Kinetics of dihaloacetic acid formation during chloramination

Batch experiments were conducted on both source and treated water from four locations to study the kinetics of dihaloacetic acid (X(2)AA) formation during chloramination. The influence of treatment, pH, bromide concentration, and periods of free chlorination on X(2)AA formation kinetics was examined. Bromine-substituted X(2)AA, i.e., bromochloroacetic acid and dibromoacetic acid, formed more rapidly than did dichloroacetic acid; short periods of prechlorination (between 5 and 20 min) significantly increased haloacetic acid (HAA) formation. This research demonstrates that Most X(2)AA formation occurs within watertreatment facilities that prechlorinate before chloramination; therefore, HAA control strategies in such plants should focus on the chlorination step.