Depth Profiles of Methane Oxidation Kinetics and the Related Methanotrophic Community in a Simulated Landfill Cover
Simulated landfill cover with real time online monitoring system was developed using cover soils.Then the system started and the concentrations of bio-gas in various depths were continuously monitored, and it was found that the system ran continually and stably after 2-3 h when methane flux changed.After that, the relationship between regularity of methane oxidation and methane flux in landfill cover was analyzed.The results indicated that concentration of oxygen decreased with increasing methane flux when the depth was deeper than 20 cm, and no obvious correlation between oxygen concentration in landfill cover surface and methane flux, however, methane oxidation rate showed positive correlation with methane flux in various depths (range of R2 was 0.851-0.999).Kinetics of CH4 oxidation in landfill cover was fitted by CH4-O2 dual-substrate model (range of R2 was 0.902-0.955) , the half-saturation constant Kmincreasing with depth was 0.157-0.729 in dynamic condition.Finally, methanotrophs community structure in original cover soil sample and that in simulated landfill cover were investigated by high-throughout sequencing technology, and the statistics indicated that the abundance and species of methanotrophs in simulated landfill cover significantly increased compared with those in original cover soil sample, and type Ⅰ methanotrophs including Methylobacter and Methylophilaceae and type Ⅱ methanotrophs Methylocystis were dominant species.
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