Manna Energy Foundation installed close to 500 gravity fed water systems and ultraviolet (UV) filtration systems in secondary schools in Rwanda. Water is forced by gravity through a rapid sand filter. The water is then passed under solar powered UV light which decontaminates the water. Decontaminating water with filters eliminates the need to boil water to disinfect it which reduces the number of trees that are cut down as fuel.
If communities could afford to tap an aquifer, they’d be unlikely to have the money to maintain the infrastructure that would deliver the water. Technology to purify water has to be more efficient than boiling over a wood fire, and at the same time must be sustainable in a remote area of a country where the gross national income per capita is about $1,300.
So residents in the town of Muramba, as so many people do in the developing world, rely on ground water, with all the risks attendant to a water supply open to contamination.
A team of students from the University of Colorado, representing the school’s chapter of Engineers Without Borders-USA, pitched in with residents of the town and with students from a nearby vocational school. They came up with a water-purification system that makes efficient use of the landscape to work.
The main cost will be replacing the UV lamps, which are available through a supplier in Kigali, Rwanda’s capital. The team has budgeted a replacement of the lamp every six months, although based on expected usage of seven to eight hours day, he expects a lamp to last as long as two years. The power is provided by a 102-watt solar panel.