Electrocoagulation strategies for oily wastewater treatment: a review on process efficiency and optimization

Abstract Electrocoagulation (EC) has emerged as a viable alternative for oily wastewater treatment, offering distinct advantages over conventional treatment methods. In EC, an electric current dissolves sacrificial anode, releasing metal ions that help clump and remove a wide range of contaminants. This technology is applicable across diverse industries and effectively addresses complex water challenges, including oil-contaminated wastewater. The efficiency of EC is influenced by operational parameters such as current density, electrode material, pH, electrode spacing, and treatment time, all of which require careful optimization. Notwithstanding its benefits, such as ease of operation, minimal chemical usage, and small sludge production, EC faces challenges related to electrode passivation and energy consumption, necessitating enhancement strategies. Given the growing interest in EC and the diversity of treatment conditions, a comprehensive synthesis of current knowledge is essential to guide both research and industrial applications. This review evaluates the principles and mechanisms of EC, the role of operational parameters, and strategies for process optimization. Recent innovations are highlighted, particularly hybrid systems that integrate EC with membrane filtration, advanced oxidation processes, and renewable energy sources. Applications across various wastewater types are discussed, alongside economic feasibility and scalability considerations. By identifying key research gaps, particularly in system scale-up, cost reduction, and long-term performance, this review provides a comprehensive resource to inform the future development of sustainable oily wastewater treatment technologies. Graphical abstract