This work investigated the formation of carbonaceous and nitrogenous disinfection by-products (C-DBPs, N-DBPs) upon chlorination of water samples collected from a surface water and a ground water treatment plant (SWTP and GWTP) where the conventional treatment processes, i.e., coagulation, sedimentation, and filtration were employed. Twenty DBPs, including four trihalomethanes, nine haloacetic acids, seven N-DBPs (dichloroacetamide, trichloroacetamide, dichloroacetonitrile, trichloroacetonitrile, bromochloroacetonitrile, dibromoacetonitrile and trichloronitromethane), and eight volatile chlorinated compounds (dichloromethane (DCM), 1,2-dichloroethane, tetrachloroethylene, chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene and 1,2,4-trichlorobenzene) were detected in the two WTPs. The concentrations of these contaminants were all below their corresponding maximum contamination levels (MCLs) regulated by the Standards for Drinking Water Quality of China (GB5749-2006) except for DCM (17.1 microg/L detected vs. 20 microg/L MCL). The SWTP had much higher concentrations of DBPs detected in the treated water as well as the DBP formation potentials tested in the filtered water than the GWTP, probably because more precursors (e.g., dissolved organic carbon, dissolved organic nitrogen) were present in the water source of the SWTP.
