Greenhouse gases emissions from a landfill in Rio de Janeiro

The emission of methane (CH4) and carbon dioxide (CO2) from landfills is one of the most important sources of greenhouse gases in metropolitan areas. This study quantified the emission rate of greenhouse gases (GHGs) by the intermediate cover layer of Seropedica landfill, in Rio de Janeiro, Brazil, as well as the concentration of these gases in the atmosphere above the landfill cells. A total of 21 samples from the cover layer and 31 samples from the atmosphere above the landfill was collected. Two flow chambers with 0.66 m(2) and 33.2 L were used, and the samples were collected with 60 mL polypropylene syringes at five-minute intervals, for 15 minutes. The samples were collected in areas with and without cracks in the intermediate cover layer. Sample analysis was performed by gas chromatography, by multiple detectors. GHGs emission rates varied from 0.1 to 575.0 g m(-2) day(-1) for CH(4)and 0.1 to 316.0 g m(-2) day(-1) for CO2. The ambient air concentrations ranged from 3.5 to 150.0 ppm and 333 to 655 ppm for CH(4)and CO2, respectively. Higher emissions were found in areas containing the larger cracks at the time of collection.