Performance investigation of electrocoagulation and Electro-Fenton processes for high strength landfill leachate: operational parameters and kinetics

Leachate landfills contain significant amounts of heavy metals, organic pollutants, inorganic salts, ammonia nitrogen, and chlorinated organics, which negatively influence the environment. Therefore, it is a must to treat them before being released into the environment efficiently. This study investigated the effectiveness of batch Electrocoagulation (EC) and Electro-Fenton (EF) processes to treat the high-strength landfill leachate. The effect of operating parameters, including initial pH of the leachate, contact time, and a mass ratio of COD: H2O2, was investigated on the removal efficiencies of chemical oxygen demand (COD) and color from leachate. The result shows that, under the optimal pH 6 and reaction time of 17.5 min, EC achieved COD and color removal of 66.2% and 94.4%, respectively. However, EF obtained a higher COD removal of 69.8% and 88.1% of color removal at pH of 9 and COD: H2O2 Ratio of 9.5 within 6.7 min. The result revealed that both processes are reported to remove more than 80% color. However, EF obtained a higher degradation rate than EC. Besides, the EF process also generated 47.4% less sludge than the EC process under the optimal conditions. Cost estimation indicates that EF is less expensive (0.48 USD) than electrocoagulation (0.75 USD). In summary, Electro-Fenton is a more reliable, cost-effective, and energy-efficient method of removing landfill leachate than electrocoagulation, requiring less treatment time and producing less sludge.