Mechanism of multi-component gas migration in unsaturated cover

A multi-component gas migration model is presented for determining each component flux of landfill gas. The method to determine transport parameters in unsaturated soils is also given. A soil column test is conducted to simulate the progress of gas migration in landfill final cover. The test results are compared with the theoretical ones. It shows that the multi-component gas migration model can give the flux of each component more accurately. Change in the injected gas component fraction has a significant influence on the gas distribution in soils. Amount of apparent gas permeability depends on gas pressure. Bulk diffusion is the main factor to determine the distribution of each component in soils. Changing in effective diffusion coefficient may improve the methane oxidation capacity.