Aplicação da eletrocoagulação no tratamento de efluentes contendo pesticidas

Abstract

This work was the result of a legal gap regarding a scientifically based treatment model for effluents from threefold bottle washing and equipment containing pesticides, mainly insecticides applied to pests and vectors control in urban environments. Emphasis was given to the treatment of this effluent through the use of the electrolytic process as a possibility inspired by numerous advantages cited in other works, with similar effluents, where its use is much explored scientifically for many different types of effluents by the national and international scientific community. The collection of this effluent obeyed a real scenario for its generation, defining two active principles as the basis for this work: cypermethrin and malathion, with field and laboratory tests carried out at Tecma - Tecnologia de Meio Ambiente and SGS. The field tests were carried out using a 4 L electrolytic reactor, with intercalated iron and aluminium electrodes every 1.8 cm, with wear on the aluminium electrode, and added KCl in the effluent to increase the conductivity of the medium, considering the physico-chemical parameters to evaluate its efficiency as COD, SST, SSV, Iron, Aluminium, pH, temperature, sludge volume and concentration of the active principle by chromatography. The parameters for process control such as COD, pH and temperature were controlled during the entire electrolysis, and it was analyzed that the legal compliance with the requirements for the criteria and standards for effluent discharge for COD, pH, temperature and Soluble Iron are adequate for the legally permitted amounts in both assets. The concentration of the active principle malathion was reduced from the effluent from the triple wash to the treated effluent in the order of 94.85%. For the cypermethrin concentration of the effluent it was observed a reduction of the 1st washing to the treated effluent for the other stages in 97.25%. There was destabilization of the colloidal suspended solids in both effluents related to the active principles, confirmed by the volume of the sludge at the end of the electrolysis, either sedimented or floated, confirming the efficacy of the treatment, observed that the volume of sludge expressed in Kg Sludge / year / company reduced by 43.6% of the active principle cypermethrin to malathion, accompanying the 29.8% reduction in energy consumption expressed in Wh / L also from the active principle cypermethrin to malathion. The treated effluent supernatant has the clear appearance, being this treatment model, with a viable possibility to reduce the impact of this effluent on the environment.