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This study investigates the feasibility of utilizing drainage water for reclamation of saline and sodic soils in the Dosalagh plain of Khuzestan province, Iran. With significant drainage water generated in the region's irrigation networks, repurposing it for soil reclamation emerges is a low-risk strategy. Leaching, a practical technique for soil desalination, was examined using the double ring method at depths up to 150 cm. Four water qualities (electrical conductivities of 2.12, 7, 25 and 40 dS m−1) and depths (0, 25, 50 and 75 cm) were tested, with intermittent leaching over three cycles. Results indicate a substantial reduction in electrical conductivity (117.7 to 29 dS m−1) and sodium content (1415.9 to 39.83 mEq L−1) at the 0-25 cm depth with drainage water incorporation. The study highlights the beneficial impact on soil quality, emphasizing decreased sodium content, sodium adsorption ratio, and electrical conductivity. Overall, reusing drainage water proves advantageous for soils with high salinity levels, showcasing its potential for sustainable soil management in saline regions. This research underscores the importance of effective drainage water management for soil reclamation and agricultural sustainability in arid regions like Khuzestan province. HIGHLIGHTS Soil electrical conductivity (EC) decreased by increasing the depth of leaching water.; By increasing the depth of water in the leaching process, the amount of soil sodium and chloride decreased.; The combination of saline drainage water and non-saline river water is suitable for irrigation and reducing soil salinity.; The amount of EC reduction was more than exchangeable sodium percentage reduction.;

The occurrence and removal of dissolved organic nitrogen (DON) is an issue of increasing importance for the reclamation of treated wastewater. Effluent DON may act as a precursor of disinfection by-products during wastewater disinfection and may contribute to eutrophication of receiving surface waters. The aim of this study was to understand the effect of the post-denitrification process on final effluent DON (organic nitrogen filtered by 0.45 μm pore size) concentration to further gain knowledge on how to optimize denitrifying filtration, in order to reach the required discharge standards. To evaluate DON variation, denitrification batch experiments were carried out with suspended and attached biomass under different shear conditions. For both conditions, with suspended and attached biomass, DON concentration did not increase or decrease during the denitrification process with addition of an external carbon source. Moreover, the increase of shear rate did not affect the DON concentration. Apparently, there is no direct link between DON evolution and the denitrification process itself. [ABSTRACT FROM AUTHOR]

The study was conducted on Długie Lake (area 26.8 ha, maximum depth 17.3 m), located in the town of Olsztyn, in north-eastern Poland (the Masurian Lake District). For 20 years starting in the 1950s, Długie Lake was used as a receiver of raw domestic and storm sewage in quantities oscillating between 350 and 400 m³ day-1. This led to complete degradation of the lake, known as saprotrophy. After some preliminary protective treatments in the catchment, the lake has been renewed by artificial aeration with thermal destratification and the phosphorus inactivation methods. Long-term reclamation of the reservoir has resulted in distinct and durable improvement of water quality. Before the restoration, the average phosphorus concentration in the surface water layer was 0.079 mg P L-1 and in the overbottom water it reached 2.277 mg P L-1. The total phosphorus (TP) level also was very high, i.e. up to 3.5 mg P L-1. After the restoration, these values have declined to 0.001-0.017 mg P L-1 in the case of mineral P, and the current TP concentrations do not exceed 0.350 mg P L-1. [ABSTRACT FROM AUTHOR]

A wastewater treatment and reclamation facility in north-east Spain was monitored over 1 year to determine the occurrence and concentrations of different microbial indicators (Escherichia coli, fecal enterococci, somatic bacteriophages and spores of sulfite-reducing clostridia). The removal of the indicators and its relationships through the wastewater treatment and reclamation trains were evaluated. The results obtained show that the reclamation treatments evaluated present a different efficiency in indicator microorganisms' removal depending on the type of microorganism. The E. coli and enterococci present an average reduction slightly higher than the other indicators, followed by somatic bacteriophages and spores of sulfite-reducing clostridia. The Spearman's correlations indicate that it is not suitable to use any of the bacterial indicators evaluated to predict the content of virus or spores of sulfite-reducing clostridia. Therefore, in order to evaluate the microbiological risk of the reclaimed effluent use, it is necessary to monitor the three types of indicator microorganisms (bacteria, virus and protozoa). [ABSTRACT FROM AUTHOR]

