Norwegian researchers have developed fuel cells powered by wastewater digested by bacteria.
Generating only a small amount of electricity, these biological fuel cells can be used to purify water polluted with industrial contaminants.
"In simple terms, this type of fuel cell works because the bacteria consume the waste materials found in the water," explained Luis Cesar Colmenares, a scientist at Norwegian SINTEF research institute. "As they eat, the bacteria produce electrons and protons. The voltage that arises between these particles generates energy that we can exploit.”
The researchers would like to scale up the process in the future to produce enough electricity to fully power the water purification process.
"Our challenge has been to find the mechanisms and bacteria that are best suited for use in this water purification method," said Colmenares’s colleague Roman Netzer. "To start with we had to find a bacterium which was not only able to consume the waste products in the water, but which could also transfer electrons to a metal electrode."
The researchers constructed a small demonstration unit in a lab which is running on dirty water from a local dairy in Tine, Norway. Although they are currently experimenting with wastewater rich in organic acids, they say other chemical contaminants would provide similar results.
"At the moment, we're not talking about producing large volumes of energy," said Netzer. "But the process is very interesting because water purification processes are very energy-demanding using current technology. We're particularly pleased at being able to produce just as much energy using low-cost materials as others are achieving using much more expensive approaches."