of a facultative pond and to determine the reaction coefficient (K) in general terms . Therefore, it is important to evaluate if these coefficient values can be used satisfactorily in regional cases . For this purpose the data of two full-scale facultative ponds located in Brazlandia and Samambaia, in the mid-west region of Brazil, were used . A correlation between applied COD load and reaction coefficient (K) was obtained based on a mathematical adjustment using the dispersed flow hydraulic model . The results provide a suggested regional design parameter for facultative ponds in this region in terms of domestic wastewater.

Bioresour Technol, 2001 May, 78(1), 63 - 9
Influence of process variables in the ethanol pulping of olive tree trimmings; Jimenez L et al.; A central composition design was developed to study the influence of process variables (temperature, pulping time and ethanol concentration) on the properties of the pulp produced (yield and holocellulose, alpha-cellulose and lignin contents) and the pH of the resulting wastewater, in the ethanol pulping of olive tree trimmings . The proposed equations reproduce the experimental results for the dependent variables with errors less than 5% for the holocellulose and alpha-cellulose contents, yield and wastewater pH, and less than 15% for the lignin content . Obtaining pulp with acceptably high yield (37.6%), high holocellulose and alpha-cellulose contents (above 88.8% and 46.9%, respectively), and low lignin contents (below 7.2%), entails operating at a pulping temperature of 200 degrees C, using an ethanol concentration of 75% and a pulping time of 60 min.

Sci Total Environ, 2001 Feb 5, 266(1-3), 259 - 64
Radium migration through clay liners at waste disposal sites; Bosco ME et al.; The migration of 226Ra through the bottom compacted clay liner of the wastewater disposal reservoirs of an industrial plant that processes uranium ore was evaluated . An instrumental method for 226Ra analysis in soils, consisting of detector calibration, the determination of detector counting efficiency, cumulative counting of both background and soil samples in regular counting intervals, and photo-peak smoothing was developed . The 226Ra was analyzed by means of its granddaughter 214Bi, at a photo-peak of 609 keV . The results showed that most of the 226Ra which diffused from the solution into the soil was retained in the upper layer of the sample, and that just a small percentage migrated to the subjacent layers . This methodology is adequate for the assessment of the migration of radionuclides through soil layers and for environmental impact studies related to contamination of soils by radionuclides.

Sci Total Environ, 2001 Feb 5, 266(1-3), 221 - 8
The degradation of xenobiotic branched carboxylic acids in anaerobic sediment of the Pearl River in Southern China; Chua H et al.; Xenobiotic branched carboxylic acids (BCAs) discharged by industries are often persistent in biological wastewater treatment systems and end up in water and sediments . In this study, the degradation of 12 typical BCAs in an anaerobic environment of river sediment was studied in vitro using enrichment shake-flask cultures . The anaerobic consortium taken from the river sediment, comprising BCA-degrading and methane-producing genera, degraded BCAs with tertiary carbons through beta-oxidation, followed by methanogenesis mechanisms . The maximum cell densities in the cultures using BCAs as the sole carbon source ranged between 5.0 and 6.0 x 10(5) cells/ml . The maximum degradation rates were between 5.0 and 8.5 x 10(-3) mmol/h . The consortium could not degrade BCAs with quaternary carbons . The degree of branching at the alpha or beta position along the carbon chain interfered with the beta-oxidation mechanisms . These BCAs would accumulate in the sediment and significantly affect the cycling of organic carbon and nutrients.

Water Res, 2001 Jan, 35(1), 77 - 90
Ultrafiltration of wastewater: effects of particles, mode of operation, and backwash effectiveness; Bourgeous KN et al.; The effects that wastewater quality and mode of operation have on the performance of an asymmetric, hollow fiber, polysulfone, ultrafiltration (UF) membrane with a molecular weight cutoff of 100,000 Daltons were investigated . Performance was assessed through monitoring membrane flux, transmembrane pressure, effluent biochemical oxygen demand, and operational cost of the experimental system while treating filtered secondary, secondary, and filtered primary effluents . Fluxes achieved for filtered secondary (129-173 l/m2 h), secondary (101-158 l/m2 h), and filtered primary (20-41 l/m2 h) effluents were compared to those obtained at three other locations where similar UF systems were operated . A conceptual model of the impact of an insufficient backwash and of operating the UF system at constant flux on membrane performance is presented to explain the differences in fluxes . Employing pre-membrane granular filtration to remove a portion of the problematic particles in secondary effluent prior to UF led to optimal operational conditions . The costs associated with the operation of pre-membrane granular filtration were offset by the increase in production achieved . Although the use of recirculation could increase maintainable flux when treating a concentrated feed (e.g., filtered primary effluent), the associated costs were high . Improved UF performance was found to result from allowing flux to decline naturally, rather than using a constant flux mode of operation . The effluents produced when filtered secondary and secondary effluents were the feeds would be equivalent to an oxidized, coagulated, clarified, and filtered wastewater as per Title 22 California Wastewater Reclamation Criteria.

