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.

The purpose of this study was to assess the economic feasibility of using large-scale, restored wetlands to assist publicly owned treatment works (POTWs) in meeting the U.S. Environmental Protection Agency's (USEPA) recommended criteria for nutrients, specifically, total nitrogen (2.18 mg/l) and total phosphorous (0.076 mg/l). The assessment compares the cost of nutrient control by advanced wastewater treatment technology to that of wetland treatment technology. The comparison was based on several economic factors: annual operating costs, average costs, marginal costs, and present value. To explore the economic relationship between wastewater and treatment wetlands and to quantify the magnitude of wetland area needed, a case study was developed using the seven water reclamation plants (WRPs) owned and operated by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) and proposed treatment wetlands located adjacent to the Illinois River in the upper Illinois River watershed. Cost functions for both technologies were developed. Using these functions, the economic characteristics of the two technologies were compared assuming, first, that the USEPA's proposed nutrient criteria would be enacted as the enforceable water quality standard by the state regulator, and, second, that a less stringent standard would be established (3.0 mg/l TN and 1.0 mg/l TP). However, the USEPA's phosphorus criterion was modified due to the technical difficulty in achieving an effluent concentration of 0.076 mg/l TP. The more stringent phosphorous criterion was set at 0.5 mg/l TP for this comparison study. To meet the future nutrient criteria, the physical facilities of the seven MWRDGC treatment plants must be upgraded to incorporate biological nutrient removal (BNR) technology. A detailed capital cost analysis for the addition of BNR treatment, specifically the 5-stage Bardenpho (with methanol addition), was performed by the MWRDGC for one of its larger WRPs, Calumet. The capital costs for the other plants were estimated using Calumet's cost formulas and prorated by the design flows. The operating and maintenance (O&M) costs were estimated to add approximately 50% to those for the conventional treatment currently being employed by MWRDGC. The capital costs for upgrading the seven WRPs with the Bardenpho system has been estimated at $1.6 billion with the total present value cost at $2.5 billion.

Wastewater and drinking water treatment are essential elements of urban infrastructure. In the course of the last century there has been enormous technical development, so successful that for the general public in industrialized countries this infrastructure is hardly noticed. Nevertheless there is ongoing activity to further improve the existing processes. The IWA Leading Edge Technology conference held in Prague helped to stimulate this development and this book helps disseminate the results. A selection of presentations from the conference are included in this volume. Wastewater and drinking-water treatment are normally considered as two separate fields due to the very different boundary conditions that apply. Nevertheless several issues such as membrane processes, removal of micropollutants and water reuse are of crucial importance to both. This potential for cross-fertilization further enhances the value of this collection of high-quality articles that delineate the leading edge of research and development in water and wastewater treatment.

Water policy seems in perpetual crisis. Increasingly, conflicts extend beyond the statutory authority, competence, geographical jurisdictions, and political constituencies of highly specialized governing authorities. While other books address specific policy approaches or the application of adaptive management strategies to specific problems, this is the first book to focus more broadly on adaptive governance, or the evolution of new institutions that attempt to resolve conflicts among competing authorities.

Adaptive Governance and Water Conflict investigates new types of water conflicts among users in the seemingly water-rich Eastern United States. Eight case studies of water quality, water quantity, and habitat preservation or restoration in Florida were chosen to span the range of conflicts crossing fragmented regulatory boundaries. Each begins with a history of the conflict and then focuses on the innovative institutional arrangements-some successful, some not-that evolved to grapple with the resulting challenges. In the chapters that follow, scholars and practitioners in urban planning, political science, engineering, law, policy, administration, and geology offer different theoretical and experience-based perspectives on the cases. Together, they discuss five challenges that new institutions must overcome to develop sustainable solutions for water users: Who is to be involved in the policy process? How are they to interact? How is science to be used? How are users and the public to be made aware? How can solutions be made efficient and equitable?

In its diverse perspectives and unique combination of theory, application, and analysis, Adaptive Governance and Water Conflictwill be a valuable book for water professionals, policy scientists, students, and scholars in natural resource planning and management.

