Emissões fugitivas de biogás em célula de aterro sanitário.

Abstract

Fugitive biogas emissions can represent an important part of landfills gas flux, difficult the use of methane (CH4), and pose risks to the environmental health of localities near the project, as well as at regional and global levels. In this context, this work aimed to evaluate the fugitive emissions and the factors that interfere in the flow of biography in the final coverage layer (lining) of landfill. The study area consisted of a landfill cell, with a mass of 62,359.44 tons of waste deposited. This Cell is located at Landfill in Campina Grande, which receives municipal waste and other nine cities from the State of Paraíba, Brazil. The Cell in question was denominated Cell 2, in which the monitoring of the quality of the biogas in vertical markets and measurements of the fugitive emissions in the layer of cover of compacted soil was realized by static chamber methodology. In addition, gas concentrations at the soil-waste interface were analysed using gas Concentration Measurement Devices (CMDs); and mapping of gas emissions, applying data intermediation techniques in Kriging. The results indicated that concentrations of methane (CH4) and carbon dioxide (CO2) in the vertical drains ranged from 50.3 to 59.6% for CH4, 39.1 to 44.7% for CO2. The fluxes of CH4 and CO2 in the landfill top layer ranged from 0 to 0.09 g.m-2.day-1 and 24.62 to 331.31 g.m-2.day-1, respectively. The percentage of retention of CH4 and CO2 by the upper liner, above 95%, was influenced mainly by the high degree of average compaction obtained for the Cell (91.84%), absence of differential pressures at the soil-waste interface and the performance of the gás drainage system. Therefore, this result is very favourable when it is intended to implement biogas energy utilization systems under the Clean Development Mechanism (CDM), since the research carried out indicates the efficiency of the cover layer of Cell 2 in gas retention.