News - full story

RESEARCHERS at Oregon State University, US have discovered that by plating graphite anodes with gold nanoparticles, they can produce more electricity from sewage.

The plated anodes can produce up to 20 times more electricity than has previously been possible from sewage in microbial electrochemical cells, and could offer a novel way to produce electricity while treating it. The research was led by Frank Chaplen, an associate professor of biological and ecological engineering at Oregon.

Microbes present in sewage or other biowaste form biofilms on the anodes, and as they consume the sewage and grow, they release electrons which are harvested by the anodes. The technology has been proven on a laboratory scale but still requires scale-up. The researchers found that gold nanoparticles were far more effective than palladium nanoparticles, and speculate that similar results could be obtained with much cheaper iron nanoparticles.

"This is an important step toward our goal," says Chaplen. "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."

The researchers say the system could reduce the cost of sewage treatment in developed countries, and could also provide a sustainable way to produce useful quantities of electricity in developing countries. Work will now focus on improving the efficiency of the system and identifying the lowest-cost materials.

The research will be published online in Biosensors and Bioelectronics.