中试紫外/氯工艺对饮用水中微量有机污染物及消毒副产物的削减OA北大核心CSTPCD

Against the background of water sources being contaminated by micropollutants,a pilot-scale UV/chlorine system was set up in a drinking water treatment plant to explore the efficacy and mechanism of trace organic contaminants removal as well as the elimination of disinfection by-products and the formation potentials under different process conditions.Results show that the UV/chlorine process was efficient in removing metolachlor,carbendazim,imidacloprid and other pesticides found in the sand-filtered water.A gross removal efficiency of 87.1％was achieved under the benchmark operation condition,while an elevated UV fluence was more beneficial than an increased chlorine dose.The removal of perfluorinated compounds(PFCs)by UV/chlorine was relatively low with the largest removal efficiency found with perfluorooctanoic acid(PFOA),which was 46.4％.The content of perfluorohexanoic acid(PFHxA)was found to increase under some operation conditions.This indicates that the transformation of long-chain PFCs to short-chain PFCs could exist during the process.Meanwhile,disinfection by-products(DBPs)consisting mainly of trichloromethane(TCM)were generated with a maximum concentration of 8.8 μg·L-1,yet the disinfection by-products formation potential(DBPsFP)of the effluent decreased significantly.The minimum DBPsFP occurred with the largest chlorine dose,which was 12.9 μg·L-1,66.3％lower than that before UV/chlorine treatment.Moreover,the changes in dissolved organic matter in the sand-filtered water were characterized with parameters such as the UV absorbance at 254 nm(UV254)and fluorescence excitation emission matrix.The aromatic and fluorescent constitutions of the organics were reduced significantly by UV/chlorine treatment as evidenced by the lowered SUVA(＜1.0 L·mg-1·m-1)and the prominent removal efficiencies of the three identified fluorescent compositions(41.8％～71.6％).A correlation analysis was conducted which revealed the strong correlations between the formed DBPs or the subsequent DBPsFP and the contents of aromatic and fluorescent constitutions in the water.