Precursor control in waters containing bromide

Trihalomethane and haloacetic acid precursors in water containing high concentrations of bromide ion can be controlled by ozonation and biodegradation without excessive bromate formation. Two coagulated and settled waters of differing quality and dissolved organic carbon concentration, but with the same bromide concentration, one natural and one spiked, were treated with robust ozonation followed by biodegradation. After free chlorination, these waters were tested for the formation of trihalomethanes (THMs) and, in some cases, haloacetic acids (HAAs). The formation of bromate was also determined. Results were promising, with prospects being good for controlling THMs, HAAs, and bromate in bromide‐containing water.