Landfill methane models are tools used to project methane generation over time from a
mass of landfilled waste. These models are used for sizing landfill gas (LFG) collection
systems, evaluations and projections of LFG energy uses, and regulatory purposes.
Compared to other alternatives (such as installation of a full-scale LFG recovery system or
the use of test wells and the performance of a pump-test program), models have
advantages in terms of low cost and relatively rapid results.
Improvement of landfill methane models has been a priority for the LFG industry. The
literature is not replete with models that have been compared or calibrated with landfill
methane field data and modeling of methane generation and recovery is not sufficiently
advanced. Current landfill methane models are uncertain. However, as more LFG
collection systems are installed (for regulatory and other reasons) and operated within
lined landfills, better landfill data will become available for modeling. As a result, model
uncertainties probably can be reduced.
The objective of this project was to select various landfill methane models and to provide a comparison of model outputs to actual long-term gas recovery data from a number of well
managed and suitable landfills. Another objective was to use these data to develop better
estimates of confidence limits that can be assigned to model projections.