DAF (Dissolved Air Flotation)
Mit Water manufactures dissolved air flotation (DAF) systems for removal of suspended solids, oil, grease and other low-density materials from water and wastewater. DAF is a proven clarification technology widely used in industrial pre-treatment and municipal applications where conventional sedimentation is less effective due to low-density or buoyant contaminants.
Working Principle
Pressurised water saturated with dissolved air is released into the DAF tank at atmospheric pressure through a pressure-reducing valve. The sudden pressure drop releases millions of microscopic air bubbles (20 to 80 microns) that attach to suspended particles, oil droplets and flocs, reducing their effective density and causing them to float to the surface. The resulting float sludge layer is skimmed off by a surface scraper while clarified water is collected from the bottom of the tank.
System Configuration
A complete DAF system includes a flotation tank, air saturation vessel, recycle pressurisation pump, air compressor, surface skimmer mechanism, chemical coagulation and flocculation tanks, and a PLC-based control panel. The system can be circular or rectangular in configuration and is constructed from SS304, SS316L or epoxy-coated carbon steel. A portion of treated effluent is recycled for air saturation.
DAF systems effectively treat a wide variety of water and wastewater streams:
- Food processing wastewater (dairy, meat, edible oil, beverage)
- Petroleum refinery and petrochemical oily wastewater
- Slaughterhouse and rendering plant wastewater
- Palm oil mill effluent (POME) treatment
- Paper and pulp mill whitewater and fibre recovery
- Algae removal from surface water and lagoons
- Metal finishing and plating wastewater pre-treatment
Technical Parameters
| Flow Rate | 1 to 500 m3/h per unit |
| Surface Loading Rate | 5 to 15 m3/m2/h |
| Recycle Ratio | 20% to 50% of inlet flow |
| Saturation Pressure | 4.0 to 6.0 bar |
| Tank Material | SS304, SS316L, or epoxy-coated carbon steel |
| TSS Removal | Up to 95% (with chemical pre-treatment) |
| Oil and Grease Removal | Up to 98% |
| Control System | PLC with level control and skimmer automation |