Now I have heard everything! But I wasn't surprised to find that bacteria made this crazy concept possible. Naturally occurring bacteria in the cow's rumen, the first of the chambers in a cows stomach where microbial fermentation takes place,are to thank. These bacteria feed on cellulose which is converted into carbon dioxide, releasing electrons. A microbial fuel cell (MFC) generates electricity by acting as the electron acceptor in the bacterial metabolic process in an anaerobic environment.
Here is the basic principal of a MFC. There are two compartments that are separated by a thin membrane made of special material to allow the passage of protons. The bacteria (the rumen fluid) and substrate (the cellulose), are place in one compartment with a graphite rod. This is the anode. As the bacteria metabolises the cellulose the process releases electrons that move through the anode to the cathode compartment through a wire with a resistor. The movement of protons together with the flow of electrons across the wire creates an electrical current.
It takes two of the newest cells to produce enough electricity to recharge a AA battery. That doesn't seem like much now, but considering that cellulose is the most abundant resource on the planet this technology has promising possibilities for clean energy. And cellulose is just one type of organic matter that bacteria can convert to electricity, take for instance human waste.
Researches at Pennsylvania State University have build a microbial fuel cells that runs off of human waste water. Waste water is passed through a plastic tube that contains a graphite rod that acts as the anode and a home for the bacteria. As the bacteria feed on the waste they produce electrons that travel up the anode through wire to a cathode, producing an electrical current. The only thing is you have to keep the bacteria fed. Considering the food source, that shouldn't be a problem! This amazing device uses bacteria to treat waste water while producing energy. Could you image a sewage treatment plant that powered itself, a plant that cleans our water and powers our homes!