Shocking Way to Transform Waste

For the first time, a microbial fuel cell has generated electricity while cleaning wastewater, a development that could make sewage treatment more affordable for both industrialized and developing nations, researchers said.

The prototype fuel cell, developed at Pennsylvania State University with support from an $87,000 National Science Foundation grant, is described in the next issue of the journal Environmental Science & Technology (subscription required).

The article reports that the fuel cell removed up to 78 percent of organic matter from the water and produced between 10 and 50 milliwatts of power per square meter of electrode surface. Since the paper's submission, the cell has produced up to 200 milliwatts per square meter -- enough to power a small light bulb, said Bruce Logan, the Penn State professor of environmental engineering who directed the project.

While a typical fuel cell runs on hydrogen, a microbial fuel cell relies on bacteria to metabolize food, releasing electrons that yield a steady electrical current. Other microbial fuel cells have used fuels like glucose or ethanol. In this case, the fuel was skimmed from the settling pond of a wastewater treatment plant.