Sulfate reduction at micro-aerobic solid-liquid interface in landfill

H2S can be produced under aerobic conditions, which goes against the traditional view of an obligatory anaerobic metabolism process. In this research, the sulfate-reduction behavior at the micro-aerobic solid-liquid interface in a landfill was investigated. H2S emission from mineralized waste from the landfill material could be enhanced when exposed to O-2. The highest H2S concentration of 56.54 mg. m(-3) , observed at an O-2 concentration of 2%, was 4.5 times higher than the highest concentration of H2S recorded under anaerobic conditions. The presence of leachate influenced protection of the anaerobic sulfate-reducing bacteria against O-2, allowing the bacteria to survive and even undergo significant sulfate reduction under micro-aerobic conditions. The sulfate concentration could be maintained at a high level because of possible oxidation-reduction cycling under micro-aerobic conditions and the risk of H2S emission was always high. This research provides a theoretical basis for controlling the release of H2S within landfills. (C) 2019 Elsevier B.V. All rights reserved.