Disinfection of wastewater is a necessary treatment process for protecting the public from potential exposure to pathogenic microorganisms because many wastewater effluents are discharged into water bodies that may be used for recreation or as future drinking water supplies. Two common forms of disinfection are chlorine and ultraviolet (UV) light. However, microorganisms differ in their susceptibility to UV and chlorine disinfectants. It is necessary to understand how different classes of pathogens respond to UV and chlorine disinfection processes in wastewater to better develop strategies for optimizing the treatment of pathogens in wastewater. It is also recognized that water quality may impact disinfection effectiveness, such as protection of pathogen by particles and disinfectant demand. This study investigated bacteria, viruses and protozoan pathogens. All species of bacteria tested were susceptible to both UV and chlorine, despite differences in antibiotic resistance and tendency to aggregate. Upon exposure to disinfection conditions that could indicate viability of the bacteria tested, but not culturability using common methods, it was found that UV and chlorine were effective in eliminating the capability of viable but non-culturable bacteria to resuscitate and become re-infective. Clostridium spores were resistant to free chlorine and UV disinfection but found to be susceptible to long exposure to monochloramine. Cryptosporidium was resistant to all chlorine forms but very susceptible to UV irradiation. Pathogenic and indicator viruses tested were very susceptible to free chlorine and UV disinfection. UV radiation throughout the 200 to 300 nm range was effective for inactivation of viruses and C. parvum, but wavelengths between 260-270 nm and below 220 nm appeared to be more effective for viruses, suggesting a possible advantage for polychromatic UV sources. Sequential disinfection strategies were proposed and tested to enhance inactivation of various microorganisms. One scenario integrated UV disinfection followed by dynamic chloramination through addition of free chlorine and subsequent transformation to combined chlorine. Further, disinfection of microorganisms in wastewater presents challenges that are inherent to the water matrix, such as pathogens associated with particles. UV and chlorine were both effective for disinfection of coliform in wastewater but chlorine was found to be more effective during long contact times for inactivation of particle associated coliform. In addition to coliform, both Cryptosporidium parvum and Salmonella typhimurium were identified as being particle associated in wastewater using molecular approaches developed to detect microbes in environmental samples

This report presents the results of an evaluation of technologies that may result in less biomass production in activated sludge processes. The report summarizes the results of a comprehensive literature review that was done to evaluate technologies in terms of their sludge reduction potential, ease of implementation, impacts on plant operations and effluent quality, reliability, and relative capital and operating costs. Reporting testing results supported significant biomass reduction by processes using chemical and thermal methods, higher life forms (predator processes), anaerobic instead of aerobic respiration, and extreme solids retention times, but biomass reduction for enhanced biological phosphorus removal (EBPR) processes and a mechanical disintegration process were less conclusive. The predator enhancement process showed promise for industrial wastewater treatment, but is less attractive for municipal wastewater treatment for which a lower soluble COD fraction is present. Extreme solids retention time processes may be practical for small wastewater flows and perhaps with the use of membrane separation technology. Anaerobic treatment processes are known to have a lower biomass yield (one fourth or a less than for aerobic treatment), but work is needed to develop their applications for low strength, low temperature wastewaters, such as in municipal wastewater treatment. For some processes such as the cell disruption using mechanical, thermal, and chemical means, the cost of implementing the biomass reduction technology was greater than the cost savings associated with less sludge production. Addition of chemical uncouplers can greatly reduce biomass production, but pose problems of toxic chemicals in the treated effluent. In a series of bench-scale tests carried out at the Seattle West Point wastewater treatment facility and the University of Washington environmental engineering laboratories the presence and mechanism of COD loss (and subsequent less biomass production) in the anaerobic zone of EBPR processes was investigated. The results of the test work and fundamental evaluation could not support previous claims of a COD loss in EBPR processes, nor was less sludge production observed.

