Enhanced Water Age Performance Assessment in Distribution Networks

Laura Monteiro,Dídia Covas,Ricardo Algarvio

doi:10.3390/w13182574

Abstract

Water age is frequently used as a surrogate for water quality in distribution networks and is often included in modelling and optimisation studies, though there are no reference values or standard performance functions for assessing the network behaviour regarding water age. This paper presents a novel methodology for obtaining enhanced system-specific water age performance assessment functions, tailored for each distribution network. The methodology is based on the establishment of relationships between the chlorine concentration at the sampling nodes and simulated water age. The proposed methodology is demonstrated through application to two water distribution systems in winter and summer seasons. Obtained results show a major improvement in comparison with those obtained by published performance functions, since the water age limits of the performance functions used herein are tailored to the analysed networks. This demonstrates that the development of network-specific water age performance functions is a powerful tool for more robustly and reliably defining water age goals and evaluating the system behaviour under different operating conditions.

Highlights

Water age is defined as the time taken for the water to travel from the source to the consumption locations within the distribution system [1]
The methodology is based on the establishment of a system-specific relationship between water age and chlorine concentrations and on a general chlorine performance function
This methodology, though based on chlorine content, does not require additional sampling, experimental decay tests, or water quality models other than those routinely carried out in the systems for water quality control purposes. It can be applied by making use of the chlorine data that the utilities gather for mandatory water quality control programmes and the simulated water age at the sampled nodes

Summary

Introduction

Water age is defined as the time taken for the water to travel from the source to the consumption locations within the distribution system [1]. Chlorine residual concentrations decline with increasing travel time (water age), which is usually followed by an increase in bacterial counts and diversity [6,7]. The extent of such reactions increases with water age; for this reason, this parameter is considered a useful indicator of the quality of the water [8,9] and has been used as a surrogate for water quality in many WDN studies [10,11]

Methods

Results

Conclusion