Comparação entre o método físico-químico de coagulação e floculação utilizando o coagulante de policloreto de alumínio (PAC) com o processo de eletrocoagulação utilizando eletrodos de aço inox em efluentes têxteis

Abstract

The textile industry is of great importance for the national economy, in addition to having great weight in the PIB, it is given as the second largest employer of the transformation industry. However, this branch is characterized by consuming a considerable volume of water during the various processes that compose it, generating a large amount of textile effluent that, because it is highly polluting, needs previous treatment in order to fit its parameters within the limits imposed by CONAMA and by CEMA, for later discharge in water body. The objective of this study is to present a method of treatment of textile effluents by electrocoagulation using stainless steel electrodes and to compare the results with those of the physicalchemical method of coagulation and flocculation using the coagulant PAC applied and published by Souza (2016). After treatment by electrocoagulation, the results were analyzed and the optimal treatment conditions were determined: crude effluent with pH 8, current of 3 A and electrode spacing of 20 mm. At the end of the work, the two treatments were effective, since both presented results of color, turbidity, COD and temperature within the parameters established by CONAMA, for electrocoagulation the results after treatment were, respectively, 6,00 gPt-Co.L-1, 23,50 NTU, 184,85 mgO2.L-1 and 36 ºC, and for the method using coagulant PAC, the results were 26,38 gPt-Co.L-1, 70,20 NTU, 144,27 mgO2.L-1 and 29 ºC. For the two treatments, the pH of the treated effluent was outside the limit established by CONAMA, thus requiring a correction of the same before the effluent discharged in the receiving body.