Advanced oxidation of synthetic leachate: Performance of the photo-Fenton process for COD removal

Abstract

As part of optimizing leachate treatment, this study evaluates the efficiency of the Fenton-like photo-oxidation process (Fe 3+ /H 2 O 2 /UV) for the degradation of organic contaminants in highly loaded synthetic leachate. The process relies on the in situ generation of hydroxyl radicals from hydrogen peroxide activated by ferric iron (Fe 3+ ) under UV irradiation. Experiments were conducted using a photoreactor equipped with UV-A lamps (210 W and 113 W) and a UV-C lamp (75 W). The influence of several operating parameters, such as reagent concentrations, contact time, and light intensity, was investigated. Results showed that the highest treatment efficiency was achieved with UV-C irradiation, reaching an 80 % reduction in COD at optimal concentrations of 1.5 mmol/L Fe 3+ and 0.2 mol/L H 2 O 2 . The process was also successfully tested on real leachate from the controlled landfill of Al Hoceima, achieving a 67.9 % COD removal after 24 h. These findings confirm the potential of the Fenton-like photo-oxidation process as an effective, economical, and environmentally friendly alternative for leachate treatment. • Optimized photo-Fenton treatment (Fe 3+ /H₂O₂/UV) achieved up to 80 % COD removal in highly loaded synthetic leachate. • UV-C irradiation (75 W) outperformed UV-A (210 W, 113 W) in generating hydroxyl radicals and enhancing degradation. • Optimal reagent dosages were identified at 1.5 mmol/L Fe 3+ and 0.2 mol/L H₂O₂ for maximum efficiency. • Process performance scaled to real landfill leachate from Al Hoceima yielded 67.9 % COD reduction after 24 h. • The homogeneous photo-Fenton system proves to be an effective, low-cost, and eco-friendly leachate treatment alternative.