M-DAF (Michigan Dissolved Air Flotation)
Brief Description of M-DAF
DAF uses dissolved air for producing micro and/or nano bubbles. Air and water are compressed into a confined container at the same time, of which name is ADT, Air Dissolving Tank, or Air saturator in 4~6Kg/cm2. Generated micro bubbles separate SS, oil mater, surfactants, flocs, and algae from water by flotation.
DAF uses dissolved air for producing micro and/or nano bubbles. Air and water are compressed into a confined container at the same time, of which name is ADT, Air Dissolving Tank, or Air saturator. Compressed air is dissolved in water within a confined container. When saturated water by air is released in a flotation column under the atmospheric pressure, numerous micro or nano bubbles are generated. Volume of over saturated air is precipitated into micro or nano bubbles by the same volume as over saturation. Generated micro bubbles separate floated flocs which contain SS, oil mater, surfactants, flocs, and algae from water by flotation.
[Process Diagram, P&ID]
Core Technologies of M-DAF
Air saturated water of 98% is produced in the vertical saturator where part of effluent of M-DAF is effectively contacted with air. This air saturated water is sent to the micro and/or nano bubble generating system, where the optimum sizes of bubbles are generated.
Micro and/or nano bubble generating system which is developed by Michigan Technology generates uniform size of micro/nano bubbles without macro-bubbles. This generated micro/nano bubbles combine with flocs produced in flocculated basin, maximizes removal rate of floc.
A motor rotating in one direction, and reciprocating motion of blade removes floated sludge effectively without trouble or breakdown. Moving speed of the blade may be controlled depending on the accumulated floating sludge.
Advantages of Core Technologies of the M-DAF system
Saturation rate of air in ADT (Air Dissolving Tank) is maximized using the Michigan ADT.
Contact efficiency between flocs and uniformly generated micro/nano bubbles was maximized, and removal rate of floc was maximized.
Bubble density is maximized in flotation basin, which maximizes removal rate of flocs, and minimizes settling of flocs in flotation basin.
- Coagulation and flocculation, and flotation are completed in one unit.
- The whole M-DAF system is fully automated by the PLC control system.
- Quick response for the trouble shooting by accumulated experiences.
- Water content in removed sludge was lowered below 98%, and reduced sludge treatment cost.
- Footprint of the DAF site is minimized by reducing hydraulic retention time to 20~30minutes.
- Lowered electric power by setting a high rate of invertor in the flocculation mixing motor and in the pressure pump.