Electrocoagulation of Palm Oil Mill Effluent for Treatment and Hydrogen Production Using Response Surface Methodology

Palm oil mill effluent from the palm oil processing industry has been documented as a cause of severe damages to aquatic systems and a significant increase in greenhouse gases. This study was designed to use electrocoagulation for the pre-treatment of palm oil mill effluent to simultaneously reduce the pollutants and produce hydrogen gas. In this research, response surface methodology was applied to evaluate the effects of the main process parameters (voltage supply, retention time, and the addition of sodium chloride) in removing chemical oxygen demand, turbidity and metals from palm oil mill effluent. Response surface methodology was also applied to optimize the production of hydrogen gas from palm oil mill effluent during the electrocoagulation process. The obtained quadratic regression model has a high variance coefficient (R) value, which is greater than 85%. The optimal conditions to achieve highly efficient wastewater treatment and maximum hydrogen gas production were determined to be 4 volts, 6 hours retention time, and no added NaCl. At optimal conditions, electrocoagulation was able to remove 42.94% chemical oxygen demand (COD), 83.16% turbidity, 23.62% Fe, 27.56% Mg, and 47.83% Ca. Additionally, the production of hydrogen gas (28.87%) was also achieved, which enhances the cost effectiveness of the process.