Water Res, 2001 Jan, 35(1), 33 - 40
Removal of DDD and DDE from wastewater using bagasse fly ash, a sugar industry waste; Gupta VK et al.; Bagasse fly ash, a waste from the sugar industry, was converted into an effective adsorbent and was used for the removal of DDD {2,2-Bis(4-chlorophenyl)-1,1-dichloroethane} and DDE {2,2-Bis(4-chlorophenyl)-1,1-dichloroethene} pesticides from wastewater . The DDD and DDE are removed by the developed adsorbent up to 93% at pH 7.0, with the adsorbent dose of 5 g/l of particle size 200-250 microns at 30 degrees C . The removal of these two pesticides was achieved up to 97-98% in column experiments at a flow rate of 0.5 ml/min . The adsorption was found to be exothermic in nature . The bagasse fly ash system has been used for the removal of DDD and DDE from the wastewater . The developed system is very useful, economic, and reproducible.

Water Res, 2001 Jan, 35(1), 327 - 32
Evaluation of a second derivative UV/visible spectroscopy technique for nitrate and total nitrogen analysis of wastewater samples; Ferree MA et al.; A method for nitrate analysis based on second derivative UV/Visible spectroscopy was developed by Simal et al . (1985: Simal J., Lage M . A., and Iglesias I . (1985) Second derivative ultraviolet spectroscopy and sulfamic acid method for determination of nitrates in water . J . Assoc . Analyt . Chem . 68, 962-964) and Suzuki and Kuroda (1987: Suzuki, N . and Kuroda R . (1987) Direct simultaneous determination of nitrate and nitrite by ultraviolet second-derivative spectrophotometry . Analyst 112, 1077-1079), and later modified for the analysis of total nitrogen in aqueous samples of varying nitrate:organic nitrogen ratios (Crumpton et al., 1992: Crumption W . G., Isenhart T . M . and Mitchell P . D . (1992) Nitrate and organic N analyses with second-derivative spectroscopy . Limnol . Oceanogr . 37, 907-913) . The procedure uses the second derivative of the absorption spectrum for nitrate (NO3-), which has a peak at approximately 224 nm that is proportional to the NO3- concentration . Samples for total N analysis are first oxidized to NO3- by persulfate digestion . The objectives of this study were to: (1) test the accuracy and precision of the second derivative method through the use of NIST-traceable wastewater check samples; (2) determine whether the second derivative method for nitrate analysis can be used for wastewater samples and whether the method compares favorably with other currently used nitrate analysis methods; and (3) use the method to analyze wastewater samples containing a range of nitrate and total nitrogen concentrations . Our results indicated that the method needed to be modified to include a longer digestion time (60 min) and dilution of samples prior to digestion (if needed) . With the modified method, nitrogen recoveries were not significantly different (P > or = 0.05) from samples with known N concentrations . In addition, nitrate concentrations in constructed wetland and wastewater samples analyzed by both second derivative spectroscopy and ion chromatography were not significantly different . Total nitrogen concentrations in wastewater samples also compared favorably to the same samples analyzed by Kjeldahl digestion . The method is faster, simpler, requires smaller sample volumes, and generates less waste than many EPA-approved methods of N analysis, and may offer a suitable alternative to current methods for analysis of nitrate and total N in wastewater samples.

Water Res, 2001 Jan, 35(1), 300 - 10
Immobilization of heavy metals from aqueous solutions using polyacrylamide grafted hydrous tin (IV) oxide gel having carboxylate functional groups; Shubha KP et al.; A new adsorbent containing a carboxylate group has been prepared by the surface modification of a polyacrylamide grafted hydrous tin (IV) oxide gel . The product exhibits a very high adsorption potential for Pb(II), Hg(II) and Cd(II) . The effect of initial metal ion concentration, adsorbent dose, pH, concentration of light metal ions, and temperature on metal removal has been studied . The process follows a first-order rate kinetics . The intraparticle diffusion of metal ions through pores in the adsorbent was shown to be the main rate limiting step . The equilibrium data fit well with the Langmuir adsorption isotherm . The selectivity order of the adsorbent is Pb(II) > Hg(II) > Cd(II) . Adsorption rate constants and thermodynamic parameters were also presented to predict the nature of adsorption . The method was applied on synthetic wastewaters . Acid 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 Environ Monit, 2000 Oct, 2(5), 436 - 42
Characterization of landfill leachates and studies on heavy metal removal; Cecen F et al.; This study covers a thorough characterisation of landfill leachates emerging from a sanitary landfill area . The landfill leachates were obtained in the acidic stage of landfill stabilisation . Their organic content was high as reflected by the high BOD5 (5 day biological oxygen demand) and COD (chemical oxygen demand) values . They were also highly polluted in terms of the parameters TKN (total Kjeldahl nitrogen), NH4-N, alkalinity, hardness and heavy metals . Nickel was present in these wastewaters at a significant concentration . With regard to the high heavy metal content of these wastewaters, several physicochemical removal alternatives for the heavy metals Cu, Pb, Zn, Ni, Cd, Cr, Mn and Fe were tested using coagulation, flocculation, precipitation, base addition and aeration . Additionally, COD removal and ammonia stripping were examined . Co-precipitation with either alum or iron salts did not usually lead to significantly higher heavy metal removal than lime alone . The major methods leading to an effective heavy metal removal were aeration and lime addition . Nickel and cadmium seemed to be strongly complexed and were not removed by any method . Also lead removal proved to be difficult . The results are also discussed in terms of compliance with standards.

