Eletrocoagulação aplicada ao tratamento do efluente líquido da indústria cafeeira

Abstract

With the growth of the effluent generated by the coffee industry, due to its large and continuous export, it is necessary to investigate alternative ways for its treatment. Electrocoagulation, which uses electrodes and electrical energy to coagulate polluting particles is one of those alternatives. This work aimed to apply the electrocoagulation process in the treatment of the coffee industry efluente, with and without the application of sodium chloride (NaCl), in order to verify the ideal method and time for the best reduction in turbidity, total dissolved solids and to verify the behavior of the electrical conductivity, pH and finally evaluate its operating cost taking into account the consumption of electricity and electrodes. Tests were carried out, with and without NaCl, over 40 minutes, using aluminum electrodes with the effluent from the coffee industry. The first test after the eletrocoagulation, without the use of NaCl, showed the values of 426 uT of turbidity, 207 mg.L1 of total dissolved solids, 0.87 mS.cm1 of electrical conductivity and 7.10 of pH. In the second test, with NaCl, it generated values of 16.1 uT of Turbidity, 618 mg.L1 of total dissolved solids, 11.89 mS.cm1 of electrical conductivity and 8.10 of pH. It was found that the presence of NaCl helped to reduce turbidity. There was a considerable increase in electrical conductivity and the pH remained at the same level. There was a greater wear on the part of the aluminum electrodes in the presence of NaCl and also a marked increase in the consumption of electrical energy. It can be concluded that the best values obtained were with the presence of NaCl, which resulted on a total cost of R$ 17,837 per m³.