U.S. researchers say biofilters could treat methane venting into the atmosphere from passive landfill vents and reduce its impact on global warming.
Researchers writing in the International Journal of Environmental Engineering say organic matter rotting in smaller, older landfill sites generates a slow trickle of the potent greenhouse gas, amounting to about 2 or 3 kilograms per day per vent.
Tapping or capturing this slow stream of the gas is not viable technologically or economically, they say, although methane has a global warming impact 21 times greater than carbon dioxide and must be considered when attempting to balance the climate change books.
Old landfills typically have passive gas vents that simply release the gas into the atmosphere, but U.S. researchers say methane oxidation is a better alternative to venting of landfill methane.
The researchers tested two biofilter designs capable of oxidizing methane gas into carbon dioxide and water by using so-called methanotrophic bacteria, microbes that digest methane.
Both types of filter, a radial model and a vertical type, were effective in converting methane, they said, providing a significant oxidation rate.
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