Removal of chemical oxygen demand from real petroleum refinery wastewater through a hybrid approach: Electrocoagulation and adsorption

In the Algiers refinery's effluent treatment plant (ETP), conventional methods fall short in handling highly concentrated liquid effluents, especially in biological treatment. Consequently, there's an urgent need for advanced pre-treatment. This study investigated the efficacy of a hybrid adsorption electrocoagulation (AD-EC) process for treating Algiers refinery effluent. The study focused on assessing the AD-EC method's capacity to remove crucial contaminants: COD, turbidity, and TSS. In the EC process, aluminum electrodes were used, and activated carbon was the adsorbent. Unfavorable operational conditions were applied for hybrid AD-EC processes including the adsorbent dosage, current density, and electrolysis duration. The SEM/EDS and BET were employed to analyze the solid generated. The result indicated that the hybrid process presented an economy of the treatment time, and was well efficient in removing COD, TSS, and turbidity. The treatment resulted in removing 82 % of COD, 96.5 % of turbidity, and 98.64 % of TSS, all well within the specified range of discharge limits set by Algeria. Likewise, these results confirm a synergistic effect between AD and EC. Moreover, this hybrid approach offers potential as a practical tertiary treatment step, enhancing the effluent quality and overall biological treatment efficiency, and providing a promising solution to the ETP.