Effect of Coagulation and Activated Carbon Adsorption on Removing DOM Fractions of Bio-treated Sewage Effluent

摘要

In this study, the effects of coagulation, powdered activated carbon adsorption and their combined process on removal of DOM fractions in BTSE were evaluated in terms of reduction of DOC, UV254, toxicity, and THMFP. The tested samples were secondary effluent from a municipal sewage treatment plant. Coagulation had obvious selective effect on removing DOM fractions in BTSE,tending to give priority to remove hydrophobic organics, followed by transphilics, and removal effect of hydrophilic organics was the worst. PAC adsorption exhibited good removal effects on both hydrophobic organics and hydrophilic organics. PAC adsorption was not selective on removing DOM fractions in BTSE. Combined coagulation and adsorption process could greatly improve the performance compared with coagulation or PAC adsorption alone. Hydrophobic acids were main THMs precursors in BTSE, accounting for 80%. Coagulation could reduce THMFP by 70%,higher than PAC adsorption, and combined process could increase the removal to 84%.Coagulation was a useful method to remove THMs precursors.