More and more research effort has been put into the development of affordable and high-efficiency wastewater reclamation technology for small communities. In this study, an integrated chemically enhanced primary treatment (CEPT), trickling filter (TF) and ultrafiltration (UF) process was developed with success. Coagulant produced from fly ash was used to enhance primary treatment, while trickling filter packed with coal cinder through four-layer structure without aeration was employed for further removal of COD and ammonium-nitrogen from the CEPT effluent. 95 and 88% removal of COD and ammonium were achieved, while total phosphorus (TP) and suspended solid (SS) were found to be removed completely at a coagulant dosage of 2.5 mL/L in the CEPT-TF-UF system. The product water can meet the standard of Reuse of Recycling Water for Urban Water Quality Standard for Urban Miscellaneous Water Consumption (GB/T 18920-2002, China). [ABSTRACT FROM AUTHOR]

Bench-scale experiments were conducted to investigate the application of ozonation pre-treatment for biologically treated textile and dyeing wastewater to improve performance of the RO process. Based on ozonation experiments, four specific ozone consumptions (SOC), 0, 0.3, 0.6, 4.0mgO3/mgDOC0 were chosen for study of the effects of ozonation on the reverse osmosis (RO) process. Membrane flux was recorded. Also, the permeate water quality parameters such as TOC, conductivity were analyzed. In addition, fouled membrane cleaning was studied. The study further examined the nature and mechanisms of membrane fouling using scanning electron microscopy (SEM) and the energy dispersive X-ray spectrometer (EDS). The effect of ozonation on RO filtration was found to depend on SOC. The study revealed that significant improvement can be achieved in the efficiency of RO filtration by employing ozonation with 0.6mgO3/mgDOC0 SOC. Although the product water purity slightly decreased, the ozonation pre-treatment showed advantages at 0.6mgO3/mgDOC0 SOC for the following: (i) mitigation of flux decline due to membrane fouling; (ii) improvement in foulants cleanability. In addition, hypotheses were put forward to explain the reasons from the aspect of organic matter characteristics changed by ozonation, such as changing on functional groups and molecular weight of organic matter. [ABSTRACT FROM AUTHOR]

As the final closure of the world's longest sea dike of 33 km, the use of the Saemangeum reclaimed land becomes an issue in Korea. The Korean government has proclaimed that the Saemangeum Reclamation Project will be handled in an environmentally friendly manner but its effect on the water quality of reservoirs has always been controversial. This study was conducted to estimate the water quality of the Saemangeum reservoir using WASP5 according to the new land use plan adopted in 2007. Predictions on water quality shows that Dongjin reservoir would meet the standards for COD, T-P, and Chl-a if the wastewater from the Dongjin region was properly managed. However, T-P and Chl-a in Mangyeong reservoir would exceed the standards even without releasing the treated wastewater into the reservoir. With further reductions of 20% for T-P and Chl-a from the mouth of Mangyeong river, the water quality standards in the reservoir were achieved. This means that additional schemes, as well as water quality management programs established in the Government Master Plan in 2001, should be considered. Although the Saemangeum reservoir would manage to achieve the standards, it will enter a eutrophic state due to the high concentration of nutrients. [ABSTRACT FROM AUTHOR]

In Sardinia, as in many other Mediterranean regions, recurrent droughts and climate change have dramatically reduced available water resources. As a result of this critical situation, in 1995 the Italian Government declared a state of emergency and drew up a program for financial support by the State and local authorities with the aim of reducing this serious deficit. One of the actions focused on reclaiming and reusing the effluent from the sewage treatment plant of Cagliari. This article reports on the multidisciplinary preliminary study performed by the Ente Acque della Sardegna (ENAS) to evaluate the suitability of reusing Is Arenas effluent for irrigation and on the operation of the tertiary treatment plant. [ABSTRACT FROM AUTHOR]

