Applications
Drinking Water
Rapid gravity and pressure filters producing potable water for towns and cities.
Specifying note
Standard specification is 0.5–1.0 mm sand at 600–800 mm depth over a four-layer gravel set. Dual-media with anthracite above extends filter runs where influent turbidity is variable.
Design parameters
- Filtration rate
- 5 – 12 m/h
- Backwash rate
- 35 – 45 m/h
- Bed expansion
- 20 – 30%
- Target effluent turbidity
- < 0.3 NTU
Typical bed configuration
| Layer | Media | Gradation | Depth |
|---|---|---|---|
| Filtration layer | Silica filter sand | 0.5 – 1.0 mm | 600 – 800 mm |
| Support layer 1 | Support gravel | 2 – 4 mm | 100 mm |
| Support layer 2 | Support gravel | 4 – 8 mm | 100 mm |
| Support layer 3 | Support gravel | 8 – 16 mm | 100 mm |
| Bottom layer | Support gravel | 16 – 32 mm | 150 mm |
- Layer
- Filtration layer
- Media
- Silica filter sand
- Gradation
- 0.5 – 1.0 mm
- Depth
- 600 – 800 mm
- Layer
- Support layer 1
- Media
- Support gravel
- Gradation
- 2 – 4 mm
- Depth
- 100 mm
- Layer
- Support layer 2
- Media
- Support gravel
- Gradation
- 4 – 8 mm
- Depth
- 100 mm
- Layer
- Support layer 3
- Media
- Support gravel
- Gradation
- 8 – 16 mm
- Depth
- 100 mm
- Layer
- Bottom layer
- Media
- Support gravel
- Gradation
- 16 – 32 mm
- Depth
- 150 mm
A starting point, not a design. Final layer depths follow from vessel diameter, design filtration rate and target effluent quality.
Recommended media
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