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These projects collect the methane gas and treat it, so it can be used for electricity or upgraded to pipeline-grade gas. (Methane gas has twenty-one times the global warming potential of carbon dioxide). [21] For example, in the U.S., Waste Management uses landfill gas as an energy source at 110 landfill gas-to-energy facilities. This energy ...
The use of landfill gas is considered a green fuel source because it offsets the use of environmentally damaging fuels such as oil or natural gas, destroys the heat-trapping gas methane, and the gas is generated by deposits of waste that are already in place. 450 of the 2,300 landfills in the United States have operational landfill gas ...
Landfills are the primary method of waste disposal in many parts of the world, including United States and Canada.Bioreactor landfills are expected to reduce the amount of and costs associated with management of leachate, to increase the rate of production of methane (natural gas) for commercial purposes and reduce the amount of land required for land-fills.
Landfill gas typically has methane concentrations around 50%. Advanced waste treatment technologies can produce biogas with 55–75% methane, [21] which for reactors with free liquids can be increased to 80–90% methane using in-situ gas purification techniques. [22] As produced, biogas contains water vapor.
Methanogenesis can also be beneficially exploited, to treat organic waste, to produce useful compounds, and the methane can be collected and used as biogas, a fuel. [21] It is the primary pathway whereby most organic matter disposed of via landfill is broken down. [ 22 ]
Typically landfills try to keep oxygen levels to less than 5%, because higher levels can speed up decomposition, produce heat and raise the risk of an underground landfill fire.
Oxygen is critical because it allows for respiration of both plant roots and soil organisms. Other natural soil gases include nitric oxide , nitrous oxide , methane , and ammonia . [ 3 ] Some environmental contaminants below ground produce gas which diffuses through the soil such as from landfill wastes, mining activities, and contamination by ...
In sites with large volumes of building waste, especially those containing gypsum plaster, the reaction of leachate with the gypsum can generate large volumes of hydrogen sulfide, which may be released in the leachate and may also form a large component of the landfill gas. The physical appearance of leachate when it emerges from a typical ...