Biosand Filters
Many communities have a reliable supply of water, such as a nearby river or lake, but that water is usually so contaminated with human or animal waste that it is not safe to drink. Technologies abound for removing bacteria, parasites, and harmful chemicals from drinking water. However, most require a source of power, depend on complicated manufacturing procedures, or involve frequent maintenance. Only a few water treatment methods are appropriate for a poor village without electricity.

Biosand filters are very effective at reducing the concentration of disease-causing organisms and even some harmful chemicals. The design that was originally developed by the Davnor Corporation has been adopted by many development organizations and is used around the world. The filter consists of a concrete vessel that is filled with sand. The outlet is arranged so that the top of the sand is always covered with water. The “biological layer” that develops in this moist environment contains organisms that feed on harmful bacteria. The filter only needs maintenance when the biological layer becomes too thick.

The biosand filter is made of common locally-available materials and is very easy and inexpensive to construct. It is an appropriate technology around which small businesses can be developed. Lifewater offers our partners training in constructing and marketing biosand filters.