In many industrial processes, wastewater contains suspended solids, grease, and other contaminants that must be removed before discharge or further treatment. Technologies such as dissolved air flotation (DAF) are widely used in industrial wastewater treatment systems to separate solids from water and support compliant discharge.
Aerofloat designs and manufactures a range of proprietary DAF water treatment systems used across industrial wastewater treatment solutions, including applications in food production, manufacturing, and other sectors that generate trade waste.
One of these systems is the AeroCIRC DAF, a compact dissolved air flotation unit designed to remove solids and grease from wastewater after chemical treatment.
This video explains how the AeroCIRC system operates and how it forms part of a complete effluent treatment plant or trade waste system.
Aerofloat’s dissolved air flotation systems
Aerofloat has developed several proprietary dissolved air flotation systems used in industrial wastewater management.
These include:
- AeroDAF
- AeroCIRC DAF
- AeroVDAF
While each system has its own design characteristics, they all perform the same essential role in DAF system wastewater treatment.
Their purpose is to separate suspended solids, grease, and other contaminants from water. This separation step is critical in many wastewater treatment systems, particularly when treating industrial effluent before discharge or further processing.
Preparing wastewater before flotation
Before wastewater enters the AeroCIRC DAF, it typically undergoes several chemical treatment stages.
These stages include:
- pH adjustment in water treatment
- Coagulation
- Flocculation
These processes help bind small particles together into larger flocculated solids. Once these particles have formed, they can be removed more easily during the flotation stage.
After these treatment steps are completed, the wastewater enters the central mixing chamber inside the AeroCIRC DAF unit.
How dissolved air flotation removes solids
The key mechanism behind DAF flotation is the introduction of air bubbles that attach to suspended particles.
Inside the AeroCIRC system, a recirculation loop introduces compressed air into the wastewater stream. This process generates extremely small bubbles.
These bubbles attach to the flocculated particles created during coagulation and flocculation.
Once attached, the bubbles increase the buoyancy of the particles, allowing them to rise toward the surface of the tank.
As the bubbles lift the solids upward, a floating layer of solids forms on the surface of the flotation chamber.
This flotation process is widely used in industrial wastewater treatment, particularly where wastewater contains oils, grease, fats, or suspended solids.
Removing solids from the surface
Once solids reach the surface of the DAF water treatment unit, they must be removed to prevent them from reentering the treated water stream.
The AeroCIRC system uses a rotary scraper mounted at the top of the tank.
This scraper slowly rotates across the surface of the flotation chamber, pushing the floated solids toward the sludge collection point.
The collected solids are directed into the sludge chute where they exit the DAF unit.
From here, a mechanical diaphragm pump transfers the sludge to a sludge tank for storage and further handling within the treatment plant.
In many effluent treatment plants, sludge collected from DAF systems may later undergo dewatering or be processed in a sludge dewatering unit.
How treated water leaves the DAF system
While solids are removed at the surface, the clarified water exits the system from a different location.
The treated water flows from a low point within the DAF unit and rises over a weir, allowing the clarified water to leave the tank.
This treated water is then transferred to an effluent tank.
At this stage of treatment, much of the suspended solids and grease have been removed. Depending on the design of the overall wastewater treatment plant, the water may then be suitable for trade waste discharge to sewer or further treatment.
A self cleaning DAF design
One of the key features of the AeroCIRC system is its self cleaning design.
Traditional dissolved air flotation systems may require regular draining and cleaning to remove accumulated sludge or grease.
The AeroCIRC system is designed to reduce this maintenance requirement.
Many installations have operated for long periods without requiring internal cleaning. This is supported by a hot water solenoid system that periodically sprays hot water into the sludge chute.
This process helps keep the sludge chute and sludge beach clear and prevents material from building up inside the unit.
Managing grease and solids buildup
Even with a self cleaning design, some types of wastewater can create additional buildup within a treatment system.
Grease or residue may accumulate on the internal walls of the DAF tank depending on the characteristics of the wastewater.
In these situations, operators can simply hose down the internal surfaces of the unit to remove buildup.
Some wastewater streams also contain gritty solids that may pass through the system.
These characteristics depend heavily on the industry producing the wastewater and highlight why industrial wastewater treatment solutions must be designed specifically for each application.
Treatment outcomes depend on wastewater characteristics
Every wastewater stream is different.
Industries produce wastewater with varying levels of solids, grease, oils, chemicals, and other contaminants.
Because of this, the design of an effective industrial wastewater treatment system must take into account the specific characteristics of the wastewater being treated.
Systems such as the AeroCIRC dissolved air flotation unit play an important role within a larger wastewater treatment system, but overall treatment performance depends on the complete treatment plant design.
By tailoring system configuration and chemical treatment processes, water treatment plant companies such as Aerofloat are able to deliver reliable industrial wastewater treatment solutions that support compliant effluent management across many industries.