What are the rules of international water law that govern the use of the transboundary aquifers shared by Palestine and Israel? This book addresses this issue through an interdisciplinary approach, identifying first the special problems tied to the management of shared groundwater, and next critically analysing the applicable rules of international law. The innovative contribution of this work is its attempt to devise and suggest the means to implement a "progressive framework" for cooperation in the development and management of these shared waters. A solid review of hydro-politics, supported by current up to date information and rigorous examination of the evolution of the relevant rules of international law makes this book an important contribution to this very problematic area. Dr Fadia Diabes Murad was awarded the Edgerg Award 2005, presented at a special awards ceremony in Stockholm. The award recognised her contribution to peace in the Middle East through her work on water law, including using water as a catalyst for peace in the Middle East.

Aerobic Granular Sludge has recently received growing attention by researchers and technology developers, worldwide. Laboratory studies and preliminary field test led to the conclusion that granular activated sludge can be readily established and profitably used in activated sludge plants, provided "correct" process conditions are chosen. But what makes process conditions "correct"? And what makes granules different from activated sludge flocs? Answers to these questions are offered in Aerobic Granular Sludge. Major topics covered in this book include: - Reasons and mechanisms of aerobic granule formation - Structure of the microbial population of aerobic granules - Role, composition and physical properties of EPS - Diffusion limitation and microbial activity within granules - Physico-chemical characteristics - Operation and application of granule reactors - Scale-up aspects of granular sludge reactors, and case studies Aerobic Granular Sludge provides up-to-date information about a rapidly emerging new technology of biological treatment.

When water leaves a treatment works and travels through a distribution system, its quality, with respect to many chemical and biological parameters, will degrade. The quality of the delivered water will be largely influenced by: .The quality of treated water supplied into the network .The condition of distribution assets within the network .The retention time within the network. The water industry has focused predominantly on the quality of treated water and the physical condition of distribution assets when improving the quality of water at the customer's tap. However the quality of the water delivered is also affected by the time the water is retained in the different elements of the distribution network. Retention time is controlled both by the physical characteristics of the system and the operational regime. Physical characteristics such as pipe roughness may change throughout the life of the asset or be modified by rehabilitation. Operational activities may be structured; for example, pump scheduling and planned maintenance, or uncontrolled as in the case of demand driven operational responses. Changes to water quality result from the reactions in the bulk water with time and through the chemical and biological reactions with the distribution system materials with which The chemical and biological reactions in the bulk water are relatively well understood enabling development of models and software for predicting changes. The reactions of the water at the pipe-water interface are more complex and less well understood. The aim of this research is to demonstrate that water quality within distribution networks can be managed effectively by controlling retention time and to develop practical and pragmatic methodologies for doing so.

Two methods for the detection of important human pathogens, Cryptosporidium parvum and Helicobacter pylori, were investigated: a fiber optic biosensor, and real time PCR. The mechanism for specific detection in both methods is recognition of specific DNA sequences in the target organisms. The biosensor that was used, the Analyte 2000, was originally developed for the detection of chemicals. It utilizes a fiber optic wave guide that propagates an evanescent light wave of very specific wavelength. The light excites fluorescent molecules bound to the waveguide, but not in the bulk solution, which theoretically enhances signal while reducing background interference. Attempts to develop this system for the detection of DNA were not successful due to poor detection of the target molecules. An assay analogous to a sandwich immunoassay was designed for use on the Analyte 2000. Specific oligonucleotide probes were designed to bind to the waveguides via biotin-streptavidin interaction, and were used to capture the target DNA. Pure target DNA representing unique genes in the organisms were synthesized by PCR. Detection of captured DNA was then attempted using an oligonucleotide detection probe designed to bind to the target. Two detection systems were employed: an indirect signal amplification system based on biotin-tyramide deposition, or direct detection of fluorescent signal from Cy-5 molecules. In all experiments performed there was very little difference between the signal generated with or without the target molecules. Many experiments were conducted to attempt to identify reasons for the poor signal. Signal was only of any significance when target amplicons were internally labeled with Cy-5 by PCR. Real time PCR as a method to detect the pathogens was also investigated. Though the PCR technique itself is very rapid, DNA extraction and purification requires preparation time. Filtration of up to one liter of well water, followed by concentration and "cleaning" Helicobacter pylori cells by immunomagnetic separation, was used to detect H. pylori seeded in a water source. Following cell lysis, the extracted DNA could be used directly in conventional PCR targeting the 16S rRNA gene to detect less than 265 cells per liter of water. DNA purification was not required for this level of detection. Initial studies to amplify lysed cells by real time PCR indicated that an incorrect product was made. When purified DNA was used for real time PCR, the correct product was produced from DNA representing as few as 100 cells. This publication can be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

