Using microbes to harvest energy from wastewater now has a silver lining
Silver, the precious metal once thought to protect against werewolves and make magic mirrors, has a new, real talent: helping microbes turn sewage into power.
Engineers have long used microbes to wring out electrical energy trapped in wastewater, and relied on oxygen to soak up the harvested electrons. But these mini power plants can be finicky and leak oxygen and microbes. When the two mingle, the bugs guzzle the gas and short-circuit the system.
Now researchers at Stanford University have replaced bubbling oxygen with solid silver oxide that gobbles up electrons, making a more reliable, rechargeable bacterial battery. The researchers report the finding September 16 in the Proceedings of the National Academy of Sciences.
All microbe-based batteries and fuel cells need a place to send electrons, says coauthor Craig Criddle, “but putting oxygen in there is a problem.” By