TRATAMENTO DE LIXIVIADO UTILIZANDO ELETROCOAGULAÇÃO COM ELETRODOS DE FERRO E ALUMÍNIO

Abstract

The landfill leachate is characterized as an effluent with high concentrations of organic matter, solids and recalcitrant material of difficult degradation. The present study aimed to evaluate the landfill leachate treatment by electrocoagulation using iron and aluminum electrodes in the removal of color, turbidity, Abs254, COD, BOD, NH3, sulfate and chloride, as well as evaluating the change in pH and conductivity throughout the treatments, employing different current densities (DC) (161.08, 128.86, 96.64 and 64.4 A/m2) at the electrolysis times (15, 30, 60 and 90 min). The best removals occur with the application of DC 161.08 A/m2 in 90 minutes of electrolysis time, removing 90% of color with the iron electrodes and 83% with aluminum, 82% of turbidity using iron electrodes and 89% with aluminum. In relation to organic matter, the proposed treatment achieved COD removal of 46% for Fe and 40% Al, the maximum Abs254 removal was 45% for aluminum and 46% for iron. The BOD was removed at 87 % and 90% with Fe and Al electrodes respectively. There was also a rise in pH as higher DC's and higher electrolysis times were applied. No behavior trend was observed in relation to electrical conductivity. With the aluminum electrodes the sulfate concentrations decreased more than with iron. The sulphate removal increased along the times of electrolysis and with the application of higher DC's. For both electrodes low efficiencies of 23% ammoniacal nitrogen removal were obtained. The electroflotation phenomenon was observed in a higher rate with the application of the larger DC's, being more expressive with the use of the aluminum electrode.