Developed countries spend about 3 percent of all their electrical power treating wastewater. The juice purifies contaminated material so it can be returned safely to the environment. Now researchers think they can turn this power drain into a power source. Because a new kind of battery uses microbes to produce electricity from wastewater. The work is in the Proceedings of the National Academy of Sciences. [Xing Xie et al., Microbial battery for efficient energy recovery]

Like us, some microbes draw their energy from organic matter. And wastewater is chock full of such fuel.

So scientists gave microorganisms polluted water and wired them up. When the microbes harvested electrons, the particles traveled through the electronic components to power a battery. This system had a net efficiency of 30 percent, about the same as a commercial solar cell.

In theory, microbial batteries like this one could eventually be made more efficient, producing enough electricity to power the treatment of the wastewater three times over. Which gives a whole new meaning to the saying, “Waste not, want not.”

—Sophie Bushwick

[The above text is a transcript of this podcast.]

