In the category of "environmentally friendly process for purifying water and creating electricity," we have this idea from scientists at Norway's research institute, SINTEF.
It's a biological battery - a fuel cell - powered by bacteria.
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Fuel cells have two electrodes, one positive and one negative. They also contain a solution called an electrolyte that carries electrically charged particles from one electrode to the other.
In this biological fuel, the electrons are produced by bacteria. SINTEF researcher Luis Cesar Colmenares explains:
"In simple terms, this type of fuel cell works because the bacteria consume the waste materials found in the water," said Colmenares in a press release. He is running the project together with his colleague Roman Netzer.
"As they eat, the bacteria produce electrons and protons. The voltage that arises between these particles generates energy that we can exploit."
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As a bonus, because the bacteria consumer the organic waste in the water, they clean it.
Ideally, the technique would be expanded to an industrial-sized scale outside the lab to generate enough energy to power the water purification process.