The biosand filter is an adaptation of the traditional slow sand filter, which has been used for community drinking water treatment for almost 200 years. The biosand filter is smaller and adapted for intermittent use, so it's perfect to have in a home.
These filters are made of concrete and and filled with layers of specially selected and prepared sand and gravel. The sand layer removes pathogens and suspended solids from contaminated drinking water. This unit removes up to 97% of bacteria and 100% of parasites. It removes turbidity, iron and manganese, and can filter up to 20 liters an hour.
These biosand filters only cost about $25 US, and can conceivably last forever with no replaceable parts! What are we waiting for?
--Bibi Farber
For more information on Impact Nations, the group that produced this video, see:
http://www.impactnations.com/page/about-1