Engineers at Stanford University have devised a new way to generate electricity from sewage using naturally-occurring “wired microbes” as mini power plants, producing electricity as they digest plant and animal waste.
The battery prototype has two electrodes —
one positive, the other negative — plunged into a bottle of wastewater.
At the battery's negative electrode, colonies of wired microbes cling to carbon filaments that serve as efficient electrical conductors. Using a scanning electron microscope, the Stanford team captured images of these microbes attaching milky tendrils to the carbon filaments.
The Stanford engineers estimate that the microbial battery can extract about 30 percent of the potential energy locked in wastewater. That is roughly the same efficiency at which the best commercially available solar cells convert sunlight into electricity.
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