Dissolved organic matter fractions and disinfection by-product formation potential from major raw waters in the water-receiving areas of south-to-north water diversion project, China

Abstract

The raw waters from the Yellow River and the Danjiangkou Reservoir are the two most important sources of water in the water-receiving areas of the south-to-north water diversion project (SNWDP). This paper compared the constitution of dissolved organic matter (DOM) in the two waters based on XAD resins isolation, ultrafiltration fractionation, and the disinfection by-product formation potential of each fraction. The dissolved organic carbon (DOC), UV254, trihalomethanes, and nitrogenous disinfection by-product (N-DBP) formation potential of the raw water from the Yellow River were higher than those from the Danjiangkou Reservoir. The molecular weight (MW) < 1 kDa fraction contained the most DOM and dominated the major THM formation potential (THMFP) and N-DBP formation potential (N-DBPFP) in both waters. The hydrophilic fraction possessed the highest proportion in the Yellow River water, while the transphilic fraction was predominant in the Danjiangkou Reservoir water. In both waters, the hydrophobic fraction owned the highest THMFP and the hydrophilic fraction contained the highest N-DBPFP. Meanwhile, the molecular weight (MW) < 1 kDa and hydrophilic fractions contributed more bromated THMFP than the other fractions. Very toxic bromoform, bromochloroacetonitrile, and dibromoacetonitrile were only detected in DOM fractions from the Yellow River water. Therefore, the hydrophobic/hydrophilic organic compounds with low MW in both raw waters and bromide in Yellow River water should receive attention during the upgrading and reforming of drinking water treatment processes for adapting waters with different qualities in the water-receiving areas of SNWDP.