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Degradation of landfill gas constituents in soil

Conference ·
OSTI ID:381456
; ;  [1]
  1. Technical Univ. of Denmark, Lyngby (Denmark)

Landfill gas (LFG) contains high concentrations of methane which contributes to the greenhouse effect. LFG also contains aromatic hydrocarbons and chlorinated aliphatics which by emission to ambient air can be a local health threat. In addition, chlorinated aliphatics may also influence the earths ozone layer. The objectives of the study were to investigate the degradation of landfill gas constituents in LFG affected soils, and to evaluate the importance of the degradation processes to the emission. High methane oxidation potentials were found in laboratory experiments at 25{degrees}C. The degradation seemed to follow a zero order reaction kinetics, and was 3-4 times slower at 10{degrees}C as compared to 25{degrees}C. Also high degradation rates for benzene and toluene were observed. In soils sampled away from the landfill where almost no LFG contamination had been observed, longer lag phases and lower degradation rates of the two aromatic hydrocarbons were observed. Slow cometabolic degradation of trichloroethylene (TCE) and 1,1,1-trichloroethane (TCA) was observed when methane was present in the batch experiments. The rates were much lower than the rates for the aromatic hydrocarbons. In the field at Skellingsted Landfill, Denmark high methane emissions were observed in an area just outside the landfill area, probably as a result of the clay landfill covering, which has led to significant lateral migration of LFG. Indications of active methane oxidation in the field were observed by measuring soil gas profiles. By comparison of the results obtained in the laboratory with the field results it is shown, that degradation processes may have a significant effect on the emission of all the compounds studied. However the subject needs much more attention.

OSTI ID:
381456
Report Number(s):
CONF-9603165--
Country of Publication:
United States
Language:
English