Student project may give developing world simple, cheap clean water

University Park, Pa. — Ten dollars' worth of PVC piping and hardware may be the key to providing cleaner drinking water in the developing world if an engineering student’s project comes to fruition.

Lydia Karlheim, a civil engineering senior, has been developing a chlorination device designed to simplify water purification. This past summer, Karlheim and her adviser, Richard Schuhmann, the Walter L. Robb Director of Engineering Leadership Development, traveled to Tiout, Morocco, to examine the village's water source and delivery system.

Schuhmann said, "Probably the most common problem in the developing world is the quality of the source water for the community. That source water may be affected by the dumping of materials in the vicinity of the source or from nearby latrines. Often, it's just simply affected by runoffs and particulates that result in high turbidity water sources. Here in Tiout, the situation is a little bit different. Here we have a very high quality subterranean water source that's being managed in a less than effective way."

Village officials treat the water with chlorine, but the Penn State engineers discovered that they aren't efficient about applying it.

"The problem right now is some of the men try to chlorinate the water at a big storage tank which holds thousands of gallons of water pumped from an underground aquifer. Once a week, the men throw about ten liters of liquid chlorine in the tank," Karlheim said. "With this process, there's a lot of chlorine in the water at the beginning of the week. It takes about a day for all of the chlorine to react, and then for the rest of those six days, there's virtually no chlorine."

Christina Clementi, a Peace Corps worker living in Tiout, said she can tell which day the water supply gets treated.

"The water isn't always clear," the 25-year-old New Jersey native stated. "It's sometimes white. It's sometimes fizzy, like seltzer water. But usually if you let it sit, it goes away."

Schuhmann said, "The folks here one day a week get extremely chlorinated water, where their teeth are very white and their clothes are getting white if they wash their clothes with the water. The rest of the week, the water's not chlorinated at all and the folks are susceptible to many pathogens in the water."

Clementi knows first-hand about the erratic quality of the water. "I've only lived in Tiout for two months, but I've been drinking the water. I've been sick twice for about 10-day periods."

Karlheim's mechanism has the potential to automate the chlorine dosing process so the villagers don't have to worry about pouring chlorine into the water system each week.

"What Lydia's device does is removes that responsibility for dosing that water as a function of volumetric flow rate," Schuhmann explained.

Karlheim continued, "The solution we're looking at is a flow-dependent device, which consists of PVC pipes. You put something called an orifice plate in the middle of the one of the pipes, which basically restricts flow in a certain spot. By restricting the flow, the velocity of the water increases. And this increase in velocity has a powerful suction."

Schuhmann said, "When the water begins to flow, the chlorine will begin to be pulled in by a vacuum into this device, proportional to the flow rate of water into the line. If water's not flowing through the line, then they'll be no vacuum induced through the device and no chlorine will enter the pipeline. It's a remarkably elegant device that delivers a volume proportional dose of disinfectant to the water, which is what we want."

In addition to its simplicity, the device also is cheap.

"The cost of this procedure is very minimal," the civil engineering senior said. "We're using PVC pipe which is available all over the world. PVC is inexpensive and our orifice plate is basically a metal washer. We're estimating the cost of this whole device to be under $10, which is very feasible. The device, plus the cost of chlorine, which they already buy, shouldn't incur too much additional cost for the community."

Before embarking to Morocco, Karlheim worked throughout the summer with Roberts Filter Group, the company sponsoring the project, on prototyping her designs based on design calculations using assumptions about Tiout's hydraulic conditions. After returning, Karlheim went back to the firm's Darby, Pa., laboratory to incorporate the new data from Morocco and refine her design.

"We feel hopeful that the work that Lydia's done this summer in terms of the hard lifting doing patent searches, doing the math, performing hydraulic calculations and prototyping, that she's going to have a device that's going to have a widespread and significant impact on developing world communities like this one," Schuhmann said.

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Last Updated October 20, 2010