12–20 mm Natural Sand Gravel Filter Media

The 12–20 mm natural sand gravel is a coarse-grade filter media commonly used as the bottom support layer in multimedia and pressure filtration systems. Its primary function is to facilitate drainage, maintain structural integrity, and prevent the migration of upper filtration layers. This gravel layer ensures that the finer filter media above it stay in place during high-velocity filtration and aggressive backwashing, thereby extending the life and improving the performance of the entire filtration system.

Key Properties:

- Grain Size: 12–20 mm
  Ideal for creating a stable drainage base in industrial and municipal filters.
- Specific Gravity: ~2.6 g/cm³
  Provides mechanical weight to stabilize filter beds during operation.
- Effective Size (D10): Typically 12 to 16 mm
  Offers excellent permeability and hydraulic conductivity.
- Uniformity Coefficient (UC): ≤ 1.7
  Ensures uniform packing, promotes smooth flow, and avoids clogging.
- Composition: 100% natural silica or quartz gravel; free from clay, loam, or organic matter.

Applications:

- Drainage Layer in Multimedia Filters
  Acts as the base layer to support finer filtration media and allow efficient water outflow.
- Raw Water Treatment Plants
  Ensures durability under fluctuating raw water conditions.
- Effluent & Sludge Treatment Plants
  Withstands biological and chemical loading, providing solid mechanical support.
- Rainwater Harvesting & Stormwater Filtration
  Used in gravel-based filters to trap large debris and improve drainage.
- Desalination Pre-treatment Plants
  Provides robust support in coarse filtration systems ahead of membrane filtration.

Advantages:

✅ High Strength & Durability – Withstands mechanical wear and pressure surges.
✅ Non-reactive & Chemically Stable – Does not alter the quality of treated water.
✅ Excellent Permeability – Promotes fast and uniform water flow.
✅ Supports Backwash Efficiency – Prevents media loss and enhances bed regeneration.
✅ Natural, Screen-graded, and Washed – Delivered ready for immediate use.

Installation Guidelines:

- - Installed as the lowest layer in multi-media filter beds.
  - Recommended bed thickness: 150–300 mm depending on flow rates and design.
  - Placed beneath 6–12 mm or 4–6 mm gravel, with finer media layered above.
  - Should be pre-washed and rinsed to remove surface dust before installation.

Packing & Supply:

Packaging: 25 kg / 50 kg HDPE bags or jumbo bags
Availability: In bulk quantities for municipal and industrial projects
Pre-washed & Sieve Graded: Ready to use

Standards Compliance:

Conforms to IS: 8419, AWWA B100, and NSF/ANSI standards (if applicable)
Laboratory-tested for sieve analysis, turbidity reduction, and acid solubility