Effect of Bromide Ion on Haloacetic Acid Formation during Chlorination of Biscayne Aquifer Water

Abstract

Water drawn from the Biscayne Aquifer, an extensively used potable water supply source in Florida, was used to study the effect of the bromide ion on haloacetic acid (HAA) formation during chlorination. The source water contained an ambient bromide ion concentration (160 μg/L) and a substantial concentration of natural organic matter (nonpurgeable organic carbon = 10.9 mg/L). A systematic evaluation, encompassing a range of bromide ion concentration spikes, and reaction times at fixed pH, chlorine dose, and temperature conditions, was conducted. Two chlorinated HAAs (dichloroacetic acid and trichloroacetic acid), two brominated HAAs (dibromoacetic acid and tribromoacetic acid), and three mixed HAAs (bromochloroacetic acid, bromodichloroacetic acid, and dibromochloroacetic acid) were found. Monobromoacetic acid and monochloroacetic acid were below detection limits in all of the chlorinated samples. In contrast to the findings of previous studies, the molar yield of HAAs increased as the initial bromide ion concentration increased. Concentrations of total HAAs, brominated, and mixed HAAs increased substantially, while chlorinated HAAs decreased slightly, with the addition of the bromide ion.