CAWST Biosand Filter (v10)¶
BioSand & Media Filters • Est. CapEx: Low-cost / Locally fabricated
Technical Overview¶
A household-scale, intermittently operated slow sand filter housed in concrete or sturdy plastic, using a layered bed of sand and gravel to turn unsafe water into safe drinking water. Over 2 million units have been deployed worldwide based on CAWST’s freely available open-source design, reaching deep into remote regions such as the Amazon delta.
Key Specifications & Engineering Parameters¶
| Parameter | Specification |
|---|---|
| Category | BioSand & Media Filters |
| Capital Cost | Low-cost / Locally fabricated |
| Primary Mechanism | Water poured into the filter slowly percolates downward through a biologically active ‘schmutzdecke’ layer at the fine sand surface and subsequent sand bed. Mechanical straining, predation, adsorption, and natural biological processes in the established biofilm work together to reduce bacteria, protozoa, and turbidity using only gravity. |
| Target Scale | Household / Village Cluster |
| Standard Lifespan | 10 - 20 Years |
Engineering Trade-Offs¶
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- Requires periodic community maintenance
- Site-specific hydrogeological constraints
Cross-Reference & Interactive Tools¶
Need to evaluate this technology for your specific field site? Run the WhatWater.info Selector Engine to compare it against 100+ alternative solutions.