A simulation model for methane emissions from landfills with interaction of vegetation and cover soil

Global climate change and ecological problems brought about by greenhouse gas effect have become a severe threat to humanity in the 21st century. Vegetation plays an important role in methane (CH₄) transport, oxidation and emissions from municipal solid waste (MSW) landfills as it modifies the physical and chemical properties of the cover soil, and transports CH₄ to the atmosphere directly via their conduits, which are mainly aerenchymatous structures. In this study, a novel 2-D simulation CH₄ emission model was established, based on an interactive mechanism of cover soil and vegetation, to model CH₄ transport, oxidation and emissions in landfill cover soil. Results of the simulation model showed that the distribution of CH₄ concentration and emission fluxes displayed a significant difference between vegetated and non-vegetated areas. CH₄ emission flux was 1-2 orders of magnitude higher than bare areas in simulation conditions. Vegetation play a negative role in CH₄ emissions from landfill cover soil due to the strong CH₄ transport capacity even though vegetation also promotes CH₄ oxidation via changing properties of cover soil and emitting O₂ via root system. The model will be proposed to allow decision makers to reconsider the actual CH₄ emission from vegetated and non-vegetated covered landfills.