The aim of this work was to examine the ecotoxicity of reclaimed wastewater by the use of bioassays and the determination of immunological parameters. Secondary and tertiary mucicipal wastewater samples were examined for their physicochemical and microbiological characteristics as well as for their endotoxin concentrations. The ecotoxicological characteristics were assessed by a battery of bioassays, using Vibrio fischeri, Daphnia magna and Tetrahymena thermophilla as test species and phytotoxicity. The mitogenic responses of mouse splenocytes were as well used as bioassay. The cytokines of IL-1, IL-2, IL-10, IFNγ and TNFα, were also determined in the supernatant of splenocyte cultures and served as molecular biomarkers. All bioassays exhibited decrease of the ecotoxicological responses after tertiary treatment. However, mitogenic responses were proved to be more sensitive. IL-1 increased, while IL-2 production was unaffected. The fact that IL-10 production increased in response to secondary treated effluents in conjunction with the increased endotoxin levels, suggest Th2 type immune responses. Although results obtained from the toxicity bioassays after the tertiary treatment showed comparable results to those of controls, cytokine levels indicated the induction of immune response even after tertiary treatment. Consequently, cytokine production could be used as a sensitive biomarker for the evaluation of treatment efficiency of the reclaimed wastewaters intended for reuse. [ABSTRACT FROM AUTHOR]

Cross flow microfiltration (MF) for reclaiming backwash water from two water treatment plants was studied. The results showed that both transmembrane pressure (TMP) and cross flow velocity affected the permeability significantly. Cake resistance (Rc) contributed to the majority of total filtration resistance among all MF experiments. It was found that higher solid loading of backwash water did not lead to lower permeability. On the contrary, size distribution and fractal dimension of particulate matters in backwash water were more important in determining specific cake resistance and permeability. Packing of particulate matters with higher fractal dimension induced more compact structure of cake layer, which resulted in higher specific cake resistance. It was found that the effect of fractal dimension on cake compressibility was insignificant, probably because of the decrease in cake deposition during turbulent cross flow MF. Theoretical analysis on the size distribution of deposited particulate matters indicated that the proportion of submicron to micron particulate matters deposited became higher when cross flow velocity was increased. As a result, cake porosity became lower when under turbulent cross flow. Permeate quality was satisfactory in meeting drinking water standards. [ABSTRACT FROM AUTHOR]

This study was aimed at exploring the reclamation of sewage treatment plant effluent water (SEW) as an alternative water resource. For the oxidation of SEW, an ozone-UV system, based on the results of the combined ozone/UV process performed in our previous study, was set up under practical conditions, including a series type, continuous mode, semi-pilot scale operation (1. 5 m³/d). As a result, the serial contact of the ozone and UV reactors showed lower CODCr and TOC removal efficiencies. However, these were greatly enhanced by recycling the water flow of the ozone-UV system at 40Q, as a result of the improvements in the transferred ozone dose in the ozone reactor and the contact efficiency between photons and ozone in the UV reactor, which approached that achieved in the combined ozone/UV process. For the disinfection of SEW, carried out in a syringe-type batch reactor, the increase of instantaneous ozone demand (ozone ID) led to a higher inactivation efficiency, an increased UV transmittance due to ozonation, and an enhanced inactivation rate of E. Coli in the UV reactor. Additionally, it was concluded that the ozone/UV process could overcome the limitations of the ozone alone and UV alone processes for the reclamation of sewage effluent water. [ABSTRACT FROM AUTHOR]

Biofilms play a major role in many water reclamation and reuse technologies. Normally, wherever there is water, a support surface and nutrients available, a biofilm will form. In some cases, this may result in problems for the water treatment system, due to biofouling or the growth of pathogenic or other unwanted microbes, but more frequently, the biofilm serves a very useful purpose by biodegrading organic contaminants in the water or by converting unwanted inorganic materials into harmless ones. Biofilms are commonly found associated with membrane reactors and filtration systems used in water reclamation and reuse systems, and are often a critical component. They are also found in soils where they may impact water injection or removal systems, or in situ bioremediation. Knowledge of the way biofilms form, how they grow and how to control them is critical for effective design and operation of many water reclamation facilities. This paper explores the modes of formation and growth of biofilms, modern methods for exploring the structure and function of biofilms, and how to control their growth. This paper also presents details on our development of microelectrode sensor arrays for continuous soil pore water quality monitoring. [ABSTRACT FROM AUTHOR]

