Determination of Source Strength of Landfill Gas: A Numerical Modeling Approach

Abstract

An accurate estimation of source strength of gas in a landfill is necessary to design gas extraction systems. A one-dimensional mathematical model to estimate source strength of landfill gas is presented. The model is based on fundamental principles of gas transport through porous media, and incorporates methane oxidation in landfill cover soils. The nonlinear mathematical equation for gas migration through layered soil was linearized and solved using the partially implicit Crank Nicolson technique. Apart from source strength, concentration and pressure as functions of depth and gas emissions into the atmosphere were computed. Laboratory experiments were conducted to generate data for model calibration and verification for mono- and two-layered systems. Other model parameters were estimated using information from published literature. The model data were in agreement with laboratory test results obtained for both systems.