Xela Project Water Filtration
The Xela Project, started by The Appropriate Infrastructure Development Group began manufacturing water filters after helping communities in Guatemala to purify their water using nothing but a large drum and gravel. At the bottom of the drum was gravel, with progressively finer layers of sand toward the top. When water was put into the drums, friendly bacteria would grow and kill the harmful bacteria in the water .
- Van Horn, R. (2007). Green and Non-Electric Technology. Phi Delta Kappan, 88(8), 630-631.