The Dissolved Air Flotation (DAF) system is a key technology for efficiently removing suspended solids, oils, and other contaminants from industrial wastewater. Its principle involves the use of dissolved air to separate pollutants from water, as detailed below:
- Dissolved Air Release and Mixing: Air is dissolved into water under pressure using blowers, creating a high-pressure saturated water solution. The saturated water is then released through a pressure-reducing device, forming tiny air bubbles. These bubbles attach to suspended solids, oils, and other pollutants, forming floatable flocs.
- Flotation Separation of Pollutants: The floatable flocs, with reduced density, rise to the surface, forming a scum layer that can be easily skimmed off. The treated clean water is discharged from the bottom to the next treatment stage.
- Scum Collection and Treatment: The scum is collected using mechanical skimmers and can be transported using sludge pumps to dewatering equipment such as screw presses, plate-and-frame filter presses, or belt filter presses for solid-liquid separation, reducing treatment costs.
Advantages:
- High Efficiency in Pollutant Removal: The DAF system excels at removing suspended solids (SS), fats, oils, and grease (FOG), and organic matter, significantly reducing the pollutant load in wastewater.
- Versatility in Treating Various Wastewater Types: It is effective for oily wastewater, food processing wastewater, and high-concentration organic wastewater, making it a versatile solution for various industries.
- Compatibility with Other Systems: The DAF system can integrate with other technologies, such as MBR (Membrane Bioreactor) systems for advanced treatment, or RO (Reverse Osmosis) and EDI (Electrodeionization) systems for water reuse and recovery.
- Low Maintenance Cost: With a simple design, stable operation, and easy maintenance, the DAF system is an ideal choice for cost-conscious businesses.
In the operation of the DAF system, auxiliary equipment plays a crucial role. For instance, blowers and aerators provide a stable air supply; PE tanks, fiberglass-reinforced plastic (FRP) tanks, and glass-fused-to-steel (GFS) tanks store treated water or scum. Scum can be transported to disposal facilities using sludge pumps, while the system’s chemical environment requires precise adjustment through PH/ORP controllers.
The DAF system, with its efficiency and flexibility, holds an irreplaceable position in industrial wastewater treatment. For businesses, investing in a DAF system not only ensures compliance with discharge standards but also reduces treatment costs. The demand for DAF systems in Thailand’s market is growing annually due to their effectiveness and economic benefits.