Reclamation and re-use of wastewater is one of the most effective ways to alleviate the shortage of water resources, while the safety of reclaimed water becomes one of the critical problems for protecting human health and the ecosystem. While a toxicity test can vividly reflect biological effects of chemicals as a whole, in this study, the Microtox test was used to screen toxicity changes of wastewater during conventional reclamation processes. The results showed that toxicities of water samples decreased continuously along reclamation processes except chlorination/dechlorination in which the toxicity increased significantly. Furthermore, as for different forms of residual chlorine, toxicity of wastewater was quite different with increasing chlorine dosage. NH3-N had a trend to decrease toxicity of disinfected wastewater, while UV254 had a trend to increase toxicity. It was found that there was a good linear relationship between toxicity formation and UV254/NH3-N ratio for wastewater after disinfection with combined chlorine form before peak-point. [ABSTRACT FROM AUTHOR]

Two MBR pilot systems were constructed and tested in the Bali Primary WVVTP. The pilot study shows that two MBR systems, i.e. the Green-MenBio system (MBR-1) and the Bio-MF system (MBR-2), can both fulfill the requirement of wastewater reclamation standard, The MBR-2 system is more economical compared with MBR-1 system. The cost of US$ 0.10–0.16/m³ is estimated to reclaim the effluent of primary WWTP in Taiwan. The Bali Primary VVWTP has the capacity of 1,320,000 cmd which is the biggest in Taiwan. The domestic wastewater of partial Taipei City and Taipei County are collected and transported to the Bali Primary WWTP. The effluent of the Bali Primary WVVTP is then discharged into the ocean through two 3.8 m marine outfalls. The AO processes are installed in both MBR systems. More than 90% of the NH3-N can be removed through the AO and membrane processes. The outflow of the MBR systems (without RO) can reach the quality of COD < 30 mg/l, BOD < 10 mg/l, SS < 5 mg/l, NH3-N < 3 mg/L. The outflow of the MBR system is proposed to transport 40 km south to the Taoyuan County where four new industrial parks are to be constructed. Part of the reclaimed water is to be used on irrigation and another portion is to be sent to the industries after RO treatment. [ABSTRACT FROM AUTHOR]

A novel filtration process with synthetic permeable media was investigated for secondary effluent reclamation. Polyurethane was chosen as the filter medium among three tested media. Compressibility and up-flow velocity were changed to determine the optimum operation for the system. An equation was introduced to express the relationship between the removal efficiency and up-flow velocity. In a pilot study, the synthetic medium filtration with compression showed very stable effluent quality without clogging trouble, though the system operated with three times higher filtration rate and much longer backwashing interval than conventional systems. [ABSTRACT FROM AUTHOR]

The aim of this work is to determine the technical and economic feasibility of implementing different reclamation and reuse projects that improve the quality of the Apatlaco river basin located in the central part of Mexico. A special methodology based on a decision support system was developed. This methodology allows to decide if it is convenient or not to finance a reclamation or reuse project for the most common water uses in the basin. This methodology is based on the net present value criteria (NPV) of the effective cash flow during the useful life of the project. The results obtained reveal a technical and economical feasibility for industrial reuse in Jiutepec and for agricultural reuse in Zacatepec and Emiliano Zapata. On the other hand, sanitation projects are not feasible in all cases analyzed. Therefore, Mexican Regulation (Ley Federal de Derechos en Materia de Agua) as currently implemented, does not promote and support this kind of projects. [ABSTRACT FROM AUTHOR]

Even though Japan has mean annual precipitation of 1,714 mm and hundreds of dams and reservoirs constructed, frequent and severe droughtshave 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. [ABSTRACT FROM AUTHOR]

Thames Water is working with the New Millennium Experience Company to provide a water recycling system for the Millennium Dome which willsupply 500m3/d of reclaimed water for WC and urinal flushing. The system will treat water from three sources: rainwater - from the Dome roof; greywater - from handbasins in the toilet blocks; groundwater - from beneath the Dome site The treatment technologies will range from'natural' reedbeds for the rainwater, to more sophisticated options,including biological aerated filters and membranes for the greywaterand groundwater. Pilot scale trials were used to design the optimum configuration. In addition to the recycling system, water efficient devices will be installed in three of the core toilet blocks as part of a program of research into the effectiveness of conservation measures. Data on water usage and customer behavior will be collected via acomprehensive metering system. Information from the Dome project on the economics and efficiency of on-site recycling at large scale and data on water efficient devices, customer perception and behavior will be of great value to the water industry. For Thames Water, the project provides vital input to the development of future water resource strategies. [ABSTRACT FROM AUTHOR]

