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This report collates many of the significant developments that have taken place in secondary settling tank theory, design, modelling and operation.

The primary purpose of this research was to provide methods and tools that enable a water/ wastewater utility to develop and implement a performance measurement system based on a demonstrated proven approach. To achieve the purpose, the research was conducted in three phases: Core research on existing and applicable frameworks for performance measurement with experience from utilities and other government organizations, as well as outside business and industry, on leading practices in performance measurement. Steps to develop and implement performance measurement that uniquely fit water/wastewater utilities were defined to be piloted by selected utilities in Phase II. Demonstration pilot projects for developing and implementing performance measurement were carried out over a 12-18 month period at four water and wastewater utilities that were selected from a group of over a dozen utilities that applied to be pilot demonstrations, based on a mix of utility type, size, and experience with performance measurement. Research results from the pilots and ?lessons learned were applied to adjust the piloted process. Transfer of the knowledge and methods from these projects was previously shared in WERF/WEFTEC workshops and a web-conference. A process (seven-step methodology) was developed based on a Balanced Scorecard approach to develop and implement performance measures both at the enterprise (utility-wide) level and team-based level. Ways to align and coordinate measures throughout the organization were defined for process-based and initiative-based scorecards. The testing of this approach through the utility pilots led to further recommendations for involvement, education, communication and commitment of utility participants for successful performance measurement.

Understand the effects of climate change on urban water and wastewater utilities with this collection of international scientific papers. Case studies and practical planning, mitigating and adapting information provided on greenhouse gases, energy use, and water supply and quality issues.

In recent years, concerns have been raised that low concentrations of chemicals may alter the normal functions of the endocrine system, resulting in potentially significant adverse effects on growth, reproduction, and/or development. For domestic wastewater discharges to surface water bodies, estrogenic activity of effluents has been suggested by chemical analysis, biomarkers, and /or in vitro assays. Chemical Measurements. Using sensitive analytical techniques, natural or synthetic hormones and chemicals that mimic estrogen, have been detected in some domestic wastewater effluents and associated watersheds at low concentrations. Biomarkers. Several studies have demonstrated physiological changes in fish that may be attributed to exposure to estrogenic compounds. These include the presence of vitellogenin protein in male fish and/or intersex conditions. In vitro assays. The Yeast Estrogen Screen (YES) has been used to characterize estrogenicity of effluents, influents, biosolids and surface waters. This two-year WERF project explored approaches to evaluate the potential for biomarker formation as a result of effluent exposures, and the subsequent relevance of the emerging assays and physiological measurements on potential adverse impacts to individuals or populations of fish in the receiving streams. The endocrine system is complex, and many factors can influence the physiological measurements, including methods, sex, age, reproductive status, seasonal and circadian rhythms, diet, temperature, etc. and produce transient changes in physiology but no significant effect on the individual.

The emission rates of greenhouse gases (GHGs) from individual onsite septic systems used for the management of domestic wastewater were determined in this study. A static flux chamber method was used to determine the emission rates of methane, carbon dioxide, and nitrous oxide gases from eight septic tanks and two soil dispersal systems. A technique developed for the measurement of gas flow and concentration at clean-out ports was used to determine the mass flow of gases moving through the household drainage and vent system. There was general agreement in the methane emission rates for the flux chamber and vent system methods. Several sources of variability in the emission rates were also identified. The septic tank was the primary source of methane, whereas the soil dispersal system was the principal source of carbon dioxide and nitrous oxide emissions. Methane concentrations from the soil dispersal system were found to be near ambient concentrations, similarly negligible amounts of nitrous oxide were found in the septic tank. All emissions originating in the soil dispersal system were discharged through the building vent as a result of natural, wind-induced flow. The gaseous emission rate data were determined to be geometrically distributed. The geometric mean and standard deviation (sg) of the total atmospheric emission rates for methane, carbon dioxide, and nitrous oxide based on samples from the vent system were estimated to be 10.7 (sg = 1.65), 335 (sg = 2.13), and 0.20 (sg = 3.62) g/capitad, respectively. The corresponding total anthropogenic CO2 equivalence (CO2e) of the GHG emissions to the atmosphere, is about 0.1 tonne CO2e/capitayr.

Enhanced biological phosphorus removal (EBPR) has been used for decades to remove phosphorus from municipal wastewater because it allows facilities to meet water quality goals while minimizing chemical consumption and sludge production. However, there is still substantial variability in both the practices applied to achieve EBPR and the level of soluble phosphorus removal achieved. The objective of this research project was to develop information that can be used to help municipal wastewater treatment plants more efficiently and cost effectively remove phosphorus through EBPR processes. This project included detailed analysis of routine water quality and operating data, field testing observations, and special studies conducted over the course of the project to evaluate the variability of EBPR, factors influencing EBPR performance, and the relationship between EBPR and the presence of glycogen accumulating organisms (GAOs).