J Food Prot, 2001 Mar, 64(3), 405 - 9
Polycyclic aromatic hydrocarbons in mussels (Mytilus galloprovincialis) from the Ionian Sea, Italy; Storelli MM et al.; Concentrations of eight polycyclic aromatic hydrocarbons (PAHs) (phenanthrene, anthracene, fluoranthene, pyrene, benz{a}anthracene, benzo{a}pyrene, dibenz{a,h}anthracene, benzo{ghi}perylene) were determined in mussels (Mytilus galloprovincialis) collected between June and September 1995 from 10 locations along a sound of sea formed by two inlets (Mar Piccolo) close to the Gulf of Taranto (Ionian Sea, Italy) . In mussels the concentrations of total PAHs were between 14.8 and 645.3 microg/kg wet weight . Among the single identified compounds, the predominance of phenanthrene (29.5 microg/kg wet weight) and anthracene (64.7 microg/kg wet weight) was evident . Another relevant pollutant was pyrene (18.4 microg/kg wet weight) followed by fluoranthene (7.2 microg/kg wet weight), whereas the other compounds showed low levels . The mussels that showed the highest total concentrations of PAHs were collected from stations affected by stronger human activities (industrial fallout, urban wastewaters, and contaminants transported via riverine discharge) . Our results were similar to those found in areas classified as moderately polluted . This observation suggests the need for an increased effort in controlling sources of pollution in this area recognized as one of the most productive mussel-farming areas in the Italy.

Arch Environ Contam Toxicol, 2001 Feb, 40(2), 141 - 50
Trace organic contaminants in sediment and water from Ulsan Bay and its vicinity, Korea; Khim JS et al.; Sediment and water samples collected from 32 locations in Ulsan Bay and adjacent inland areas were analyzed for polycyclic aromatic hydrocabons (PAHs), nonylphenol (NP), octylphenol (OP), bisphenol A (BPA), organochlorine (OC) pesticides (HCB, HCHs, CHLs, and DDTs), and polychlorinated biphenyls (PCBs) to characterize their spatial distribution and contamination status . PAHs were detected in nearly all sediment and water extracts from Ulsan Bay and its inland locations . The sedimentary PAH concentrations ranged from 17 to 3,100 ng/g on a dry weight basis (DW), which were predominated by two- and three-ring aromatic hydrocarbons in river and/or stream, and four- to six-ring compounds in Ulsan Bay sediment . Concentrations of PAHs in pore water samples were generally two or three orders magnitude less than those of corresponding sediment samples . Maximum concentrations of NP, OP, and BPA in sediments were 1,040, 120, and 54 ng/g DW, respectively . Concentrations of OP and BPA were, on average, 5- to 13-fold less than those of NP . PCB concentrations in sediment ranged from 1.4 to 77 ng/g DW, which were predominated by lower chlorinated congeners such as di- through pentachlorinated biphenyls . Among different OC pesticides analyzed, concentrations of DDTs were the greatest, ranging from 0.02 to 41.9 ng/g DW . NP concentrations were greater at inner locations proximal to municipal wastewater discharges into rivers and/or streams, whereas the concentrations of PCBs and PAHs were great near the sites of high industrial activities . Sediment-pore water partitioning coefficients correlated with those of reported Koc or Kow values for selected PAHs in Ulsan Bay, but these varied by an order of magnitude for stream and/or river sediments.

J Hazard Mater, 2001 Apr 20, 82(3), 291 - 8
Impact of thermal treatment on metal in sewage sludge from the Psittalias wastewater treatment plant, Athens, Greece; Zorpas AA et al.; This paper describes a laboratory study that examined the effect of thermal treatment at four different temperatures on the behavior of heavy metals in the anaerobically treated primary sludge from the Psittalias wastewater treatment plant . The sewage sludge was found to contain significant amounts of heavy metals (Cr, Cu, Fe, Ni, Pb and Zn) . The metal form distribution in the sludge samples which was determining by the application of a sequential extraction procedure revealed that a significant portion of metals was embodied in the organic and reducible fractions . Treatment at 105, 250, 650 and 900 degrees C demonstrated significant conversions of the metals to a less mobile form as well as removal by vaporization . By applying sequential analysis, it was found that most of the metals were removed from the initial mobile phases to more stable ones . Also, significant amounts were transformed to the gaseous phase.

Microbiology, 2001 Mar, 147(Pt 3), 611 - 9
Sequence variation in dichloromethane dehalogenases/glutathione S-transferases; Vuilleumier S et al.; Dichloromethane dehalogenase/glutathione S-transferase allows methylotrophic bacteria to grow with dichloromethane (DCM), a predominantly man-made compound . Bacteria growing with DCM by virtue of this enzyme have been readily isolated in the past . So far, the sequence of the dcmA gene encoding DCM dehalogenase has been determined for Methylobacterium dichloromethanicum DM4 and Methylophilus sp . DM11 . DCM dehalogenase genes closely related to that of strain DM4 were amplified by PCR and cloned from total DNA from 14 different DCM-degrading strains, enrichment cultures and sludge samples from wastewater treatment plants . In total, eight different sequences encoding seven different protein sequences were obtained . Sequences of different origin were identical in several instances . Sequence variation was limited to base substitutions; strikingly, 16 of the 19 substitutions in the dcmA gene itself encoded amino acids that were different from those of the DM4 sequence . The kinetic parameters k(cat) and K:(m), the pH optimum and the stability of representative DCM dehalogenase variants were investigated, revealing minor differences between the properties of DCM dehalogenases related to that from strain DM4.

