The bio-sand filter does not seem to have been used on a large scale, except unsuccessfully during an emergency in Latin America (this case is discussed under ‘Use in Emergencies’. However, that does not mean that there is no scope for scaling up the success of micro-project. Several scenarios can be imagined that would allow the introduction of the filters on a national or regional level. Obviously, to achieve that a very different programme approach is needed. Throughout such a programme, it will be very important to make sure the technology is applied carefully and that a substantial health benefit will be a measurable result. If anyone becomes sloppy in dissemination of the technology, the reputation of bio-sand filtration could be damaged.
For instance, it should be possible to commercially manufacture, market and sell for profit bio-sand filters, if they can be made cheaply enough. Until now, most bio-sand filters are made from concrete on a small scale by NGOs. Concrete places definite limits on the numbers of filters that can be produced per day and mass production is not feasible. On top of that, their weight and fragility would make them expensive to transport.
However, the development of a cheap, mass-producible plastic filter could change this situation. BioSandFilter.org has been researching the manufacture of such filters for the last 2 years. If sufficient demand is generated and the development of a large market succeeds, the sale of such filters should be commercially viable. The trick obviously lies in developing a market and this will be expensive. Such cost would have to be recuperated by raising the price of the filters, possibly bringing it out of reach for the poor. However, it is unlikely that commercial companies would risk large investments in return for profits that are uncertain or might take years to realise.
From an economic and humanitarian point of view it can make sense to subsidize the supply of safe drinking water. In the case of bio-sand filters, the price of the product can be kept low if certain costs are funded through a humanitarian grant or government subsidy. This could for instance apply to financing the production setup, social marketing and/or distribution of the filters to remote areas. A similar approach already works well for the Safe Water Systems initiative, which has introduced chlorine solution in a number of developing countries. Currently heavily subsidized, the eventual aim is to make the production commercially viable in the long run, once the market has been developed and sufficient demand has been generated for the product.
Since bio-sand filtration offers a number of advantages over consumable chemical water purification products, it is likely that we will see pilot projects in the near future that will test how bio-sand filtration will perform if introduced on a large scale. Several different approaches would need to be tested in combination with technical and social research to evaluate how suitable bio-sand filtration is if introduced on a large scale. The overall health impact would need to be studied especially. More information on this topic will follow soon.
Population Services International is a world leader in the field of social marketing. One of the many products they promote in various developing countries is another type of household water treatment: a bottled hypo-chloride solution. This is part of the Safe Water Initiative, which is spearheaded by the Centre for Disease Control.
‘Sanitation is a business’, is a document prepared by the Water Supply and Sanitation Collaborative Council (WSSCC) and available from their website. It has some interesting thinking on making sanitation commercially interesting, some of which can be adapted to household water supply.