Landfill_gas_migration
Landfill gas migration
Movement of gases produced by waste in a landfill to areas outside of it
Landfill gas migration is a complex process in which gases produced by waste in a landfill move from the site of original deposition to other places via diffusion, usually from areas of high concentration to low. The process is also affected by the permeability of the ground and other factors, such as pressure differences in the soil, cavities, pipes, and tunnels. Changes in atmospheric pressure [1] and the water table can encourage this migration.
These gases can include methane (CH
4), carbon dioxide (CO2), hydrogen (H
2), and volatile organic compounds (there are approximately 500 others that can be present in trace forms) from the waste on site and its degradation over time.
Steps must be taken to prevent this migration from the landfill site as it might enter buildings in the vicinity. This can be done on the site by means of combinations of geomembranes and clay based products, see gas protection.