A detailed dissolved organic matter characterization of starch processing wastewater treated by a sedimentation and biological hybrid system

In this study, to investigate the evolution of dissolved organic matter (DOM) in starch processing wastewater (SPW) during the treatment of a sedimentation and biological hybrid system, the DOM was sampled at different treatment stage, and characterized by gel permeation chromatography (GPC), fluorescence excitation-emission matrix (EEM) and UV-Vis. The chromatograms demonstrated that the majority of molecules in the influent had a molecular weight (MW) of less than 0.5 kDa, while that of the oxic basin was mainly in the range of 0.5-2 kDa. The MW distribution became narrow along the treatment line. The proteinaceous matters with simple structure were more easily biodegraded during the treatment process. Most protein-like material could be effectively decomposed by the activities of anaerobic and aerobic bacteria. The microbial byproduct-like substances and humic acid-like materials were the main components of DOM in the effluent. The parameters obtained from the analysis were clustered into two groups, which represent the different treatment state of SPW.