You really wouldn't think that there would be so many ways of creating energy from a substance that supposedly had most of it's energy extracted through digestion... but, in addition to urine, we can make electricity from poop too! The secret is in the microbial bacteria. NASA is working on a technology that converts the space-waste of the astronaut's into electricity via microbial fuel cells. The fuel cell relies on Geobacter microbes which generate electricity while they decompose organic material.
Pennsylvania State University is using a microbial fuel cell to generate electricity as it purifies water. This really does make sense to me. And, apparently to Dr. Bruce Rittmann, a professor at Northwestern University who is leading the research on these fuel cells at NASA. "You have to treat the wastes anyway," points out Rittmann. "So why not make the process an energy gainer, instead of an energy loser? By producing electricity, microbial fuel cells would make the process of purifying waste streams much more economical." Moreover, he says, "they change our focus. Microbial fuel cells transform something we think of as undesirable into a resource."
Remember that fuel cells came into being for space missions, and are now finding their way into cars. Will microbial fuel cells make the same jump?
[Source: Space.com via Hugg]