This Technical Brief summarizes the information that is currently available from scientific research on Endocrine Disrupting Compounds (EDCs), sometimes known as hormonally active agents. It was prepared in response to concerns over the potential for EDCs to enter the environment in treated wastewater and reuse of biosolids. This document provides a primer on the endocrine system, the nature and sources of EDCs, and their potential effects on human health and the environment. The potential for man-made chemicals to cause endocrine disrupting effects came to light as early as the 1960s. The first observed effects resulted from exposure to chlorinated pesticides such as DDT, since banned in the United States. Concern became more widespread in the 1990s, and scientists began to look at the potential effects from dozens of naturally occurring and man-made chemicals. Researchers are still working to define the scope of the problem. Thus the information presented in this Technical Brief represents still-evolving science and regulations. It is based on some three dozen publications, many of them review articles that summarize the state of the science on a particular topic. This publication can be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

Microbial quality of water is a prime public health concern in today's world. To protect public health, the World Health Organization and the U.S. Environmental Protection Agency have established microbial pollution indicator standards and recommended routine monitoring of water for both total and fecal coliforms. However, the adequacy of current water quality standards to indicate the presence or absence of human pathogens is still questionable. For example, human viruses are more resistant to sewage treatment processes and environmental conditions than bacterial indicators and therefore may pose a substantial threat. It is now recognized that the absence, or a low concentration, of indicator organisms in water may not adequately reflect the absence of human viruses. In our previous study of southern California coastal waters, we found over 30% of coastal waters tested contained human viruses, and the presence of these viruses did not correlate with an elevated level of bacterial indicators (Jiang et al. 2000). The goal of this research is to develop and validate a molecular method for rapid and specific detection of microbial contaminants including human viruses and bacterial indicators in treated sewage effluents and receiving waters.

Polymer demand varies considerably for different digestion processes as well as the same digestion processes at different locations and the reasons for these differences are not known. The objectives of this research were to develop a mechanistic understanding for these differences. The differences were hypothesized to depend on both the amount of charge in a sludge sample and the characteristics of the polymer. The first phase of the research was aimed at establishing the component of the sludge that creates the polymer demand and the second phase was aimed at understanding the interactions of polymers with the components of sludge. A number of samples were collected and analyzed for factors affecting polymer demand. The samples incluced MLSS, RAS, conventional aerobically and anaerobically digested, thermophilic anaerobically digested, temperature phased anaerobically digested, and an auto-thermal aerobically digested sample. Results from the first phase showed a good linear correlation between the optimum polymer dose (OPD) and biocolloid concentration as measured by soluble protein and polysaccharide concentration. In other words, these small particles (less than 4.2 mm created a significant portion of the polymer demand, especially for digested sludges. Conditioning samples with different polymers (varying charge density and configuration, linear, branched and hydrophobic) showed that the key characteristic in determining OPD is the charge density of the polymer. The shear associated with several full-scale dewatering devices was measured and quantified using the unitless Gt term. In addition, several field trials were performed to show the impact of Fe addition on polymer demand as well as methods to reduce the shear associated with high solids centrifuges.

Treatment of drinking water was once considered sufficient for reducing the risk of infection from pathogenic organisms. However, as our knowledge of established and emerging pathogens in water has expanded, so has the need to examine their occurrence, distribution, risk to humans, and control through treatment. The increased need for wastewater reuse has resulted in attention now being focused on wastewater treatment processes and their ability to reduce the numbers of pathogenic organisms to acceptable levels. A public health concern with wastewater is the potential for transmission of infectious agents that may be present in human and animal feces. Depending upon the diseases in the contributing communities, sewage can contain varying numbers of pathogenic organisms including viruses, bacteria, helminths, and protozoa. This study focused on one pathogen, Cryptosporidium parvum, and its occurrence in wastewater. In order to conduct an occurrence study, it was firstly necessary to develop methods for recovery of Cryptosporidium oocysts from wastewater matrices. Due to the differences in matrix composition from raw sewage to tertiary effluents, different methods for recovery and enumeration of oocysts were developed based on matrix quality. A single method was developed for raw sewage and primary influents; a second method for secondary and tertiary effluents; and a third method for biosolids. These methods were used in a survey of Cryptosporidium occurrence at 10 wastewater plants in the U.S. over a 15-month period. To determine if oocysts found in wastewater samples represented a public health risk, cell culture methods were employed to examine infectivity of recovered oocysts.

