Removal of cod from oil recovery industry wastewater by the advanced oxidation processes (AOP) based on H2O2

Abstract

The combinations of H2O2/Fe, UV/H2O2/Fe and UV/H2O2 process were investigated on treatment of oil recovery industry wastewater. Treatment of oil recovery industry wastewater, a typical high pollution strength industrial wastewater (chemical oxygen deman (COD): 21000 mg l(-1), biological oxygen demand (BOD): 8000 mg l(-1), oil and grease:1140 mg l(-1), total dissolved solids (TDS): 37000 mg l(-1), total suspended solids: 2580 mg l(-1)), was carried out by batch oxidation processes. The optimal mass ratio for H2O2/Fe+2 yielding the highest COD removal-was found to be 8.658 corresponding to 200.52 g 1(-1) H2O2 and 23.16 g l(-1) Fe+2 concentrations for 60 minutes reaction time. Fenton process gave a maximum COD reduction of 86% (from 21000 to 2980 mg l(-1)) and the combination of UV/H2O2 gave a COD reduction of 39% (from 21000 to 12730). The percentage of removal, after the total reaction time (3.5h), H2O2: 8.4 g l(-1) and Fe+2 : 0.05g l(-1), in the photo Fenton process, corresponded to 81 % of the total initial COD (4200 mg l(-1)). The oxidative ability of the UV/Fe+2 /H2O2 process (81 %) was greater than that of the UV/H2O2 process (55%) for 80% diluted wastewater. COD removal efficiency for UV/H(2)O2 process (COD/H2O2=1/2 (w/w)) was 90%, 55%, and 39 when initial COD was 1050, 4200, and 21000 mg l(-1), respectively, whereas COD removal was 943, 2320, and 8270 mg l(-1), respectively.