Avaliação do desempenho de remoção de poluentes de lixiviados: um estudo de caso para o sistema de tratamento de aterro municipal de Betim - Minas Gerais

Abstract

The preferable method of treatment and disposal of urban solid wastes used in Brazil is the sanitary landfill. However, this method causes negative environmental impacts through: biogas and leachates. As a result, a correct and efficient treatment for both must be a toppriority. Concerning leachates, many treatment processes are applied, such as: biological, physical, physical-chemical, etc., being the biological the most used. But there are few studies about of leachates treatment systems, in which biological processes are employed. The aim of this study was to assess the performance of a leachates treatment system situated in a sanitary landfill in Betim-MG, Brazil. This system is composed by an anaerobic pond, an UASB reactor and a facultative pond, working in series. For evaluating the system, it was necessary to use data, which had been collected from August 1999 to August 2004. Thesereferred data came from the analyses of leachates parameters.The results point out a large instability of the system in removing the pollutants from leachates. This instability is linked with: high variability in leachates characteristics, few information about biological processes used in leachates treatment and the systems are, usually, designed like domestic sewage plants. In this dissertation, the following average removal efficiencies were found: 76% of BOD, 84% of COD, 82% of Total Solids, 86% of Dissolved Solids and 45% of Suspended Solids.Concerning heavy metals, iron (Fe) and cadmium (Cd) have shown the highest average removal efficiencies: 87% and 71%, respectively.However, these averages must be analyzed with other statistic parameters due to the referred instability. Moreover, when effluents characteristics were evaluated, it was observed that some parameters, specially the organic matters, were over the limits fixed in Minas Geraisenvironmental laws.