Water Res, 2001 Mar, 35(4), 985 - 96
Characterization of isolated fractions of dissolved organic matter from natural waters and a wastewater effluent; Ma H et al.; Dissolved organic matter (DOM) was concentrated from natural waters and the effluent of a wastewater treatment plant using a portable reverse osmosis (RO) system . The humic acid (HA), fulvic acid (FA) and hydrophilic (HyI) fractions were isolated and purified by the XAD-8 resin combined with the cation exchange resin method . The FA fractions predominated in natural waters and accounted for 54-68% of the total amount of dissolved organic carbon (DOC), whereas the HA and HyI fractions constituted, respectively, 13-29 and 9-30% of the total DOC . The effluent of wastewater was almost devoid of HA and the HyI fraction exceeded FA . The elemental compositions of HA and FA were in the ranges typical for natural humic materials, but the HyI fractions did not exhibit humic character . 1H NMR spectra revealed that the HyI fractions were almost devoid of aromatic protons and the aliphatic region featured more sharp signals than HA and FA fractions, indicating that HyI fractions were consisted of more simple compounds and less complex mixtures . The aliphatic functional groups in these fractions of DOM samples followed the order HA < FA <HyI . Proton titrations indicated that HA . FA and HyI fractions of DOM samples from different sources had similar total acidity whose range was 9.0-11.6 meq/g C . This similarity may be due to the sample fractionation method . The copper titration results showed that the number of total Cu binding sites for the three fractions of different DOM samples were quite similar (1.46-1.60 mmol/g C), which was consistent with the similarity in total acidity from proton titrations . The affinity of copper with each isolated fraction followed the order HA approximately = FA > HyI . The rate of Cu complexation with the HyI fraction was faster than the rate with the HA or FA fraction of the Suwannee River DOM, implying that copper reacted with relatively weak ligands faster than with strong ligands.

Water Res, 2001 Mar, 35(4), 953 - 64
Hydraulic and purification behaviors and their interactions during wastewater treatment in soil infiltration systems; Van Cuyk S et al.; Four three-dimensional lysimeters were established in a pilot laboratory with the same medium sand and either an aggregate-laden (AL) or aggregate-free (AF) infiltration surface and a 60- or 90-cm soil vadose zone depth to ground water . During 48 weeks of operation, each lysimeter was dosed 4 times daily with septic tank effluent (STE) at 5 cm/d (AL) or 8.4 cm/d (AF) . Weekly monitoring was done to characterize the STE, percolate flow and composition, and water content distributions within the lysimeters . Bromide tracer tests were completed at weeks 0, 8, and 45 and during the latter two times, ice nucleating active (INA) bacteria and MS-2 and PRD-1 bacteriophages were used as bacterial and viral surrogates . After 48 weeks, soil cores were collected and analyzed for chemical and microbial properties . The observations made during this study revealed a dynamic, interactive behavior for hydraulic and purification processes that were similar for all four lysimeters . Media utilization and bromide retention times increased during the first two months of operation with the median bromide breakthrough exceeding one day at start-up and increasing to two days or more . Purification processes were gradually established over four months or longer, after which there were high removal efficiencies (>90%) for organic constituents, microorganisms, and virus, but only limited removal of nutrients . Soil core analyses revealed high biogeochemical activity within the infiltrative zone from 0 to 15 cm depth . All four lysimeters exhibited comparable behavior and there were no significant differences in performance attributable to infiltrative surface character or soil depth . It is speculated that the comparable performance is due to a similar and sufficient degree of soil clogging genesis coupled with bioprocesses that effectively purified the wastewater effluent given the adequate retention times and high volumetric utilization's of the sand media.

Water Res, 2001 Mar, 35(4), 1093 - 9
Ozonation of aqueous azo dye in a semi-batch reactor; Wu J et al.; The ozonation of wastewater containing azo dye in a semi-batch reactor has been studied . Results revealed that the rate of ozone transfer increased with increases in the initial dye concentration, the applied ozone dose and temperature . A model was developed to predict the enhancement factor of ozone mass transfer . This model enables the prediction of mass transfer coefficient of ozone from the following parameters: initial dye concentration, applied ozone dose, temperature and concentration of dissolved ozone in the organic-free water . This model was also valid for reactors of larger sizes . Result of kinetic studies showed that ozonation of the azo dye was a pseudo-first-order reaction with respect to dye . The apparent rate constant increased with the applied ozone dose and temperature . However, the apparent rate constant declined logarithmically with increasing initial dye concentration . In addition, ozonation reduced chemical oxygen demand and enhanced the biodegradability of the wastewater.