Biological wastewater treatment plants can be adversely affected by influent toxicity. The effects can range from poor clarifier biomass settling and elevated effluent BOD and ammonia levels to total plant kills. These problems could be minimized or eliminated if an effective method existed for continuously monitoring biological wastewater treatment plant influent for toxicity to the treatment plant microorganisms. Current influent screening methods have not been proven to be adequate for adaptation to continuous screening in the field. The primary reasons include the batch-wise nature of the assays and an inadequate correlation between the assays and plant performance. The goal of the research team was to create new bioluminescent biosensors from different types of bacteria found in biological wastewater treatment plants for the development of a multi-channel continuous monitoring system. A system built from multiple biosensors would make it possible to differentiate between potential influent toxicity effects to different classes of bacteria (such as nitrifying and heterotrophic bacteria). The research team found it unexpectedly challenging to apply common microbiological transformation methods for laboratory strains to the wastewater treatment plant strains. The research team generated six new bioluminescent bioreporters from bacteria that are typical constituents of activated sludge. Of particular significance is a bioreporter developed using a Hyphomicrobium sp., which is a slow growing bacterium known to be present in significant numbers in some activated sludge plants. Of the six generated, initial bioluminescence and toxicity screening indicated that one strain (a Pseudomonad) was a particularly promising candidate due to its ease of cultivation and high light production. Further toxicity testing, however, determined that the response of the strain to 48 organic compounds and 8 metals commonly found in wastewater was similar to that of a previously created strain, Shk1 (also a Pseudomonad). Further work is therefore needed in the generation of appropriate biosensors and test conditions for populations not represented by the new heterotrophic biosensor.

Utilities must decide whether to modify their existing treatment practices to achieve compliance with the D/DBP regulations. A regulatory impact analysis predicted that up to 70% of large surface-water systems would need to make some treatment modifications. Meeting multiple water-quality objectives plays an important role in the decision-making process of water utilities. Utilities must meet other regulatory requirements and secondary drinking-water standards. In addition, there are operational, financial, and engineering issues that affect the selection of treatment technologies. Because of the uncertainty of how stringent certain regulations will be and the high costs of advanced treatment technologies, many utilities have implemented treatment modifications in stages. Most utilities have made treatment modifications that have been cost-effective to meet their site-specific needs and objectives, while continuing to study or implement long-term treatment changes to meet more stringent future regulations. Utilities must factor in other regulatory requirements and secondary drinking-water standards when selecting a treatment modification for compliance with the D/DBP Rule. Some utilities chose advanced treatment processes (e.g., ozonation, membranes) that would enable them to satisfy other current and anticipated future regulations or other water quality objectives. Some systems chose ozone, in part because of its ability to destroy taste-and-odor-causing contaminants. Likewise, granular activated carbon was added to filters for taste-and-odor control. In addition, space and retrofit considerations affected technology choices. Many utilities have implemented treatment modifications in stages. To meet Stage 1 of the D/DBP Rule, most utilities have made treatment modifications that have been cost-effective to meet their site-specific needs and objectives, while continuing to study or implement long-term treatment changes to meet more stringent future regulations. The major disadvantage to staged implementation was that the treatment process was re-optimized each time treatment modifications were made. However, this problem was minimized if the full range of changes in treatment was envisioned in advance and if incremental modifications were made that were part of and consistent with long-term modifications. Originally published by AwwaRF for its subscribers in 2003 This publication can be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

After sex, religion is one of the most popular and pervasive topics of interest online, with over three million Americans turning to the internet each day for religious information and spiritual guidance. Tens of thousands of elaborate websites are dedicated to every manner of expression. "Religion Online" provides an accessible and comprehensive introduction to this burgeoning new religious reality, from cyberpilgrimages to neo-pagan chatroom communities. A substantial introduction by the editors presenting the main themes and issues is followed by sixteen chapters addressing core issues of concern such as youth, religion and the internet, new religious movements and recruitment, propaganda and the countercult, and religious tradition and innovation. The volume also includes the "Pew Internet and American Life Project" "Executive" "Summary," the most comprehensive and widely cited study on how Americans pursue religion online, and Steven O'Leary's field-defining "Cyberspace as Sacred Space,"

