Currently the majority of bio-sand filters in use throughout the world have been introduced through micro-projects implemented by humanitarian organizations. It is estimated that already some 50 thousand units have been built this way.
Such projects usually start by identifying an area where the majority of people relies on contaminated surface water – often there is a high level of water-borne disease. Subsequently, a filter promotion project is started. To date, this has usually involved the construction of concrete filters, where a number of technicians are trained in their construction. Initially the design of these filters was square, but an improved round version is now available that uses less materials and is therefore cheaper to build. These filters are then promoted throughout the community, either for free as a gift, but more usually for payment. Since it will be a new product, it may take time for market demand to develop. Therefore the initial payment of the filters can be subsidized, with the aim that the eventual market price will include the full cost of construction including profit for the technicians, once the market has developed to the point where there is sufficient demand. This approach is often used if the organisation aims to set up a profitable and sustainable micro-enterprise that can continue to build and sell filters once the organisation leaves.
Small-scale micro-projects have usually been started using the concrete filter, but such projects can be equally valid using the drum filter.
Mol, A. (2001). Targeting individuals: away from the concept of community involvement – the success of household sand filtration. Waterlines, Vol.20, No.1.
This article describes a successful bio-sand filter micro-project implemented by Medair in Kenya.
Forerunners in this field of bio-sand filter micro-projects include Samaritan’s Purse and Medair. The Massachusetts Institute of Technology (MIT) has played a key-role in technical research and the development of appropriate community approaches in Nepal.