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A New Solution To An Age-Old Problem: Human Waste

Crowded conditions in some developing countries make it difficult to manage human waste. An inexpensive new technology may help address the problem.

Conventional sewage treatment is not available in many parts of the world, and disposing of human waste can be both difficult  and hazardous in developing nations. So a team of researchers from NC State, with support from Grand Challenges Explorations, an initiative of the Bill & Melinda Gates Foundation, are pursuing a new approach to an ancient problem.

The handheld device functions like an Archimedes' screw, lifting waste and funneling it into containers for transport.

In crowded cities, it can be difficult or impossible for waste disposal trucks to empty septic systems or cesspools – the large trucks just can’t fit through the narrow alleyways in many neighborhoods.

To address this problem, an NC State team led by Robert Borden is developing a hand-held tool that can be used to empty these latrines. The tool utilizes a gasoline-powered earth auger (think of an industrial-sized corkscrew) as the pumping mechanism, which would divert the waste either through a hose to a nearby truck or into smaller, transportable containers.

The turning motion of the corkscrew-shaped auger lifts and carries up the waste, similar to an Archimedes’ screw.

“This seemed like a cost-effective solution to the waste-disposal problem,” says Tate Rogers, an environmental engineering graduate student who came up with the idea. “And it could be effectively implemented, with little training, in developing countries. Safety was also a key concern when we began working on this. We want to minimize contact with the waste to reduce the risk of contracting disease.”

The project received a Grand Challenges Explorations grant from the Gates Foundation this month, which the research team will use to develop a prototype of the waste-disposal tool. “We plan to have the prototype ready by the end of 2012, and to begin field-testing in the Philippines in spring 2013,” Rogers says.

“I came up with this concept in Professor Borden’s senior design class when I was an undergraduate,” Rogers says. “If it’s successful, we want to make the technology and the training available globally. Solving a real-world problem – that’s what engineering is all about.”