Estudo do processo de eletrocoagulação aplicado em efluente real da indústria de metalmecânica

Abstract

The effluent treatment process has been making significant progress on the national scene, with a view to significantly improving the process and reducing costs, as well as investments in technology for the reuse of treated effluents in the industrial environment. These processes continue to be the focus of companies so that the sustainability of the business advances at the same level as equipment technology. The metalworking industry, like all other industries, produces volumes of effluent as a result of its process stages. In this particular case, the largest volume produced is at the stage of washing the parts produced. This effluent has very specific characteristics, such as low biodegradability, high conductivity, alkaline pH and characteristic color. The use of a treatment such as electrocoagulation may therefore be interesting in the search for improvements in the effluent in question. The aim of this study was to evaluate electrocoagulation treatment applied to effluent generated in the process of cleaning the surface of metal parts in a metalworking industry, with the goal of improving the parameters of color, conductivity, chemical oxygen demand (COD) and toxicity. The electrocoagulation treatment process was chosen on the basis of preliminary tests, and because the effluent had high conductivity, which would facilitate the electron transfer process without the need to add electrolyte. Electrocoagulation applied to the effluent from the parts washing process was carried out using Fe electrodes (cathode/anode). The results obtained showed color removal of up to 98%, a reduction in COD of up to 74% and a reduction in the effluent's toxicity. The process thus showed significant improvements in the initial characteristics of this effluent. This study made it possible to visualize the potential for applying electrocoagulation treatment to this industrial effluent as a primary treatment, and based on these results, it is suggested that a secondary treatment be used next, focused on reducing electrical conductivity, since this parameter was not removed by the process.