Scientists at the U.S Department of Energy’s Brookhaven National Laboratory are exploring the use of bacteria to increase the recovery of methane and to decontaminate water produced during the methane-recovery process.
Methane gas, which burns without releasing sulphur contaminants, is becoming increasingly important as a natural gas fuel in the US. But the process of recovering methane, which is often trapped within porous, unrecovered or waste coal, produces large amounts of water contaminated with salts, organic compounds, metals, and naturally occurring radioactive elements.
‘Our idea is to use specially developed bacteria to remove the contaminants from the wastewater, and also help to release the trapped methane,’ said Brookhaven chemist Mow Lin.
Lin’s team has developed several strains of bacteria that can use coal as a nutrient and adsorb or degrade contaminants.
They started with natural strains already adapted to extreme conditions, such as the presence of metals or high salinity, then gradually altered the nutrient mix and contaminant levels and selected the hardiest bugs.
In laboratory tests, various strains of these microbes have been shown to absorb contaminant metals, degrade dissolved organics, and break down coal in a way that would release trapped methane. The use of such microbe mixtures in the field could greatly improve the efficiency and lower the associated clean-up costs of coal-bed methane recovery, Lin said.
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