Diferentes tipos de coagulantes no tratamento de efluente de frigorífico

Abstract

The modern agribusiness, characterized by the large number of animal slaughter, generates large volumes of effluent, with high polluting power. When this effluent is disposed in the environment, without treatment, it can cause major environmental problems, such as impairment of water quality and soil, besides being a problem for public health. In this context, this research aimed to evaluate the efficiency of four coagulants, which are chemical (Aluminium polychloride - PAC and aluminum sulfate) and natural (Moringa oleifera Lam and tannin), in the treatment of a pig slaughterhouse effluent, located in the municipality of Sinop - MT. The collected raw effluent was not subjected to any preliminary treatment. After the collection, the effluent sample was conditioned in a container and kept cool. Then, for an initial characterization of the effluent, analysis of the parameters color, turbidity, pH, UV254nm, metals, solids, volume of sludge, BOD, COD, nitrite and nitrate were performed. For the coagulation/flocculation assays, the coagulants were prepared in aqueous solution using distilled water and also in saline solution (NaCl – 1M e KCl – 1M), only for natural coagulants. The dosages evaluated for the coagulants PAC, aluminum sulphate and tannin were 10 to 300 mg.L-1 and for the Moringa oleifera Lam coagulant, the dosage was 500 to 5000 mg.L-1. The analyzed parameters were color, turbidity and UV254nm. The optimum dosage obtained for the coagulants PAC, aluminum sulphate and aqueous tannin was 250 mg.L-1, whereas for tannin (NaCl and KCl) solutions it was 200 mg.L-1 and for the solutions of Moringa oleifera Lam NaCl and KCl, were 2000 mg.L-1 and 5000 mg.L-1, respectively. When the results of the optimum dosages were evaluated, the coagulant that presented the highest removal efficiency of organic matter and metals of the effluent was Tanfloc in saline solution (KCl -1M).