Water Res, 2001 Mar, 35(4), 1077 - 85
Kinetics of the reaction between ozone and phenolic acids present in agro-industrial wastewaters; Beltran-Heredia J et al.; The kinetics of the ozonation of three phenolic acids is investigated from ozone absorption experiments in a semi-continuous reactor . After the evaluation of stoichiometric ratios for the individual reactions between ozone and each phenolic acid, the oxidation of p-hydroxybenzoic acid by ozone is performed in a first stage . The influence of the operating variables on the degradation process is established, and the application of a mass transfer with chemical reaction model based on the film theory leads to the determination of the reaction orders and kinetic rate constants . The experimental absorption rates obtained agree well with those calculated theoretically . In the second stage, a mixture of ferulic acid (4-hydroxy-3-methoxycinnamic acid), beta-resorcylic acid (2,4-dihydroxybenzoic acid) and p-hydroxybenzoic acid is ozonated under different experimental conditions . The kinetic study is performed by means of a competitive method that takes p-hydroxybenzoic acid as reference compound . The application of this model allows to determine the kinetic rate constants for each compound, which are correlated as a function of pH and temperature . The results obtained support that the kinetic regime of absorption is fast and pseudo-first order with respect to ozone, a condition required by the competitive method used.

Environ Pollut, 2001, 112(2), 209 - 13
Cadmium(II) removal from aqueous solutions by pre-treated biomass of marine alga Padina sp; Kaewsarn P et al.; In this study, the adsorption properties of a pre-treated biomass from marine alga Padina sp., a biomass collected from Surin Island, Thailand, for removal of cadmium(II) ions from aqueous solutions was investigated . Batch and column experiments were conducted to determine the adsorption properties of the modified biomass . At a pH of 5, the maximum removal capacity of the biomass is 0.53 mmol/g . The kinetics of cadmium(II) adsorption were fast with 90% of adsorption taking place within 35 min . This study demonstrated that the pre-treated biomass of Padina sp . could be used as an efficient biosorbent for the treatment of cadmium(II)-bearing wastewater streams.

Appl Environ Microbiol, 2001 Mar, 67(3), 1097 - 101
Molecular characterization of cryptosporidium oocysts in samples of raw surface water and wastewater; Xiao L et al.; Recent molecular characterizations of Cryptosporidium parasites make it possible to differentiate the human-pathogenic Cryptosporidium parasites from those that do not infect humans and to track the source of Cryptosporidium oocyst contamination in the environment . In this study, we used a small-subunit rRNA-based PCR-restriction fragment length polymorphism (RFLP) technique to detect and characterize Cryptosporidium oocysts in 55 samples of raw surface water collected from several areas in the United States and 49 samples of raw wastewater collected from Milwaukee, Wis . Cryptosporidium parasites were detected in 25 surface water samples and 12 raw wastewater samples . C . parvum human and bovine genotypes were the dominant Cryptosporidium parasites in the surface water samples from sites where there was potential contamination by humans and cattle, whereas C . andersoni was the most common parasite in wastewater . There may be geographic differences in the distribution of Cryptosporidium genotypes in surface water . The PCR-RFLP technique can be a useful alternative method for detection and differentiation of Cryptosporidium parasites in water.

Water Res, 2001 Feb, 35(2), 567 - 72
The treatment and reuse of wastewater in the textile industry by means of ozonation and electroflocculation; Ciardelli G et al.; Two different oxidation treatments, ozonation and electroflocculation, were experimented on a pilot scale to test their efficiency in removing polluting substances from wastewaters of textile industries . Both pilot plants used reproduced very closely a full-scale treatment in order to obtain indications about the feasibility of a transfer on industrial scale . By means of ozone treatment very high colour removal (95-99%) was achieved and treated waters were reused satisfactorily in dyeing even with light colours . This evidence despite the fact that the chemical oxygen demand of treated waters was still in a range (75-120 mg/l, a decrease up to 60%) that was usually considered to be too high for recycling purposes, especially for dyeing light colours . Treating plants working at the above-mentioned conditions should guarantee low operating costs . A biological pre-treatment and a sand filtration are absolutely essential . The transfer on industrial scale of the treatment is currently under development under an already financed European project . Electrochemical treatment showed to be very efficient in removing colour (80-100%) and chemical oxygen demand (70-90%) . Moreover, a sensible decrease of chloride and sulphate ions was detected . Removal of flocculated material (post-treatment) must be, however, perfected in order to establish a correct costs-to-benefits ratio and therefore, propose an implementation of the technique on an industrial scale.

Water Res, 2001 Feb, 35(2), 541 - 7
Potential of freezing in wastewater treatment: soluble pollutant applications; Lorain O et al.; When wastewater containing only soluble pollutants is frozen gradually, ice crystals grow from the pure water only, while pollutants are rejected into the liquid phase thus increasing their concentration . In this way, pure water can be removed from various wastewaters . Two kinds of wastewater were studied: synthetic wastewater containing water and one or more soluble pollutants, and industrial wastewaters (urban wastewater and cutting oil wastewater) . In most cases, separation efficiency close to 100% was achieved . A large range of pollutant concentrations was studied in order to determine the limits of freezing separation.

Water Res, 2001 Feb, 35(2), 485 - 95
Treatment of a foul condensate from Kraft pulping with horseradish peroxidase and hydrogen peroxide; Wagner M et al.; Foul condensates originating from the Kraft recovery process contain phenolic compounds whose removal might render these process streams more useful for reuse in other plant operations or more amenable to biological degradation . Treatment of a foul condensate with horseradish peroxidase and H2O2 selectively targeted phenolic compounds resulting in a reduction of the total phenols concentration below 1 mg/L as well as a substantial toxicity drop as measured using the Microtox assay; however, only marginal COD removal was achieved . Comparisons of treatments between synthetic wastewaters and real wastewaters to which phenol were added revealed that the condensate contained species that protect the enzyme from inactivation by reaction products . Analytical data as well as experimental results suggest that these species are lignin derivatives.

