Drinking water strategies for small-scale systems: Avoiding unintended consequences of water regulations

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Smaller communities in Canada are faced with significant challenges in providing safe drinking water to consumers.  These challenges stem from the fact that the technical and financial resources needed to provide high quality drinking water to consumers are often not available to small water providers.  As a result, the drinking water quality in small communities often does not consistently meet existing Canadian Drinking Water Quality (CDWQ) guidelines, and likely cannot meet increasingly stringent guidelines that encompass emerging contaminants that either consist of compounds that are present in the raw source water or consist of by-products that are formed within current treatment regimes.  Haloacetic acids (HAAs) are one such group of emerging contaminants for which CDWQ guidelines are currently in the developmental stages by Health Canada and the Federal-Provincial-Territorial Committee on Drinking Water.  Preliminary studies have indicated that existing drinking water systems in many small communities across Canada will not be able to meet the increasingly stringent CDWQ guidelines for certain emerging contaminants like HAAs.  Therefore, key strategies may need to be developed to improve NOM removal in the plant or switch secondary disinfectants from free chlorine to chloramines.  This project will investigate both of these treatment approaches, as either could result in a positive result for mitigating HAA formation but result in an unintended water quality change (i.e., formation of other disinfectant by-products or increased occurrence of ammonia oxidizing bacteria).  This research program will focus on identifying cost-effective and practically feasible strategies that can be used to ensure high quality drinking water is delivered to consumers in small communities.