Treatment of Manganese-Phosphate Coating Wastewater by Electrocoagulation

The effective performance of the electrocoagulation (EC) technique in removing manganese, phosphate, and iron from rinse water from a Mn-PO4 (MPO) coating plant was investigated using sacrificial aluminum electrodes in original pH. It was found that an increase in the current enhanced the speed of the removal significantly. However, simultaneous increase of electrode and energy consumption was observed. The optimum current density allowing the quickest treatment with a low cost was found to be 20 A m-2. In 20 A m-2, the process produces a removal capacity of 97.95% of manganese, 99.96% of phosphate, and 99.78% of iron, just after 30 min. The energy and electrode consumptions were determined to be 2.294 kWh m-3 and 5.584 kg m-3 of treated rinse water at the end of process, respectively. Additionally, three different electrode connection modes (MP-P, MP-S, and BP-S) were examined in choosing a better alternative in order to intensify the performance of the process. MP-P electrode connection mode was found to be a suitable configuration in consideration of removal efficiency, energy, and electrode consumptions.