Assessment of water quality in distribution networks through the lens of disinfection by-product rules

• Published in: Water S. A. Vol. 42; no. 2; pp. 337 - 349
• Main Authors: Islam, Nilufar, Sadiq, Rehan, Rodriguez, Manuel J., Legay, Christelle
• Format: Journal Article
• Language: English
• Published: Gezina Water Research Commission (WRC) 01.04.2016; Water Research Commission
• Subjects: Acids; By-products; Case studies; CCME water quality index; Chlorination; Decision making; Disinfection & disinfectants; Disinfection and disinfectants; Distribution; Methods; Spatial analysis; Stage 1 DBP Rule; Stage 2 DBP Rule; Statistical methods; Surface water; Water; Water quality; Water quality bioassay; Canada; Canada, Quebec
• ISSN: 0378-4738; 0378-4738
• DOI: 10.4314/wsa.v42i2.17

Disinfection with chlorine is a common practice to ensure secured drinking water, but results in potentially harmful disinfection by-products (DBPs), when excess chlorination is done. The US Environmental Protection Agency (US EPA) has established Stage 1 and Stage 2 disinfection by-product Rules (DBP rules) to control DBP exposure. A modified version of the Canadian Council of Ministries of the Environment water quality index (CCME WQI) is used to assess water quality. CCME WQI is a globally accepted index to assess water quality, but is too generic to be used for DBP rules. The study developed a scheme to make the index suitable for DBP rules. A scoring method based on an analytic hierarchy process (AHP) is applied to assign weights based on DBP rules. A previously modified CCME WQI (Islam et al., 2014) is adapted along with the weights to perform the assessment at the distribution network (DN). A case study was performed on 7 sampling stations in a Québec City DN. The spatial water quality variations are presented using kriging - a geostatistical method, which identifies the regions with relatively poor water quality and highlights the potential locations for re-chlorination points. The proposed assessment formulation is flexible to handle situations with limited data, which makes it especially suited to smaller municipalities.