Treatment Marshes for Runoff and Polishing represents the most comprehensive and up-date-date resource for the design, construction, and operation of marsh treatment systems. This new edition represents a complete rewrite of the surface flow sections of previous editions of Treatment Wetlands. It is based on the performance hundreds of treatment marshes over the past 40 years. Treatment Marshes focuses on urban and agricultural runoff, river and lake water improvement, and highly treated municipal effluents. New information from the past dozen years is used to improve data interpretation and design concepts. Topics included in this book are Diversity of marsh vegetation Analyses of the human use of treatment marshes New concepts of underground processes and functions Spectrum of marsh values spanning mitigation, restoration, enhancement, and water quality improvement Improved methods for calculation of evapotranspiration and wetland water temperatures Hydraulics of surface and subsurface flows in marshes Analysis of long track records for deterministic and probabilistic behavior Consideration of integrated microbial and vegetative contaminant removals via mass balances Uptake and emission of gases Performance of urban and agricultural wetlands Design procedures for urban and agricultural wetlands Reduction of trace metals, pesticides, pharmaceuticals, endocrine disruptors, and trace organics Updated capital and O&M economics, and valuation of ancillary benefits An updated list of over 1900 references

This book shows the effectiveness of DRASTIC model in a geographical setting for validation of vulnerable zones and presents the optimization of parameters for the development of precise maps highlighting several zones with varied contamination. Impact of vadose zone has also been assessed by considering every sub-surface layer. Exclusive title covering effectiveness of DRASTIC model for groundwater vulnerability assessment Reviews of the strengths and limitations of assessment methods Presents multi-criteria evaluation of hydro-geological and anthropogenic factors Discusses integration with geographic information system (GIS) and remote sensing (RS) Includes application of groundwater governance framework with a case study study of a geographical setting

This research focused on the use of sonication to destroy surfactants and surface tension properties in industrial wastewaters that affect traditional water treatment processes. We have investigated the sonochemical destruction of surfactants and a chelating agent to understand the release of metals from surfactants during sonication. In addition, the effects of physical properties of surfactants and the effect of ultrasonic frequency were investigated to gain an understanding of the factors affecting degradation. Successful partial or total destruction of surfactants resulting in the release of metals bound to surfactants may result in a significant cost savings of treatment plants. Sonochemical degradation of surfactants was observed to be more effective than nonsurfactant compounds. In addition, as the concentration is increased the degradation rate constant does not decrease as significantly as with nonsurfactant compounds in the NAP reactor. In fact, the total number of molecules degraded increases with concentration. The degradation of metal complexes is not as effective as in the absence of the metal. However, this is likely an artifact of the model complexing agent used at the hot bubble interface, significantly increasing ligand exchange kinetics and thus degradation of the complex. This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

Narrative water quality criteria are an integral component of States' water quality standards but they pose special problems when incorporated into the TMDL process. The TMDL process is typically a quantitative activity, defining numeric allowable loads necessary to meet a numeric water quality objective. Narrative criteria confound development of quantitative TMDLs, due to the absence of these numeric criteria. The objective of this research was to improve the methods for addressing narrative water quality criteria in the TMDL process. The problems associated with narrative criteria in the TMDL process are known in general terms but, prior to this research, there has not been a thorough review of the use of narrative criteria in TMDLs nor broad guidance on how to address narrative criteria in the TMDL process. The approach taken for this research was to define the range of problems associated with all types of narrative criteria by means of a comprehensive review of 120 narrative TMDLs, and provide guiding principles to help address these problems.Adherence to these guiding principles is expected to significantly improve the evaluation of water bodies for impairment of a designated use based on non-attainment of narrative water quality criteria, resulting in more accurate 303(d) lists with a greater focus on those water bodies truly impaired. Also, adherence to these guiding principles will contribute to improvements in the TMDL development process, resulting in a greater degree of success in attaining designated uses when a TMDL is implemented . This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

Thermal enrichment of coldwater streams by heated stormwater in summer months is often overlooked and even exacerbated by traditional management practices that typically account for flow moderation and pollutant removal only. Initiated in 1999, this study evaluated and identified innovative and traditional approaches to moderate this temperature impact by monitoring and analyzing the hydrologic and thermal regimes of an urban stormwater treatment system consisting of two traditional wet detention ponds and an enhanced natural wetland. Data analysis clearly shows temperature increases in the open detention ponds and the ability of the wetland to mitigate this thermal enrichment. Event-based thermal loading and temperature regime analysis indicated flow reduction via infiltration and effective vegetative cover in the wetland were the primary mechanisms for mitigating stormwater thermal enrichment. Using the concept of temperature equivalent, we also established the locations and strength of thermal enrichment areas. A heat transfer model was developed to simulate runoff temperature. Results indicated that rainfall characteristics, temperature difference between rainfall and the ground surface, and the runoff flow depth were the most important factors affecting runoff temperature.

