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

•EC experiments with aluminum anodes were carried with and without aeration.•Highest COD removal was 93.3 % for aerated cells and 84 % for non-aerated cells.•Aeration affected type of sludge, deposition on electrodes, and pH of solution.•Adsorption to Al-flocs and entrapment of oil droplets were main removal mechanisms.•Aerated cells consumed more overall energy (SEC) but achieved more efficient EEO.