Estudo experimental de emissões fugitivas de biogás em camadas de cobertura de uma célula de aterro sanitário.

Abstract

The disposal of solid waste in landfills generates by-products through aerobic and anaerobic biodegradation processes in the form of liquids and gases, which need to be monitored, processed and/or used. The gases from the waste biodegradation in landfills are composed primarily of methane (CH4) and carbon dioxide (CO2), which causes a serious problem of local air pollution and global levels. Landfills projects include biogas collection system for power generation. In this context, are employed in the roofing systems that have among its objectives, the retention of biogas fugitive emissions to the atmosphere. The survey was conducted in the operation phase of the landfill Seropédica in Rio de Janeiro, and aims to compare the fugitive emissions of CH4 and CO2 in three roofing systems built on experimental cell: conventional, capillary barrier and evapotranspiration. The field investigations consisted of the flow plate assays to measure biogas composition and flow through the layers of coverage. The tests were performed from August 2014 to February 2016. The results indicated that in conventional biogas emission layer ranged from 7,5 to 389,0 g/m2.day for CH4 and 29,0 to 843,4 g/m2.day for CO2. In capillary barrier layer, CH4 emissions vary from 7,2 to 369,2 g/m2.day and CO2 emissions ranged from 37,4 to 961,3 g/m2.day. In evapotranspiration layer provided the best performance in relation to other layers of coverage, with varying from 5,0 to 68,9 g/m2.day for CH4 and 36,5 to 207,6 g/m2.day to CO2 emissions. The vegetation in this type of coverage proved to be a decisive factor for the protection layer by reducing emissions of biogas to the atmosphere.