Deponigas

Deponigas, also known as landfill gas, is produced by the anaerobic decomposition of organic waste in landfills. It is a mixture of primarily methane (CH4) and carbon dioxide (CO2), with smaller amounts of nitrogen, oxygen, hydrogen sulfide, non-methane volatile organic compounds and siloxanes. Methane provides most of the energy content and is the major greenhouse gas component of the mix.

Formation and composition: The gas results from microbial activity as waste decomposes in anaerobic conditions. Gas generation begins soon after waste placement and can continue for many decades as materials degrade at varying rates. Typical composition ranges commonly cited are methane about 40–60% and carbon dioxide about 40–60%, with trace amounts of other gases and compounds that can vary with waste type, age, moisture, and landfill design.

Collection and use: Modern landfills often install gas collection systems that consist of wells and a network of pipes to extract deponigas. Collected gas is usually flared to oxidize methane or used for energy recovery, such as electricity generation or direct heat through combined heat and power systems. In some cases, gas may be upgraded for use as pipeline-quality natural gas, though this is less common.

Environmental and safety aspects: Capturing deponigas reduces methane emissions and odors but requires proper management; methane is highly flammable, and gas migration can pose explosion risks and air or soil contamination if not controlled.

Regulation and policy: Management of deponigas is typically addressed in environmental regulations and waste-management policies, with programs encouraging capture, utilization, and reduction of greenhouse gas emissions through energy projects and incentives.