In 2003, our President (Bruce) designed a system based on a slow sand filter (biofilter) to purify drinking water at a canoe in camp on Lake Temagami, Ontario that did not have access to electricity.
At that time, he learned that an orphanage in South Sudan that he and our draftsman were planning to help construct did not have access to safe water (the nearest safe well was 3 miles away). Therefore, Bruce introduced biofilter technology to South Sudan. According to CAWST, the Kajo Keji and Juba biofilter projects that Enviro-Stewards helped originate have provided 1,806 people with safe drinking water. Non-governmental organizations (NGOs) that attended a training session hosted by the Kajo Keji project have started their own projects that have helped 36,655 more.
The concept of a slow sand filter (pictured below) has been around for hundreds of years. It is very sustainable in the developing world as it can be constructed locally with locally available materials, has no moving parts, requires no chemicals to maintain, and lasts about 30 years. It is affordable ($100) and is less expensive (financially and environmentally) than burning charcoal or wood to purify water.
For more information on The Safe Water Project , please read the backgrounder in this link.