This investigation reviewed and evaluated methodologies used for microbial risk assessment with respect to their applicability for reclaimed water applications. The investigation was comprised of five primary components: a comprehensive database of articles, reports and books describing microbial risk assessment methodologies was established and reviewed. Risk assessment techniques and models were identified for estimating the public health risk from exposure to microorganisms via reclaimed water applications. Two models were identified for further evaluation: a static (individual based) and a dynamic (population based). In the third component, the two models were evaluated to differentiate between the conditions under which models predict similar and substantially different estimations of risk. Through numerical simulation, exposure/pathogen combinations were identified when it may be appropriate to use the less complex, static model. Case study risk assessment scenarios demonstrated the model selection process for three realistic, yet hypothetical reclaimed water scenarios.The fourth component presents a constraint analysis for existing reuse regulations. The constraint analysis is carried out by documenting the existing reuse regulations. The constraint analysis is carried out by documenting the existing regs in three states for landscape irrigation and uses that comparison as a starting point to identify how microbial risk assessment may be useful within the context of existing and potential future water reuse regulations. The investigation concludes by identifying criteria for a computer interface that would allow regulatory and/or municipal agencies/utilities to take advantage of the analysis discussed in the report. This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

TMDLs, or total maximum daily loads, are required under the Clean Water Act, Section 303(d), for waterbodies that do not attain water quality standards. The objective of this research was to review the existing TMDL process and to develop an improved design for TMDL development where improvements are needed. This objective was accomplished through: (1) Identifying and verifying problems with the existing TMDL program; (2) Formulating a range of recommended improvement options on specific topics that address identified weaknesses; and (3) Providing case studies examples that highlight these recommended changes to improve the TMDL process. The research team identified ten specific areas for improvement, based on a review of approved TMDLs, a survey of state programs, and an in-depth review of specific case study examples. These topics relate to specific steps and/or methods employed in the TMDL development process. They include: estimating background pollutant loads; quantifying nonpoint source loads using simple methods; incorporating urban wet weather sources; selecting critical conditions; guiding principles for modeling; estimating the TMDL margin of safety; approaches to the allocation of loads; linking best management practices to load reduction; implementation planning, tracking, and adaptation; and adaptive watershed management. Each topic is addressed in a separate chapter of the report, with a discussion, recommendation of improved approaches where appropriate, and specific examples to help guide water quality professionals when developing or reviewing TMDLs.

Contamination of water supplies, whether by chemical, biological or radioactive agents, requires a rapid and effective response in order to reduce or avoid impact on the environment or consumers. Using seven major incident case studies (including the Milwaukee Cryptosporidium incident, Chernobyl and the UK Foot and Mouth outbreak), Water Contamination Emergencies: Can We Cope? looks at the complete handling of emergency incidents relating to water contamination emergencies. With contributions from experts involved in real life international incidents, the book also looks at: monitoring requirements; trying to prove the absence of contamination; novel approaches to screening analysis; health risks; the importance of efficient communication; the perception of the public; and the international height of alert situation with respect to potential terrorist acts. Anyone involved in water contamination emergencies, whether researchers and professionals in the water or health industries, or government agencies, should welcome this title as a review of lessons learnt in the past and as an identification of ways in which to improve response in the future.

