Simulation on diffusion of oxygen in semi-aerobic landfill.

According to theory of semi-aerobic landfill,lab scale installment was set up.During the steady stage of landfill process,the volume fraction of methane,carbon dioxide and oxygen were detected in different sampling points.The effect of distance between sampling point and central gas tube to the volume fraction of oxygen was analyzed and simulated with mathematic model.Results showed that in the steady stage of semi-landfill,volume fraction of oxygen in different layers showed certain trend because of oxygen diffusing which resulted from the difference of temperature and oxygen concentration between inside and outside installment.With the combined effect of aerobic decomposition reaction,nitrification and methane oxidation in pile,volume fraction of O2 in bottom layer and middle layer declined under exponential law and volume fraction of O2 in upper layer showed parabolic shape because of its special structure.