Performance tests and removal mechanisms of aerated electrocoagulation in the treatment of oily wastewater

Electrochemical technologies have proven to be plausible technology for the treatment of oily wastewater. This study aimed to evaluate the performance of electrocoagulation (EC) process with and without aeration for the treatment of oily wastewater. Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) techniques were used to analyze the sludge and the electrodes. The maximum removal of the chemical oxygen demand (COD) was higher with the aerated cells (93.3 %) than with the non-aerated cells (84 %) at 120 A m⁻² current density but at the expense of higher specific energy consumption. Electrophoresis and electrodeposition of oil were observed on both electrodes, with higher intensity on the anodes. The sludge of the aerated cell was of a gel-like structure compared to the foamy and grainy sludge obtained from the non-aerated cell. Anodes in the EC aerated cells were consumed more “homogeneously”, having more depositions of oil on their surfaces. Aeration helped to improve the performance of the process, highlighting the great potential of electrocoagulation processes for the treatment of oily wastewater.