A Simulation model for estimating methane oxidation and emission from landfill cover soils

Area of Science:

• Environmental Science
• Geochemistry
• Soil Science

Background:

• Accurate quantification of methane (CH4) oxidation and emission from landfill cover soils is vital for assessing mitigation strategies against anthropogenic greenhouse gas emissions.
• Landfill cover soils play a critical role in mitigating the release of methane, a potent greenhouse gas.

Purpose of the Study:

• To develop and validate a model for simulating methane transport, oxidation, and emission in landfill cover soils.
• To analyze the sensitivity of methane emission to various model parameters, including cover soil properties.

Main Methods:

• A numerical model was established, integrating the multicomponent diffusive equation and Darcy's law with dual Monod kinetics.
• Sensitivity analysis was conducted to determine the influence of key parameters on methane dynamics.
• The model was applied to predict methane emissions using data from landfill cover soil column experiments.

Main Results:

• The study identified that a high maximum oxidation rate (Vmax) of cover soil significantly enhances methane oxidation, even with limited soil thickness.
• Methane oxidation efficiency plateaus once the cover soil thickness exceeds a specific threshold.
• The model's simulated methane emission values demonstrated strong agreement with experimental measurements.

Conclusions:

• The developed model provides a reliable and accurate method for estimating methane emissions from landfill cover soils.
• Understanding the relationship between cover soil properties and methane oxidation is key to optimizing landfill management for greenhouse gas reduction.