This project examined the development of ambient water quality criteria (AWQC) for the protection of wildlife for mercury. Mercury is considered a serious risk to wildlife in many areas. As a result, the Great Lakes Water Quality Initiative and others have developed AWQC. These AWQC have been controversial, however, because (1) the AWQC were single values that did not account for site-specific conditions; (2) derivation of the AWQC relied on a single NOAEL, and (3) the AWQC had an unknown level of conservatism because of reliance on both average and conservative assumptions and uncertainty factors. Rather than develop a single value AWQC for total mercury, we derive an AWQC model that explicitly incorporates factors controlling bioavailability, methylation rates and bioaccumulation in the aquatic environment (e.g., pH, DOC, sulfate). To derive our AWQC model, field data was collected including numerous water quality parameters and total mercury and methylmercury concentrations in whole body fish tissue from 31 lakes in Ontario and an additional 10 lakes in Nova Scotia. An independent dataset consisting of 51 water bodies in the United States was then used to confirm the validity and robustness of the AWQC model. Next we combined the results of chronic-feeding studies with similar protocols and endpoints, in a meta-analysis to derive a dose-response curve for mink exposed to mercury in the diet. Using this approach, one can derive an LD5 or other similar endpoint that can then be used as the basis for deriving -wildlife AWQC. In the final step, we used a probabilistic risk model to estimate the concentrations of methylmercury in water that would lead to levels in fish sufficient for there to be a 10% probability of exceeding the mink LD5. This analysis was repeated for various combinations of pH and DOC. The result is an AWQC model for mercury for the protection of wildlife that can be used for a variety of site-specific conditions. This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

A scientifically sound approach is needed to ensure that flushable consumer products are compatible with household plumbing fixtures, as well as wastewater collection and treatment systems. In addition to assessing disposal system compatibility, an assessment approach should also ensure that flushable consumer products do not become an aesthetic nuisance in surface waters and soil environments. This document presents an overall approach for assessing the fate and compatibility of consumer products in wastewater disposal systems. While the focus of this document is on the United States, it is believed that the conceptual approach and many of the test methods could be used to assess the compatibility of flushable consumer products in wastewater disposal systems throughout the world.

Interest in ozonation for drinking water and wastewater treatment has soared in recent years due to ozone's potency as a disinfectant, and the increasing need to control disinfection byproducts that arise from the chlorination of water and wastewater.
Ozone Reaction Kinetics for Water and Wastewater Systems is a comprehensive reference that presents practical information to water treatment and wastewater treatment operators and researchers. It describes the application of kinetics to the effective evaluation, design, and implementation of ozone technology. This information will help plant operators determine whether or not ozone treatment is suitable for their facility, and help engineers and researchers design appropriate ozone treatment systems.
By presenting complete coverage of ozone kinetics in water and wastewater, this book provides researchers and practitioners with fundamentals of ozone kinetics as well as practical "how to" information.

Rapid growth of cities and industries in China is having a dramatic impact on the environment. To counteract further decrease of water quality of rivers, lakes and groundwater bodies, an ambitious environmental remediation programme needs to be designed and brought into action. Intensive research and development activity are required to provide tailored solutions.The articles compiled in the book describe the current situation in China with respect to surface water quality and wastewater treatment, and provide results of specific research projects, leading the way to a China-specific up-to-date water treatment technology. Discussed are lessons to be learnt from the experience made in other countries, particularly with respect to regulations and management practices.

Biological denitrification by heterotrophic bacteria is common in the wastewater industry in the U.S. and in drinking water processing in Europe. To facilitate heterotrophic denitrification, organic compounds such as methanol, ethanol and acetic acid are added to provide a carbon source for the bacteria. The resulting organic carbon residual may create problems with chlorination. The addition of these carbon compounds is expensive and results in added sludge production. This study focused on the use of autotrophic hydrogen oxidizing bacteria for denitrification. The method transfers hydrogen gas to solution via microporous hollow fiber membranes. Typically, gases are supplied to a system using conventional bubble diffusers. The conventional bubble aeration system has a low gas transfer efficiency, and, as a result, the cost of dissolving the required amount of gas is very high. In this study, microporous hollow fiber membranes were employed to supply hydrogen gas to hydrogen oxidizing autotrophic bacteria. Laboratory scale membrane modules were constructed and mass transfer studies were carried out to develop the design correlations for hydrogen gas transfer. A mixed culture was obtained and acclimated for batch denitrification studies. Both Sodium carbonate and carbon dioxide were used to deliver inorganic carbon. Bench scale continuous flow biofilm reactors containing plastic media were operated to remove nitrate from water. The required hydrogen gas was supplied at a constant rate via gas transfer modules, containing sealed end microporous hollow fiber membranes. The reactors were optimized for removal of nitrate and nitrite by varying the recycle ratios and hydraulic detention time. Experimental results indicated the presence of hydrogen oxidizing denitrifiers in wastewater sludge. Adequate pH control was possible and the pH averaged around 6.95. Gas transfer studies indicated that hydrogen transfer was primarily controlled by liquid film diffusion. Hydrogen gas was successfully delivered to the reactor via the hollow fiber membrane gas transfer module. Nitrate and hydrogen concentration measurements indicated that the system did not experience hydrogen limitations at detention times of 3.25 hours or greater. The use of hollow fiber membrane module appears to be a viable technology for transferring hydrogen gas to water. The research results in this report provide valuable information for pilot and full-scale studies for the water/wastewater community focusing on membrane processes for autotrophic denitrification.

