Microbial Fuel Cells

A microbial fuel cell (MFC) is a bio-electrochemical system that drives a current by mimicking bacterial interactions found in nature. Instead of using hydrogen as a fuel, as do conventional fuel cells, microbial fuel cells use naturally occurring microbes to generate power. Bacteria live in the anode, where they eat glucose, sewage, or other waste water, and turn that into electrons and protons. The bacteria transfer electrons to the circuit, which provides small amounts of power. MFCs could be installed to wastewater treatment plants. The bacteria would consume waste material from the water and produce supplementary power for the plant. The gains to be made from doing this are that MFCs are a very clean and efficient method of energy production.

How to

To make a microbial fuel cell, you put graphite cloth--the anode--in the bottom of a bucket along with chicken wire--the cathode--and microbe-laden waste, either mud, cow manure, or residue from coffee crops. A layer of sand acts as an ion barrier while salt water helps the protons travel more easily. you also can add a power management board to regulate the power and send it to a battery. Such a fuel cell can run a cheap, efficient light-emitting diode (LED) for four to five hours per evening. A system like this will cost around $10.

Links

Wikipedia entry on MFC [1]

Mit Technology Review article on MFC [2]

Microbial Fuel Cells website [3]