Removal of organic matter from a variety of water matrices by UV photolysis and UV/H2O2 method

A re-circulated flow-through photoreactor was used to evaluate the ultraviolet (UV) photolysis and UV/H2O2 oxidation process in the purification of three different water matrices. Chemically coagulated and electrocoagulated surface water, groundwater contaminated with creosote wood preservative and 1,2-dichloroethane (DCE) containing washing water from the plant manufacturing tailor-made ion-exchange resins were used as sample waters. The organic constituents of creosote consist mainly of harmful polycyclic aromatic hydrocarbons (PAH) whereas 1,2-DCE is a toxic volatile organic compound (VOC). Besides analyzing the specific target compounds, total organic carbon (TOC) analysis and measurement of change in UV absorbance at 254 nm (UV254) were performed. Initial TOC, UV254 and pH varied significantly among treated waters. Initial H2O2 concentrations 0-200 mg/l were used. The UV/H2O2 treatment was efficient in removing the hazardous target pollutants (PAHs and 1,2-DCE) and natural organic matter (NOM). In addition, high removal efficiency for TOC was achieved for coagulated waters and groundwater. Also, the efficiency of direct photolysis in UV254 removal was significant except in the treatment of 1,2-DCE containing washing water. Overall, UV254 and TOC removal rates were high, except in case of washing water, and the target pollutants were efficiently decomposed with the UV/H2O2 method. (C) 2010 Elsevier B.V. All rights reserved.