CONICET | Buscador de Institutos y Recursos Humanos

The application of conventional physicochemical and microbiological techniques for the removal of organic pollutants haslimitations for its utilization on wastewaters as landfill leachates because of their high concentration of not easily biodegradableorganic compounds. The use of ozone-based technologies is an alternative and complementary treatment for this type ofwastewaters. This paper reports the study of the degradation of landfill leachates from different stages of a treatment plant usingozone and ozone + UV. The experimental work included the determination of the temporal evolution of COD, TOC, UV254, andcolor. Along the experimental runs, the instantaneous off-gas ozone concentration was measured. The reaction kinetics follows aglobal second order expression with respect to COD and ozone concentrations. A kinetic model which takes into account the gasliquid mass transfer coupled with the chemical reaction was developed, and the corresponding parameters of the reacting systemwere determined. The mathematical model is able to appropriately simulate COD and ozone concentrations but exhibitinglimitations when varying the leachate type. The potential application of ozone was verified, although the estimated efficienciesfor COD removal and ozone consumption as well as the effect of UVradiation show variations on their trends. In this sense, it isinteresting to note that the relative ozone yield has significant oscillations as the reaction proceeds. Finally, the set of experimentalresults demonstrates the crucial importance of the selection of process conditions to improve ozone efficiencies. This approachshould consider variations in the ozone supply in order to minimize losses as well as the design of exhaustion methods as multiplestage reactors using chemical engineering design tools.

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