RALEIGH — If ever a machine to suck sludge could be called elegant, it is the one dreamed up by an N.C. State University student to solve one of the most ancient public health dilemmas in the Third World: finding an easy, cheap and sanitary way to remove sludge in cities that don't have modern sewer systems.
Tate Rogers, now a first-year graduate student in environmental engineering, designed the simple device, which just won a $100,000 grant from the Bill & Melinda Gates Foundation. Rogers will use the money to develop the idea and demonstrate its effectiveness.
The device uses a motorized, hand-held posthole digger of a type available nearly worldwide. A pipe is slipped over the giant, screw-like digging end, and a hose from the top of the pipe will direct the sludge to a waiting truck or barrel.
The idea was Rogers' response to an assignment last spring in a senior design class for engineering students taught by Robert Borden. The Gates foundation had described the problem and asked for proposals to fix it, so Borden challenged his students to design something to do the job.
For millennia, one of the most common methods for removing sludge from urban latrines and cesspits has involved the use of buckets and shovels, Borden said. The people removing it often dump it as quickly as possible, say, for example, in the first alley they pass.
Then it gets picked up on shoes and tracked around the neighborhood and into homes or washed into nearby streams, spreading disease.
Rogers, who is 22 and from Lawsonville, a small town north of Winston-Salem, said he knew pretty quickly that he wanted to use an auger. That helped focus his thinking.
"Then one night I thought, well, why don't we just put a pipe around it?" he said.
He built the contraption along the same basic principle as the ancient Archimedes Screw, which has been used for more than 2,000 years to lift water.
He said that he and Borden, who is listed as the principal investigator on the grant, hope the device will have enough power to push the sludge 50 to 100 feet up the hose, because even in neighborhoods of twisty alleys, a truck can often be brought that close.
It would work just fine, though, Rogers said, to be able to pump it into 55-gallon drums or other containers on a simple dolly that could be wheeled away.
The enclosed drums would keep the entire system much better contained and more sanitary than the shovel and bucket method.
"It was one of those things that, once you see it, you say, why didn't someone think of that earlier?" Borden said. "When (Rogers) said he was simply going to stick a pipe over a posthole digger, I immediately thought, yeah, they could do that in India, they could do that in Africa."
First, though, they're going to do it in the Philippines.
That's where Borden and Rogers plan to take prototypes based on two or three designs once they have completed initial tests here using mud, then animal waste.
They hope to go to the Philippines in the spring of 2013, just before the initial 18-month grant ends, Rogers said. Then they hope to get a second-phase, two-year grant from the foundation for up to $1 million to start putting some of the as-yet-unnamed devices into service around the world.
Made to be copied
The idea isn't to start a giant manufacturing operation and make millions of dollars, Borden said. Instead, it's to develop equipment and methods of using it that will work in poor countries and can be built there cheaply and easily.
"If it works as good as we hope, my expectation would be that all you would have to do is distribute a few, and local people would see it and begin to copy it," Borden said.
The grant came from a Gates program called Grand Challenges in Global Health. The idea is to spark practical, but ground-breaking solutions to basic problems, said Michal Fishman, a spokeswoman for the Gates foundation.
"Basically (the selection committee) is looking for that innovative, bold idea that can easily be scaled up," she said.
The international competition for the $100,000 grants is fierce. Nearly 2,100 proposals came in for the round awarded this month, and 110 of them were funded, Fishman said.
Rogers, who visited Honduras a couple of years ago with a church mission group, said once he's out of school he wants to work on engineering projects to help people in developing countries.
That's one reason he was thrilled to hear the grant had been funded. It also means he'll get to do the research for his degree on this particular device.
"It's really, really cool because not many graduate students get to work on something they came up with," he said.