Synergistic Degradation of Organic Contaminants in Landfill Leachates Using Catalytic Ozonation with Magnetite

This study evaluated the efficiency of catalytic ozonation with magnetite (Fe3O4) in degrading recalcitrant organic compounds in leachates from two sanitary landfills in Colombia. The optimum treatment conditions were also analyzed by means of a response surface design, resulting in 6 g O3/h, 2.5 g/L Fe3O4, and pH 9, which resulted in COD removal rates of 85.3% in El Guayabal and 75.8% in La Madera. Moreover, the BOD5/COD ratio increased from 0.26 to 0.38 and from 0.23 to 0.32, respectively, suggesting increased effluent biodegradability. The most efficient ozone consumption (2.7 g O3 per gram of COD removed) was obtained under alkaline conditions with a high catalyst concentration. Magnetite demonstrated structural stability, although its catalytic efficiency progressively decreased after three cycles of use, with COD removal decreasing from 85.3% to 73.6%. These findings validate catalytic ozonation with magnetite as an efficient alternative for advanced leachate treatment, with the potential to optimize contaminant removal in industrial effluents and strengthen environmental remediation strategies.