Treatment of landfill leachate using Fenton Processes and Photo Fenton Solar

Abstract

The leachate from municipal solid waste landfills is a complex mixture of organic and inorganic substances, which can damage the environment due to toxicity and the high concentration of recalcitrant organic matter. This work applied advanced oxidation processes (AOP) to the treatment of leachate from the Gericinó (Rio de Janeiro / RJ) and Gramacho (Duque de Caxias / RJ) landfills. These landfills were both in operation for more than 30 years; the latter closed two years ago. The purpose of using AOP is to improve the leachate quality prior to a subsequent biological treatment. The bacteria Aliivibrio fischeri was used as a biological process for evaluation of toxicity. The Dark-Fenton Process employed in bench scale experiments with a pH of 3.0 and Fe+2:H2O2 ratio = 1:5 resulted in removals of 56% and 19% for COD leachate of the Gericinó and Gramacho leachates, respectively. The Solar Photo-Fenton Process conducted in pilot plant tests at pH = 3.0 and Fe+2:H2O2 ratio = 1:5 generated COD removal 88% and 78%, respectively. These conditions led to a decrease in the toxicity of leachates’ coefficient values to a degree equal to 50 % - for Aliivibrio fischeri greater than 50% - indicating a more suitable leachate for further biological treatment.