Abstract:The removals of dissolved organic matter (DOM) fractions as well as changes in the spectroscopic characteristics of DOM fractions in four municipal sewage treatment plants in the Northeast in winter were investigated. DOM was fractionated using XAD resins into five fractions: hydrophobic acid (HPO-A), hydrophobic neutral (HPO-N), transphilic acid (TPI-A), transphilic neutral (TPI-N) and hydrophilic fraction (HPI). Removals of DOM by anaerobic-anoxic-oxic (A2/O)、biological aerated filter (BAF)、suspended carrier activated sewage (SCAS) and A2/O processes were high, and the BAF process was the most efficient process for reduction of DOM. Both aromaticity and specific trihalomethaneformation potential (STHMFP) increased as a result of the four wastewater treatment processes. The increases in aromaticity of HPO-A and TPI-A caused by the A2/O process were the greatest, while those of HPO-N、TPI-N and HPI caused by the BAF process were the greatest. The increases in STHMFP of HPO-A, TPI-A and HPI caused by the SCAS process were the greatest, while those of HPO-N and TPI-N caused by the A2/O and BAF processes were the greatest, respectively. The removal efficiency of fluorescent materials in HPI was higher than that of non-fluorescent materials by the four wastewater treatment processes. On the other hand, the changes in different fluorescence peaks of the other four DOM fractions caused by different wastewater treatment processes were distinct and different.