Characterization of trihalomethane, haloacetic acid, and haloacetonitrile precursors in a seawater reverse osmosis system

Abstract Seawater reverse osmosis (SWRO) has been extensively applied to replenish the limited freshwater resources. One concern of such technology is the formation of disinfection by-products (DBPs) during the pre-chlorination process. For the SWRO tested in this study, the concentrations of trihalomethanes (THMs), haloacetic acids (HAAs), and haloacetonitriles (HANs) increased by 35.1, 23.7 and 4.9 μg/L, respectively, after a seawater sample (with UV 254 /DOC of 3.7 L/mg·m and Br − of 50.9 mg/L) was pre-chlorinated (1–2 mg-Cl 2 /L). The dissolved organic matter (DOM) with molecular weight (MW)