The primary objective of this project was to identify and communicate the benefits and risks of disinfecting wet weather flows by evaluating available disinfection technologies and identifying disinfection by-products and their potential risks to aquatic and human life. A decision-making framework was developed that could be used as a model to guide combined sewer overflow (CSO), sanitary sewer overflow (SSO) and stormwater (SW) disinfection control policies. This project was implemented as a case study in collaboration with the Onondaga County Department of Water Environment Protection (Syracuse, NY). A literature review was completed that identified appropriate disinfection technologies and the associated disinfection by-products. A disinfection demonstration was conducted to verify findings of the literature review and fill data gaps. The data collected during this project were used by local stakeholders to select the most appropriate technologies. Information regarding the benefits and risks of disinfecting wet weather flows was also presented to the public during a public workshop.

Irrigation is the dominant consumer of fresh water world-wide, accounting for as much as 80% of use in many water-short countries. Two issues dominate the problems in water resources management generally, and especially the management of irrigation systems: scarcity of water to meet competing demands, and scarcity of funds to finance operation, maintenance and renewal of existing facilities. Various international conferences, donor policies and academic papers have pointed to the contribution that appropriate irrigation service charging systems can make to both problems. This book is unique in that it connects policy objectives in water pricing with the practicalities of a setting up an irrigation water charging systems. It discusses the different types of water charging systems as well as the basis for quantifying and calculating the charges in the real world. Based on practical experiences in a range of countries , it also looks at possibilities for cost rationalizations and developing a broad range of revenue streams. The book concludes with a systematic explanation on how to design an irrigation water charging system - looking at assessment, billing and improving collection performance.

Basic Principles of Wastewater Treatment is the second volume in the series Biological Wastewater Treatment, and focusses on the unit operations and processes associated with biological wastewater treatment. The major topics covered are: microbiology and ecology of wastewater treatmentreaction kinetics and reactor hydraulicsconversion of organic and inorganic mattersedimentation aerationThe theory presented in this volume forms the basis upon which the other books of the series are built. About the series: The seriesis based on ahighly acclaimedsetof best selling textbooks. This international version is comprised by six textbooks giving a state-of-the-art presentation of the science and technology of biological wastewater treatment. Other titles in theseries are: Volume 1: Wastewater Characteristics, Treatment and Disposal; Volume 3: Waste Stabilisation Ponds; Volume 4: Anaerobic Reactors; Volume 5: Activated Sludge and Aerobic Biofilm Reactors; Volume 6: Sludge Treatment and Disposal

This book covers the principles and practices of technologies for the control of pollution originating from organic wastes (e.g. human faeces and urine, wastewater, solid wastes, animal manure and agro-industrial wastes) and the recycling of these organic wastes into valuable products such as fertilizer, biofuels, algal and fish protein and irrigated crops. Each recycling technology is described with respect to: ObjectivesBenefits and limitationsEnvironmental requirementsDesign criteria of the processUse of the recycled productsPublic health aspectsOrganic Waste RecyclingIncludes case studies, examples, exercises and questionsThis book is intended as a text or reference book for third or fourth year undergraduate students interested in environmental science, engineering and management, and graduate students working in the environment-related disciplines. It also serves as a reference text for policy makers, planners and professionals working in the environment and sustainable development fields.

This book will examine and analyse the problems inherent in integrated water management in transboundary conditions. Integrated Transboundary Water Management in Theory and Practice will provide new knowledge and policy recommendations based on the experiences and results of a major 3-year interdisciplinary research project (MANTRA-East). Drawing on extensive studies of the Lake Peipsi region in Estonia and Russia, the book explores the political and social issues surrounding transboundary water management and introduces the way that qualitative-quantitative-qualitative scenarios have been used in real-life situations. The book presents conclusions and policy recommendations for integrated transboundary water management that will be invaluable to water managers, policy-makers and academic researchers working in this rapidly expanding field.

