What is the bubble generation principle of air flotation equipment

Air flotation equipment is widely used for solid - liquid separation in wastewater treatment and other industrial processes. The bubble - generation principle lies at the heart of its operation, enabling effective removal of suspended particles.

Dissolved Air Flotation (DAF)

One of the most common methods is Dissolved Air Flotation. In this process, air is dissolved in water under high pressure. Typically, water is pumped into a pressure vessel where compressed air is introduced. The high - pressure environment forces the air to dissolve in the water, forming a supersaturated solution. When this supersaturated water is released into the flotation tank at normal atmospheric pressure, the solubility of air decreases. As a result, tiny bubbles nucleate and grow. These bubbles attach to suspended particles in the wastewater. Since the combined density of the particle - bubble aggregate is less than that of water, they rise to the surface, where they can be skimmed off.

Induced Air Flotation (IAF)

Induced Air Flotation involves mechanical means to introduce air into the water. A rotating impeller or a propeller creates a low - pressure zone. Air is drawn into the water through this low - pressure area. As the impeller rotates, it shears the air into small bubbles. These bubbles are then dispersed throughout the liquid. The turbulence created by the impeller also helps in the collision of bubbles with suspended particles, promoting attachment.

Diffused Air Flotation (DAF - Alternative)

Diffused Air Flotation uses porous diffusers to release air into the water. Compressed air is passed through these diffusers, which break the air into small bubbles. The size of the bubbles depends on the porosity of the diffuser. Smaller pores produce smaller bubbles, which have a larger surface area and are more effective in particle attachment. These bubbles rise through the water column, carrying the suspended particles to the surface.

The precise control of bubble size is crucial. Smaller bubbles provide a larger surface area for particle attachment, improving the efficiency of the flotation process. By understanding these principles, operators can optimize air flotation equipment to achieve better separation results.