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Author: Precious Thabisile Biyela
Publisher:
ISBN:
Category : Drinking water
Languages : en
Pages : 176
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Book Description
The deterioration of drinking-water quality within distribution systems is a serious cause for concern. Extensive water-quality deterioration often results in violations against regulatory standards and has been linked to water-borne disease outbreaks. The causes for the deterioration of drinking water quality inside distribution systems are not yet fully understood. Mathematical models are often used to analyze how different biological, chemical, and physical phenomena interact and cause water quality deterioration inside distribution systems. In this dissertation research I developed a mathematical model, the Expanded Comprehensive Disinfection and Water Quality (CDWQ-E) model, to track water quality changes in chloraminated water. I then applied CDWQ-E to forecast water quality deterioration trends and the ability of Naegleria fowleri (N.fowleri), a protozoan pathogen, to thrive within drinking-water distribution systems. When used to assess the efficacy of substrate limitation versus disinfection in controlling bacterial growth, CDWQ-E demonstrated that bacterial growth is more effectively controlled by lowering substrate loading into distribution systems than by adding residual disinfectants. High substrate concentrations supported extensive bacterial growth even in the presence of high levels of chloramine. Model results also showed that chloramine decay and oxidation of organic matter increase the pool of available ammonia, and thus have potential to advance nitrification within distribution systems. Without exception, trends predicted by CDWQ-E matched trends observed from experimental studies. When CDWQ-E was used to evaluate the ability N. fowleri to survive in finished drinking water, the model predicted that N. fowleri can survive for extended periods of time in distribution systems. Model results also showed that N. fowleri growth depends on the availability of high bacterial densities in the 105 CFU/mL range. Since HPC levels this high are rarely reported in bulk water, it is clear that in distribution systems biofilms are the prime reservoirs N. fowleri because of their high bacterial densities. Controlled laboratory experiments also showed that drinking water can be a source of N. fowleri, and the main reservoir appeared to be biofilms dominated by bacteria. When introduced to pipe-loops N. fowleri successfully attached to biofilms and survived for 5 months.
Author: Precious Thabisile Biyela
Publisher:
ISBN:
Category : Drinking water
Languages : en
Pages : 176
Get Book Here
Book Description
The deterioration of drinking-water quality within distribution systems is a serious cause for concern. Extensive water-quality deterioration often results in violations against regulatory standards and has been linked to water-borne disease outbreaks. The causes for the deterioration of drinking water quality inside distribution systems are not yet fully understood. Mathematical models are often used to analyze how different biological, chemical, and physical phenomena interact and cause water quality deterioration inside distribution systems. In this dissertation research I developed a mathematical model, the Expanded Comprehensive Disinfection and Water Quality (CDWQ-E) model, to track water quality changes in chloraminated water. I then applied CDWQ-E to forecast water quality deterioration trends and the ability of Naegleria fowleri (N.fowleri), a protozoan pathogen, to thrive within drinking-water distribution systems. When used to assess the efficacy of substrate limitation versus disinfection in controlling bacterial growth, CDWQ-E demonstrated that bacterial growth is more effectively controlled by lowering substrate loading into distribution systems than by adding residual disinfectants. High substrate concentrations supported extensive bacterial growth even in the presence of high levels of chloramine. Model results also showed that chloramine decay and oxidation of organic matter increase the pool of available ammonia, and thus have potential to advance nitrification within distribution systems. Without exception, trends predicted by CDWQ-E matched trends observed from experimental studies. When CDWQ-E was used to evaluate the ability N. fowleri to survive in finished drinking water, the model predicted that N. fowleri can survive for extended periods of time in distribution systems. Model results also showed that N. fowleri growth depends on the availability of high bacterial densities in the 105 CFU/mL range. Since HPC levels this high are rarely reported in bulk water, it is clear that in distribution systems biofilms are the prime reservoirs N. fowleri because of their high bacterial densities. Controlled laboratory experiments also showed that drinking water can be a source of N. fowleri, and the main reservoir appeared to be biofilms dominated by bacteria. When introduced to pipe-loops N. fowleri successfully attached to biofilms and survived for 5 months.