Anaerobic biological treatment systems can offer a number of advantages over their aerobic counterparts. The operational costs associated with anaerobic systems are typically lower than with aerobic systems, and anaerobic systems also generate less waste sludge. In addition, the energy associated with the biogas produced during anaerobic biological treatment can potentially be recovered. However, to date, the use of conventional anaerobic biological systems for the treatment of dilute wastewaters has been relatively limited. The present study was designed to address this current knowledge gap. The specific objectives of the present study were (1) to assess and compare the treatment performance of external and a submerged membrane AnMBRs operated at different OLRs when treating a low strength municipal wastewater at a relatively low temperature, (2) to assess and compare the membrane filtration characteristics of mixed liquors generated in external and submerged membrane AnMBRs, (3) to assess and compare the membrane filtration characteristics of a mixed liquor in AnMBRs when filtering through inorganic and organic membranes, and (4) to assess and compare the membrane filtration characteristics of the mixed liquors generated in AnMBRs to the mixed liquor generated in an aerobic MBR operated with the same influent wastewater.

Activated Sludge and Aerobic Biofilm Reactors is the fifth volume in the series Biological Wastewater Treatment. The first part of the book is devoted to the activated sludge process, covering the removal of organic matter, nitrogen and phosphorus.A detailed analysis of the biological reactor (aeration tank) and the final sedimentation tanks is provided. The second part of the book covers aerobic biofilm reactors, especially trickling filters, rotating biological contractors and submerged aerated biofilters. For all the systems, the book presents in a clear and informative way the main concepts, working principles, expected removal efficiencies, design criteria, design examples, construction aspects and operational guidelines. About the series: The series is based on ahighly acclaimedsetof best selling textbooks. This international version is comprised by six textbooks giving a state-of-the-art presentation of the science and technology of biological wastewater treatment. Other titles in the series are: Volume 1: Waste Stabilisation Ponds; Volume 2: Basic Principles of Wastewater Treatment; Volume 3: Waste Stabilization Ponds; Volume 4: Anaerobic Reactors; Volume 6: Sludge Treatment and Disposal

Anaerobic Reactors is the forth volume in the series Biological Wastewater Treatment. The fundamentals of anaerobic treatment are presented in detail, including its applicability, microbiology, biochemistry and main reactor configurations. Two reactor types are analysed in more detail, namely anaerobic filters and especially UASB (upflow anaerobic sludge blanket) reactors. Particular attention is also devoted to the post-treatment of the effluents from the anaerobic reactors. The book presents in a clear and informative way the main concepts, working principles, expected removal efficiencies, design criteria, design examples, construction aspects and operational guidelines for anaerobic reactors.About the series: The seriesis based on ahighly acclaimedsetof best selling textbooks. This international version is comprised by six textbooks giving a state-of-the-art presentation of the science and technology of biological wastewater treatment. Other titles in the series are: Volume 1: Waste Stabilisation Ponds; Volume 2: Basic Principles of Wastewater Treatment; Volume 3: Waste Stabilization Ponds; Volume 5: Activated Sludge and Aerobic Biofilm Reactors; Volume 6: Sludge Treatment and Disposal

Waste Stabilisation Ponds is the third volume in the series Biological Wastewater Treatment. The major variants of pond systems are fully covered, namely: facultative ponds anaerobic ponds aerated lagoons maturation ponds The book presents in a clear and informative way the main concepts, working principles, expected removal efficiencies, design criteria, design examples, construction aspects, operational guidelines and sludge managment for pond systems. About the series: The series is based on ahighly acclaimedsetof best selling textbooks. This international version is comprised by six textbooks giving a state-of-the-art presentation of the science and technology of biological wastewater treatment. Other titles in theseries are: Volume 1: Waste Stabilisation Ponds Volume; 2: Basic Principles of Wastewater Treatment; Volume 4: Anaerobic Reactors; Volume 5: Activated Sludge and Aerobic Biofilm Reactors; Volume 6: Sludge Treatment and Disposal

The long-term viability and sustainability of biosolids land application is dependent on continuously earning stakeholder confidence, trust and support. This requires ongoing and effective engagement and communication with key stakeholders about the beneficial use of biosolids in their communities. The goal of the risk communications research was to develop processes, tools and materials to help biosolids managers conduct effective outreach and dialogue with key stakeholders in the communities where they operate, first on biosolids land application and its beneficial use, then on specific challenges such as communicating about potential health risks due to pathogens in biosolids. The researchers developed a state-of-the-science Strategic Risk Communications Process, tools and materials that can be adapted and used by biosolids program managers. The Process was applied and validated through two case studies, which involved in-depth research with landowners who receive biosolids and neighbors to biosolids land application sites and, in one case, community health officials.The research demonstrated that the key influence on these stakeholders' judgments on the acceptability of biosolids land application is the trust they have in the people who are producing the product, the people who are using the product and the people are overseeing and ensuring the safe appropriate use of biosolids. These stakeholders recognized the benefits and risks associated with biosolids land application and support its beneficial use. However, their support was not unconditional - they had questions about the long-term health and environmental impacts of such application. The process, tools and materials developed through this project will serve to address these and other key questions, while enabling biosolids managers to continually build stakeholder support for biosolids land application.

