Drinking water quality assessment in distribution networks: A water footprint approach

Abstract

Reliable water quality monitoring and assessment can help to minimize the risk of water quality failures (WQFs) in water distribution networks (WDNs). Indexing-based water quality assessment approaches classify water quality based on contaminant concentrations. However, the resultant indices do not provide any information on trade-offs between water quality and quantity. The need to preserve the earth's natural resources has drawn attention to the use of footprint approaches to assess water quality. This paper uses a water footprint concept to develop a grey water footprint (GWF)-based framework for water quality assessment. A probabilistic human health risk assessment (HHRA) is also incorporated in the GWF approach to address the uncertainties. The proposed framework was implemented by considering the disinfection by-products (DBPs) in WDNs as a case study, and the results were compared with those generated using the Canadian Water Quality Index (CWQI) approach. Six drinking water quality management strategies (DWQMSs) were evaluated. The results from both approaches were correlated, indicating GWF as an alternative to CWQI. The assessment results showed that DWQMSs having groundwater as a source deliver better water quality in terms of DBPs occurrence compared to those using a surface water source. The GWF approach helps categorize water quality by estimating the theoretical volume of fresh water required to dilute the contaminant concentrations to below threshold levels. Water stakeholders can apply this framework considering any contaminants to drinking water quality using a quantitative water footprint scale and develop a trade-off between water quality and quantity management.