Dissolved Air Flotation System from CST Wastewater Solutions for Efficient Solids Separation

CST Wastewater Solutions has recently launched a new dissolved air flotation system based on the latest European technology. The dissolved air flotation system or DAF system finds application in dairy and cheese factories, paper industry, food industry, oil industry, wineries, tanneries, textile industry, large laundries, chemical industry, refineries, sludge thickening as well as primary and secondary clarification in municipal and industrial biological wastewater plants.

CST Wastewater Solutions has recently launched a new dissolved air flotation system based on the latest European technology.

The dissolved air flotation system or DAF system finds application in dairy and cheese factories, paper industry, food industry, oil industry, wineries, tanneries, textile industry, large laundries, chemical industry, refineries, sludge thickening as well as primary and secondary clarification in municipal and industrial biological wastewater plants.

The core of the dissolved air flotation system is a CST-supplied SAT air dissolving reactor, which generates the micro bubbles that separate and thicken the suspended solids.

Its unique double-injector air dispersal method results in exceptional air dissolving efficiency up to 90%.

The first stage of air dissolution up to a theoretical maximum saturation of 50% occurs in the high turbulence, high intensity mixing zone of the central tube inside the vessel.

The second stage where the additional 30-40% air dissolution takes place occurs in the larger volume of this vessel, where longer air-liquid contact provides a large exchange with very fine bubbles and a high exchange surface.

The CST SAT is also capable of improving the performance of existing flotation systems that employ low efficiency micro bubble generators.

The SAT air dissolving reactor operates automatically, requires no maintenance and has a unique non-clogging design.

Manufactured entirely from AISI 316 stainless steel, the SAT reactor is tested and certified to gas pressure vessel codes.

Raw wastewater and saturated recycle water is fed and uniformly distributed into a multifunctional central column in the dissolved air flotation system. The central column also collects the clarified water and thickened sludge.

Raw wastewater mixed with air saturated recycle water is introduced into the main body of the flotation tank through a series of openings located around the circumference of the lower part of the central column.

Solids are rapidly carried to the surface by the micro bubbles and evenly distributed as sludge on the surface of the flotation tank in a uniform hydrodynamic condition.

A rotating adjustable scroll scoop or surface skimmer removes the sludge float without disturbing the sludge blanket.

The DAF unit is designed by Aqua Engineering, which has built more than 400 wastewater treatment systems over a 30-year period.

Key features of the dissolved air flotation system from CST Wastewater Solutions:

High saturation efficiency > 90%
Complete dissolving of injected air
Automatic control of the injected air
Automatic control of the sludge blanket
Flexible operation: recycle, partial flow or full flow
No requirement for purging of excess air
Access and maintenance are facilitated by:
Low-head circular tank
Bottom sediment removal system
Continuous cleaning system for the inside wall
Inspection window for visual control of the flotation process

DAF systems available from CST Wastewater Solutions range in size from 1.48m to 15.40m in diameter and 1.00m to 2.58m in height.

Source: CST Wastewater Solutions