Coagulação/floculação e adsorção de lixiviado de aterro sanitário na remoção de matéria orgânica e avaliação da toxicidade

Abstract

Although in Brazil, until now, the sanitary landfill is more suitable to treat solid waste, it is important to carry out ecotoxicological tests due to its variability of characteristics, verifying the removal of harmful parameters to nature and humanity. To reduce possible impacts, previous treatments, such as physicochemicals, have been widely studied. For the present research, the coagulation/flocculation treatments using chemical and natural coagulants and adsorption on granular activated carbon (GAC) were evaluated, alone and in combination. Higher removals of color, turbidity and UV254nm came from the combination of adsorbent and coagulants, with the optimal dosages obtained for PAC 1000 mg L-1 + 5 mg L-1 CAG (removals of 77.97%- color, 94.56%- turbidity and 45.57%- absorbance at UV254nm); Tanfloc 1250 mg L-1 + 25 mg L-1 CAG (removals of 78.93%- color, 99.99%- turbidity and 34.45%- absorbance at UV254nm); and Moringa 5000 mg L-1 + 10 mg L-1 CAG, (removals of 70.41%- color, 96.07%- turbidity and 33.82%- absorbance at UV254nm). Based on the individual and combined results, toxicity tests were carried out with the microcrustacean Artemia sp. in the nauplii phase, in six concentrations, performed in quadruplicate, showing different mortality effects as the treatment progressed. It is possible to relate the removal of parameters with a reduction in toxicity, as observed for CAG + Tanfloc, whose toxicity was, in all situations, lower than LC50. The tests using the microcrustacean demonstrated the toxicity of the raw leachate and the need for treatment.