THM, haloacetic acids and other organic DBPs formation in disinfection of bromide rich Sea of Galilee (Lake Kinneret) water

Abstract

Lake Kinneret (Sea of Galilee) is the main freshwater body in Israel and is the water source for the National Water Carrier (NWC). The lake water has a uniquely high bromide content 1.9 mg/L which affects DBPs (disinfection by-products) formation. Controlled experiments using different disinfectants were carried out with the lake water in order to study DBPs formation. Formation and distribution of TOX (total organic halogen) trihalomethanes (THM), haloacetic acids (HAA) and cyanogen halides were studied during the application of the following disinfectants: Chlorine, chloramine, chlorine dioxide and a combination of chlorine dioxide with chloramine. Brominated species dominated the distribution of THM, HAA and cyanogen halide. When a high dose of chlorine was applied an unusually high percent (75%) of the TOX formation potential was identified; THM constituted about 50% of the TOX formation potential and haloacetic acids 22-28%. Tribromoacetic acid was found to undergo decomposition to form bromoform. Chlorine dioxide produced insignificant concentrations of organic DBPs and chloramine produced low concentrations. Chlorine dioxide in combination with chloramine enhanced production of CNBr and THM, but their concentrations were much lower than during chlorination.