Processos eletrolíticos no tratamento de efluentes industriais e lixiviado de aterros: revisão sistemática

Abstract

Discharges of sanitary and industrial wastewaters cause water pollution, therefore their treatment before the discharge is essential so that the balance of the water bodies is maintained. The electrolytic treatment is gaining importance and playing a key role in unconventional industrial effluent treatment technologies. The general objective of this work was to evaluate the efficiency obtained in the electrolytic treatment of industrial effluents and landfill leachates, allowing a comparison of this treatment method with others. The systematic review (RS) method was used to synthesize the studies already done on the subject. The parameter for comparison of treatment efficiency was the reduction of COD. The researched publications were included or excluded from the present review according to the criteria defined in the RS protocol. It was found 10,987 publications in total covering the searched terms: leachate, oily water, textile effluent, electrocoagulation, electro-flocculation, electro-flotation and electrolytic treatment. After application of the eligibility criteria, 69 articles were left to carry out the analysis. The data were analyzed globally, that is, considering all types of effluent, and also separately. No correlation was identified between the variables (individually) and the COD reduction. The variables were distributed in ranges, to allow the correlation between more than one variable at the same time. For the textile effluents and for the oily effluent no correlation was found considering the data obtained by this review. For the landfill leachate, there was a positive correlation between the retention time of the effluent in the reactor and the reduction of COD. When the analysis was done with all the data of the three effluents, a positive correlation was also verified, where it was observed that the greater the retention time of the effluent in the reactor (inside the ranges), the tendency is that the reduction of the COD is greater too. The optimal conditions of the electrolytic treatment will be a combination of the different operational variables of the process. It was possible to conclude that the electrolytic treatment can perform satisfactorily, reducing the COD of the effluent to close to 100%.