Comparison of topological, empirical and optimization-based approaches for locating quality detection points in water distribution networks

Giovanni Francesco Santonastaso,Dino Musmarra,Enrico Creaco,Roberto Greco,Armando Di Nardo

doi:10.1007/s11356-020-10519-3

Abstract

The positioning of quality detection points as well as the frequency of sampling is a crucial aspect for the implementation of Water Safety Plans (WSPs), which have been proposed worldwide to ensure water quality and to minimize the risk from contamination in water distribution networks (WDNs). In this regard, some international legislations and best practices about quality of drinking water suggest very fine sampling frequencies, but they do not specify where the detection points should be located in a WDN. In this paper, three different approaches, based on empiricism, optimization and topology, respectively, were applied to locate detection quality points in a WDN. The comparison highlighted that empirical approach commonly adopted by water utility practitioners is unsatisfactory. The optimization-based approach, although performing significantly better, is difficult to apply, since it requires a calibrated hydraulic model. The topological approach, based on the use of the betweenness centrality and not requiring any hydraulic information and simulation, proves to be effective, and it can be easily adopted by water utilities to identify the location for quality detection points, due to its simplicity compared with the optimization-based approach.

Highlights

Water distribution networks (WDNs) are among the most important critical infrastructures of modern society, because their security is a priority issue for public health
Though European law 98/83/CE (European Comission 1998) and Italian Legislative Decree 31/2001 suggest only a minimum number of samplings based on total delivered water volume without giving indications on the positioning of the monitoring points; this paper compares three different approaches with the aim of providing an effective and simple method to identify a set of nodes where quality detection points or sensors can be located: (1) an empirical approach, generally adopted by Water Utility to comply with legal requirements; (2) an optimization-based approach, proposed by Sandia National Laboratories in the Chama framework (Klise et al 2017), based on the linear programming; (3) a topological approach
It is worth highlighting that the results show that, in all the investigated approaches, the number of 9 detection points defined by the municipality for the Water Safety Plans (WSPs) of the WDN of Giugliano is inadequate to monitor all possible contamination events

Summary

Introduction

Water distribution networks (WDNs) are among the most important critical infrastructures of modern society, because their security is a priority issue for public health. Though European law 98/83/CE (European Comission 1998) and Italian Legislative Decree 31/2001 suggest only a minimum number of samplings based on total delivered water volume without giving indications on the positioning of the monitoring points; this paper compares three different approaches with the aim of providing an effective and simple method to identify a set of nodes where quality detection points or sensors can be located: (1) an empirical approach, generally adopted by Water Utility to comply with legal requirements; (2) an optimization-based approach, proposed by Sandia National Laboratories in the Chama framework (Klise et al 2017), based on the linear programming; (3) a topological approach.

Results

Conclusion