Tratamento de lixiviado de aterro sanitário por fotocatálise heterogênea

Abstract

Over the years has been a production growing of solid waste, resulting in a large amount of landfill leachate. Landfill leachate has a great pollution potential, and its disposal or inappropriate treatment can pollute the soil and groundwater. The main treatment method used in Brazil is the biological, however an alternative method has been drawing the researchers’ attention, such a method is heterogeneous photocatalysis using TiO2 as a catalyst. This work aims the analysis of the landfill leachate treatment with heterogeneous photocatalysis using artificial ultraviolet radiation emitted by a mercury vapor lamp and titanium dioxide (TiO2) as a catalyst. Seven preliminary tests were performed to define a standard, and then four tests were performed with concentrations of 0.05 g.L-1; 0.10 g L -1; 0.25 g.L-1; 0.50 g L -1; 1.00 g.L- 1 . For the avaliation of the results were carried out analysis of: Chemical Oxygen Demand (COD); concentrations of copper, zinc, chromium and aluminum; toxicity using Lactuca Sativa L. (lettuce) seeds as indicators; and Anova statistical analysis through the BioEstat 5.3 program. The COD results were not satisfactory, since they did not present a constant COD reduction. In the metals’ results, the tests with the samples that received the photocatalytic treatment showed reductions of copper, zinc and aluminum, no traces of chromium were found in the samples. Toxicity analyzes showed a significant reduction in the samples treated with photocatalysis, showing that the crude landfill leachate has highest toxicity to the seeds. The contributed to confirm the toxicity test, indicating that the photocatalytic treatment with TiO2 influenced the growth of the roots. However, the results indicated that heterogeneous photocatalysis should not be used as a single treatment, but rather as a pre-treatment. The concentration of TiO2 with the best results was 0.25 g.L-1.