Water quality transformations during soil aquifer treatment at the Mesa Northwest Water Reclamation Plant (NWWRP) were evaluated by sampling a network of groundwater monitoring wells located within the reclaimed water plume. The Mesa Northwest Water Reclamation Plant has used soil aquifer treatment (SAT) since it began operation in 1990 and the recovery of reclaimed water from the impacted groundwater has beenminimal. Groundwater samples obtained represent travel times from several days to greater than five years. Samples were analyzed for a wide range of organic and inorganic constituents. Sulfate was used as atracer to estimate travel times and define reclaimed water plume movement. Dissolved organic carbon concentrations were reduced to approximately 1 mg/L after 12 to 24 months of soil aquifer treatment with an applied DOC concentration from the NWWRP of 5 to 7 mg/L. The specific ultraviolet absorbance (SUVA) increased during initial soil aquifer treatment on a time-scale of days and then decreased as longer termsoil aquifer treatment removed UV absorbing compounds. The trihalomethane formation potential (THMFP) was a function of the dissolved organic carbon concentration and ranged from 50 to 65 mgTHMFP/mgDOC. Analysis of trace organics revealed that the majority of trace organics were removed as DOC was removed with the exception of organic iodine.The majority of nitrogen was applied as nitrate-nitrogen and the reclaimed water plume had lower nitrate-nitrogen concentrations as compared to the background groundwater. The average dissolved organic carbon concentrations in the reclaimed water plume were less than 50% of the drinking water dissolved organic concentrations from which the reclaimed water originated. [ABSTRACT FROM AUTHOR]

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 havemade irrigation supply more problematic. Wastewater reuse could represent a viable solution to meet water demand. The focus of this paperis 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 practicing 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. [ABSTRACT FROM AUTHOR]

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, Floridareuse 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 effluentshave 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. [ABSTRACT FROM AUTHOR]

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 favorable to UV, the ozone alternative should be examined in cases such as the disinfection of low-quality effluentsor 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. [ABSTRACT FROM AUTHOR]

The trend towards reuse of effluent for land application of domesticand industrial wastewater is driven by the need to maximize limited water resources and benefit from the plant nutrients available in theeffluent. Of significant impact upon the value of the wastewater forreuse is its chemical properties as well as biochemical oxygen demand and suspended solids. While the sewage treatment plant is expected to treat all wastewater received to a minimum environmental standard,no efforts are given to reducing the chemical load derived from usesof chemicals in the domestic household. That the regulation of industry and commerce far exceeds those of the combined effects of thousands of household is remiss of environmental regulators. This paper examines the results of research into the more common sources of chemical additives to the wastewater stream. Twenty five potable water supplies are examined for their salt load, 20 liquid and 40 powder laundrydetergents and five dishwashing products were used to simulate discharges to the sewer, measured for their phosphorus, salt and sodium concentrations. The results of the research indicate that choices in the products available for general use within the house can be made only where product labeling and consumer education is improved. Technical improvements in wastewater treatment are not the answer. The improvement in effluent quality will have significant beneficial effects upon land application areas and expand the range of reuse options available for commercial operations. [ABSTRACT FROM AUTHOR]

