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

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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Topological clustering as a tool for planning water quality monitoring in water distribution networks

Water Science & Technology Water Supply ◽

10.2166/ws.2015.056 ◽

2015 ◽

Vol 15 (5) ◽

pp. 1011-1018 ◽

Cited By ~ 1

Author(s):

Jonas Kjeld Kirstein ◽

Hans-Jørgen Albrechtsen ◽

Martin Rygaard

Keyword(s):

Water Quality ◽

Decision Support ◽

Network Model ◽

Water Distribution ◽

Water Movement ◽

Decision Support Tool ◽

Water Quality Monitoring ◽

Distribution Networks ◽

Quality Monitoring ◽

Support Tool

Topological clustering was explored as a tool for water supply utilities in preparation of monitoring and contamination contingency plans. A complex water distribution network model of Copenhagen, Denmark, was simplified by topological clustering into recognizable water movement patterns to: (1) identify steady clusters for a part of the network where an actual contamination has occurred; (2) analyze this event by the use of mesh diagrams; and (3) analyze the use of mesh diagrams as a decision support tool for planning water quality monitoring. Initially, the network model was divided into strongly and weakly connected clusters for selected time periods and mesh diagrams were used for analysing cluster connections in the Nørrebro district. Here, areas of particular interest for water quality monitoring were identified by including user-information about consumption rates and consumers particular sensitive towards water quality deterioration. The analysis revealed sampling locations within steady clusters, which increased samples' comparability over time. Furthermore, the method provided a simplified overview of water movement in complex distribution networks, and could assist identification of potential contamination and affected consumers in contamination cases. Although still in development, the method shows potential for assisting utilities during planning of monitoring programs and as decision support tool during emergency contingency situations.

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Decision Support Tool for Design and Reliability Assessment of Water Distribution Networks

Pattern Recognition for Reliability Assessment of Water Distribution Networks ◽

10.1201/b11795-14 ◽

2012 ◽

pp. 263-298

Keyword(s):

Decision Support ◽

Water Distribution ◽

Reliability Assessment ◽

Decision Support Tool ◽

Distribution Networks ◽

Water Distribution Networks ◽

Support Tool

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Coupling Decision Support Systems For The Optimization of The Management of Water Distribution Networks

10.21203/rs.3.rs-1038410/v1 ◽

2022 ◽

Author(s):

Yacine Abdelbaset Berrezel ◽

Chérifa Abdelbaki ◽

Bouchrit Rouissat ◽

Tarik Boumaaza ◽

Khaldoon A Mourad

Keyword(s):

Decision Making ◽

Decision Support ◽

Decision Support Systems ◽

Water Distribution ◽

Support Systems ◽

Distribution Network ◽

Water Distribution Network ◽

Distribution Networks ◽

Water Distribution Networks ◽

Multi Criteria Decision Making

Abstract The analysis of the current situation of water distribution networks is based on all the alternatives that are technically feasible and implemented from the decision-maker's point of view. Taking the water distribution network of Tourville city as a case study, this paper combines a set of Decision Support Systems (DSS) including the Geographic Information Systems (GIS), multi-criteria analysis and hydraulic simulation models to establish a multi-criteria decision-making aid method for renovation and rehabilitation of water distribution networks. This combination creates an expert management system based on multi-criteria decision making that strengthens the optimization of the management of water distribution networks in terms of renovation and rehabilitation. After dividing the water distribution network into three emergency levels, it was concluded that 26% of the network is in urgent need of rehabilitation.

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A study on appropriate investment of pipeline rehabilitation for water distribution network

Water Science & Technology Water Supply ◽

10.2166/ws.2005.0019 ◽

2005 ◽

Vol 5 (2) ◽

pp. 31-38

Author(s):

