MSW Landfill Leachate Treatment by Coagulation-Flocculation Coupled with a Photo-Fenton Process

Abstract

A treatment process for municipal solid waste (MSW) landfill leachate was evaluated, consisting of a coagulation-flocculation step followed by a photo-Fenton reaction. Four coagulants were tested using the Jar Test methodology, with AlCl₃ selected as the most efficient in terms of TOC and color removal. Subsequently, the pretreated effluent was subjected to a 180-minute photo-Fenton reaction, optimizing the initial reagent doses and H₂O₂ reinjection frequency. Under all evaluated conditions, overall TOC reductions exceeding 90% were achieved. Kinetic analysis identified two stages: an initial phase (0–90 minutes), limited by parallel reactions, followed by a second phase characterized by higher oxidative activity. The most efficient condition involved an initial dose of 100 mg/L Fe⁺³ and 500 mg/L H₂O₂, with reinjections every 30 minutes. It was also demonstrated that increasing the initial Fe⁺³ dose reduces TOC removal efficiency.