A modified Assimilable Organic Carbon (AOC) procedure was adopted inconjunction with Heterotrophic Plate Count (HPC) method to assess the effect of Single Effect Distillation (SED) and Reverse Osmosis (RO)lab-scale systems on the biological stability of industrial water. Industrial water was collected from a local Industrial Water Works, pre-treated with alum coagulation and cartridge filtration, before being subjected to advanced water treatment. The results obtained in thisstudy indicated that AOCs in the SED product water were in the rangeof 70-80 mg acetate-C/L, while those in the RO product water ranged from 30-40 mg acetate-C/L in the 15-min permeate to 55-65 mg acetate-C/L in the 3-hr permeate. The above findings suggested that product water of both systems were potentially biologically unstable and wouldlikely lead to bacteria regrowth during its distribution and storage. Removal efficiencies of lab-scale RO and SED systems on AOC were ashigh as 90%, dependent on the concentration of AOC-NOX in the industrial water. The RO system had much higher organic removal efficiencies in terms of AOC and DOC than the SED system. Organics removed from both feed waters were found to be concentrated in the brine water andrejected water in SED and RO systems respectively. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study aims to remove the color substances, which normally causedifficulties in membrane filtration processes due to fouling using heterogeneous UV/TiO2/H2O2 reactor. It is confirmed that the technique used in this study was effective toremove TOC at 38% and color400 at 89% within 150-min irradiation. The experiment results showed that low concentrations of hydrogen peroxide dosage (less than 0.016 M) to UV/TiO2 system accelerated the TOC and Color400 removal rate from 9% to 38% and 40% to 89% respectively, while over-dosage made this positive effect decline. The humic acid solution treated by photo catalytic oxidation in UV/TiO2/H2O2 reactor did not change the zeta potential on membrane surface and membrane rejection rate. [ABSTRACT FROM AUTHOR]

An integrated technical-economic model is used to address water management issues in the French island of Noirmoutier. The model simulates potable water production and supply, potable and non potable water demand and consumption, wastewater collection, treatment and disposal, water storage, transportation and reuse. A variety of water management scenarios is assessed through technical, economic and environmental evaluation. The scenarios include wastewater reclamation and reusefor agricultural and landscape irrigation as well as domestic non potable application, desalination of seawater and brackish groundwater for potable water supply. The study shows that, in Noirmoutier, wastewater reclamation and reuse for crop irrigation is the most cost-effective solution to the lack of water resources and the protection of sensitive environment. Some water management projects which are regarded as having less economic benefit in the short-term may become competitive in the future, as a result of tightened environmental policy, changed public attitudes and advanced water treatment technologies. The model provides an appropriate tool for water resources planning and management. [ABSTRACT FROM AUTHOR]

Due to water resource shortage and socio-economic development withintwenty years, China faces serious problems of water supply and waterpollution. 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. [ABSTRACT FROM AUTHOR]

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 identifythe 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 paperdiscusses various technical, institutional and management related issues to promote industrial wastewater reuse, with few case studies. [ABSTRACT FROM AUTHOR]

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 mindthe quality of most of surface waters in Italy, the main parameters to control for a general purpose reclaimed water supply are microbialquality and TSS content. Therefore a contact filtration followed by disinfection is to be considered the minimum option, while the use ofpolishing 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. [ABSTRACT FROM AUTHOR]

This paper aims to use quantitative risk analysis, risk modeling andsimulation modeling tools to assess the performance of a proprietarysingle house grey water recycling system. A preliminary Hazard and Operability study (HAZOP) identified the main hazards, both health related and economic, associated with installing the recycling system ina domestic environment. The health related consequences of system failure were associated with the presence of increased concentrations of micro-organisms at the point of use, due to failure of the disinfection system and/or the pump. The risk model was used to assess the increase in the probability of infection for a particular genus of micro-organism, Salmonella spp, during disinfection failure. The increasein the number of cases of infection above a base rate rose from 0.001% during normal operation, to 4% for a recycling system with no disinfection. The simulation model was used to examine the possible effects of pump failure. The model indicated that the anaerobic COD release rate in the system storage tank increases over time and dissolved oxygen decreases during this failure mode. These conditions are likelyto result in odor problems. [ABSTRACT FROM AUTHOR]

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 sustainableform 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. [ABSTRACT FROM AUTHOR]

In Tunisia, golf courses are irrigated with secondary treated effluent stored in landscape impoundments. The impact of the conveyance andstorage 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: nutrientand 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 asthe 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 meettarget quality criteria recommended by WHO (1989) for water intendedfor 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. [ABSTRACT FROM AUTHOR]

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 insummer. [ABSTRACT FROM AUTHOR]

The reuse of treated wastewater to augment natural drinking water supplies is receiving serious consideration. Treatment of secondary andtertiary effluent by membrane filtration was investigated by assessing nanofiltration (NF) membrane and ultrafiltration (UF) membranes inbench-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. [ABSTRACT FROM AUTHOR]