A. Asakura ◽

A. Koizumi ◽

O. Odanagi ◽

H. Watanabe ◽

T. Inakazu

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Water Supply ◽

Water Distribution ◽

Ad Hoc ◽

Distribution Network ◽

Water Distribution Network ◽

Distribution Networks ◽

Optimal Basis ◽

Model Case

In Japan most of the water distribution networks were constructed during the 1960s to 1970s. Since these pipelines were used for a long period, pipeline rehabilitation is necessary to maintain water supply. Although investment for pipeline rehabilitation has to be planned in terms of cost-effectiveness, no standard method has been established because pipelines were replaced on emergency and ad hoc basis in the past. In this paper, a method to determine the maintenance of the water supply on an optimal basis with a fixed budget for a water distribution network is proposed. Firstly, a method to quantify the benefits of pipeline rehabilitation is examined. Secondly, two models using Integer Programming and Monte Carlo simulation to maximize the benefits of pipeline rehabilitation with limited budget were considered, and they are applied to a model case and a case study. Based on these studies, it is concluded that the Monte Carlo simulation model to calculate the appropriate investment for the pipeline rehabilitation planning is both convenient and practical.

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Improving water age estimation in a drinking water distribution network by field study and digital modeling

10.5194/egusphere-egu21-14741 ◽

2021 ◽

Author(s):

Jon Kristian Rakstang ◽

Michael B. Waak ◽

Marius M. Rokstad ◽

Cynthia Hallé

Keyword(s):

Water Quality ◽

Drinking Water ◽

Network Model ◽

Age Estimation ◽

Water Distribution ◽

Distribution Network ◽

Distribution Networks ◽

Plate Count ◽

Water Age ◽

Drinking Water Distribution

<p>Municipal drinking water distribution networks are complex and dynamic systems often spanning many hundreds of kilometers and serving thousands of consumers. Degradation of water quality within a distribution network can be associated to water age (i.e., time elapsed after treatment). Norwegian distribution networks often consist of an intricate combination of pressure zones, in which the transport path(s) between source and consumer is not easily ascertained. Water age is therefore poorly understood in many Norwegian distribution networks. In this study, simulations obtained from a water network model were used to estimate water age in a Norwegian municipal distribution network. A full-scale tracer study using sodium chloride salt was conducted to assess simulation accuracy. Water conductivity provided empirical estimates of salt arrival time at five monitoring stations. These estimates were consistently higher than simulated peak arrival times. Nevertheless, empirical and simulated water age correlated well, indicating that additional network model calibration will improve accuracy. Subsequently, simulated mean water age also correlated strongly with heterotrophic plate count (HPC) monitoring data from the distribution network (Pearson&#8217;s R= 0.78, P= 0.00046), indicating biomass accumulation during distribution&#8212;perhaps due to bacterial growth or biofilm interactions&#8212;and illustrating the importance of water age for water quality. This study demonstrates that Norwegian network models can be calibrated with simple and cost-effective salt tracer studies to improve water age estimates. Improved water age estimation will increase our understanding of water quality dynamics in distribution networks. This can, through digital tools, be used to monitor and control water age, and its impact on biogrowth in the network.</p>

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Optimal placement of valves in a water distribution network with CLP(FD)

Theory and Practice of Logic Programming ◽

10.1017/s1471068411000275 ◽

2011 ◽

Vol 11 (4-5) ◽

pp. 731-747 ◽

Cited By ~ 13

Author(s):

MASSIMILIANO CATTAFI ◽

MARCO GAVANELLI ◽

MADDALENA NONATO ◽

STEFANO ALVISI ◽

MARCO FRANCHINI

Keyword(s):

Logic Programming ◽

Distribution Systems ◽

Water Distribution ◽

Distribution Network ◽

Real Life ◽

Water Distribution Network ◽

Distribution Networks ◽

Constraint Logic Programming ◽

Optimal Placement ◽

Isolation System

AbstractThis paper presents a new application of logic programming to a real-life problem in hydraulic engineering. The work is developed as a collaboration of computer scientists and hydraulic engineers, and applies Constraint Logic Programming to solve a hard combinatorial problem. This application deals with one aspect of the design of a water distribution network, i.e., the valve isolation system design. We take the formulation of the problem by Giustolisi and Savić (2008 Optimal design of isolation valve system for water distribution networks. InProceedings of the 10th Annual Water Distribution Systems Analysis Conference WDSA2008, J. Van Zyl, A. Ilemobade, and H. Jacobs, Eds.) and show how, thanks to constraint propagation, we can get better solutions than the best solution known in the literature for the Apulian distribution network. We believe that the area of the so-calledhydroinformaticscan benefit from the techniques developed in Constraint Logic Programming and possibly from other areas of logic programming, such as Answer Set Programming.

