Memphis Light, Gas and Water Division Experience With Aging of Electric, Gas, and Water Systems

1993 ◽  
Vol 46 (5) ◽  
pp. 183-186
Author(s):  
Charles Pickel

Electric, gas and water distribution systems can have an extremely long life when properly designed, installed and maintained. MLGW is proof positive that aging distribution systems can be managed in an effective manner. Customer satisfaction is a high priority with Division management. According to a recent survey, Memphians enjoy the lowest average monthly utility bills among the 25 largest cities in the United States.

2010 ◽  
Vol 3 (2) ◽  
pp. 91-99 ◽  
Author(s):  
P. Deines ◽  
R. Sekar ◽  
H. S. Jensen ◽  
S. Tait ◽  
J. B. Boxall ◽  
...  

Abstract. Microbiology in Urban Water Systems (MUWS) is an integrated project, which aims to characterize the microorganisms found in both potable water distribution systems and sewer networks. These large infrastructure systems have a major impact on our quality of life, and despite the importance of these systems as major components of the water cycle, little is known about their microbial ecology. Potable water distribution systems and sewer networks are both large, highly interconnected, dynamic, subject to time and varying inputs and demands, and difficult to control. Their performance also faces increasing loading due to increasing urbanization and longer-term environmental changes. Therefore, understanding the link between microbial ecology and any potential impacts on short or long-term engineering performance within urban water infrastructure systems is important. By combining the strengths and research expertise of civil-, biochemical engineers and molecular microbial ecologists, we ultimately aim to link microbial community abundance, diversity and function to physical and engineering variables so that novel insights into the performance and management of both water distribution systems and sewer networks can be explored. By presenting the details and principals behind the molecular microbiological techniques that we use, this paper demonstrates the potential of an integrated approach to better understand how urban water system function, and so meet future challenges.


1988 ◽  
Vol 20 (11-12) ◽  
pp. 153-159 ◽  
Author(s):  
William D. Rosenzweig ◽  
Wesley O. Pipes

In recent years various types of imperfect fungi have been isolated from water systems. Fungal spores and mycelia can be inactivated by low concentrations of chlorine in the laboratory but survive in some habitats in water distribution systems. This report describes a field study which provides evidence that some types of fungi are able to grow in water distribution systems. Replicate samples from private residences were used to demonstrate that fungal densities are sometimes much greater than the levels which could be explained by adventitious spores. The microbiological content of water samples from fire hydrants was often significantly different from that of water samples from nearby private residences. The treated water input to distribution systems was found to be significantly lower in fungus content than water from private residences. Elevated storage tanks open to the atmosphere appear to be significant sources of fungal input to some systems.


2010 ◽  
Vol 3 (1) ◽  
pp. 43-64
Author(s):  
P. Deines ◽  
R. Sekar ◽  
H. S. Jensen ◽  
S. Tait ◽  
J. B. Boxall ◽  
...  

Abstract. Microbiology in Urban Water Systems (MUWS) is an integrated project, which aims to characterize the microorganisms found in both potable water distribution systems and sewer networks. These large infrastructure systems have a major impact on our quality of life, and despite the importance of these systems as major components of the water cycle, little is known about their microbial ecology. Potable water distribution systems are large, highly interconnected and dynamic, and difficult to control. Sewer systems are also large and subject to time varying inputs and demands. Their performance also faces increasing loading due to increasing urbanization and longer-term environmental changes. Therefore, understanding the link between microbial ecology and any potential impacts on short or long-term engineering performance is important. By combining the strengths and research expertise of civil-, biochemical engineers and molecular microbial ecologists, we aim to link the abundance and diversity of microorganisms to physical and engineering variables so that novel insights into the ecology of microorganisms within both water distribution systems and sewer networks can be explored. By presenting the details of this multidisciplinary approach, and the principals behind the molecular microbiological methods and techniques that we use, this paper will demonstrate the potential of an integrated approach to better understand urban water system function and so meet future challenges.


Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3338
Author(s):  
Joseph O. Falkinham

Members of the Mycobacterium avium complex (MAC) are waterborne, opportunistic pathogens whose characteristics make urban water distribution systems and household plumbing ideal habitats for their survival, persistence and growth. Rather than contaminants, MAC are colonists of drinking water systems. MAC are normal inhabitants of natural soils and water, and enter drinking water treatment systems through surface sources. A proportion of MAC survive transmission through the treatment plant, and regrow in the distribution system and household plumbing. Once within household plumbing, MAC adhere to surfaces and form biofilms, thus preventing their washout. The thermal tolerance of MAC leads to growth in water heating systems. Stagnation does not reduce MAC numbers, as MAC can grow at low oxygen levels. MAC present challenges to current water monitoring approaches as their numbers do not correlate with E. coli, fecal coliforms or heterotrophic plate count bacteria.


