Human Waste-Powered Robots May Be Future of Machines

13/02/2012

Human waste might someday turn human urine or waste into useful electricity for radios or space robots EcoBot-III was able to both eat and crap inside its lab environment. Image: Bristol Robotics Laboratory, UK

Today's robots that fly, jump or roll around must refuel or recharge as does any gadget that runs out of energy. Tomorrow's new generation of self-sustaining robots might keep going nearly forever by grazing on dead insects, rotting plant matter or even human waste.

The vision of robots capable of plugging themselves into the natural world of living organisms has begun taking shape in several labs around the world, and even NASA has shown renewed interest in powering space robots with microbes. But one British lab has already been building on the work of robotics pioneers to create small "EcoBots" that extract energy from microbial fuel cells since 2002.

"Robots that eat biological fuels could find enough fuel almost anywhere," said John Greenman, a microbiologist at the Bristol Robotics Laboratory, a joint venture between the University of the West of England and the University of Bristol. "There is organic matter anywhere on Earth — leaves and soil in the forest, or even human waste such as urine and feces."

The first EcoBot (created in 2003) was powered by E. coli bacteria feeding on refined sugar. Then "EcoBot-II" (2005) harnessed sludge microbes to break down dead flies, prawn shells and rotten apples. Finally, "EcoBot-III" (2010) showed how a "digesting" robot could also dump its leftover waste, so that its microbes wouldn't be poisoned by their own filth and could keep powering the robot.

"EcoBot-III is a robot that collects its own food and water from the environment," said Ioannis Ieropoulos, a roboticist at the Bristol Robotics Laboratory (BRL). "It performs the task we design it to do, and at the end of the day, it gets rid of its own waste. It literally craps into its own 'litter' tray."
Ieropoulos, Greenman and BRL Director Chris Melhuish, give credit to other researchers for first showing how robots could use bacteria, and for pioneering the development of microbial fuel cells powered by sludge. But they have pushed the field forward by making robots capable of performing tasks — such as maintaining a circulatory system and wirelessly reporting on their environment while moving toward food, water or light — when solely powered by microbial fuel cells (MFCs) to digest organic matter and dump any waste.

"We know MFCs will last as long as they're fed; there's nothing mechanical to go wrong with them," Greenman told InnovationNewsDaily. "They could go 20 or 30 years. As long as the microbes grow, they can keep going."

The EcoBot team's work with such technology has not gone unnoticed. They received funding from the Bill & Melinda Gates Foundation in late 2011 so that they could push the limits of stacking microbial fuel cells that help tackle sanitation and energy needs by turning human urine or waste into useful electricity for radios or other gadgets.

Human waste might also someday help power space robots that accompany astronauts on long-distance space missions or to planetary colonies, Ieropoulos said. On Earth, the robots might crawl through the debris of growing cities, or survive on their own for years in the great outdoors.

For now, the robots remain limited by the power available in microbial fuel cells so that they must sit still and charge their batteries before doing activities in short bursts. But the EcoBot team hopes that each new robot can both shrink in size and have more available power based on boosting the stacks of microbial fuel cells — a goal for EcoBot-IV.

By Kim Anh

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