Water resource management in the United States is evolving in the face of continuing challenges to protect water quality, provide adequate quantities of water for competing uses, and protect habitat and other natural resources. In many jurisdictions and agencies this evolution is increasingly leading toward adoption of watershed management. This approach is characterized by planning and decision making on a watershed scale, integration of a variety of competing water resource priorities and goals, cooperation of multiple stakeholders and governmental agencies, and increased levels of public participation. While the number and diversity of watershed management initiatives underway in the United States is impressive, successful transition to this integrated approach remains challenging due to institutional, regulatory, and information barriers. In certain respects - Geographic Information Systems mapping, wetlands regulations, citizen participation - U.S. watershed initiatives are highly advanced and serve as models for efforts around the world. In other respects - cross jurisdictional coordination and cooperation, agreements on the sharing of resources, habitat protection and restoration - innovatie approaches implemented outside the U.S. show great promise and offer important lessons to U.S. decision makers. This report identifies the most promising watershed planning and management approaches from around the world; evaluates how they operate, their benefits and limitations; and assesses the degree to which these approaches could be successfully adapted to the U.S. context. Drawing on this international experience, the report is intended to inform policy makers and practitioners and to promote the implementation of integrated watershed management approaches that are most likely to succeed.

The main objective of this research was to investigate the capabilities of three chemical oxidation processes as pretreatment technologies with the goal of making wastewaters containing persistent organic compounds amenable to biotreatment. The processes investigated are ozonation, ultraviolet radiation/ hydrogen peroxide (UV/H2O2) and Fenton reaction. The studies were focused on two organic compounds: Dichloro diethyl ether (DCDE) and methyl tertiary butyl ether (MTBE). Synthetic solutions, and a real groundwater and an industrial wastewater were used for experimentation. The experimental method involved oxidation of solutions of the target organic compounds at various percentages by the three oxidation processes. The pre-oxidized solutions of the organic compounds were subjected to biodegradation and toxicity studies. Four different respirometric tests (two Short-term, one Mid-term, and one Long-term) and a bench scale Sequencing Batch Reactor (SBR) test were used for full assessment of the effectiveness of the chemical oxidation processes. Activated sludge, as acclimated and non-acclimated to the organic compounds, was used as the test culture. All three chemical oxidation processes were able to transform DCDE and MTBE to a variety of oxidation by-products. Oxidation by-products by all three oxidation methods were significantly more biodegradable than the non-oxidized parent compounds. This project clearly showed that integration of chemical oxidation processes with biotreatment may lead to effective handling of "problem" wastewaters.

Enteroviruses, hepatitis A virus (HAV) and other enteric viruses can survive wastewater treatment processes, even after chlorination, and are found in the final effluents. These viruses can be detected by cell culture techniques with observations for cytopathic effect (CPE). Recently molecular detection of viral nucleic acids has been used. Most viruses found in wastewater are RNA viruses and RT-PCR is a rapid and sensitive method to detect these single-strand RNA enteric viruses. This methodology does not distinguish between infectious and non-infectious viruses. Viruses inactivated in the treatment process can be detected but do not pose a public health threat. Methods are needed to quickly distinguish the infectious viruses from inactivated viruses, both of which may be present in effluents. In this project we investigated the use of a method that combines cell culture and molecular detection. If a sample contains viruses that replicate in cell culture even without CPE, the proof of replication can be demonstrated by the detection of a replicative form (RF) in cell culture that is only present during replication of infectious RNA viruses. A negative sense strand of RNA is generated from the viral positive strand virus, and these two are found primarily bound in a replicative form. This RNA was specifically detected by RT-PCR, including the positive and negative strands. This assay was developed and explored for the detection of low levels of CVB3 and HAV laboratory strains first and then for low levels of wild-type enteroviruses isolated from sewage samples. As few as four infectious units of wild-type enteroviruses, contained in 2.0 ml of water concentrate prepared from 600 ml of treated wastewater effluent, could be detected within two days. Treated wastewater effluents were collected weekly over an 18 months period, and viruses were concentrated with a developed method. About 7% of the final effluent wastewater samples were found positive for infectious enterovirus with the developed RF method, although only 1% of the samples were positive by presence of cytopathic effect. This method avoids the use of two complete cycles of cell culture to detect infectious virus, while confirming infectivity with a molecular method.

