Removal of Oil and Grease from Produced Water Using Electrocoagulation

A method to remove oil and grease (O&G) from synthetically produced water using electrocoagulation in a batch process with a mild steel anode is proposed. Preliminary studies were conducted to explore the effects of operating parameters on chemical oxygen demand (COD) and O&G removal. Individual and interactive influences of causal variables were investigated using a response surface methodology. The experimental results indicated that electrocoagulation is very effective in pollutant removal and could successfully reduce COD and O&G to 99.7% and 96.43%, respectively, from an influent oil-in-water (O/W) emulsion concentration of 1,250 +/- 50 mg/L under optimal operating conditions. A notable observation was made on the contribution of the electrooxidative mechanism in COD and O&G removal. It was found that removal due to the oxidative mechanism was increased with increases in current density and salt composition. The methodology is very suitable for the treatment of water produced from offshore basins in particular due to the higher rate of operation and smaller amount of sludge compared with conventional biological treatment and to the presence of supporting electrolyte in situ.