Attenuation of hydrogen sulfide at construction and demolition debris landfills using alternative cover materials

The attenuation of H2S emissions by various landfill cover materials was evaluated using both laboratory and field experiments. The results demonstrated that cover materials consisting of selected waste products (compost and yard trash) and soils amended with quicklime and calcium carbonate effectively attenuated H2S emissions and detectable H2S emissions were only encountered in a testing plot using a sandy soil cover (average emission rate was 4.67 × 10−6 mg m−2 s−1). H2S concentration profiles in the cover materials indicated that H2S was removed as it migrated through the cover materials. At the same depth in the testing area, the H2S concentration in the sandy soil field plot was always higher than that of other testing plots because the sand (a) demonstrated less ability to remove H2S and (b) exhibited a higher H2S concentration at the base of the cover. Laboratory experiments confirmed these observations, with a combination of physical adsorption, chemical reactions, and biological oxidation, accounting for the enhanced removal. In addition to removal, the results suggest that some of the cover materials reduced H2S generation by creating less favorable conditions for sulfate-reducing bacteria (e.g., high pH and temperature).