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crumb trail: Home >> Whistle Online >> Archives >> Sept. 5, 2006

Students work to improve sanitation in developing countries

Megan McRainey
Institute Communications and Public Affairs

  Georgia Tech undergraduates Calvin Johnson and Brad Davis stand with Christine Moe and Robert Dreibelbis of Emory University’s Center for Global Safe Water as they build a solar latrine prototype. The lack of water and infrastructure contribute to millions of deaths annually from inadequate water supplies and poor sanitation practices.

When given a choice this summer between helping out with designs for environmentally friendly luxury condos less than a mile away from campus and designing and building solar latrines to improve sanitation in Bolivia, Georgia Tech undergraduate student Calvin Johnson chose the latrine project without hesitation.

“Are you sure?” pressed Kevin Caravati, a student project advisor and senior research scientist at the Georgia Tech Research Institute. “The other project is right down the street.”

But Johnson, who is also an All-American wide receiver on Tech’s football team, was brief and to the point. “I want to help the less fortunate,” he said.

He began work the next day on designs for an inexpensive dry latrine system that could provide schoolchildren in remote areas of Bolivia with much needed basic sanitation facilities that use the sun’s rays to safely transform bacteria-laden waste into fertilizer.

“You realize how fortunate you are when you see that people around the world don't have clean water and sanitation,” Johnson said.

Four billion people globally suffer from chronic waterborne disease, and an estimated 13 million children die annually of diarrhea — conditions linked to a lack of adequate sanitation. In a developing country with extreme conditions like Bolivia, poor sanitation poses a serious health risk, contaminating the limited water supply and attracting disease-carrying insects.

Emory University’s Center for Global Safe Water approached Tech’s School of Civil and Environmental Engineering and GTRI to help remove a sanitation roadblock faced by developing countries — the design and cost flaws of current United Nations latrines.

“We wanted help with the project, but it was tough to find students enthusiastic about latrines,” Caravati said.

Johnson was joined by his project partner Brad Davis, a building construction undergraduate student, and the two hammered out a final design with Caravati. The goal was to create an improved solar latrine out of the most affordable and available materials. The waste needed to be heated by the sun to a temperature that would kill pathogenic bacteria, but the design and materials had to be as simple as possible.

“We focused on designing the most inexpensive and durable model, taking into account what materials would be readily available in those nations,” Davis said.

The team made two prototypes from a hodgepodge of household items including a bicycle tube to insulate the waste and retain heat, a bleach bottle, Plexiglas, scrap wood and tin foil. The central idea was to “bake” the waste with an oven-like design that could reach temperatures of more than 150 degrees Fahrenheit while still keeping the inhabited area cool enough for users.

Johnson, Davis and Caravati built two very effective prototypes that would cost only $78 per unit, compared to $120 for existing models. In an area where families make less than $3 per day, that cost difference could make the latrines available for schools, villages and families.

With the initial prototypes completed, the team plans to travel in January to a remote area of Bolivia’s Andes Mountains to build several of the new latrines and instruct locals on how to build their own.

“It has been a great experience for Calvin and me to design and build a latrine that has the ability to vastly improve sanitation throughout the developing world,” Davis said.



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Last Modified: September 5, 2006