Building a BioSand Filter for Purifying Water

Biosand filter is an inexpensive way to purify water. It can use local material. The biosand filters remove organic materials, protozoans, worms, bacteria, and viruses.

Purification Process


Four basic process exist in the bio-sand filtering process: biological layer, mechanical trapping, absorption,  natural death. The first layer, the biological layer captures organism and kills bacteria. Micro-organisms feed on each other. The biological layer is located in the first inches of sand. As the water travels, organisms are captured via mechanical trapping. In the third process, static charges in the sand grains capture organisms via the process of absorption. Going further down the sand, natural death occurs, when organism are denied light and food and die. The whole water purification process is simultaneous.


A Simple Biosand filter


Building a biosand filter for purifying water is simple. 

1. Get a container--a bucket, a drum etc
2. Make a hole at the bottom side of the container.
3. Add a pipe in the hole
4. Add gravel in the bucket, so the gravel is above the hole
5. Add sand on top of the gravel
6. Then add water on top of the sand to be purified

Works Cited

How to build a biosand filter. On Youtube by the resident

External Link: