What is a Shallow Dissolved Air Flotation

Solid Liquid Separator September 14, 2024 Dissolved Air Flotation

The high-efficiency shallow dissolved air flotation unit integrates coagulation, air flotation, skimming, sedimentation, and sludge scraping into one system. It is cylindrical, compact in structure, and has a shallow tank, making it suitable for wastewater treatment of more than 1,000 cubic meters.

The unit consists of five main parts: the tank, rotating water distribution mechanism, dissolved air release mechanism, frame structure, and water collection mechanism. The inlet, outlet, and scum discharge ports are all located in the central area of the tank.

The water distribution mechanism, water collection mechanism, and dissolved air release mechanism are tightly connected to the frame and rotate around the center of the tank. This unit provides a complete set of equipment and control systems, utilizing both centralized and decentralized control to achieve optimal performance.

Precautions During Use

Inflow Water Volume: After selecting the DAF model, a flow meter should be installed at the inlet to set the correct chemical dosing ratio and manage the water load.
Inflow pH: The pH of the wastewater entering the DAF system should be controlled between 7-8. When the pH is below 6.5, the effect of the flocculant decreases significantly, impacting the separation of suspended solids in the release zone. A pH that is too high increases operational costs and negatively affects downstream biological processes.
Chemical Dosing: The concentration of coagulant added varies depending on the wastewater. Overdosing or underdosing will affect wastewater treatment results. Suitable dosing amounts can be determined based on on-site pilot testing.
Dissolved Air Pressure: The formation of dense micro-bubbles is optimal at a pressure of 0.4-0.5 Mpa.
Releaser Types: There are TS, TJ, and TV types of releasers. It is recommended to use the TV type to overcome issues with uneven water distribution and releaser clogging.
Regular Sludge Removal: It is advised to regularly discharge and clean the sludge to prevent high suspended solids in the effluent.
Discharge Gate Valve: Control the water output to match the skimmer blade level. If the level in the skimming area is too low, the blade won't reach the scum. If the level is too high, the dewatered sludge will have high moisture content. If excessive suspended solids are present, consider adding an additional skimmer blade.