GasSim simulates the fate of landfill gas arising from managed or unmanaged landfill sites.

GasSim was developed by Golder Associates for the Environment Agency of England and Wales.

The model uses information on waste composition and quantity, landfill engineering, and landfill gas management techniques to enable assessment of the best combination of control measures for a particular design and rate of filling. Model outputs include the following:

  • estimates of the quantity of landfill gas generated;
  • combustion emissions from flares and gas engines;
  • fugitive emissions through the cap and lateral liner;
  • short-term and long-term air quality impacts using the atmospheric dispersion module;
  • lateral terrestrial migration;
  • Pollution inventory calculations;
  • human exposure to trace constituents.

The Environment Agency requires risk assessments to be made in support of permit applications for the operation of landfills and for other purposes.

These risk assessments need not be made using GasSim, however this tool has been developed for the Environment Agency to provide a systematic consistent approach.

Other models used in simulations may require justification and demonstrated validation before they may be accepted as providing suitably validated outputs.