On the performance of electrocoagulation treatment of high-loaded gray water: kinetic modeling and parameters optimization via response surface methodology

01.May.2025

​This study explores the electrocoagulation (EC) treatment of high-loaded gray water (HLGW), with the goal of optimizing operating parameters such as current densities (Cd) and EC time. Moreover, the research examines the kinetics involved in the removal of COD, color, and turbidity from HLGW. Various HLGW samples were treated at different current densities over a 90-min EC period. Kinetic analysis shows that COD removal follows a second-order model, while turbidity and color removal adhere to a pseudo-first-order model, with parameters dependent on Cd. The findings indicate that pollutant removal improves with longer EC treatment times and higher Cd values. At lower Cd levels, removal efficiencies for COD and color are relatively low, even with a 90-min EC treatment. However, at a higher Cd (20 mA/cm²), there is a substantial increase in removal efficiency, with 85% removal for both COD and color within the same duration. Turbidity is completely removed when the Cd is set to 10 mA/cm² after 45 min of EC treatment. These results highlight that achieving high pollutant removal from HLGW requires high energy consumption. As a result, combining EC with other processes, either as a pre-treatment or post-treatment step, may address the challenges faced by standalone EC systems. Using response surface methodology (RSM), optimal operating conditions were determined, achieving pollutant removals of 76.4% for COD, 80.5% for color, and 98.5% for turbidity, with a minimum energy consumption of 5.07 kWh/m³ at an EC time of 44 min and a Cd of 15.5 mA/cm².

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