The strategic planning of urban water systems is a complex task. The Urban Water programme covered projects from various disciplines at 9 Swedish Universities, from 1999 to 2006. The projects developed a "e;toolbox"e; for strategic planning of drinking-, waste- and stormwater management, covering aspects such as the environment, health and hygiene, financing, organisation, households, and technical function. Strategic Planning of Sustainable Urban Water Management synthesises the results and presents a comprehensive approach, which includes not only the technical, economic and environmental aspects, but also the challenges of institutional capacity and public participation in the planning process. Furthermore, the experience from a number of case studies are summarised and can offer readers inspiration for their own planning situations.

This study focuses on sustainability impacts as wastewater treatment plants implement treatment technologies to meet increasingly stringent nutrient limits. The objective is to determine if a point of "e;diminishing returns"e; is reached where the sustainability impacts of increased levels of nutrient removal outweigh the benefits of better water quality. Five different hypothetical treatment trains at a nominal 10 mgd flow were developed to meet treatment targets that ranged from cBOD mode (Level 1) to four different nutrient removal targets. The nutrient removal targets ranged from 8 mg N/L; 1 mg P/L (Level 2) to the most stringent at <2 mg N/L; <0.02 mg P/L (Level 5). Given that sustainability is a broad term, the industry-accepted three pillars of sustainability were evaluated and discussed, and particular emphasis was placed on the environmental and economic pillars. The following variables received the most attention: greenhouse gas (GHG) emissions, a water quality surrogate that reflects potential algal growth, capital and operational costs, energy demand, and consumables such as chemicals, gas, diesel, etc. The results from the GHG emissions metric are shown below. Note that biogas cogeneration is represented by negative values as biogas production can be used to offset energy demands. The nitrous oxide (N2O) emissions values are based on the average biological nutrient removal (BNR) and non-BNR plants evaluated in the United States national survey by Ahn et al. (2010b). The error bars represent the data range of the national survey.The GHG emissions results suggest that a point of diminishing return is reached at Level 4 (3 mg N/L; 0.1 mg P/L). The GHG emissions show a steady increase from Levels 1 to 4, followed by a 65% increase when moving from Level 4 to 5. Despite a 70% increase in GHGs, the discharged nutrient load only decreases by 1% by going from Level 4 to 5. The primary contributors to GHG emissions are energy related (aeration, pumping, mixing). The GHG emissions associated with chemical use increases for the more stringent nutrient targets that required chemical treatment in addition to biological nutrient removal. In terms of cost, the total project capital cost increases approximately one-third from $9.3 million to $12.7 million for changing from Level 1 to 2, followed by a more than doubling in cost when changing from Level 1 to 5. Total project capital costs in this report are for a Greenfield plant. The operational cost increase between levels is more pronounced than total project capital cost with more than five-times increase from Level 1 to 5 ($250/MG treated to $1,370/MG treated, respectively).This report focused on in-plant (point source) options for nutrient removal and the implications for cost and sustainability. Other approaches, such as addressing non-point sources, could be added to the assessment. Rather than focusing strictly on point source dischargers and requiring Level 4 or 5 treatments, Level 3 or 4 treatments complimented with best management practices of non-point sources might be a more sustainable approach at achieving comparable water quality.

Integrated River Basin Governance - Learning from International Experience is designed to help practitioners implement integrated approaches to river basin management (IRBM). It aims to help the coming generation of senior university students learn how to design IRBM and it provides current researchers and the broader water community with a resource on river basin management. Drawing on both past and present river basin and valley scale catchment management examples from around the world, the book develops an integration framework for river basin management. Grounded in the theory and literature of natural resources management and planning, the thrust of the book is to assist policy and planning, rather than extend knowledge of hydrology, biophysical modelling or aquatic ecology. Providing a classification of river basin organizations and their use, the book also covers fundamental issues related to implementation: decision-making. institutions and organizations. information management. participation and awareness. legal and economic issues. integration and coordination processes. building human capacity. Integrated River Basin Governance focuses on the social, economic, organizational and institutional arrangements of river basin management. Methods are outlined for implementing strategic and regional approaches to river basin management, noting the importance of context and other key elements which have been shown to impede success. The book includes a range of tools for river basin governance methods, derived from real life experiences in both developed and developing countries. The successes and failures of river basin management are discussed, and lessons learned from both are presented. The ebook for this title is available to download for free on the WaterWiki.