Avaliação da remoção de bisfenol A no tratamento combinado de esgoto doméstico e lixiviado de aterro pelo processo de lodo ativado

Abstract

The landfill leachate may contain endocrine disrupting compounds (EDCs), which are present in the environment at concentrations in the order of μg.L-1 and ng.L-1. Bisphenol A (BPA) is one of the most recently studied EDCs. Its presence has been detected in several matrices, such as atmospheric air, surface waters, wastewater treatment plant effluents and landfill leachate. Wastewater treatment plants (WWTPs) usually use biological processes as the main technology. These effluent treatment systems are designed with the aim of reducing the organic pollutant load and eventually, nutrients and pathogenic microorganisms. It is not a specific goal of these systems the removal of BPA. Any removal of this compound during treatment is random and inherent in the treatment process used. Therefore, the present work had as objective to evaluate the removal of bisphenol A in the combined treatment of leachate and domestic sewage through the process of activated sludge operating in batch and continuous regime. For that, it was used bench scale reactors that were fed leachate/sewage mixtures of 0%, 2% and 5% (v / v). The physical-chemical parameters were evaluated in order to verify the efficiency of the treatment in relation to the removal of organic matter. The concentration of BPA was evaluated in the affluents, effluents, sludge and landfill leachate used, and SPE and HPLC/FLU were used to detection and quantification. Regarding the removal of organic matter, a decrease in the quality of the effluent treated with the leachate increment in the mixture was observed. The efficiencies found in the continuous regime were 89%, 82% and 63%, respectively for the 0%, 2% and 5% mixtures. In relation to the quantification of BPA in the different matrices, a concentration of BPA in the range of 2 to 20 μg.L-1 was found for the leachate, from 0.147 to 2.084 μg.L-1 in the affluents, from 0.081 to 6.938 μg. L-1 in the treated effluents and of 3.506 to 86.568 μg.g-1 of dry sludge in the sludge used. The activated sludge process operating on continuous basis proved to be better than the batch process, both for the removal of BPA and organic matter. The amount of BPA in the final effluent increased with the increase of BPA in the blends. No removal of BPA was observed in the batch regime and in the continuous regime the removal efficiencies were 24% and 42.5%, respectively for the sewage and for the 2% mixture. No removal was observed in the 5% mixture. The presence of BPA was detected in the sludge used.