english Shallow Air Flotation (SAF) Technology Overview
Shallow Air Flotation (SAF) is a highly effective wastewater treatment technology for removing suspended solids (SS), oils, and colloidal particles. Its SS removal efficiency typically ranges between 85% and 95%, depending on operational conditions, influent characteristics, and pretreatment methods.
Key Factors Influencing SS Removal Efficiency
SAF systems produce fine bubbles (20–100 µm), which enhance particle adhesion and flotation, improving SS removal.
Adding coagulants (e.g., alum, ferric chloride) or flocculants (polyacrylamide) can increase removal rates to 90–98% by forming larger, more floatable flocs.
A typical HRT of 5–15 minutes ensures sufficient contact between bubbles and particles.
Higher influent SS (e.g., 1,000–5,000 mg/L) may slightly reduce removal efficiency unless optimized with chemical aids.
An optimal 0.01–0.1 kg air/kg SS ensures effective flotation without excessive energy use.
Performance Comparison
- Without Chemicals: ~80–90% SS removal (for easily floatable particles).
- With Coagulants/Flocculants: ~90–98% SS removal (enhanced floc formation).
- Industrial Applications (e.g., food processing, pulp/paper): Consistently achieves >90% SS removal when properly optimized.
Advantages Over Conventional DAF
| Feature | Shallow Air Flotation (SAF) | Conventional DAF |
|---|---|---|
| Tank Depth | 0.4–0.6 m (shallow design) | 2–3 m (deeper tanks) |
| Separation Efficiency | Reduced turbulence improves separation | More prone to turbulence |
| Flotation Time | 3–5 minutes | 10–20 minutes |
| Flow Dynamics | Optimized for faster particle-bubble contact | Standard flow patterns |
