Landfill gas

Methane, produced as a result of the automatic anaerobic digestion in a landfill of municipal organic waste, has a strong negative impact on the environment. It is a greenhouse gas whose greenhouse potential is twenty times higher than that of carbon dioxide. Other landfill gas hazards include:

• with respect to plants – deterioration of the rooting area
• with respect to buildings – settlement, explosions, fires
• with respect to people – unpleasant smell, insufficient amount of oxygen, toxicity, explosions or fires
• with respect to water – contamination or degradation of underground water.

The area covered by the hazard may include not only the landfill, but also its surroundings.
The best way to avoid the threat to the environment and to people's life and health is to build a gas recovery and recycling plant and use it for the production of heat and electricity.
Biogas can be produced in a landfill for as long as 30 years from the moment of waste disposal. The composition and quantity of the biogas generated in such a way depends mainly on the quantity and quality of the organic fraction deposited in the landfill. Other factors which play an important part include the height of the disposed waste, ambient temperature and atmospheric pressure.
It is assumed that in practice 200-250 m³ of landfill gas with 45-65% content of methane can be produced from one ton of waste.
With the passing time the amount of organic substances in waste becomes reduced as a result of microbiological processes and thus the amount of the acquired methane and cost-effectiveness of its acquisition and utilisation for energy purposes decrease.
Capital expenditures related to the construction and operation of landfill degassing plants are high when compared to energy production results. From many perspectives it is more an ecological undertaking rather than a business one.

Degassing of landfill sites by voivodships in 2014 (GUS – Central Statistical Office, "Environment 2015")

*Estimated data