Total Trihalomethane Formation during Targeted and Conventional Chlorination of Seawater for Biofouling Control

A study was conducted to compare the potential for total trihalomethane (TTHM) formation using conventional versus targeted chlorination. Results indicate that targeted chlorination significantly decreases TTHM formation when compared to conventional chlorination in cooling waters where chlorine is applied for biofouling control. Bromoform was the predominant THM formed in all cases, owing to the oxidation of naturally occurring bromide in seawater to bromine when chlorinated, with subsequent conversion to bromoform when it reacted with organic precursors. Introduction of additional chlorine to all samples yielded considerable TTHMs after a 7-day incubation.