Dissolved Air Flotation

DAF Unit for Industrial and Municipal Wastewater treatment

Dissolved Air Flotation
Dissolved Air Flotation
Dissolved Air Flotation


dissolved air flotation (DAF) A flotation machine is a wastewater treatment system that purifies wastewater (or other water) by removing suspended matter such as oil or solids.


Widely used in machinery, chemical industry, light textile, transportation, food and other industries, especially suitable for the treatment of oilfield drilling sewage, oilfield reinjection water, and oil refinery sewage.

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Working Princple

Schematic diagram of the interaction between bubbles and flocs

How it works: In a DAF unit, millions of tiny air bubbles are released from the air sparger, allowing flocculent particles to attach and float on the surface of the water.

Air is dissolved under pressure in a clean liquid, usually the effluent recovered from a DAF unit, which is then injected into the original feed stream. Upon entering the DAF unit, the air pressure is released and combined with the liquid, which becomes supersaturated and filled with micron-sized air bubbles.

The suspended matter attaches to the air bubbles, making the specific gravity of the clumps (floc) lower than that of water, thereby effectively lifting the suspended particles to the liquid surface, forming a floating sludge layer, which is periodically removed by the skimmer into the sludge tank . The clarified water flows to the bottom of the flotation cell and then to the effluent control weir for treatment or reuse.

Working principle diagram of dissolved air flotation machine







Platform width(mm)

Recovery flow

QY-DAF-5 5350010001700


QY-DAF-10 10
QY-DAF-15 155000150020002000
QY-DAF-20 205000180020002000
QY-DAF-30 306000200021002100
QY-DAF-40 407000220021002100
QY-DAF-50 507000270021002100
QY-DAF-70 709000300021002100
QY-DAF-100 10010500360021002100


*To improve our system, dimensions are subject to change without notice

*Flow rates are based on a typical rate of ascent of 6m/h. Depending on the type of wastewater, the rate of rise varies from 4 - 8m3/m2.

*Recovery flow will vary depending on the type of wastewater, the concentration or suspended solids level in the wastewater, and the desired effluent quality at the outlet of the DAF unit.

Engineering case

Dissolved air flotation machine installation project case