Abstract

MENDEZ NOVELO, Roger Iván et al. Assesment of the optimal dose of Fenton reagent in a leachate treatment by Fenton-adsorption. Rev. Int. Contam. Ambient [online]. 2010, vol.26, n.3, pp.211-220. ISSN 0188-4999.

Leachates are formed as a result of the percolation of liquids, through the solid wastes in stabilization process. Their composition is variable and highly toxic; therefore, leachates treatment is a complex task. Due to the high permeability of the soil of the Yucatán Peninsula leachates represent a high risk to health. Fenton type oxidation and adsorption treatment have been tested, and they have showed better results than other types of biological or physicochemical treatment. Fenton process consists in treating the contaminant load with a combination of H₂O₂ and FeSO₄ under acidic conditions. Experiments were conducted in order to determine if filtration was better than the sedimentation of the sludges. The optimum contact time and the best relations [Fe²⁺]/[H₂O₂] and [COD]/[H₂O₂] were determined. Subsequently, the oxidized samples were filtered and the adsorption process was tested using two columns in series packed with activated carbon. It was concluded that the sludge generated by the Fenton process was removed more efficiently through filtration than sedimentation. Optimal contact times were 5 min for COD removal, and 1 hour for colour removal; process time was set to one hour in order to protect the activated carbon. The best relations for [Fe²⁺]/[H₂O₂] and [COD]/[H₂O₂] were 0.6 and 9 respectively. The maximum removal efficiency after the adsorption process was 98.9% for COD and 100% for colour at zero time of the column. A final biodegradability index of 0.24 was reached after the Fenton-adsorption tests.

Keywords : Advanced oxidation; landfill; adsorption; granular activated carbon; biodegradability index.