Villagers in Muramba, Rwanda, now have an effective, easy-to-use water purification system that can deliver clean drinking water to the entire community, thanks to an Engineers Without Borders team from the University of Colorado.
The "Bring Your Own Water" system, a unique combination of previously proven water purification technologies, will provide Muramba's residents with up to 7,000 liters of safe water for everyday use. The system, consisting of a gravity-fed settling tank, rapid sand filter and solar-powered UV sanitation light, was installed this summer by members of the nonprofit organization Engineers Without Borders-USA, which is working with developing communities throughout the world to find engineering solutions to water, sanitation and other problems.
Evan Thomas, a doctoral student in aerospace engineering at CU-Boulder who works full time on water recovery systems at NASA's Johnson Space Center, said the unusual combination of treatment technologies was required by Muramba's badly contaminated surface water, mountainous environment and poor population.
"We wanted to clean a high volume of water at very little cost," he said, adding that the strict requirements were similar to those he faces on a lunar outpost project he is working on for NASA. "In both cases, we have to use renewable energy and develop a system that is reliable and easily maintainable."
Maximilian Gold, a graduate student in civil engineering and lead engineer for the Bring Your Own Water system, explained that the Muramba system consists of an input bucket on the top of a retaining wall where residents can pour turbid and bacteria-contaminated water collected from nearby streams and taps. The water passes through a 55-gallon drum containing PVC tube settlers, and then down the retaining wall to another drum about 12 feet below, which contains 6 inches of gravel, 24 inches of sand and 6 inches of volcanic stone. After the water is forced through the rapid sand filter, it passes into a solar-powered UV sanitation system where it gets a second cleansing, Gold said.
When users open the tap at the bottom, they get a measured amount of water almost equal to what they put in at the top. A very small amount of water is taken by the system for backwashing purposes.
Although the initial system cost $3,000, including shipping to Rwanda, it will require very little maintenance, Thomas said. Trials made in Boulder showed a total elimination of bacteria in a highly contaminated test sample using the system.
The Bring Your Own Water system is the latest in a series of new systems engineered by the EWB-CU chapter and installed with the help of local partners in Rwanda. During the last two and a half years, the team has repaired the community's 75-year-old, gravity-fed water system, built two rainwater catchment systems to enhance water supply, and installed solar-powered lighting in a clinic, hospital and school.
During its five-week visit this summer, the CU team also worked with students from Kigali Science and Technology University to install a family-scale demonstration biogas reactor, which captures methane from animal waste to burn for cooking needs; and took steps toward installing an ultraviolet sanitation light on the main water supply line for the Mugonero Hospital. The latter project was stalled when a surge in the hospital's grid power burned out the ultraviolet light ballast. Once operational, however, the ultraviolet light is expected to kill most of the bacteria in the water supply, which is used for dressing wounds and other medical care.
The EWB-CU team involves students, faculty and professional engineers, as well as some medical doctors. Dr. Richard Byyny of CU-Denver and Health Sciences Center was among those who worked with the team this summer. The EWB chapter from NASA Johnson Space Center also has been working with the CU group in Rwanda, focusing its efforts this summer on installing a new rainwater catchment system for the hospital.
Funding for the projects came from UNESCO, EPA, AmCom Insurance, CU-Boulder, Rotary Clubs, EWB-USA and other private and grant donations.
For more information go to ceae.colorado.edu/ewb/.