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AIDG slow sand filtration |
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| Description |
Slow sand filtration is an inexpensive chemical-free method of water purification. For communities with access to sand, this filtration technique is one of the most cost effective and environmentally friendly forms of water treatment available. |
| Primarily For
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Water |
| Other Purposes
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Livable Communities, Sanitation, Sustainability, Water |
| Climate |
Cold, Dry/Arid, Temperate, Tropical |
| Emphasis |
Communities, Individuals |
| Effort to Implement
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Simple |
| Maximum Cost |
$
75 |
| Why |
Also known as biosand filters, slow sand filters do not require any special type of sand, but rather can make use of any fine-grained sand. Typically, river sand is used, as it is the most freely available in the majority of areas. Slow sand filters have been and are used in many municipal water treatment stations around the world. Municipal filters are usually large circular boxes of up to ten meters in diameter, with a filter depth of one to two meters. The family-sized filters may be as little as 30 cm in diameter. They do, however, still maintain a filter depth of around one meter. This depth is essential for the effectiveness of the filter. Many different types of storage containers have been used to hold the sand: oil drums, concrete tubes, and plastic barrels. AIDG uses plastic barrels, avoiding the oxidation and bad taste that sometimes is associated with metal drums while providing easier transportability and assembly than concrete tubes.
Properly managed sand filters remove 96%-98% of water borne pathogens such as E. Coli and Giardia, producing a positive significant impact on the health of target users. The greatest effect is expected for young children, who are extremely susceptible to diarrheal diseases caused by exposure to contaminated water. Diarrheal disease causes approximately 2 million deaths per year among children in developing countries.
The implementation of sand filters, particularly when combined with other sanitation and hygiene practices is an effective and economical way of dealing with this major problem. The primary drawbacks of slow sand filtration include the need for diligence in the maintenance of the filter and the speed of filtration (slow).
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| URL(s) |
http://www.aidg.org/water.htm
http://www.who.int/water_sanitation_health/publications/ssf/en/index.html
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| Availability Limits |
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| Resources |
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| Email |
info@aidg.org |
