Scientists closer to creating electricity from sewage.

From Oregon State University:

CORVALLIS, Ore. – Engineers at Oregon State University have made a significant advance toward producing electricity from sewage, by the use of new coatings on the anodes of microbial electrochemical cells that increased the electricity production about 20 times.

The findings, just published online in Biosensors and Bioelectronics, a professional journal, bring the researchers one step closer to technology that could clean biowaste at the same time it produces useful levels of electricity – a promising new innovation in wastewater treatment and renewable energy.

Engineers found that by coating graphite anodes with a nanoparticle layer of gold, the production of electricity increased 20 times. Coatings with palladium produced an increase, but not nearly as much. And the researchers believe nanoparticle coatings of iron – which would be a lot cheaper than gold – could produce electricity increases similar to that of gold, for at least some types of bacteria.

“This is an important step toward our goal,” said Frank Chaplen, an associate professor of biological and ecological engineering. “We still need some improvements in design of the cathode chamber, and a better understanding of the interaction between different microbial species. But the new approach is clearly producing more electricity.”

In this technology, bacteria from biowaste such as sewage are placed in an anode chamber, where they form a biofilm, consume nutrients and grow, in the process releasing electrons. In this context, the sewage is literally the fuel for electricity production.