Given the pressures on the world's freshwater resources, recycled water is a valuable resource. Recycled water can increase the reliability of water supply because it is an independent source of water. Water recycling requires effective measures to protect public health and the environment. In the absence of comprehensive international guidelines, different countries have developed different approaches to managing water recycling depending on the understanding of the health risks, their individual economic circumstances, and affordability. Approaches vary between high technology/high cost/low risk and low technology/low cost/controlled risk. Furthermore, differences occur between countries and within individual countries. Inconsistencies can often be traced to lack of a unified scientific position on health effects.These inconsistencies increase public concerns about health risks and may give rise to conservative controls on responses to water recycling projects that some countries may be unable to afford. In this paper, an international panel of authors discusses how the different water recycling approaches might be linked together into international water recycling guidelines. These guidelines would incorporate a uniform approach to assessing hazards and risks while providing flexibility for individual countries to vary requirements to suit local circumstances of affordability and risk. The authors propose a framework of guidelines in which individual countries can progressively improve recycled water quality as lower risk levels become more affordable. Theauthors argue that a uniform international approach will result in anumber of benefits including a better focus on risk management, better targeted research and development efforts and greater public confidence in water recycling. The authors invite discussion on the concepts put forward in the paper. [ABSTRACT FROM AUTHOR]

Abstract Variations in water quality of waste water treatment plant (WWTP) effluent complicate ultrafiltration of this feed water. Traditional parameters do not provide sufficient information to explain thefouling of membranes during ultrafiltration of WWTP effluent. New parameters for measuring and monitoring the fouling potential of feed water for ultrafiltration membranes need to be developed. The normalized membrane fouling index for ultrafiltration membranes (MFI-UFn) can be used as such and is according to the cake filtration theory calculated from the ratio of filtration time and filtration volume as a function of the filtration volume. MFI-UFn can becalculated from both experiments with constant Trans Membrane Pressure (TMP) and from experiments with constant flux. This parameter can also be calculated independent of the scale of the experiment. Results show that differences in fouling potential can be measured for various feed waters using the same membrane type and for various membranetypes using the same feed water. Variation in feed water quality leads to a deviation of the MFI-UFn, as was found especially for WWTP effluent. The applied TMP influences the value of the MFI-UFn, indicating cake compression when applying a higher TMP.MFI-UFn can be used to identify the effect of pre-treatment methods, which is useful when using WWTP effluent as feed water for an ultrafiltration processes. [ABSTRACT FROM AUTHOR]

In this study the removal of a diversity of microorganisms during different stages of treatment was evaluated. The process scheme consisted of Advanced Primary Treatment (APT), sand filtration, and chlorinedisinfection. During the first 2 stages, fecal coliforms were reduced from 1.24X109 to 1.2X108 MPN/100 mL and helminth ova were reduced to less than 1 ova/L. Nevertheless, to obtain aneffluent water quality that meets the microbiological standards recommended by the World Health Organization (1989) and the Mexican norm for water destined for agricultural reuse it was necessary to disinfect the effluent with a chlorine dose of 12 mg/L for a 3 hour contact time. Under these conditions, fecal coliforms were reduced from 1.2X109 to 5.8X101 MPN/100 mL, Salmonella spp. from 5.0X108 MPN/100 mL to below the detection limit, Pseudomonas aeruginosa from 2.0X105 MPN/100 mL to below the detection limit, and protozoan cysts from 1052 to 31 cysts/L. Regrowth of bacteria was never observed during the 48 hours period following disinfection. The active chlorine was primarily in the form of chloramines thus reducing the formation of other potentially carcinogenic disinfection byproducts. [ABSTRACT FROM AUTHOR]

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 purposeof wastewater reclamation in electronics industries. ORP monitor wascombined into the system to obtain the optimum ratio of H2O2 to O3 by automatically adjusting the dosageof 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 300mV or 800 mV and 900mV was proper for H2O2/O3 control. The treatability of the model substances was in an order of IPA<

This paper presents a successful water reclamation and reuse projectin 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 ofpotential large industrial customers. Current customers are a mix ofpublic, 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 distributionof reclaimed water to external customers requires least energy. [ABSTRACT FROM AUTHOR]

