What Is the Core Principle of Air Flotation Equipment

Air flotation equipment is widely used in water treatment and solid - liquid separation processes. Its core principle revolves around the adhesion of air bubbles to suspended particles, enabling their separation from the liquid phase.

The first step in the operation of air flotation equipment involves the generation of tiny air bubbles. There are mainly two methods to produce these bubbles: dissolved air flotation (DAF) and dispersed air flotation (DAF - different from the previous abbreviation in operation). In DAF, air is dissolved in water under pressure. When the pressure is suddenly released, the dissolved air comes out of solution as fine bubbles. These bubbles range in size from about 20 - 100 micrometers. In dispersed air flotation, air is introduced into the liquid through mechanical means, such as turbines or porous diffusers, creating relatively larger bubbles.

Once the bubbles are formed, they attach to the suspended particles in the water. Particles that are hydrophobic, or water - repelling, have a natural tendency to adhere to the air bubbles. For hydrophilic particles, chemical coagulants and flocculants are often added. These chemicals react with the particles, changing their surface properties to make them more hydrophobic and more likely to attach to the bubbles.

The combined bubble - particle aggregates are less dense than the surrounding liquid. As a result, they float to the surface of the liquid, where they form a foam layer. This foam layer can then be skimmed off, effectively removing the suspended particles from the water. For example, in wastewater treatment plants, air flotation equipment can remove contaminants like oil droplets, suspended solids, and some biological matter. By understanding this core principle, operators can optimize the performance of air flotation equipment, enhancing the efficiency of water treatment and solid - liquid separation processes.