2017 ◽  
Vol 11 (1) ◽  
pp. 49
Author(s):  
Jason R. Barrett, PhD Candidate ◽  
P. Edward French, PhD

The events of September 11, 2001, increased and intensified domestic preparedness efforts in the United States against terrorism and other threats. The heightened focus on protecting this nation’s critical infrastructure included legislation requiring implementation of extensive new security measures to better defend water supply systems against physical, chemical/ biological, and cyber attacks. In response, municipal officials have implemented numerous safeguards to reduce the vulnerability of these systems to purposeful intrusions including ongoing vulnerability assessments, extensive personnel training, and highly detailed emergency response and communication plans. This study evaluates fiscal year 2010 annual compliance assessments of public water systems with security measures that were implemented by Mississippi’s Department of Health as a response to federal requirements to address these potential terrorist threats to water distribution systems. The results show that 20 percent of the water systems in this state had at least one security violation on their 2010 Capacity Development Assessment, and continued perseverance from local governments is needed to enhance the resiliency and robustness of these systems against physical threats.


Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1521
Author(s):  
Kegong Diao

Multiscale resilience, i.e., coordinating different scales within a system to jointly cope and mitigate risks on any single scale, is identified as the feature of a complex resilient system. However, in water distribution systems (WDSs) and urban drainage systems (UDSs), the inherent resilience is usually not multiscale resilience. By referring to the larger scale to larger pipes serving both local users and some other users at smaller scales, it can be found that smaller scales are not responsible for providing resilience to cope with failures in larger scales. These are because the main function of traditional water systems is to deliver water from upstream to downstream. This study demonstrates that improving multiscale resilience in WDSs and UDSs needs to allow water to travel reversely in the system via providing extra capacities and/or connections at smaller scales. This hypothesis is verified via case studies on a real world WDS and UDS.


1994 ◽  
Vol 40 (12) ◽  
pp. 993-999 ◽  
Author(s):  
Outi M. Zacheus ◽  
Pertti J. Martikainen

The occurrence of legionellae in the hot water distribution systems of 67 buildings located in different parts of Finland was studied. Most of the buildings were apartment buildings. They had different hot water temperatures, and some received their cold potable water from surface water plants and some from ground water plants. Hot water samples were taken from taps, showers, and water mains just before and after the heat exchanger. Legionella pneumophila was isolated from 30% of the distribution systems. In the legionella-positive samples the legionella concentration varied from < 50 to 3.2 × 105 colony-forming units (cfu)/L (mean 2.7 × 103 cfu/L). The highest concentration of legionellae was found in the shower water. Legionellae appeared more often and with higher concentrations in hot water systems using cold water processed in surface water plants than in hot water systems associated with ground water plants. A high organic matter content in surface waters might favor the occurrence of legionellae and also the growth of other heterotrophic microbes. Mean water temperature just after heating was slightly higher in the legionella-negative systems than in the legionella-positive systems (53.5 vs. 51.5 °C).Key words: Legionella, organic carbon, hot water distribution system, water temperature.


2006 ◽  
Vol 4 (S2) ◽  
pp. 19-30 ◽  
Author(s):  
Michael F. Craun ◽  
Gunther F. Craun ◽  
Rebecca L. Calderon ◽  
Michael J. Beach

Epidemic waterborne risks are discussed in this paper. Although the true incidence of waterborne illness is not reflected in the currently reported outbreak statistics, outbreak surveillance has provided information about the important waterborne pathogens, relative degrees of risk associated with water sources and treatment processes, and adequacy of regulations. Pathogens and water system deficiencies that are identified in outbreaks may also be important causes of endemic waterborne illness. In recent years, investigators have identified a large number of pathogens responsible for outbreaks, and research has focused on their sources, resistance to water disinfection, and removal from drinking water. Outbreaks in surface water systems have decreased in the recent decade, most likely due to recent regulations and improved treatment efficacy. Of increased importance, however, are outbreaks caused by the microbial contamination of water distribution systems. In order to better estimate waterborne risks in the United States, additional information is needed about the contribution of distribution system contaminants to endemic waterborne risks and undetected waterborne outbreaks, especially those associated with distribution system contaminants.


1988 ◽  
Vol 20 (11-12) ◽  
pp. 437-439 ◽  
Author(s):  
K. Power ◽  
B. Cooper ◽  
H. Watts ◽  
L. A. Nagy

Aftergrowths in drinking water distribution systems were investigated in Sydney Australia. The microbiological monitoring results, collected over a 2 year period were used to provide information on interactions between various parameters. Results indicated that microorganisms and total coliforms were usually absent in waters with total chlorine levels over 0.2 mg/L. Results also indicated inhibition between plate count organisms (at 20 and 35°C), and total coliforms, particularly once plate count levels exceeded 100 CFU/mL.


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