CONICET | Buscador de Institutos y Recursos Humanos

Imazalil (IMZ) is a widely used fungicide for thepost-harvest treatment of citrus, classified as Blikely to becarcinogenic in humans^ for EPA, that can be only partiallyremoved by conventional biological treatment. Consequently,specific or combined processes should be applied to preventits release to the environment. Biological treatment withadapted microorganism consortium, photo-Fenton, andcoupled biological photo-Fenton processes were tested as alternativesfor the purification of water containing high concentrationof the fungicide and the coadjutants present in thecommercial formulation. IMZ-resistant consortium with thecapacity to degrade IMZ in the presence of a C-rich co-substratewas isolated from sludge coming from a fruit packagingcompany wastewater treatment plant. This consortium wasadapted to resist and degrade the organics present in photo-Fenton-oxidized IMZ water solution. Bacteria colonies fromthe consortia were isolated and identified. The effect of H2O2initial concentration and dosage on IMZ degradation rate, averageoxidation state (AOS), organic acid concentration,oxidation, and mineralization percentage after photo-Fentonprocess was determined. The application of biological treatmentto the oxidized solutions notably decreased the totalorganic carbon (TOC) in solution. The effect of the oxidationdegree, limited by H2O2 concentration and dosage, on thepercentage of mineralization obtained after the biologicaltreatment was determined and explained in terms of changesin AOS. The concentration of H2O2 necessary to eliminateIMZ by photo-Fenton and to reduce TOC and chemical oxygendemand (COD) by biological treatment, in order to allowthe release of the effluents to rivers with different flows, wasestimated.

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