[via The Science Blog] A microbial fuel cell developed by Penn State researchers does double duty, generating energy while cleaning domestic wastewater. Better yet, they just made it much cheaper and substantially better at producing energy.
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.
For the more technically minded:
Microbial fuel cells produce current through the action of bacteria that can pass electrons to an anode, the negative electrode of a fuel cell. The electrons flow from the anode through a wire to a cathode, the positive electrode of a fuel cell, where they combine with hydrogen ions (protons) and oxygen to form water.
The naturally-occurring bacteria in wastewater drive power production via a reaction that allows them to transport electrons from their cell surface to the anode. In addition, a reaction (oxidation) that occurs in the interior of the bacterial cell lowers the biochemical oxygen demand, cleaning the water.
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