Microbial fuel cells (MFCs) are something of a worldchanging icon: biological systems that clean wastewater and generate electricity in the process. One system with two useful results. With so many different research teams on the job, MFCs are moving rapidly towards the "predetermined element" category of near-future scenarios.
Researchers at Washington University at St. Louis have developed -- and patented -- a new MFC design that has improved overall energy density and a structure better suited for real-world use. The "Upflow MFC" has stacked chambers, and the test model they built is described as the size of a "thermos bottle".
Moreover, the researchers claim that, when the efficiency is scaled up to closer to theoretical maximum, a single (presumably bigger-than-a-thermos) unit at a food-processing plant could power as many as "900 American single-family households" (and again -- you now have a sense of scale).