Classification of dissolved air flotation


Time:

2022-10-21

Dissolved air flotation (DAF) is applicable to the treatment of water with low turbidity, high color, high organic content, low oil content, low surfactant content or algae rich water. Compared with other air flotation methods, it has the advantages of high hydraulic load, compact tank, etc. However, its application is limited by its complex process, large power consumption, and loud noise of air compressor.

Dissolved air flotation (DAF) is applicable to the treatment of water with low turbidity, high color, high organic content, low oil content, low surfactant content or algae rich water. Compared with other air flotation methods, it has the advantages of high hydraulic load, compact tank, etc. However, its application is limited by its complex process, large power consumption, and loud noise of air compressor.
According to different classification principles, DAF can have different classifications.
1. According to the different pressures at which bubbles separate from water, they can be divided into vacuum air flotation and pressure dissolved air flotation.
The former uses vacuum method to dissolve air under normal pressure or pressure, and then releases microbubbles under negative pressure for air flotation; The latter is to force the air to dissolve in the water under pressure, and then suddenly reduce the pressure to release the dissolved gas from the water, adhere the flocs in the form of microbubbles, and float together.
2. Although the energy consumption of vacuum air flotation tank is low, the bubble formation and the adhesion between bubbles and flocs are relatively stable; However, the amount of bubbles released is limited; Moreover, all equipment parts shall be sealed in the air flotation tank; The structure of air flotation tank is complex; It is only applicable to the treatment of wastewater with low pollutant concentration (no more than 300mg/l), so there are few practical applications.
3. Pressure dissolved air flotation is a method commonly used at home and abroad at present, and three basic processes can be selected: full process dissolved air flotation, partial dissolved air flotation and partial reflux dissolved air flotation.