Degradation of Organics and Change Concentration in Per-Fluorinated Compounds (PFCs) during Ozonation and UV/H2 O2 Advanced Treatment of Tertiary-Treated Sewage

Abstract

This study aimed to investigate the effect of H2 O2 addition, ozone feed rate, and UV addition on the change in the concentration of organics such as CODMn, CODCr, TOC, and PFCs in tertiary-treated effluent from a sewage treatment plant (STP) during the O3 and UV/H2 O2 process. The degradation of organic pollutants from tertiary effluent is a significant challenge because bio-logical treatment cannot degrade these recalcitrant pollutants. Therefore, the O3 /UV/H2 O2 process was an effective method for treating recalcitrant organics. Several batch tests were conducted to investigate the direct UV photolysis, UV/H2 O2, and ozone-based advanced oxidation process to degrade CODMn, CODCr, TOC, and PFCs. The chemical oxygen demand (COD) and total organic carbon (TOC) with UV irradiation showed 95% and 50% removal efficiency percentages under optimal conditions (initial pH = 6.7, H2 O2 dosage = 50 mg/L, ozone feed rate = 5.8 mg/L/min. Moreover, UV irradiation, with the addition of H2 O2, and a sufficient dose of ozone, demonstrated the efficient removal of organic compounds by the indication of radical oxidation. (·OH) is the dominant mecha-nism. However, AOPs are not sufficient to fully treat the PFC compound; thus, additional procedures are required to degrade PFCs. In this study, the removal of organic recalcitrant contaminants and the change in added PFC concentration in tertiary-treated sewage were investigated by applying the ozone-based advanced oxidation process.