Please make a donation

Visit us on FacebookSee us on YouTubeFollow us on TwitterFollow us on Wordpress

Bio Sand Filter (BSF)

The Rain Tree Foundation aims at provide the villagers in rural areas with access to clean and safe drinking water. Therefore we use the technology of a BioSand Filter which is promoted all over the world from CAWST, a Canadian organization.

The BioSand Filter (BSF) is an adaptation of the traditional slow sand filter, which has been used for community drinking water treatment since 200 years. The BioSand Filter is smaller (about 1 m tall, 0.3 m wide on each side) and adapted so that it does not flow continuously, making it suitable for use in people’s homes.


The filter container can be made of concrete or plastic. It is filled with layers of specially selected and prepared sand and gravel. The sand removes pathogens and suspended solids from contaminated drinking water. A biological community of bacteria and other micro-organisms grows in the top 2 cm of sand. This is called the biolayer. The micro-organisms in the biolayer eat many of the pathogens in the water, improving the water treatment.

We have installed hundreds of BioSand Filters already and the great impact is measurable through our own tests as well as with official laboratories in Chiang Mai, Thailand. The people need less fire wood to boil their drinking water and they have to spend less money for water born diseases.


More infromation's about the BioSand Filter :

Click on file to open as PDF document !