Assessing the performance of a UV/H2O2 process for removing TOC from petroleum refinery wastewater and the respirometric effects of adding UV/H2O2 treated wastewater to activated sludge from the refinery WWTP biological treatment process

The treatment of petroleum refinery wastewater was studied using a bench scale ultraviolet/hydrogen peroxide (UV/H2O2) process. The highest treatment performance of the bench scale UV/H2O2 process to reduce the total organic carbon (TOC) from the petroleum refinery wastewater took place at a reaction time of 45 min and a pH of 5.0. A three factor analysis of va riance (ANOVA) analysis verified that the initial H2O2/TOC molar ratio did not have a significant effect on the bench scale UV/H2O2 process treatment performance. The effects of adding UV/H2O2 treated petroleum refinery wastewater to activated sludge microorganisms form the refinery WWTP biological treatment process was studied using respirometry. Overall, the UV/H2O2 treated refinery wastewater inhibited the refinery activated sludge microorganisms. This occurred when the raw refinery wastewater was treated with a UV/H2O2 process for 45 min. with an initial H2O2/TOC molar ratio of 1.7 mol H2O2/mol C, an initial H2O2 concentration of 202 mg H2O2/L and a pH of either 5 or 7.