The High-Efficiency Dissolved Air Flotation (DAF) System is a precision solid-liquid separation device developed by our company, operating on the principle of pressure dissolved air. This innovative technology forcibly dissolves air into water under pressure, then releases it at atmospheric pressure to generate a large number of microbubbles. It effectively removes suspended solids, oils, algae, and colloidal substances with water-like density. As a mature separation technology, it provides a proven solution for improving effluent quality and recovering valuable substances in water treatment processes across multiple industries.
- Structure and Working Principle
- Core structural composition
The system is usually composed of pressure dissolved air system, air flotation separation tank, automatic control system and optional flocculation reaction system.
- Pressure dissolved air system: The core unit, including the dissolved air tank, pressurized dissolved air pump, air compressor, air inlet control valve, and dissolved air release device (or pressure relief valve). This system is designed to efficiently prepare saturated dissolved air water.
- The air flotation separation zone typically features a rectangular or circular tank with the following components:
- Contact zone: where dissolved air water mixes with raw water, microbubbles collide with flocs and adhere.
- Separation zone: Provides a stable environment for the flotation separation of the "flocculent-bubble" complex.
- The water collection area and slag discharge system are equipped with a water collection pipe at the bottom and a chain scraper or rotary skimmer at the top.
- Electrical control and dosing system (optional): An integrated control cabinet enables automatic operation; it can be paired with a dosing unit for adding coagulants/flocculants.
- Working Principle
- Aeration: A portion of the treated water (typically 20%-40% of the total treatment volume) is pumped into an aeration tank under pressure, while air is simultaneously injected using a compressor or ejector. At a pressure of 0.3-0.5 MPa, the air dissolves completely into the water, resulting in saturated aeration water.
- Release and Contact: Saturated dissolved air water enters the contact zone of the dissolved air flotation tank through a dedicated release device, where the pressure drops abruptly to atmospheric pressure. The dissolved air is released in the form of dense microbubbles with an average diameter of approximately 20-40 micrometers. These microbubbles instantly mix with the raw water (which has typically been treated with chemicals to form flocs).
- Attachment and detachment: Microbubbles combine with suspended particles (oil droplets, flocs, etc.) in wastewater through adsorption and bridging, forming a composite with an overall density lower than that of water.
- Flotation and removal: The complex rapidly rises to the surface under buoyancy, forming a scum layer that is removed by a skimmer. The separated clear water is discharged through the collection pipe at the bottom of the tank.
- The bubbles are fine and uniform with high capture efficiency. The bubbles produced by pressure dissolved air have small size, high density and large total surface area, which may help to improve the removal effect of fine particles and emulsified oil.
- The system has good stability: the mature pressure dissolved air and release technology makes the bubble generation stable and controllable, and the influent water fluctuation is relatively small, and the effluent water quality is relatively stable.
- Strong process adaptability: By adjusting dissolved air pressure, reflux ratio, and chemical dosing, the system can accommodate various influent water qualities and treatment requirements (e.g., oil removal, SS removal, or algaecide) within a defined range.
- The technology is mature and widely applied: As a classic physical-chemical separation technique, it has extensive application cases and practical experience across various industries, with its process reliability well-established.
- Main technical parameters
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Parameter item
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Description / Reference Range
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handling capacity
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Standard Series: 5-500 m³/h (Supports modular combinations and customization)
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aeration water reflux ratio
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Conventional design range: 20% -40%
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working pressure of dissolved air tank
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0.30 - 0.55 MPa
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surface load of separation zone
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Design reference range: 5-12 m³/(m²·h)
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Total stay time
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It usually takes about 15 to 30 minutes.
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Main material
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Carbon steel corrosion-resistant, stainless steel (SS304/316L)
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Core supporting
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gas dissolving tank, gas dissolving pump, air compressor, gas release device, slag scraper, electrical control cabinet
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- Typical Application Fields
This device is designed for various scenarios requiring efficient liquid-solid or liquid-liquid separation.
- industrial waste disposal ：
- Food, oil, and meat processing: Remove animal and vegetable oils as well as suspended organic matter.
- Papermaking: white water fiber recovery and wastewater pretreatment.
- Mechanical processing, electroplating, and coating: removal of metal hydroxides, suspended particles, and oils.
- Petroleum and coking: pretreatment of oily wastewater.
- Municipal and water treatment:
- The pretreatment of the primary sedimentation of sewage treatment plant or the deep treatment.
- The waterworks treated the reservoir water with high algae and low turbidity.
- Algae removal in seawater desalination pretreatment.
- Circulating cooling water system bypass treatment
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