Collecting and using biogas from landfills
Landfills for municipal solid waste can be a source of energy. Anaerobic bacteria—bacteria that can live without the presence of free oxygen—living in landfills decompose organic waste to produce a gas called biogas. Biogas contains methane. Methane is the same energy-rich gas found in natural gas, which is used for heating, cooking, and producing electricity.
Landfill biogas can be dangerous to people and the environment because methane is flammable, and it is a strong greenhouse gas. In the United States, regulations under the Clean Air Act require landfills of a certain size to install and operate a landfill gas collection and control system.
Some landfills control the methane gas emissions simply by burning or flaring methane gas. Methane gas can also be used as an energy source. Many landfills collect biogas, treat it, and then sell the methane. Some landfills use the methane gas to generate electricity.
Using biogas from animal waste
Some farmers produce biogas in large tanks called digesters where they put manure and used bedding material from their barns. Some farmers cover their manure ponds (also called lagoons) to capture biogas. Biogas digesters and manure ponds contain the same anaerobic bacteria found in landfills. The methane in the biogas can be used for heating and for generating electricity on the farm.