Water Res, 2001 Feb, 35(2), 471 - 7
Novel method for enhancing permeate flux of submerged membrane system in two-phase anaerobic reactor; Lee SM et al.; A two-phase anaerobic reactor system with a submerged membrane in the acidogenic reactor was designed for the enhancement of organic acid conversion and methane recovery . A submerged membrane system in a two-phase anaerobic reactor was tested to increase the sludge retention time (SRT) of acidogen and to enhance the solid separation . The pilot plant experiment was performed for piggery wastewater treatment for a year . The membrane material used was mixed esters of cellulose of 0.5 micron pore size . COD removal efficiency was 80% and the methane production showed 0.32 m3/kg COD removed for the submerged membrane system in the anaerobic digester . As the cake resistance of the membrane caused a serious problem, a stainless-steel prefilter and air backwashing methods were applied to minimize the cake resistance effectively . Among the tested prefilters, the 63 microns pore prefilter showed the best performance for reducing cake resistance and a successful long-term operation . By cleaning with alkali first and acidic solutions later, the permeate flux decreased by long-term operation was recovered to 89% of that with a new membrane.

Water Res, 2001 Feb, 35(2), 387 - 96
Oxidation of p-hydroxybenzoic acid by Fenton's reagent; Rivas FJ et al.; Fenton's reagent has been shown to be a feasible technique to treat phenolic-type compounds present in a variety of food processing industry wastewaters . A model compound, p-hydroxybenzoic acid was oxidised by continuously pumping two solutions of ferrous iron and hydrogen peroxide . Typical operating variables like reagent feeding concentrations and flowrate, temperature and pH were studied . A mechanism of reactions based on the classical Fenton's chemistry was assumed, and computed concentration profiles of the parent compound, ferrous ion and dihydroxybenzene were compared to experimental results . The model qualitatively predicted the influence of several operating variables, however, calculated results suggested the presence of parallel routes of substrate elimination and/or a initiating rate constant with a higher value . The low efficiency of a well-known hydroxyl radical scavenger (tert-butyl alcohol) also supports the contribution of oxidising species different from the hydroxyl radical to substrate removal . Further evidence of the presence of reactions different from the hydroxyl radical oxidation was observed from comparison of the simultaneous Fenton's or UV/H2O2 oxidations of p-hydroxybenzoic acid, tyrosol and p-coumaric acid.

Water Res, 2001 Feb, 35(2), 373 - 8
Heavy metal removal with Mexican clinoptilolite: multi-component ionic exchange; Vaca Mier M et al.; This paper describes the interactions of Pb(II), Cd(II), and Cr(VI) competing for ion-exchange sites in naturally occurring clinoptilolite . Dissolved Pb and Cd were effectively removed within 18 h in batch reactors, with higher removal efficiencies (> 95%) in the acidic pH range . The presence of Cr(VI), which can interact with these metals to form anionic complexes, significantly diminished the Pb and Cd removal efficiencies . A decrease in the efficiency of clinoptilolite to remove Pb was also observed in the high (> or = 10) pH range . This was attributed to the formation of anionic hydroxo-complexes with little affinity for cationic ion exchange sites . Pb outcompeted Cd for ion exchange sites in a flow-through column packed with clinoptilolite (contact time = 10 s) . The preferential removal of Pb in column, but not in batch reactors, reflects that competitive retention can be affected by contact time because diffusion kinetics may influence the removal efficiency to a greater extent than equilibrium partitioning . Phenol, which was tested as a representative organic co-contaminant, slightly hindered heavy metal removal in batch reactors . This was attributed to the formation of organometallic complexes that cannot penetrate the zeolite exchange channels . Altogether, these results show that natural zeolites hold great potential to remove cationic heavy metal species from industrial wastewater . Nevertheless, process efficiency can be hindered by the presence of ligands that form complexes with reduced accessibility and/or affinity for ion exchange.

Water Res, 2001 Feb, 35(2), 351 - 62
Anaerobic pre-treatment of herbal-based pharmaceutical wastewater using fixed-film reactor with recourse to energy recovery; Nandy T et al.; The concept of immobilization technology has been incorporated in this research study for biomethanation of high strength herbal based pharmaceutical wastewater . Accordingly, an investigation has been made on laboratory scale to assess the feasibility of an anaerobic fixed film fixed bed reactor system to pre-treat herbal-based pharmaceutical wastewater with recourse to energy recovery, including influence of operating conditions . The work was carried out with laboratory-scale upflow reactor, equipped with nylon scrubber as random support . The reactor was operated at 35 degrees C . COD removal efficiencies ranging from 76 to 98% were achieved for organic loading rates upto 10 kgCOD/m3 d, while the highest organic loading rate (around 48 kg COD/m3 d) led to efficiencies of 46-50% . The influences of hydraulic retention time and substrate concentration were also studied . The reactors did now show destabilization under impulse hydraulic and organic overloadings . Reactor stability was easily achieved under intermittent operation, with breaks, after which the reactors rapidly returned to their optimal performance.