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 removalefficiencies 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 to10 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 expectedfrom 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 veryeconomical for Istanbul City due to increasing industrial water supply tariffs. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Reclaimed wastewater transport is studied in a concrete-lined cast iron pipe, where a nitrification-denitrification process occurs. The pipe is part of the Reuse System of Reclaimed Wastewater of South Tenerife (Spain), 0.6 m in diameter and 61 km long. In order to improve wastewater quality, at 10 km from the inlet there is injection of fresh water saturated in dissolved oxygen (DO), after which a fast nitrification process usually appears (less than two hours of space time). The amount of oxidized nitrogen compounds produced varies between 0.8and 4.4 mg/l NOX--N. When DO has disappeared, a denitrification process begins. The removal of nitrite is complete at the end of the pipe, whereas the nitrate does not disappear completely, leaving a concentration of about 0.4-0.5 mg/l. For a COD/NOX--N ratio higher than 5, a first order nitrification rate in NOX--N has resulted, with the constant k20 = 0.079 h-1, for a NOX--N concentration range of 0.8-4.4 mg/l. Finally the following temperature dependency for the first order denitrification rate constant has been found : k = k20.1X15 T-20. Although nitrogen could be used as nutrient in the agricultural reuse, its removal from reclaimed wastewater could be useful in order to diminish the chlorine needs for reclaimed wastewater disinfection. [ABSTRACT FROM AUTHOR]

The feasibility of the membrane bioreactor (MBR) process for water reclamation was studied. Process evaluation was based on the following: literature review of MBRs, worldwide survey of MBRs, and preliminary costs estimates. The literature review and the survey have shown that the MBR process offers several benefits over the conventional activated sludge process, including: smaller space and reactor requirements, better effluent water quality, disinfection, increased volumetricloading, and less sludge production. The MBR process can exist in two different configurations, one with the low-pressure membrane modules replacing the clarifier downstream the bioreactor (in series), and the second with the membranes submerged within the bioreactor. Four major companies are currently marketing MBRs while many other companies are also in the process of developing new MBRs. The MBR process operates in a considerably different range of parameters than the conventional activated sludge process. The preliminary cost evaluation has shown that the MBR process is cost competitive with other conventional wastewater treatment processes. [ABSTRACT FROM AUTHOR]

A study was carried out to compare the inactivation of faecal bacteria and one type of bacteriophage in a full-scale UV disinfection system. The system is part of a water reclamation facility for effluent reuse in golf course and agricultural irrigation. Influent and effluent samples were taken over two sampling periods (three consecutive days in July and one day in August), with three different UV doses applied each day (ranging from 10 to 40 mW.s/cm2 and 20 to 80 mW.s/cm2 in July and August, respectively). Effluent samples were also taken from a chlorine disinfection channel (5 mg Cl2/L dose) operating in parallel to the UV system. Total coliforms (TC), faecal coliforms (FC), faecal streptoccoci (FS) and somatic coliphages (SC) were measured in each sample. F-specific RNA bacteriophages and bacteriophages of Bacteroides fragilis were also measured one day in July. The decay ratio observed for all the microorganisms was similar when UV doses applied were low (July), ranging from 1.15 to 1.25 log-units. This suggests that bacterial indicators may be suitable for virus inactivation control when low UV doses are applied; however, such low doses are inadequate to achieve effluent quality requirements for unrestricted irrigation. At higher UV doses (August), decay ratios for TC and FC were 3.1 and 2.8 log-units respectively, indicating that they were more susceptible to UV exposure than SC and FS, with decay ratios of 2.6 and 1.0 log-units, respectively. Nevertheless, these higher doses were also inadequate to achieve water qualityrequirements for unrestricted irrigation. The decay ratio of SC during chlorine disinfection was clearly lower than that of the other microorganisms. Bacteriophages of Bacteroides fragilis were more resistant to UV disinfection than SC and F-specific RNA. In fact, bacteriophages of Bacteroides fragilis were not affected during UV exposure. A UV dose ranging from 40 to 80 mW.s/cm2 marks the borderline [ABSTRACT FROM AUTHOR]