The purpose of this research project was to examine construction projects that successfully reduced Rainfall Dependent Infiltration/Inflow (RDII). The research began with a literature review of all published records describing RDII removal projects. Initially, the review identified many projects; however, subsequent evaluation of available information revealed several important realities. First, most RDII removal projects in the country go undocumented. Second, of the RDII removal project summaries that have been published, few provide good data. Third, data gathering and analyses for this report were hampered by lack of documentation, lost or unavailable monitoring data, and weaknesses in monitoring techniques. Projects with sufficient information describing the conditions before the RDII removal project received a detailed analysis. In all, the case studies from the six agencies presented in this report (1) document before-and-after RDII levels, (2) quantify the RDII reduction achieved, and (3) describe the cost-effectiveness of the removal. As more than one project was documented for some agencies, a total of 12 RDII projects received review. The projects examined include both those that ?successfully? reduced RDII and those that did not. In general, the conclusion was that utilities run the risk of not removing significant RDII unless they address private sewer laterals. The only cases examined where significant RDII was removed were those that addressed private sewers or inflow sources. A major recommendation of this report was to establish a standard reporting protocol for documenting RDII removal projects. This protocol details what specific information should be provided when documenting an RDII removal project and how to perform an evaluation of RDII removal effectiveness. The protocol touches on issues ranging from flow meter maintenance to statistical analysis of flow data. By using the proper documentation recommended in this report, communities allow others who are preparing to perform similar work to examine and utilize the results of any RDII removal project. This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

Non-potable and potable (principally in-direct potable) water reuse initiatives in the United States have faced increasing public opposition. Several high-profile initiatives have been halted after several years of planning and tremendous expenditures. To understand why the public holds the perceptions they do and what public participation options exist to address water reuse more constructively, a multidisciplinary analysis was undertaken by a team of social scientists, engineers, and water professionals. Through a comprehensive literature review, three in-depth case studies, and a 2-day interactive symposium this framework was developed for water professionals. The framework summarizes five underlying principles that contribute to shaping public perception and acts as a guide for water professionals in their selection of public outreach, education, and participation activities. Adhering to the principles outlined in this report contributes to building public confidence and trust, which in turn helps water utilities engage constructively with the public on challenging, contentious issues. The five principles are: ? Manage information for all ? Maintain individual motivation and demonstrate organizational commitment ? Promote communication and public dialog ? Ensure fair and sound decision making and decisions ? Build and maintain trust However, no checklist of "to-do's" exists for establishing public confidence and trust. Quite the opposite, this research suggests that a one-size-fits-all model cannot work because the most appropriate ways to achieve the principles can vary from case to case. Thus, the framework includes an analytical structure to assess the community in which a water reuse initiative is underway. Using diagnostic questions and analytical techniques, a comprehensive picture of the community can be generated and monitored over time. Through application of the diagnostic tools and a commitment to the principles outlined above, water professionals can build the public confidence and trust they need to engage with the public on difficult water reuse issues.

