title: Impact of leachate composition on the advanced oxidation treatment.
abstract: Advanced oxidation processes (AOPs) are gaining importance as an alternative to the biological or physicochemical treatments for the management of leachates. In this work, it has been studied the effect of the characteristics of the leachate (content in humic acids, landfill age and degree of stabilization) on the wet oxidation process and final quality of the treated effluent. A high concentration of humic acids in the leachate had a positive effect on the COD removal because this fraction is more easily oxidizable. Additionally, it has been demonstrated that the simultaneous presence of humic acid and the intermediates generated during the oxidation process improved the degradation of this acid, since such intermediates are stronger initiators of free radicals than the humic acid itself. Similar values of COD removals (49% and 51%) and biodegradability indices (0.30 and 0.35) were observed, after 8 h of wet oxidation, for the stabilised leachate (biologically pretreated) and the raw one, respectively. Nevertheless, final colour removal was much higher for the stabilised leachate, achieving values up to 91%, whereas for the raw one only 56% removal was attained for the same reaction time. Besides, wet oxidation treatment was more efficient for the young leachate than for the old one, with final COD conversions of 60% and 37%, respectively. Eventually, a triangular "three-lump" kinetic model, which considered direct oxidation to CO2 and partial oxidation through intermediate compounds, was here proposed.
authors.affiliation: Department of Chemical and Environmental Engineering, University of Oviedo, c/ Julián Clavería s/n, E-33071, Oviedo, Spain.
authors.forename: Paula
authors.initials: P
authors.lastname: Oulego
authors.affiliation: Department of Chemical and Environmental Engineering, University of Oviedo, c/ Julián Clavería s/n, E-33071, Oviedo, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Collado
authors.affiliation: Department of Chemical and Environmental Engineering, University of Oviedo, c/ Julián Clavería s/n, E-33071, Oviedo, Spain.
authors.forename: Adriana
authors.initials: A
authors.lastname: Laca
authors.affiliation: Department of Chemical and Environmental Engineering, University of Oviedo, c/ Julián Clavería s/n, E-33071, Oviedo, Spain. Electronic address: mariodiaz@uniovi.es.
authors.forename: Mario
authors.initials: M
authors.lastname: Díaz
mesh_terms: D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D006812:Humic Substances; D008962:Models, Theoretical; D010084:Oxidation-Reduction; D013030:Spain; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry* / Q000633:toxicity
chemical_list: D006812:Humic Substances; D014874:Water Pollutants, Chemical
keywords: Advanced oxidation; Biodegradability; Humic and fulvic acids; Landfill leachates; Lumped kinetic model; Toxicity