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Scientists at the University of Manchester may have found a novel way to dispose of nuclear waste: unleash bacteria that love to devour it.
The bacteria don’t seem to have a name yet, but the researchers group them with “extremophile” bacteria, which live in environments once thought to be uninhabitable. In fact, bacteria that devour waste aren’t new: What’s new is that the waste these bacteria eat is radioactive.
Much nuclear waste is buried deep underground. Generally, “intermediate level” waste is encased in concrete before it’s buried in underground pits. Eventually, ground water reaches this waste, which makes it highly alkaline and sets off a series of chemical reactions that break down the cellulose in the waste.
This process creates toxic isosaccharinic acid (ISA), which can bind with radioactive materials in the waste, then leach out of their underground crypts and poison the food chain, including drinking water. But the Manchester researchers discovered that extremophile bacteria can stop this.
The scientists discovered bacteria that thrive in highly alkaline, non-radioactive soil, which has the same alkaline level as cement-based radioactive waste. The microbes eat the toxic ISA under conditions similar to a dump containing intermediate radioactive waste.
Often, those dumps have no oxygen for the bacteria to breathe. But scientists discovered that when these bacteria digest the ISA, they can alter their metabolism to breathe in other chemicals in the ambient water, including iron or nitrate.
The Manchester team is studying the bacteria’s unusual biological processes with the goal of finding a safer method to dispose of nuclear waste underground.
The bacteria and alkaline soil samples the researchers used were from an industrial site in the Peak District, a highland area that spans northern and central England. Professor Jonathan Lloyd, of Manchester’s School of Earth, Atmospheric and Environmental Sciences, said their source may be an important clue to how the microbes may react with nuclear waste.
“Given that they must have evolved to thrive at the highly alkaline lime-kiln site in only a few decades,” Johnson told the University of Manchester News, “it is highly likely that similar bacteria will behave in the same way and adapt to living off ISA in and around buried cement-based nuclear waste quite quickly.”
Johnson says there’s plenty of time for the bacteria to adapt because nuclear waste is buried for millennia. As for the critters’ effect on the waste itself, he says, “We expect them to help keep radioactive materials fixed underground through their unusual dietary habits, and their ability to naturally degrade ISA.”
By Andy Tully of Oilprice.com
Andy Tully is a veteran news reporter who is now the news editor for Oilprice.com