Treatment of reverse osmosis concentrate of oil refining wastewater by coupling ozonation and photoelectrocatalysis

Reverse osmosis( RO) concentrated water from a refinery wastewater treatment system was treated using a coupling process of catalytic ozonation and photoelectrocatalysis to control the environment contamination from the refinery wastewater,and the influences of the factors( mainly pH,current density and O3dosage) on the coupling system were investigated. The results showed that RO concentrated water could be effectively degraded by the coupling process. The removal rates of oil and COD increased first and then declined as pH increased.COD removal rate had the same tendency as current density increased,while the oil removal rate increased first and then kept constant. With a larger O3 dosage,the removal rates of oil and COD increased first and then tended to be stable. The effluent COD≤50 mg /L and oil≤0. 5 mg /L were achieved with the pH of 7. 5,O3 dosage of 8mg /L,current density of 50 mA /cm2and hydraulic retention time of 30 min.