AWWA JAW65071

This research elucidates the influence of natural organic matter (NOM) characteristics and reactivity, pH, chlorine-to-nitrogen ratio, disinfectant residual concentration, and bromide concentration on dihaloacetic acid (DXAA) formation during chloramination in several diverse water sources. Analysis of variance over a broad variety of experimental conditions usually pointed to pH as being the most significant factor in DXAA formation, followed by bromide concentration. A shift in speciation to the bromine-substituted species occurred as the bromide concentration increased and the pH decreased. Temperature and chloramine residual also affected DXAA formation, but were much less influential than other factors. The effectiveness of treatment, which can have a significant effect on DXAA formation, is largely related to overall DOC removal, although preferential removal of more-reactive NOM fractions also may contribute to reduction of DXAA formation. The conclusions of this research will help utilities make more-informed decisions regarding the control of disinfection byproduct formation while maintaining disinfection requirements. Includes 26 references, tables, figures.