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GAP FILLERS OR PIONEERS: INFORMAL WATER SUPPLIERS IN PERI-URBAN AREAS OF THE TECHIMAN MUNICIPALITY OF GHANA

UDS International Journal of Development ◽

10.47740/562.udsijd6i ◽

2021 ◽

Vol 8 (1) ◽

pp. 525-539

Author(s):

Lydia Kwoyiga

Keyword(s):

Urban Areas ◽

Water Distribution ◽

Water Source ◽

Water Quality Monitoring ◽

Distribution Networks ◽

Sub Saharan Africa ◽

Formal Sector ◽

Public Provision ◽

Sub Saharan ◽

Municipal Assembly

There is continuous expansion and growth of urban and peri urban areas in Sub-Saharan Africa with projections indicating that this will double. Some peri-urban areas such as those in the Techiman municipality of Ghana are experiencing this trend. Nonetheless, the spate of growth of these areas outstrips the supply of utilities by municipal water distribution networks. As a result, some areas have little or no public provision. In order to address the water supply challenge, places with favourable hydrological settings are witnessing the emergence of informal water suppliers as “gap fillers” or “pioneers”, providing water services. Noteworthy, however, existing studies about informal water suppliers in peri-urban areas in Ghana lump them together, without considering the water source. This study differs in that it specifically examines the evolution and the features of informal water suppliers who privately and independently abstract and supply groundwater. Additionally, it attempts to understand the nature of informality of the suppliers and the possibility of formalisation. The paper is an exploratory study using the case of private mechanised borehole operators who supply water in their respective areas. The findings showed that in some peri-urban areas in the Techiman municipality, some dwellers constructed and operated mechanised boreholes, which provide in-situ water and utilities to others. They are mostly pioneer water suppliers in some of the areas. Their services are informal by nature because they are largely independent of the formal sector and apply informal arrangements in rendering their services. Seen also as business enterprises, they are not licenced. However, the boreholes are registered with the Municipal Assembly, which indicated some level of formalisation. The study recommended that efforts to formalise them further should focus on improving water quality monitoring for consumption and promoting sustainable abstraction.

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Proposal of optimal operation strategy applied to water distribution network with statistical approach

Ambiente e Agua - An Interdisciplinary Journal of Applied Science ◽

10.4136/ambi-agua.2455 ◽

2020 ◽

Vol 15 (2) ◽

pp. 1

Author(s):

Alex Takeo Yasumura Lima Silva ◽

Fernando Das Graças Braga da Silva ◽

André Carlos da Silva ◽

José Antonio Tosta dos Reis ◽

Claudio Lindemberg de Freitas ◽

...

Keyword(s):

Genetic Algorithms ◽

Water Distribution ◽

Distribution Network ◽

Water Distribution Network ◽

Distribution Networks ◽

Optimal Operation ◽

Optimization Techniques ◽

Experimental Techniques ◽

Computational Optimization ◽

Depth Analysis

Inefficiency of sanitation companies’ operation procedures threatens the population’s future supplies. Thus, it is essential to increase water and energy efficiency in order to meet future demand. Optimization techniques are important tools for the analysis of complex problems, as in distribution networks for supply. Currently, genetic algorithms are recognized by their application in literature. In this regard, an optimization model of water distribution network is proposed, using genetic algorithms. The difference in this research is a methodology based on in-depth analysis of results, using statistics and the design of experimental tools and software. The proposed technique was applied to a theoretical network developed for the study. Preliminary simulations were accomplished using EPANET, representing the main causes of water and energy inefficiency in Brazilian sanitation companies. Some parameters were changed in applying this model, such as reservoir level, pipe diameter, pumping pressures, and valve-closing percentage. These values were established by the design of experimental techniques. As output, we obtained the equation of response surface, optimized, which resulted in values of established hydraulic parameters. From these data, the obtained parameters in computational optimization algorithms were applied, resulting in losses of 26.61%, improvement of 16.19 p.p. with regard to the network without optimization, establishing an operational strategy involving three pumps and a pressure-reducing valve. We conclude that the association of optimization and the planning of experimental techniques constitutes an encouraging method to deal with the complexity of water-distribution network optimization.

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