Electrocoagulation or it coupling with ozonation for sustainable wastewater treatment: A comprehensive review of mechanisms, performance, and emerging applications

Abstract

To address the increasing global water pollution crisis, efficient water and wastewater treatment technologies are critical for safeguarding sustainable development and ensuring long-term water security. Although ozonation-assisted electrocoagulation (ECO) research has attracted growing attention, there is currently a lack of systematic summary to bridge the gap between lab-scale studies and pilot-scale applications. Therefore, we summarize existing findings on ECO, clarify current challenges and propose future research directions. This review outlines the progress and practical applications of ECO, covering synergistic contaminant removal mechanisms, electrode and reactor design, life cycle assessment and contaminant elimination. The innovative contribution of this review is that it is the first to systematically summarize the research on ECO, providing theoretical guidance for transitioning ECO from the laboratory scale to practical applications. In summary, the maximum synergistic coefficient between electrocoagulation (EC) and ozonation reaches 19.09, depending on the interaction between EC-generated flocs and ozone. Such a high synergistic coefficient demonstrates that the ECO is worthy of in-depth research. ECO can achieve approximately 100 % removal efficiency for SS, over 80 % removal efficiency for COD and ROCs, as well as partial removal of heavy metals. Notably, the energy consumption of the ECO ranges from 3.77 to 47.65 kWh/m³ , which is significantly lower than that of other EC-related processes, proving ECO feasibility for pilot-scale treatment. In the future, ECO research should be focused on the synergistic reaction mechanism, sludge resource utilization, design and optimization of scaling-up reactors, renewable energy integration and multi-technology coupling to advance practical applications.