The Electrochemical removal of Oil and COD from petroleum wastewater

Abstract

Recently, COD and oil concentrations in the water have increased, as a result of reduced water volumes and increased industrial waste being dumped into the river. Increased concentrations of these pollutants lead to health and environmental problems. As the water treatment plants use the usual methods of water treatment and could not reduce the concentration of oil and COD to the limit set by the World Health Organization, so an effective way to treat these pollutants became absolutely necessary. In this study, electrochemical method was used to treat water contaminated with oil and COD, using aluminium and iron electrodes as positive electrode and cathode electrode. A coagulation cell with a volume of 2 litters was also used in the work. Several factors affecting the process of treating oil and carbon dioxide pollutants were studied, and these factors were as follows: Submerge depth, Number of electrodes, the distance between the electrodes. From the results, it was found that the optimum removal was 94.2% for oil, and 99.5% for COD. It was achieved when the number of electrodes was 4 aluminium and 4 irons, the distance between the electrodes was 2 cm, the depth was 12 cm, and the function variables were acidic equal to 7, time 50 min, and voltage 10.5 V. The concentration of sodium chloride is 0.5 g/l and the electrode material is aluminium as anode and cathode and the initial oil concentration is 95 mg per litter, initial COD concentration is 710 mg per litter and the consumption of energy was estimated to be 12 kwh/m³, the TSS was 73 mg/l. The results demonstrated that the electrochemical is a feasible technique for treatment of oily contaminated petroleum refinery wastewater.