Investigation of Disinfection By-Product Formation Potential Test Methodologies in Drinking Water Systems

Abstract

Natural organic matter (NOM) is present in all surface waters and is a major issue in drinking water treatment plants. If introduced into the distribution system, NOM will react with chlorine to form harmful disinfection by-products (DBP), some of which are known human carcinogens. Monitoring DBPs in drinking water treatment utilities is extremely important to public health. This study investigated DBP formation potential testing methods, specifically the uniform formation conditions (UFC) test and the simulated distribution system (SDS) test. From this analysis, a modified SDS test was proposed which simulates chlorine booster stations within a distribution system. Varying conditions of pH and temperature were tested on the proposed modified SDS test in order to investigate its effect on chlorine decay and DBP formation. The results of this study suggest that modeling chlorine boosting in SDS testing will result in slightly higher DBP formation concentrations. Both pH and water temperature test conditions for the proposed modified SDS method were found to impact DBP concentrations and free chlorine residuals, and should be considered as important variables in evaluating DBP formation potential in distribution systems that practice chlorine boosting