Intensifying Activated Sludge Using Media-Supported Biofilms will be of interest to practicing wastewater treatment process designers, along with those seeking more compact and energy-efficient wastewater treatment options. The advantages of Moving Bed Biological Reactor (MBBR)-based hybrid processes are now well-established in practice, leading to their increased use in the field. Membrane Aerated Biofilm Reactor (MABR)-based hybrid processes are much newer and offer further systematic process and energy advantages. This book examines the evolution of hybrid technologies as well as the potential for continued improvement of biological wastewater treatment techniques. Features: Reviews current approaches for intensifying biological wastewater treatment processes and their mechanistic bases. Examines hybrid suspended growth/biofilm-based wastewater treatment processes, including the newly-developed MABR-based processes, and their unique dynamic performance characteristics. Presents a novel method for characterizing the performance and process intensification advantages of hybrid processes. Provides guidance for simulating the performance of hybrid processes, including oxygen transfer in MABR hybrid processes.

Rural-Urban Water Struggles compiles diverse analyses of rural-urban water connections, discourses, identities and struggles evolving in the context of urbanization around the world. Departing from an understanding of urbanization as a process of constant making and remaking of multi-scalar territorial interactions that extend beyond traditional city boundaries and that deeply reconfigure rural-urban hydrosocial territories and interlinkages, the chapters demonstrate the need to reconsider and trouble the rural-urban dichotomy. The contributors scrutinize how existing approaches for securing urban water supply - ranging from water transfers to payments for ecosystem services - all rely on a myriad of techniques: they are produced by, and embedded in, specific institutional and legal arrangements, actor alliances, discourses, interests and technologies entwining local, regional and global scales. The different chapters show the need to better understand on-the-ground realities, taking account of inequalities in water access and control, as well as representation and cultural-political recognition among rural and urban subjects. Rural-Urban Water Struggles will be of great use to scholars of water governance and justice, environmental justice and political ecology. This book was originally published as a special issue of Water International.

With contributions from an international team of experts, this book offers planners, engineers, and designers guidelines for using recycled water in landscape and agricultural applications. The book thoroughly covers all of the relevant technical, economic, financial, agronomic, health, environmental, regulatory, and social issues. It covers how to develop, implement, and operate wastewater reuse systems based on rigorous, best management practices that maximize efficiency, reliability, and economy while minimizing the potential for adverse effects to the environment and human health. Comprehensive tables, charts, figures, photographs, and case-studies make the information easy to find. Lazarova; Valentina Suez Environment Services Locaux, CIRSEE, Le Pecq, France,Akissa; Bahri INRGREE, Ariana, Tunisia

This is the first monograph in English on the topic of the sienese acqueducts. The book reviews scholarly literature and archival sources including maps and diagrams, to better situate Siena's achievement in urban history and broadens our understanding of medieval technology and urban life. Michael P. Kucher argues that urban patronage of anonymous craftsmen provided the cultural foundations for the careers of better known engineers like Francesco di Giorgio and Leonardo da Vinci. The book joins the rapidly expanding field of works that focus on urban technology to shed new light on daily life in the medieval city.