The objectives of this project were to develop (1) a better understanding of the effects of storage on reclaimed water quality, (2) a methodology to help understand/predict water quality changes during storage, and (3) effective management tools for minimizing water quality problems. The research team reviewed approximately 120 published articles, conducted a gray literature survey to analyze the impact of surface storage on reclaimed water quality. The team also evaluated federal guidelines for reclaimed water and developed a brief update on what individual states are doing. It was determined that state and federal water quality objectives can be met at the treatment site. However, because of the seasonal nature of reclaimed water use, water often must be stored in open reservoirs, where changes occur that can affect water quality. The nature of these changes was evaluated, including physical, chemical, and biological processes. The research team evaluated several reservoir management strategies to improve water quality, and reviewed water quality models to assess their applicability for open reclaimed water storage reservoirs. It also developed procedures to evaluate and select management strategies and reservoir water, along with matrices to distill the information learned in the study into a useful format for risk assessors and water quality managers. These tools will enable users to readily equate their specific storage reservoirs to representative examples, and to identify actions most applicable to their specific reclaimed water systems.

Under the National Pollution Discharge Elimination System (NPDES), many municipal and industrial wastewater treatment facilities must perform Whole Effluent Toxicity (WET) Testing. Regulatory agencies determine the level of compliance of each facility by making inferences about the results of these tests. There has been some concern regarding appropriate ways to integrate WET tests into NPDES permits. The central issue of this concern involves determining the relationship between WET tests and instream biological conditions. Previous research (WERF project 95-HHE-1) has examined this issue using historical data. Because of issues with data comparability, i.e. questionable data quality, and project design, results were inconclusive. This study plan was designed to collect new data on method performance for both WET and bioassessment that would help answer the outstanding question. The study plan was designed using a Data Quality Objective (DQO) approach in which DQOs and MQOs were defined. These DQOs and MQOs were characterized using technical input from many scientists from federal, state, and private organizations. It was through this effort that certain technical design issues arose that needed further investigation before implementing the definitive study. Among these issues were determining if DQOs and MQOs were achievable, and determining appropriate biological assessment methods for various ecoregions (e.g. effluent dependent streams in the arid west). In order to appropriately address these issues, it was determined that a pilot study would be implemented before the definitive study. The pilot study is designed as a one-year study in which participating facilities will perform quarterly WET tests (Ceriodaphnia, P. promelas, Selenastrum) and at least one bioassessment (macroinvertebrate, fish, algae) as well as providing other prescribed data requirements. Results of the pilot will provide answers to technique design issues and will ultimately determine the most appropriate study design for the definitive study.

The central theme of the book is the flow of information from experimental approaches in biofilm research to simulation and modeling of complex wastewater systems. Probably the greatest challenge in wastewater research lies in using the methods and the results obtained in one scientific discipline to design intelligent experiments in other disciplines, and eventually to improve the knowledge base the practitioner needs to run wastewater treatment plants. The purpose of Biofilms in Wastewater Treatment is to provide engineers with the knowledge needed to apply the new insights gained by researchers. The authors provide an authoritative insight into the function of biofilms on a technical and on a lab-scale, cover some of the exciting new basic microbiological and wastewater engineering research involving molecular biology techniques and microscopy, and discuss recent attempts to predict the development of biofilms. This book is divided into 3 sections: Modeling and Simulation; Architecture, Population Structure and Function; and From Fundamentals to Practical Application, which all start with a scientific question. Individual chapters attempt to answer the question and present different angles of looking at problems. In addition there is an extensive glossary to familiarize the non-expert with unfamiliar terminology used by microbiologists and computational scientists. The colour plate section of this book can be downloaded by clicking here. (PDF Format 1 MB)

Originally written for the construction of gravity-flow drinking water systems in Nepal, this book is equally applicable for other locations around the world. Organized for quick reference, it is quickly and easily understood.

The design of wastewater treatment plants with redundancy to assure a quality end product may be in conflict with efforts to assure effectiveness. Redundancy of major system components is to assure compliance with regulations and protection of the environment and the health and safety of the public and treatment plant staff. However, the capital costs and maintenance associated with redundant equipment does not necessarily enhance facility performance. There are a number of forces driving the level of redundancy in plant designs. Federal and state compliance regulations and the design engineer's past experiences will influence the plant design. To some extent the plant staff may also provide input into the plant design and, therefore, contributes to the redundancy. This report determines alternative methods to address treatment plant redundancy, including examples of methods currently in place and, ideally, insight on the premises leading to these applications. A secondary objective is to identify the similarities and differences in redundancy requirements associated with federal and state regulatory agencies. This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below