http://www.dailykos.com/story/2004/2/27/155226/981

Microbes in wastewater make a handy household battery.

By Philip Ball

Flushing the toilet could help supply your home with electricity, thanks to a device developed by US researchers.

They have shown that electricity can be generated from domestic wastewater, which is full of organic matter from cooking, cleaning or sewage.

As a bonus, the dirty water is made cleaner by the process, making sewage treatment easier. By turning wastewater into a valuable economic resource, Bruce Logan and colleagues at Pennsylvania State University think that their system might help make basic sanitation more affordable in developing countries.

The process relies on bacteria that are already present in most wastewater and munch on household organic matter. These bugs burn anything from sewage to left-over cabbage, mainly turning it into carbon dioxide: as they oxidise their food, they strip electrons from the organic matter. Researchers can harness these electrons, generating an electric current that can be tapped for power generation.

(more at site)