Haiti's combination of poverty and poor water quality creates a need for a water quality technology that is both inexpensive and effective. We believe that this need is best met through the use of biosand water filters (BSF).
Essentially a concrete box filled with gravel and sand, a BSF uses biological and mechanical processes to remove contaminants from water. A BSF user simply fills the reservoir at the top of the filter with water from any natural source and collects the clean water in a new container as it exits through a small tube located on the filter's face. On the first day of use, the filter removes all worms and protozoa present in the source water along with most bacteria.
Over the next two to three weeks, a naturally occurring process creates a biological layer within the top four inches of the filter's sand. This layer traps and feeds off of the smaller contaminants in the source water. Bacteria that make it through the first two barriers (the diffuser box and biological layer) either get trapped by the sand particles, or die off because of the lack of food, light, oxygen, and anything else needed to survive.
Once its biological layer is fully established, a BSF can remove between 95% and 99% of contaminants. If properly used and with less than fifteen minutes of maintenance every three to six months, a BSF can provide a household with clean water for over twenty years.
Since 2012, when Water Project for Haiti produced and installed its first biosand filter, we have supported the mission of bringing better water to Haitians. Hundreds of families, schools and churches - and thousands of individuals - realize the benefit of clean, safe water by using a WPH biosand filter. Nearly 1,000 concrete filters are in use in the Artibonite Valley, and we have helped place an additional 600 (and counting) by providing filter media to other organizations.
For more information about the BSF technology, please visit the Centre for Affordable Water and Sanitation Technology (CAWST) website.