Avaliação da emissão de GEE e BTEX em aterro sanitário de grande porte.

Abstract

This study aims to quantify the emission of greenhouse gases (GHG) and organic volatile monoaromatic compounds (BTEX) thought the cover layer of Seropédica Landfill in Rio de Janeiro, as well as measure the concentration of these gases in the atmosphere above the landfill cells. For this study we used two flow chambers of 0.66 m2 and 33.2 L, which operated for 15 minutes. GHGs were sampled using 60 mL polypropylene syringes every 5 minutes, BTEX samples were collected using a flow chamber with 1.0 m2 and 50 L at 0.7 L min-1, using coconut shell charcoal double-bed cartridges. GHGs and BTEX samples were also collected directly from the ambient air atmosphere. BTEX samples were analyzed by gas chromatography with mass spectrometry and GHGs by multiple detectors. The emission rates observed for methane varied from 0,1 e 575 g m-2 day-1, for carbon dioxide between 0,1 e 316 g m-2 day-1 and the concentration in the atmosphere from 3,5 e 150 ppm, and 333 e 655 ppm, respectively. BTEX average emission rate were 11,7; 492,2; 153,7; 67,2; 21,7 μg m-2 day-1, respectively for benzene, toluene, ethyl benzene, m+p-xylene and o-xylene. For the samples collected in the atmosphere, it was not observed benzene concentrations above 0,2 μg m-3. The average concentrations of toluene, ethyl benzene, m+p-xylene and o-xylene were 2,14; 1,35; 0,49 e 0,08 μg m-3, respectively. Higher emissions of both GHG as BTEX, were found in spots containing cracks.