Bruce Logan
A process that cleans wastewater and generates electricity can also remove 90 percent of salt from brackish water or seawater, according to an international team of researchers from China and the U.S.
In reading the current issue of New Scientist, I found a pointer to a blog entry called "Bug eats electricity, farts biogas."
Needless to say, I had to learn more.
A new technology is being developed that can turn raw sewage into raw power. The device, called a microbial fuel cell, not only treats wastewater, but also provides a clean energy source with the potential for enormous financial savings, according to scientists at Pennsylvania State University. Although power output is still relatively low, they say the technology is improving rapidly and eventually could be used to run a small wastewater treatment plant, which would be especially attractive in developing countries. It also could be used to treat waste from animal farms, food processing plants and even manned space missions.
Environmental engineers have removed and replaced one of the most expensive parts of their prototype microbial fuel cell and the device now costs two-thirds less and produces nearly six times more electricity from domestic wastewater. Earlier this year, the team was the first to develop a microbial fuel cell (MFC) that can generate electricity while simultaneously cleaning domestic wastewater skimmed from the settling pond of a sewage treatment plant. Now, they've shown that by modifying their original MFC to make it cheaper, they can also boost electricity production from about 26 milliwatts per square meter to about 146 milliwatts per square meter.
Something big may be brewing on the sewage treatment circuit thanks to a new design that puts bacteria on double-duty-treating wastewater and generating electricity at the same time. The key is an innovative, single-chambered microbial fuel cell. A fuel cell operates akin to a battery, generating electricity from a chemical reaction. But instead of running down unless it's recharged, the cell receives a constant supply of fuel from which electrons can be released. Typical fuel cells run off of hydrogen. In a microbial fuel cell, bacteria metabolize their food-in this case, organic matter in wastewater-to release electrons that yield a steady electrical current.
