Assessment of Microbiological Water Quality after Low Pressure Events in a Distribution System

Hooper, Stuart M.; Moe, Christine L.; Uber, James G.; Nilsson, Kenneth A.

doi:10.1061/40941(247)157

Cited by 8 publications

(10 citation statements)

References 3 publications

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“…For the purpose of this review, intrusion will be defined as in Besner et al (2011), i.e., contamination of the drinking water due to adverse pressure conditions and physical breaches in the system. In order for microbial contamination to occur from intrusion, three conditions are necessary: presence of pathogens surrounding the distribution system (source); occurrence of pressure transients or low-pressure events (adverse pressure conditions); and deteriorated physical conditions of the pipes (physical breach) (Hooper et al 2008;Lindley and Buchberger 2002). Intrusion was considered a medium priority issue by the National Research Council (2005); however, awareness has increased substantially since then (Besner et al 2011).…”

Section: Söderbergh Et Al 2017a)mentioning

confidence: 99%

Overview of microbial risks in water distribution networks and their health consequences: quantification, modelling, trends, and future implications

2019

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The water distribution network (WDN) is usually the final physical barrier preventing contamination of the drinking water before it reaches consumers. Because the WDN is at the end of the supply chain, and often with limited online water quality monitoring, the probability of an incident to be detected and remediated in time is low. Microbial risks that can affect the distribution network are: intrusion, cross-connections and backflows, inadequate management of reservoirs, improper main pipe repair and (or) maintenance work, and biofilms. Epidemiological investigations have proven that these risks have been sources of waterborne outbreaks. Increasingly since the 1990s, studies have also indicated that the contribution of these risks to the endemic level of disease is not negligible. To address the increasing health risks associated to WDNs, researchers have developed tools for risk quantification and risk management. This review aims to present the recent advancements in the field involving epidemiological investigations, use of quantitative microbial risk assessment (QMRA) for modelling, risk mitigation, and decision-support. Increasing the awareness of the progress achieved, but also of the limitations and challenges faced, will aid in accelerating the implementation of QMRA tools for WDN risk management and as a decision-support tool.

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Section: Söderbergh Et Al 2017a)mentioning

confidence: 99%

Overview of microbial risks in water distribution networks and their health consequences: quantification, modelling, trends, and future implications

2019

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“…Kirmeyer et al (2001) provided a detailed list of causes of low or negative pressure events in the daily operation of a distribution system, including valve operation, pump trip resulting from a power failure, main breaks, flushing operations, and so on. Pressure monitoring studies (Besner et al, 2011; Hooper et al, 2006; Gullick et al, 2005, 2004; Kirmeyer et al, 2001) have also indicated low or negative pressures in distribution systems. Besner et al (2011) discussed two types of low or negative pressure events: transient events lasting from milliseconds to minutes and sustained events with durations ranging from minutes to hours.…”

Section: Summary Of Existing Water Quality Modelsmentioning

confidence: 99%

Contaminant intrusion in water distribution systems

et al. 2013

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FIGURE 5 Variations in head over time at junctions 1-5-case study 1 H-head Mansour-Rezaei et al | http://dx.FIGURE 5 Variations in head over time at junctions 1, 2, 3, 4, and 5-case study 1 Mansour-Rezaei et al | http://dx.CM-cumulative mass, G-normalized value of index, PC-peak concentration, TCM-total cumulative mass, TPC-total peak concentration Mansour-Rezaei et al | http://dx.In this research, the proposed model was used when intrusion occurred at junctions; however, in real-life distribution systems, intrusion can occur wherever a leak point exists. The proposed model can be used in these cases as well, provided internal points along the pipes are defined. ACKNOWLEDGMENTThe financial support provided by the University of British Columbia and the Okanagan Basin Water Board is greatly appreciated. The authors also thank Elodie Culiolo for technical support.

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“…High-speed pressure transient data loggers (range: minus 11 m to 141 m (−15 to 200 psi)) were installed at the outlet of the WTP and on fire hydrants in the system to allow for the detection of transient low and negative pressures. These were recording between 1 to 4 pressure values per second, a resolution that is typical for studies characterizing the occurrence of low or negative pressure events in full-scale distribution systems (Kirmeyer et al, 2001;Friedman et al, 2004;Gullick et al, 2004;Fleming et al, 2006;Hooper et al, 2006). While other types of application such as inverse transient analysis, used for leak detection and system parameter calibration, requires higher frequency of pressure information (kHz resolution), the current measuring frequency of 1 to 4 Hz is considered adequate for the application presented here, where the main interest is to detect the occurrence of negative pressure.…”

Section: Pressure Monitoringmentioning

confidence: 99%

“…Previous studies have shown that low or negative pressure events are not uncommon in distribution systems (Kirmeyer et al, 2001;LeChevallier et al, 2004;Gullick et al, 2004Gullick et al, , 2005Hooper et al, 2006) and that the soil and water surrounding water mains may contain fecal contamination and viruses (Karim et al, 2003). Aging drinking water infrastructure certainly provides some potential pathway for contaminant intrusion.…”

Section: Introductionmentioning

confidence: 99%

Negative pressures in full-scale distribution system: field investigation, modelling, estimation of intrusion volumes and risk for public health

Besner

Ebacher

Jung

et al. 2010

Drink. Water Eng. Sci.

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Various investigations encompassing microbial characterization of external sources of contamination (soil and trenchwater surrounding water mains, flooded air-valve vaults), field pressure monitoring, and hydraulic and transient analyses were conducted in the same distribution system where two epidemiological studies showing an increase in gastrointestinal illness for people drinking tap water were conducted in the 1990's. Interesting results include the detection of microorganisms indicators of fecal contamination in all external sources investigated but at a higher frequency in the water from flooded air-valve vaults, and the recording of 18 negative pressure events in the distribution system during a 17-month monitoring period. Transient analysis of this large and complex distribution system was challenging and highlighted the need to consider field pressure data in the process

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Assessment of Microbiological Water Quality after Low Pressure Events in a Distribution System

Cited by 8 publications

References 3 publications

Overview of microbial risks in water distribution networks and their health consequences: quantification, modelling, trends, and future implications

Overview of microbial risks in water distribution networks and their health consequences: quantification, modelling, trends, and future implications

Contaminant intrusion in water distribution systems

Negative pressures in full-scale distribution system: field investigation, modelling, estimation of intrusion volumes and risk for public health

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