Unregulated Disinfection By‐Products: Spatiotemporal Variation in Water Distribution Networks

Abstract

Abstract Residual disinfectants react with various natural organic matter in distribution networks (DNs) to form disinfection by‐products (DBPs), which are a public health concern. The regulated DBPs in various jurisdictions are trihalomethanes, haloacetic acids, bromate, and chlorate, which are mostly associated with chlorine. Owing to this, several alternative disinfectants, such as chloramines, ozone, and chlorine dioxide are also used. Although the use of alternate disinfectants has reduced the formation of regulated DBPs, these disinfectants have gathered much attention by introducing another cluster of DBPs known as unregulated DBPs (U‐DBPs). Many U‐DBPs are potentially toxic, mutagenic, and/or carcinogenic. This study reviews the models for predicting the spatiotemporal variation of U‐DBPs and analyzes their variability in DNs in the provinces of Quebec, and Newfoundland and Labrador, Canada. The findings show that limited predictive models are available for U‐DBPs compared to regulated DBPs. The concentrations of haloacetonitriles, chloropicrin, and haloketones significantly differed along the DNs based on the distance traveled and/or residence time. Similarly, temporal variability was significant in different seasons and in various weeks in summer but not significant by days from Monday to Friday. The formation of U‐DBPs can be controlled by source water protection, use of advanced treatment, alternative disinfectants, etc.