Oregon State University Engineers Turn Sewage Into Electricity
Rocky's cantankerous trainer Mick famously said "Rock, you're gonna eat lightning and crap thunder." Turns out, he had it backwards. Researchers at Oregon State University have figured out how to turn waste water (crap) into electricity (lightning). Their findings have been published in the latest edition of the journal Energy And Environmental Science. The engineers have developed a new technology that increases the efficiency of microbial fuel cells, bacteria that can convert organic matter into electricity. The breakthrough can potentially produce as much as 50 times more electricity than other MFC systems, which could allow waste water treatment plants to generate their own electricity as well as effectively treat waste water. Some facilities may even be able to sell excess power back to the grid. The discovery is being seen as particularly useful for developing nations, where electricity and waste water treatment are often woefully inadequate.
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"If this technology works on a commercial scale the way we believe it will, the treatment of wastewater could be a huge energy producer, not a huge energy cost," Hong Liu, an associate professor in the OSU Department of Biological and Ecological Engineering, said in a press release on the university's website.
The current wastewater-to-electricity system uses what researchers call an "activated sludge" of waste water treated with methane to produce power. That technology, in addition to being less efficient than the techniques developed by OSU, also produces noxious gases such as hydrogen sulfide. The OSU engineers have found a way to make bacteria oxidize organic matter in such a way that it produces electrons that travel between the anode and cathode in a fuel cell, thus generating electricity. The technology isn't limited to sewage and any type of organic waste can be used to generate electricity. This means the technology can be used to generate power from grass straw, animal waste and byproducts from alcohol and dairy manufacturing.
OSU researchers have been working on the new process for several years, but thanks to new concepts - reduced anode-cathode spacing, evolved microbes and new separator materials - the technology can now produce more than two kilowatts per cubic meter of liquid reactor. Currently, experts estimate about three percent of the electricity used in the U.S. goes towards treating wastewater. Liu believes the discovery has a great deal of potential.
"This could have an impact around the world," he said. "It would save a great deal of money, provide better water treatment and promote energy sustainability."
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