Tratamento de lixiviado de um aterro sanitário por eletrocoagulação: eficiência na remoção de poluentes e avaliação da fitotoxicidade

Abstract

Population growth and urbanization have intensified the generation of urban solid waste, making the management and treatment of landfill leachate a significant environmental challenge due to its high organic load and the presence of toxic compounds. Given the limitations of conventional treatment methods, such as biological and physicochemical processes, electrocoagulation emerges as a promising alternative by combining efficiency, operational simplicity, and less dependence on external reagents. This work aimed to evaluate the efficiency of the electrocoagulation process in reducing the toxicity of leachate from a landfill. To this end, a reactor with aluminum electrodes in a series monopolar configuration was constructed and operated, conducting tests with different current intensities and leachate concentrations, according to a 2² factorial design. The samples were analyzed for apparent color, turbidity, electrical conductivity, and chemical oxygen demand, in addition to conducting bioassays with Cucumis sativus seeds to evaluate phytotoxicity. The results demonstrated significant reductions in physicochemical parameters, with color and turbidity removal efficiencies exceeding 90% in the most dilute samples and intermediate currents, showing that increasing the electrical intensity favors coagulation and particle flotation. Conductivity reductions ranged from 1.6% to 17.1%, indicating partial removal of dissolved ions. Bioassays showed an absence of acute toxicity and improved relative growth and germination rates after treatment, especially in samples with higher initial concentrations, suggesting a reduction in effluent toxicity. Therefore, electrocoagulation appears to be a promising alternative as a complementary treatment for landfill leachate, promoting improved effluent quality and mitigating its environmental impacts.