Diferentes coagulantes para o tratamento de lixiviado de aterro sanitário

Abstract

The sanitary landfill is a technique of final disposal of residues that aims to avoid the propagation of vectors, risks to public health and environmental degradation. And for an effective operation, sanitary landfills are provided for: soil sealing, burning of gases generated by the degradation of organic matter, rainwater drainage systems, collection and treatment of leachate. The variety and concentration of the components present in the leachate, the operating time and the local climatic conditions lead to great variations in the characteristics of the effluent. This complexity requires individual analyzes for treatment effectiveness. Therefore, the objective was to evaluate the use of different coagulants in the coagulation and flocculation process for the treatment of crude leachate. For the treatments, with the aid of a flocculant anionic polymer, 6 coagulants were used: PLC-115, PLC 120 aluminum polychlorides, PLC-2000 aluminum sulfate; PLC-8030, PLC-8034 ferric chlorides; and Tanfloc, an organic polymer of plant origin. The leachate was collected in a sanitary landfill in Primavera, district of the municipality of Sorriso-MT, and taken to the Water and Waste Laboratory of the Federal University of Mato Grosso to characterize the parameters of turbidity (TB), pH, color, chemical demand of oxygen (COD), and absorbance at ultraviolet 254 nm (UV abs). After characterization, the effluent was treated in the coagulation/flocculation process in a jar test, with dosages ranging from 0 – 2,500 mg.L-1. In the treatment of raw leachate, for the parameters of color, turbidity and abs UV254nm, the results found show similar behavior among the coagulants, reaching maximum removal ranges between 87-90% for color, 98-99% for turbidity and 62-66 % for UV abs. COD removal increased as the coagulant concentration increased, with PLC 115 showing the highest removal (52%), and PLC 8034 the lowest (16%). Despite not achieving high removal, Tanfloc showed satisfactory results, with 26% COD removal at a dosage of 500 mg.L-1. PLC 115 and PLC 8030 produced the largest volume of sludge, increasing with the addition of coagulants. The pH did not show significant variations in the treatments tested, the highest variation being 9% in the treatment with PLC 8030. The bioassays with Artemia Franciscana indicated toxicity of the effluent after treatment by coagulation/flocculation.