Author: Edwin E. Geldreich
Publisher: CRC Press
ISBN: 1000157555
Category : Technology & Engineering
Languages : en
Pages : 516
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Book Description
Hidden problems, buried deep in the pipe networks of water distribution systems, are very serious potential threats to water quality. Microbial Quality of Water Supply in Distribution Systems outlines the processes and issues related to the degradation of water quality upon passage through networks of pipes, storage reservoirs, and standpipes on its way to the consumer. The risks associated with biofilm accumulation, bacteria, and other contaminants are discussed in great detail. In addition to its excellent microbiological coverage of organisms in drinking water and biofilms in distribution systems, Microbial Quality of Water Supply in Distribution Systems provides clear treatments of the technical and public communication issues most commonly affecting the quality of water and water supply systems. The inclusion of numerous case histories in this new book makes it a complete reference source for anyone concerned with water quality and water distribution systems.
Author: Gregory J. Kirmeyer
Publisher: American Water Works Association
ISBN: 1583211020
Category : Drinking water
Languages : en
Pages : 286
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Book Description
Reports on a project that identifies pathogen routes of entry into water distribution systems and develops monitoring and control strategies for protecting the system. Contains chapters on pathogens and pathways, existing control strategies, transient surge modeling, pressure monitoring, field monitoring, recommended control strategies, and recommendations to utilities. The project was completed by a multi-disciplinary team of engineers and practitioners with funding from the American Water Works Association Research Foundation and the Environmental Protection Agency. The book is not indexed. Annotation c. Book News, Inc., Portland, OR (booknews.com)
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309103061
Category : Science
Languages : en
Pages : 405
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Book Description
Protecting and maintaining water distributions systems is crucial to ensuring high quality drinking water. Distribution systems-consisting of pipes, pumps, valves, storage tanks, reservoirs, meters, fittings, and other hydraulic appurtenances-carry drinking water from a centralized treatment plant or well supplies to consumers' taps. Spanning almost 1 million miles in the United States, distribution systems represent the vast majority of physical infrastructure for water supplies, and thus constitute the primary management challenge from both an operational and public health standpoint. Recent data on waterborne disease outbreaks suggest that distribution systems remain a source of contamination that has yet to be fully addressed. This report evaluates approaches for risk characterization and recent data, and it identifies a variety of strategies that could be considered to reduce the risks posed by water-quality deteriorating events in distribution systems. Particular attention is given to backflow events via cross connections, the potential for contamination of the distribution system during construction and repair activities, maintenance of storage facilities, and the role of premise plumbing in public health risk. The report also identifies advances in detection, monitoring and modeling, analytical methods, and research and development opportunities that will enable the water supply industry to further reduce risks associated with drinking water distribution systems.
Author: Hé́lène Baribeau
Publisher: American Water Works Association
ISBN: 1583214100
Category : Water
Languages : en
Pages : 324
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Book Description
Assesses the impact of dynamic water quality conditions in the distribution system on the inactivation of microorganisms in bulk water. Addresses questions about the usefulness of maintaining a secondary residual and the target level to be maintained. Bridges research related to distribution system water quality with that of microbial inactivation.
Author: OECD
Publisher: OECD Publishing
ISBN: 9264099476
Category :
Languages : en
Pages : 292
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Book Description
This book provides a state-of-the-art review on approaches and methods used in assessing the microbial safety of drinking-water.
Author: LeChevallier M.W.
Publisher: World Health Organization
ISBN: 9241562552
Category : Business & Economics
Languages : en
Pages : 136
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Book Description
Annotation This publication provides a critical analysis of the literature on removal and inactivation of pathogenic microbes in water to aid the water quality specialist and design engineer in making decisions regarding microbial water quality.
Author: Ainsworth R.
Publisher: World Health Organization
ISBN: 924156251X
Category : Business & Economics
Languages : en
Pages : 168
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Book Description
This publication addresses the factors affecting the presence and growth of micro-organisms in piped networks as well as the practices of water supply organisations that can directly or indirectly influence them. The book shows that there are often public health reasons for adopting a more proactive approach to many of the traditional practices used in designing, operating and maintaining distribution networks, and to modifying the composition of the water that is fed into those networks.
Author: Michael J. MacPhee
Publisher:
ISBN:
Category : Political Science
Languages : en
Pages : 216
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Book Description
Offering a high-level view of key distribution system water quality issues that utilities will confront in the coming decades, and a new view of an integrated treatment process, this book covers such topics as microbial regrowth and recontamination, risks associated with release of trace metals from system scale, and impacts of secondary disinfection practices. This resource targets water utility managers, water quality professionals, policy makers, regulators, consultants, and educators.
Author: World Health Organization
Publisher: World Health Organization
ISBN: 9789241545037
Category : Medical
Languages : en
Pages : 260
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Book Description
This volume describes the methods used in the surveillance of drinking water quality in the light of the special problems of small-community supplies, particularly in developing countries, and outlines the strategies necessary to ensure that surveillance is effective.
