AVALIAÇÃO DE EMISSÕES DE BIOGÁS E GERAÇÃO DE ENERGIA EM ATERRO SANITÁRIO NO SEMIÁRIDO BRASILEIRO

The biogas generated by the anaerobic decomposition of the organic fraction of Municipal Solid Waste (MSW) in landfills is an alternative energy source that can be used on the operation of these plants or for other purposes. The biogas use contributes to minimizing adverse environmental impacts by avoiding emissions of greenhouse gases to the atmosphere. However, the generation of landfill gas is conditioned by several factors, among them those related to the residues characteristics and climatic conditions. The Brazilian semiarid region is characterized by peculiar environmental conditions, requiring specific studies to consolidate the knowledge on the presented theme, through a broader database, that consider local specificities. Therefore, the objective of this article was to evaluate the biogas emissions and energy generation in a landfill located at the Brazilian semiarid region. In this research, this database was collected through studies carried out at the Campina Grande Landfill, Paraiba. The methodology included in situ investigations, relating aspects of the quality and quantity of biogas generated, as well as the collection of fresh and more advanced biodegradation residues. By studying the residues biodegradability it was possible to obtain the methane generation potential and the decay constant for the estimation of the biogas emissions and the energy generation in the analyzed landfill. Maximum methane concentrations, around 55.0%, were observed shortly after the final landfill covering layer. In quantitative terms, the average methane flow rate was 7.0 Nm³.h-1 per gas drain, compatible with large landfills, such as Aterro Bandeirantes-SP. The estimates made in this study, even when it was considered an unfavorable scenario of biogas collection and burning, point to a project power of 2.5 MW.