The main objective of this project is to demonstrate that the technology of on line monitoring of waterborne metals by X-ray Fluorescence (XRF) at part per billion (ppb) and sub-ppb levels, which has been successfully applied in the power industry for several years, can be applied to water and wastewater treatment plants. A specially designed on line XRF monitor was assembled, tested in the laboratory, and used at the City of Alliance, Ohio Wastewater and Water Treatment Plants from July 2002 until March 2004. At various times through this project, the metals monitored included iron, copper, chromium, nickel, zinc, manganese, arsenic, cadmium, mercury and lead. The results indicate that XRF on line monitoring of waterborne metals at trace levels is feasible for the influent and effluent of water treatment plants, and the effluent of wastewater treatment plants.

Sustainable Water Services: A Procedural Guide is the result of the Sustainable Water industry Asset Resource Decisions (SWARD) project, undertaken by a consortium of UK academics in collaboration with water service providers in Scotland, England and Romania. It has been developed to act as a practical tool to assist with the explicit inclusion of ?sustainability? in the decision-making processes of those responsible for providing water services. The book contains a framework that comprises a set of decision support processes that can be used by water service providers to explicitly incorporate sustainability considerations into their decision-making procedures, through the use of sustainability principles, criteria, indicators and processes. These principles and criteria can be applied at an overall corporate strategic level, for example in the service provider?s mission statement, or at an application level, where these strategic principles are being applied to a particular decision. Sustainable Water Services is designed to inform and to provide support for strategic activity, both as a resource containing information about sustainability, and by employing feedback from application to inform the strategic processes of the water service provider. Presents an inclusive and generic set of sustainability criteria for use in water industry decision making processes; Discusses the legislative drivers for sustainable decision making for the UK water industry; Presents clear case study examples of the sustainability framework in action; Discusses the use and applicability of a wide range of tools and techniques for undertaking environmental, economic and social analyses, e.g. life cycle assessment, multi-criteria analysis.

Drinking water provides an efficient source for the spread of gastrointestinal microbial pathogens capable of causing serious human disease. The massive death toll and burden of disease worldwide caused by unsafe drinking water is a compelling reason to value the privilege of having safe drinking water delivered to individual homes. On rare occasions, that privilege has been undermined in affluent nations by waterborne disease outbreaks traced to the water supply. Using the rich and detailed perspectives offered by the evidence and reports from the Canadian public inquiries into the Walkerton (2000) and North Battleford (2001) outbreaks to develop templates for understanding their key dimensions, over 60 waterborne outbreaks from 15 affluent countries over the past 30 years are explored as individual case studies. Recurring themes and patterns are revealed and the critical human dimensions are highlighted suggesting insights for more effective and more individualized preventive strategies, personnel training, management, and regulatory control. Safe Drinking Water aims to raise understanding and awareness of those factors that have most commonly contributed to or caused drinking-water-transmitted disease outbreaks - essentially a case-history analysis within the multi-barrier framework. It contains detailed analysis of the failures underlying drinking-water-transmitted disease epidemics that have been documented in the open literature, by public inquiry, in investigation reports, in surveillance databases and other reliable information sources. The book adopts a theme of 'converting hindsight into foresight', to inform drinking-water and health professionals including operators, managers, engineers, chemists and microbiologists, regulators, as well as undergraduates and graduates at specialty level. Key Features: Contains details and perspectives of major outbreaks not widely known or understood beyond those directly involved in the investigations. Technical and scientific background associated with case studies is offered in an accessible summary form. Does not require specialist training or experience to comprehend the details of the numerous outbreaks reviewed. By providing a broad-spectrum review using a consistent approach, several key recurring themes are revealed that offer insights for developing localized, tailor-made prevention strategies.

One approach to the introduction of computational material to the classroom is to supplement a textbook with modern computer codes. Unfortunately most codes are expensive, designed for commercial use, without source code and may require special software. Visual Hydrology provides a cheaper and simpler alternative, supplying computational exercises that can be fully assimilated by students, and allowing them to activate, understand and reproduce modern computer code. Visual Hydrology aims to: explain the structure of modern object-oriented computer code provide the source code for worked examples numerically check the worked examples used in text show how worked examples can be used with alternative data describe and reference the underlying theory provide additional exercises with each worked example use Microsoft Excel software alone Requiring only a basic knowledge of Microsoft Excel, this Primer teaches the use of modern and readily-available computer code for engineering computation. Visual Hydrology demonstrates codes for common and practical examples used in hydrological engineering, and will be a valuable resource to students, research workers and consulting engineers in the water-related sector. Examples of source code to accompany this publication can be downloaded by clicking here.

