New Self-sustaining Robot Eats Sewage, Excretes Fuel

EcoBotII, No. 3

Researchers at Bristol Robotics Lab in the United Kingdom have brought the world one step closer to full-on humanoid robots: They’ve created the first synthetic gut for use in self-sustaining robots.

Bristol's Ecobot III consumes meals, turns nutrient-rich, partially processed sewage into fuel and then excretes.

From Popular Science:

The method is pretty simple: the 'bot navigates itself to a dispenser filled with the sewage mixture and takes in what it needs. The mixture is distributed into 48 bacteria-filled MFCs where it is metabolized into hydrogen atoms that in turn migrate to an electrode where, through the magic of fuel cells, a current is generated. Once every 24 hours -- Ecobot III is admirably regular -- the robot purges its synthetic gut into a special waste chamber.

Ecobot III has demonstrated the ability to survive unaided for up to seven days, feeding and watering itself -- it needs periodic drinks of water to maintain power generation -- and even exhibiting small intelligent behaviors, like moving toward sources of light. But it moves very slowly and is highly inefficient, capitalizing on just one percent of the chemical energy actually available within its food.