F

Flocc aggregate

Dissolved Air Flotation

Like tiny balloons the bubbles change the specific gravity of the flocc, making it less dense than the water, and lifting it upwards.

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Microbubbles injected into the DAF tank’s water glom onto the surfaces of flocc aggregates in the tank.

D

Clarified water

...leaving clarified water that's collected for additional treatment.

Microbubbles

Microbubbles injected into the water glom onto the flocc aggregate.

Sludge blanket

A

The floccs form a sludge blanket on the surface that is scraped off...

DISSOLVED AIR FLOTATION

Like tiny balloons the microbubbles change the specific gravity of the flocc —making it less dense than the water— and floating it upwards.

The floccs float upward forming a sludge blanket on the water’s surface.

The sludge is scraped off leaving clarified water that is sent for additional treatment, such as rapid sand filtration. NEXT: Inside DAF Tank

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To Filters

INFLUENT

Multiple DAF tanks can run in parallel in order to process large volumes of water.

AIR INJECTION

FLOTATION

INFLOW

Wastewater enters at one end of the DAF unit and exits at the opposite end after completing processing.

CLARIFIED WATER

Chlorination of NOM can lead to elevated levels of disinfectant byproduct precursors (DBPs), which has become a challenge for water treatment plants (WTPs) in recent years.

Adding DAF provides a new way for removal of NOM prior to chlorination, allowing facilities to meet their DBP challenges and produce higher quality water for their customers.

DAF tanks are subdivided into sections that treat water in specific ways. The three primary treatments are flocculation, air injection, and flotation.

OUTFLOW

SLUDGE

DAF is a high-rate water clarification process that removes particles and natural organic matter (NOM) from water.

Gentle mixing and adding coagulant sticks the particles and NOM together (where the particles collide with one another and form larger particles or flocc aggregates).

Rotating Scraper Blades

FLOCCULATION

Water, super-saturated with air, is injected to create micro- bubbles that float flocc aggregates to the surface, where they are scraped off. NEXT: DAF Animation