Annemiek ter Heijne, assistant professor from the department of environmental science of Wageningen UR, investigates a new method to produce electricity from waste water. She uses bacteria as battery chargers. A small reactor has been built and proved that the principle is working. The challenge is to make the process faster and more efficient. At this moment a lot of energy is needed to clean the waste water. In the near future it will be a real option to clean waste water on an energy neutral basis.