Water Res, 2001 Feb, 35(2), 339 - 50
Surface properties of sludge and their role in bioflocculation and settleability; Liao BQ et al.; The influence of sludge retention time (SRT) on the extracellular polymeric substances (EPS) and physicochemical properties (hydrophobicity and surface charge) of sludge was studied using laboratory-scale sequencing batch reactors (SBRs) fed a synthetic wastewater containing glucose and inorganic salts . Sludge surfaces were more hydrophobic (larger contact angle) and less negatively charged at higher SRTs (16 and 20 d) than at lower SRTs (4 and 9 d) . The ratio of proteins to carbohydrates within the EPS of the sludges increased as the SRT increased from 4 to 12 d corresponding to the changes in the physicochemical properties of the sludge . The protein:carbohydrate ratio remained constant at SRTs of 16 and 20 d . A transition in sludge properties appeared to occur between the upper range of low- (9 d) and lower range of high-SRTs . The total EPS content, however, was independent of the SRT . A higher sludge volume index (SVI), an indication of poorer settleability or compression, was associated with a larger amount of total EPS but no significant correlation between SVI and the surface properties of sludge was observed . A more hydrophobic and less negatively charged surface corresponded to lower levels of ESS . These results indicate that it is the surface properties, hydrophobicity, surface charge and composition of EPS, of sludge, rather than the quantity of EPS, that govern bioflocculation . In contrast, the EPS content is more important in controlling the settleability of sludge.

Water Res, 2001 Mar, 35(3), 817 - 29
Effect of process configuration and substrate complexity on the performance of anaerobic processes; Azbar N et al.; The roles of substrate complexity (molecular size of the substrate) and process configuration in anaerobic wastewater treatment were investigated to determine optimal methanogenic technology parameters . Five substrates (glucose, propionate, butyrate, ethanol, and lactate) plus a mixed waste (60% carbohydrate, 34% protein, and 6% lipids) were studied under five reactor configurations: batch-fed single-stage continuous stirred tank reactor (CSTR), continuously fed single-stage CSTR, two-phase CSTR, two-stage CSTR, and single-stage upflow anaerobic sludge blanket (UASB) . The substrate feed concentration was 20,000 mg/L as COD . The solids retention time (SRT) and hydraulic retention time (HRT) in the CSTR reactors were 20 d, while HRT in the UASB was 2 d . All reactors were operated for at least 60 d (equal to 3SRT) . Substrate complexity was observed to be less significant under two-phase, two-stage and UASB reactor configurations . Two-phase CSTR, two-stage CSTR, and single-stage UASB configurations yielded the lowest effluent chemical oxygen demands (130-550, 60-700, and 50-250 mg/L, respectively) . The highest effluent chemical oxygen demands were detected when feeding glucose, propionate, and lactate to continuously fed single-stage CSTRs (10, 400, 9900, and 4700 mg/L COD, respectively) and to batch-fed single-stage CSTRs (11, 200, 2500, and 2700 mg/L COD, respectively) . Ironically, the one stage CSTR--most commonly utilized in the field--was the worst possible reactor configuration.

Water Res, 2001 Mar, 35(3), 745 - 9
Color and chlorinated organics removal from pulp mills wastewater using activated petroleum coke; Shawwa AR et al.; Delayed petroleum coke, a waste by-product from the oil sand industry, was utilized in the production of activated carbon . The activated carbon was then evaluated for color and chlorinated organics reduction from pulp mill wastewater . The activation of the petroleum coke was evaluated using a fixed bed reactor involving carbonization and activation steps at temperature of 850 degrees C and using steam as the activation medium . The activation results showed that the maximum surface area of the activated coke was achieved at an activation period of 4 h . The maximum surface area occurred at burnoff and water efficiency of 48.5 and 54.3%, respectively . Increasing the activation period to 6 h resulted in a decrease in the surface area . Methylene blue adsorption results indicated that the activation process was successful . Methylene blue adsorbed per 100 g of applied activated coke was 10 times higher than that adsorbed by raw petroleum coke . Adsorption equilibrium results of the bleached wastewater and the activated coke showed that significant color, COD, DOC and AOX removal (> 90%) was achieved when the activated coke dose exceeded 15,000 mg/L . Adsorption isotherms, in terms of COD, DOC, UV and color were developed based on the batch equilibrium data . Based on these isotherms, the amount of activated coke required to achieve certain removal of color and AOX can be predicted . The utilization of the petroleum coke for the production of activated carbon can provide an excellent disposal option for the oil sand industry at the same time would provide a cheap and valuable activated carbon.

Water Res, 2001 Mar, 35(3), 605 - 12
Sorption kinetic analysis for the removal of cadmium ions from effluents using bone char; Cheung CW et al.; The adsorption of cadmium ions onto bone char has been studied using a batch adsorber . The experimental data was analyzed using four sorption kinetic models--the pseudo-first order, the Ritchie second order, the modified second order and the Elovich equations--to determine the best-fit equation for the sorption of metal ions onto bone char . The best-fit equation was identified using the sum of the errors squared (SSE) . Finally, equilibrium studies were used to evaluate the sorption capacity of bone char for cadmium ions and experimental results showed this to be 0.57 mmol g-1 at an equilibrium solution concentration of 3.0 mmol dm-3 . Since the sorption capacity is relatively high, bone char can be considered as a suitable sorbent for the adsorption of cadmium in wastewater treatment systems.

