english DAF for Oil Removal from Sewage
The Dissolved Air Flotation (DAF) plant is highly effective in removing oil from sewage, leveraging its unique bubble attachment mechanism to achieve exceptional separation efficiency.
1. Oil Removal Mechanism
Bubble Formation Process
- Air dissolved under pressure into recycled water
- Pressure release creates microbubbles (10-100μm)
- Bubbles attach to oil droplets via hydrophobic interaction
Separation Efficiency
- Removes 90-95% of free oils
- Removes up to 85% of emulsified oils
- Oil droplet size range: 0.5-100μm
2. Industrial Performance
| Industry | Influent Oil (mg/L) | Effluent Oil (mg/L) | Removal Rate |
|---|---|---|---|
| Automotive | 500-2,000 | 15-20 | 95%+ |
| Petroleum | 1,000-5,000 | 10-30 | 97%+ |
| Food Processing | 200-800 | 5-15 | 96%+ |
Regulatory Compliance: DAF consistently achieves effluent oil concentrations below 20 mg/L, meeting strict discharge standards.
3. Process Enhancements
Chemical Conditioning
- Coagulants destabilize emulsified oils
- Flocculants promote oil droplet aggregation
- Improves bubble attachment efficiency
Operational Advantages
- Short retention time (10-30 minutes)
- Effective in cold climates (5-40°C)
- Handles high-viscosity oils
- Compact footprint
4. Industry Applications
| Application | Oil Type | Key Benefit |
|---|---|---|
| Petroleum Refineries | Crude oil residuals | High viscosity tolerance |
| Metal Finishing | Cutting oils, lubricants | Emulsion breaking |
| Food Processing | Vegetable/animal fats | High organic load handling |
| Marine Operations | Bilge oils | Salinity resistance |
Maintenance Advantage: Produces concentrated oil sludge (4-6% solids) for easier disposal compared to gravity systems.
