Thesis (M.Sc.)--Chulalongkorn University, 2009

To study the optimal condition for petrochemical wastewater treatment by electrocoagulation. The experiment was divided into two steps. The first part: Different operational conditions were examined using one variable at a time method. The electrode material for anode and cathode were used aluminum and graphite. The initial pH from 4-9, current density from 5.11 to 12.10 mA/cm2 and retention time from 10 to 40 minutes were tested. The result showed that the optimal condition for treatment of petrochemical wastewater was using initial pH of 6, current density 8.32 mA/cm2 and retention time of 25 minutes. The removal efficiency was found to be 97.49% for COD, 76.92% for SS and 79.09% for grease & oil (G&O). Furthermore, 330.4 grams of electrode lost after the experiment 390 ml of gases occurred from the reaction. The second part: Box-Behnken. The parameters are initial pH of wastewater, voltage and retention time by using Al-C electrode. The experiment showed that the suitable condition is similar to the 1st part experiment including the removal efficiency and the electric cost. It does can confirm that the result of both experiment are reliable. However, the treating condition for the treatment plant should proper to the equipment and technology for the easier operation and the most benefit