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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
A practical guide to wastewater pathogens The fourth volume in Wiley's Wastewater Microbiology series, Wastewater Pathogens offers wastewater personnel a practical guide that is free of overly technical jargon. Designed especially for operators, the text provides straight facts on the biology of treatment as well as appropriate protective measures. Coverage includes: * An overview of relevant history, hazards, and organisms * Viruses, bacteria, and fungi * Protozoa and helminthes * Ectoparasites and rodents * Aerosols, foam, and sludge * Disease transmission and the body's defenses * Removal, inactivation, and destruction of pathogens * Hygiene measures, protective equipment, and immunizations
Milestones in Water Reuse: The Best Success Stories illustrates the benefits of water reuse in integrated water resources management and its role for water cycle management, climate change adaptation and water in the cities of the future. Selected case studies are used to illustrate the different types of water reuse, i.e. agricultural irrigation, golf course and landscape irrigation, urban and industrial uses, environmental enhancement, as well as indirect and direct potable reuse. The various aspects related to water reuse are covered, including treatment technologies, water quality, economics, public acceptance, benefits, keys for success and main constraints. These international case studies highlight the best practices for the implementation of water reuse and provide the perspective for the integration of water recycling projects in the future, both for megacities and rural areas. Milestones in Water Reuse: The Best Success Stories demonstrates that planned water reuse is a cost competitive and energy-saving option to increase water availability and reliability. This book provides policy makers and regulators with a good understanding of water reuse and helps them to consider recycled water as safe and how it can be used. It is intended to be read by all people in the water sector and shows how water reuse is safe, economically viable, environmentally friendly and can provide high social benefits. Editors: Valentina Lazarova, Suez Environnement, France Takashi Asano, University of California at Davis, USA Akica Bahri, African Development Bank, Tunisia John Anderson, Afton Water, Australia
Contemporary Municipal Wastewater Treatment Plant Design Methods Fully revised and updated, this three-volume set from the Water Environment Federation and the Environmental and Water Resources Institute of the American Society of Civil Engineers presents the current plant planning, configuration, and design practices of wastewater engineering professionals, augmented by performance information from operating facilities. Design of Municipal Wastewater Treatment Plants, Fifth Edition, includes design approaches that reflect the experience of more than 300 authors and reviewers from around the world. Coverage includes: Integrated facility design Sustainability and energy management Plant hydraulics and pumping Odor control and air emissions Thoroughly updated information on biofilm reactors Biological, physical, and chemical liquid treatment Membrane bioreactors, IFAS, and other integrated biological processes Nutrient removal Sidestream treatment Wastewater disinfection Solids minimization, treatment, and stabilization, including thermal processing Biosolids use and disposal
There is currently intense interest in the use of ultraviolet technology for helping to meet future regulations relating to improved microbial inactivation and decreased disinfection byproducts (DBPs). Much of this interest has been fueled by recent research indicating the effectiveness of UV technologies for the inactivation of Cryptosporidium. This scientific discovery, combined with proposed regulations concerning DBPs in the United States, has resulted in a need to evaluate the feasibility and effectiveness of UV irradiation for use as a disinfectant for drinking water.The objectives of this project were to:(1) develop and evaluate physical, chemical, and biological methods for calculating effective germicidal UV dose from medium-pressure (MP) and Pulsed-UV (P-UV) lamps;(2) establish a UV dose/log inactivation relationship for specific bacterial and viral indicators for MP and P-UV lamps;(3) determine the extent of photoreactivation and dark repair of heterotrophic bacteria after treatment by MP and P-UV lamps; and(4) compare the ability of MP and P-UV lamps to inactivate Cryptosporidium. Originally published by AwwaRF for its subscribers in 2003 This publication can also be purchased and downloaded via Pay Per View on Water Intelligence Online - click on the Pay Per View icon below

Wastewater Blending

United States. Congress. House. Committee on Transportation and Infrastructure. Subcommittee on Water Resources and Environment

Published: 2005

Total Pages: 260


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Recent and forecasted advances in microbiology, molecular biology, and analytical chemistry have made it timely to reassess the current paradigm of relying predominantly or exclusively on traditional bacterial indicators for all types of waterborne pathogens. Nonetheless, indicator approaches will still be required for the foreseeable future because it is not practical or feasible to monitor for the complete spectrum of microorganisms that may occur in water, and many known pathogens are difficult to detect directly and reliably in water samples. This comprehensive report recommends the development and use of a "tool box" approach by the U.S Environmental Protection Agency and others for assessing microbial water quality in which available indicator organisms (and/or pathogens in some cases) and detection method(s) are matched to the requirements of a particular application. The report further recommends the use of a phased, three-level monitoring framework to support the selection of indicators and indicator approaches.Â