The objective of this project was to develop and evaluate a practical technique to indicate the probability of the presence of bacterial pathogens in receiving waters. A "practical" method was defined as one that would limit the use of defined culture-based microbiological methods, and would be based on: (1) validating indicator organisms that predicted the presence of pathogens, or (2) detection of pathogens by polymerase chain reaction (PCR)-based assays. The study also assessed the utility of PCR-based technology for bacterial pathogen detection with respect to technology transfer to a wider range of water and wastewater facilities.

Anaerobic/aerobic (AnA) and completely aerobic (CA) laboratory-scale sequencing batch reactors operating on an acetate- and casamino acids-based synthetic wastewater were used to investigate the suitability of the AnA process for treating nutrient?deficient wastewaters in plants that have stringent effluent nutrient requirements. Of particular interest is the case where phosphorus (P)-deficient wastewaters with highly variable influent COD loading are being treated to meet both effluent TSS and P limits. At a 4 d mean cell residence time, AnA activated sludge had an approx. 20% lower P requirement than CA activated sludge. The difference between the end-of-aerobic cycle polyhydroxyalkanoate and carbohydrate contents of the sludges indicated that the AnAsludge used more influent carbon than the CA sludge for synthesis of non-P-containing storage products. The nitrogen requirements of AnA sludge were similar to those of the CA sludge. The AnA and CA SBRs were subjected to three different transient influent COD loading patterns that simulated (#1) daily COD Loading fluctuations, (#2) low weekend COD loading, and (#3) extended low COD loading periods. During the Loading Pattern #1 experiment, the average effluent soluble P concentrations for the AnA and CA SBRs were 0.4 and 1.0 mgP/L respectively, and complete removal of influent acetate was observed. During the Loading Pattern #2 experiment, the average effluent soluble P concentrations for the AnA and CA SBRs were 0.3 and 0.9 mgP/L respectively, but effluent acetate was detected during the first high COD loading cycle following the low weekend COD loading period. During the Loading Pattern #3 experiment, the VSS content of both reactors dropped sharply, effluent acetate breakthrough occurred, and effluent P concentrations exceeding 1 mgP/L were detected in both the AnA and CA SBRs. Based on these findings, the AnA process has potential as a technologically and economically superior alternative for wastewater treatment plants treating P-deficient wastewasters to meet stringent effluent TSS and P limits. This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

This research attempts to evaluate nitrification treatment performance in combined carbon/nitrogen municipal wastewater reactors using traditional physical/chemical methods and modern molecular techniques. Bench scale activated sludge reactors were operated at different SRTs under varying DO levels and temperatures over a 21-month period. Real-time PCR assays were used to determine cell concentrations of total bacterial 16S rDNA, a gross measure of biomass content, the amoA gene, a measure of ammonia-oxidizing bacteria (AOB), and the Nitrospira 16S rDNA gene, a measure of nitrite-oxidizing bacteria (NOB). As expected, gravimetric biomass and total bacterial 16S rDNA levels increased with increasing SRT. Ammonia oxidation rates and N. oligotropha-type AOB concentrations did not follow similar trends with respect to changes in SRT, temperature, and DO nor were they highly correlated. The concentration of available nitrite and SRT were positively correlated with Nitrospira cell densities, while DO concentration and temperature were negatively correlated with NOB levels. The percentage of the total population comprised of AOB and NOB obtained with the real-time PCR assays were compared to predicted values estimated from design equations using typical kinetic parameters. While the percentages of NOB measured using the real-time PCR assay corresponded very well with the predicted values, the measured percentages of AOB were much lower than those estimated from the design equations, suggesting that N. oligotropha-type AOB were not the dominant ammonia-oxidizing species in these reactors. This publication can be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

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

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