Parasitol Int, 2000 Jan, 48(3), 249 - 54
Geohelminthic infections associated with raw wastewater reuse for agricultural purposes in Beni-Mellal, Morocco; Habbari K et al.; This study was undertaken to determine the possible risk associated with raw wastewater use for agricultural purposes, particularly, the transmission of geohelminthic infections among children of five regions in Beni-Mellal, Morocco . In a randomly selected sample of 1343 children, 740 of them were from five communities using raw wastewater for agriculture, and 603 were from four control communities that do not practice wastewater irrigation . A questionnaire-interview with children and parents was used to collect data on possible demographic, hygiene and behavioral-contact risk factors such as sex, age, family size, parental education, parental occupation, source of water, toilet in house, hand-washing, contact with wastewater and contact with wastewater irrigated land . Ascariasis prevalence was found to be approximately five times higher among children in wastewater-impacted regions compared to control regions . Contact with wastewater and wastewater irrigated land and public water supply were found to be associated with higher infection rates . Trichuris rates did not show a statistically significant difference between the wastewater-impacted and the control regions . In conclusion, raw wastewater use in Beni-Mellal can lead to a high risk of geohelminthic infections . Adequate treatment of wastewater and public health education are highly recommended.

Fresenius J Anal Chem, 2000 Dec, 368(7), 641 - 3
Fiber-in-tube solid-phase microextraction: a fibrous rigid-rod heterocyclic polymer as the extraction medium; Saito Y et al.; A novel "fiber-in-tube" configuration has been applied to the extraction tube of solid phase microextraction (SPME), and the direct coupling of the extraction process to liquid chromatography (LC) has been accomplished for the analysis of n-butylphthalate in wastewater . By using this fiber-in-tube SPME/LC system the preconcentration factor for the phthalate was about 160 with 20 min extraction and no interference peak was observed in the chromatogram . The results also showed the potential applications of this fiber-in-tube SPME/LC for the analysis of sub-ppb level (i.e., lower than 1 ng/mL) of various organic analytes in aqueous sample matrix without a large solvent consumption during the preconcentration process.

Fresenius J Anal Chem, 2000 Jul, 367(6), 590 - 2
Flow injection spectrophotometric determination of ultra trace amounts of oxalic acid; Ensafi AA et al.; A new simple, sensitive and rapid catalytic-spectrophotometric method for the determination of oxalic acid has been described based on its catalytic effect on the redox reaction between dichromate and Brilliant cresyl blue in acidic media by means of a flow injection analysis method . The color change of Brilliant cresyl blue due to its oxidation was monitored spectrophotometrically at 625 nm . The calibration graph was linear in the range of 0.020-4.70 microg/mL oxalic acid with a limit of detection 0.005 microg/mL of oxalic acid . The relative standard deviation for ten replicate measurements of 0.020 microg/mL and 0.900 microg/mL was 2.2% and 1.7%, respectively . No serious interference was identified . Oxalic acid was determined in wastewater and in spinach by the proposed method with satisfactory results.

Water Purification, Molecular Microbiology, Yeast, Microorganism, Bioreactor, Microorganisms, Rhizobia, Microbiology, Genetics, Microbe, Environmental Microbiology, Bacteriology, Prokaryote, Microbes, i, Genetic Engineering, f, Bacteria, p, Fermentation, e, Bacterium, b, Activated Sludge, Bioremediation, Anaerobic bacterium, c, Streptococcus, s, Phages, c, Proteus, l, Campylobacter, b, Haemophilus, a, Saccharomyces cerevisiae, e, Cryptococci, a, Bacteremia, m, Yeast, a, Vibrio, c, Staphylococci, b, Pseudomonas fluorescens, b, Enterobacters, e, Thermophile, g, B. anthracis, m, Erythromycin, p, Streptococcus, p, Saccharomyces yeast, e, Salmonella, b, Escherichia coli, r, Microorganisms, m, Listeriosis, y, Microbiological, p, Biofilm, c, Clostridium, a, Salmonella, b, Cryptococcus, g, Antimicrobial, Thermophile,

Scientific Publications - Work Done by Microbiology Reader Bioscreen C
Agricultural Microbiology Anaerobic Microbiology Antimicrobial Susceptibility Artificial Atmosphere Bioassay of Antibiotics Biofilm Microbiology Bioreactor Technology Biotechnology Cell Biology Clinical Microbiology Environmental Microbiology Experiments with Yeast	Fermentation Food Microbiology Functional Genomics Gene Technology Growth Media Development Growth Rate and Lag Time Industrial Microbiology Medical/Pharmaceutical Field Microbiological Assay Microbiological Research Microbiology of Cosmetics go to a specific theme...	Military Microbiology Molecular Microbiology Mutagenicity and Genotoxicity Oral Microbiology Patents Postantibiotic Studies Soil Microbiology Spore Microbiology Veterinary Microbiology Waste/Wastewater Treatment Water Microbiology Wine Microbiology

� 2005 Transgalactic Ltd (manufacturer of Bioscreen C software) | Privacy Statement | P.O. Box 1393, 00101 Helsinki, Finland, phone: +358 9 85172920, fax: +358 9 8749481, e-mail: microbiology@bionewsonline.com

Last modified: May 25, 2005