Community-Scale Slow Sand Filter¶
Pumps & Lifting • Est. CapEx: Low-cost / Locally fabricated
Technical Overview¶
A gravity-driven municipal or communal water purification system that treats raw surface water by percolating it through a 1–2 meter deep bed of fine sand and gravel. First deployed in 1804 and still used in cities like London, it provides centralized potable water without chemical coagulation or high-energy pumps, making it suitable for both developed utilities and rural communities with available land.
Key Specifications & Engineering Parameters¶
| Parameter | Specification |
|---|---|
| Category | Pumps & Lifting |
| Capital Cost | Low-cost / Locally fabricated |
| Primary Mechanism | Water is applied at a low hydraulic loading rate (0.1–0.4 m/h) to the surface of a fine sand bed (effective size 0.15–0.35 mm). A gelatinous biofilm layer called the schmutzdecke naturally develops within 1–3 weeks, biologically digesting organic matter and pathogens while the underlying sand provides physical straining and adsorption. Treated water is collected by an underdrain system beneath a supporting gravel layer. |
| Target Scale | Household / Village Cluster |
| Standard Lifespan | 10 - 20 Years |
Cross-Reference & Interactive Tools¶
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