Study on the efficiency of the preoxidation–coagulation process in removing disinfection by-product precursors from micropolluted water

Abstract

Recently, disinfection by-products (DBPs) have received widespread attention, and the control and removal of DBPs from drinking water is crucial for ensuring water supply safety. Although conventional coagulation treatment can effectively remove DBPs, such as trihalomethanes (THMs) and haloacetic acids (HAAs), emerging disinfection by-products, such as halogenated benzoquinones (HBQs), pose a significant potential threat to the safety of drinking water. This article focuses on the study of two types of water sources, namely the Yellow River source and the South to North Water Diversion source. Queshan Reservoir water is selected as the representative water of the Yellow River source, and Nansihu Reservoir water is selected as the representative water of the South to North Water Diversion source. This study explores the efficiency of preoxidation–coagulation technology in removing precursors of DBPs and organic compounds from slightly polluted surface water and the effect of this technology on the generation of DBPs. It was found that preoxidation–coagulation had a positive effect on the removal of precursors of DBPs from the two types of water. The removal rates of precursors of DBPs from water ranged from 10% to 75%, with the highest removal rate of HBQ precursors reaching over 70%. Moreover, the organic matter removed by preoxidation–coagulation was mainly macromolecular organic matter, and the removal rates of macromolecular organic matter from both types of water sources were above 30%. The removal of small-molecule organic matter was limited. It is speculated that the removal of DBP precursors from water by preoxidation–coagulation is mainly achieved by controlling the content of macromolecular organic matter in the water. The results of this study provide a reference for future research on the removal of precursors of emerging DBPs from water.