A new solution to an age-old problem

Tate Rogers, an environmental engineering graduate student, demonstrates the hand-held tool that can be used to empty latrines.

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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, is pursuing a new approach to an ancient problem.

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, Tate Rogers, an environmental engineering graduate student, and his advisor, Dr. Robert Borden, are 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. The tool is similar to an Archimedes screw traditionally used to bring low-lying water to irrigation ditches above it.

"This seemed like a cost-effective solution to the waste-disposal problem," Rogers said. "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."

Rogers developed the original idea and the Gates Foundation proposal as part of an undergraduate senior design class taught by Borden, a professor of civil, construction, and environmental engineering at NC State. The research team is using the Gates Foundation grant, received in November, to develop a prototype of the waste-disposal tool that should be ready by the end of 2012. Field testing in the Philippines could begin in spring 2013.

"If it's successful, we want to make the technology and the training available globally," Rogers said. "Solving a real-world problem — that's what engineering is all about." end of story

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