Dissolved Air Flotation (DAF) systems use air to remove suspended solids from the surface of wastewater. These systems are common in the food processing, meat packaging, oil and gas, chemical, and pulp and paper industries. The DAF process creates a sticky sludge, bubbles and voids that can cause the pump to run dry, which can damage the stator, rotor, and mechanical seals of some pumps. The manufacturers cannot control when or if these bubbles appear.
To solve this problem, we recommend installing a DJ-HDF2 heavy duty flap valve pump. The AODD pumps are equipped with a flap check valve that easily passes solids and viscous fluids and can run dry without damaging the pump. Other key benefits of this series include a small footprint, easy installation, and simplified ongoing maintenance.
Advantages:
1. Low Shear — Microbubbles Stay Intact
AODD pumps are positive displacement pumps that operate with very low shear on the fluid. This is critical for DAF systems because:
- The dissolved air water contains numerous microbubbles used to lift flocs.
- High shear from centrifugal pumps can break bubbles, reducing flotation efficiency.
AODD pumps gently transfer fluid, helping preserve microbubble structure and maintain performance.
2. Strong Self-Priming & Dry Running Capability
In DAF applications, pumps often need to:
- Draw from tanks or sludge pits
- Start dry or run intermittently
AODD pumps offer excellent self-priming (4–6 m dry lift) and can run dry without damage.
Ideal for variable or intermittent conditions in DAF systems.
3. Capable of Handling Air-Liquid Mixtures
AODD pumps can transfer:
- Air-liquid mixtures
- Sludge with suspended solids
No need for degassing or separation systems.
Especially suitable for recycled water or scum discharge in DAF.
4. Energy-Efficient, Safe & Easy to Maintain
- Powered by compressed air — no electric motor
- Explosion-proof, ATEX-compliant
- Simple structure — easy maintenance
5. Corrosion-Resistant Materials Available
DAF systems often use chemicals like PAC, PAM, sodium hypochlorite. AODD pumps can be made of:
- PP, PVDF, SS316, (ALU, IRON) etc.
Ensures compatibility with aggressive or corrosive media.
Summary Table
| Feature | Benefit for DAF System |
|---|---|
| Low shear | Preserves microbubbles |
| Handles air-liquid flow | Ideal for dissolved air or scum |
| Self-priming & dry running | Handles variable conditions |
| Corrosion-resistant options | Withstands chemical additives |
| No electric motor | Safe, explosion-proof |
Application Suggestions
AODD pumps are highly recommended for the following in DAF systems:
- Dissolved air water recycling
- Chemical dosing
- Scum/sludge discharge
- Pre-treatment wastewater transfer
Products
- 2″ Flap Valve Pumps
- Compatible with Sandpiper
- Aluminum, 316 Stainless Steel
- Santoprene, Neoprene, Nitrile (Buna-N), PU, EPDM, Hytrel, FKM Viton …. diaphragms
- NPT, BSPT
- Capacity Flow: 790 lpm, 209 gpm
- Heads up to: 125 psi / 289 ft. of water
- Solids: 1.8 in. / 45 mm
- 1″, 3″, 4″ is available
If you need more information or request a manual, please contact us.
Email: ian@pumpfromchina.com WhatsAPP: +8617895103629
