Characteristics and Chlorinated Disinfection By-products Formation Potential of Dissolved Organic Matter Fractions in Treated Wastewater

Dissolved organic matter (DOM) from a biological treated wastewater of municipal wastewater treated plant was isolated and fractionated using resin adsorption into four different fractions. These fractions are operationally categorized as hydrophilic substances (HIS), hydrophobic acids (HOA), hydrophobic neutrals (HON), and hydrophobic bases (HOB). The dissolved organic carbon (DOC) and specific UV absorbance, characteristics of three dimensional excitation emission matrix fluorescence spectroscopy (3DEEM) and disinfection byproducts formation potential of each fraction was investigated in this paper. The results showed that HIS and HOA were the main fractions and occupied 33% and 30% of DOC in the treated wastewater sample, respectively. The fraction of HIS contained more humus, which were predominately microbially derived, while the fraction of HOA contained more aromatic proteins and soluble microbial products by the analysis of 3DEEM. The chlorinated trihalomethane formation potential (THMFP) of HIS fraction was 630.4 microg x L(-1) and occupied 73.7% of that formed in wastewater sample. The chlorinated haloacetic acids formation potential (HAAFP) of HIS and HOA fractions were 644.6 microg x L(-1) and 123.2 microg x L(-1), which was found to be the most reactive precursor in the fractions of treated wastewater to the disinfection by-products formation.