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Author: Precious Thabisile Biyela Publisher: ISBN: Category : Drinking water Languages : en Pages : 176
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
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
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
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
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
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: Jamie Bartram Publisher: IWA Publishing ISBN: 9781843390251 Category : Science Languages : en Pages : 278
Book Description
Heterotrophic Plate Counts and Drinking-water Safety provides a critical assessment of the role of the Heterotrophic Plate Count (HPC) measurement in drinking water quality management. It was developed from an Expert workshop of 32 scientists convened by the World Health Organization and the WHO/NSF International Collaborating Centre for Drinking Water Safety and Treatment in Geneva, Switzerland. Heterotrophs are organisms, including bacteria, yeasts and moulds, that require an external source of organic carbon for growth. The HPC test (or Standard Plate Count), applied in many variants, is the internationally accepted test for measuring the hetrotrophic microorganism population in drinking water, and also other media. It measures only a fraction of the microorganisms actually present and does not distinguish between pathogens and non-pathogens. High levels of microbial growth can affect the taste and odor of drinking water and may indicate the presence of nutrients and biofilms which could harbor pathogens, as well as the possibility that some event has interfered with the normal production of the drinking water. HPC counts also routinely increase in water that has been treated by an in-line device such as a carbon filter or softener, in water-dispensing devices and in bottled waters and indeed in all water that has suitable nutrients, does not have a residual disinfectant, and is kept under sufficient conditions. There is debate among health professionals as to the need, utility or quantitative basis for health-based standards or guidelines relating to HPC-measured regrowth in drinking water. The issues that were addressed in this work include: the relationship between HPC in drinking water (including that derived from in-line treatment systems, dispensers and bottled water) and health risks for the general public the role of HPC as an indirect indicator or index for pathogens of concern in drinking water the role of HPC in assessing the efficacy and proper functioning of water treatment and supply processes the relationship between HPC and the aesthetic acceptability of drinking water. Heterotrophic Plate Counts and Drinking-water Safety provides valuable information on the utility and the limitations of HPC data in the management and operation of piped water systems as well as other means of providing drinking water to the public. It is of particular value to piped public water suppliers and bottled water suppliers, manufacturers and users of water treatment and transmission equipment and inline treatment devices, water engineers, sanitary and clinical microbiologists, and national and local public health officials and regulators of drinking water quality.
Author: LeChevallier M.W. Publisher: World Health Organization ISBN: 9241562552 Category : Business & Economics Languages : en Pages : 136
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: World Health Organization Publisher: World Health Organization ISBN: 9789241545037 Category : Medical Languages : en Pages : 260
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.
Author: Ainsworth R. Publisher: World Health Organization ISBN: 924156251X Category : Business & Economics Languages : en Pages : 168
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: Precious Thabisile Biyela
Author: Precious Thabisile Biyela
Author: Edwin E. Geldreich
Author: Gregory J. Kirmeyer
Author: National Research Council
Author: Hé́lène Baribeau
Author: Jamie Bartram
Author: OECD
Author: LeChevallier M.W.
Author: World Health Organization
Author: Ainsworth R.