Dissolved Air Flotation Machine: Working Principle, Applications and Future Development Prospects

Dissolved air flotation (DAF) machines are water treatment devices that utilize the principle of air flotation to remove suspended solids, oil, and grease from water that are difficult to settle by gravity. They achieve solid-liquid separation through the following process:

Pressurization: Part or all of the water is pressurized and mixed with air, increasing the amount of dissolved air in the water.

Release: Upon pressure release, the air escapes from the water, forming a large number of tiny bubbles.

Attachment: These bubbles attach to the pollutants that have been previously flocculated using coagulants.

Flotation: Due to the buoyancy of the bubbles, the overall density of the flocculated matter becomes less than that of water, causing it to rise to the surface.

Scum Removal: Finally, a skimming device removes the flocculated matter floating on the surface.

Applications of Dissolved Air Flotation Machines

Dissolved air flotation machines are widely used in the water treatment industry, particularly effective in removing the following substances:

Suspended solids from various sources that are difficult to settle in wastewater

Oil and grease commonly found in industrial wastewater

Colloidal pollutants generated by industries like dyeing and papermaking

Advantages of Dissolved Air Flotation Machines

Dissolved air flotation machines offer several advantages in wastewater treatment:

Efficient Removal of Flocs: Effectively removes light flocs that traditional sedimentation tanks struggle to handle.

Broad Applicability: Suitable for treating various types of wastewater.

Simple Operation: Easy to operate and maintain.

Energy-Efficient and Environmentally Friendly: Low energy consumption and meets environmental requirements.

Future Development Prospects of Dissolved Air Flotation Machines

With increasing environmental awareness, water quality standards are becoming more stringent. Dissolved air flotation machines are expected to have even broader applications in the future.

Types of Dissolved Air Flotation Machines

Based on their structural design, DAF machines can be classified into three categories:

Horizontal DAF machines (also known as side-flow DAF machines): Simple structure, small footprint, suitable for treating wastewater with small flow rates.

Upflow DAF machines: Large treatment capacity, high efficiency, suitable for treating wastewater with large flow rates.

Hybrid DAF machines: Combine the advantages of side-flow and upflow DAF machines, compact structure, high efficiency, small footprint.

Key Parameters of Dissolved Air Flotation Machines

The main parameters of DAF machines include:

Air Dissolution Volume: The maximum amount of air that can be dissolved in the dissolution tank per hour, measured in m³/h. Air dissolution volume affects the number of bubbles and consequently the flotation effect.

Bubble Diameter: The average particle size of bubbles, measured in μm. Smaller bubble diameters increase the contact area between bubbles and pollutants, enhancing the flotation effect. Generally, bubble diameters should be controlled below 50μm.

Coagulant Dosage: The amount of coagulant added to promote flocculation, measured in mg/L. Coagulant dosage should be determined based on the wastewater characteristics and water quality requirements.

Retention Time: The time wastewater spends in the DAF tank, measured in min. Longer retention times allow for more contact between bubbles and pollutants, improving the flotation effect. Typically, retention times should range from 10 to 20 min.

Operation and Maintenance of Dissolved Air Flotation Machines

Routine operation and maintenance of DAF machines involve:

Regular Inspection: Regularly check all components of the DAF machine for integrity, secure connections, and proper operation.

Cleaning: Regularly clean the dissolution tank, DAF tank, skimming device, and other components of the DAF machine to prevent the accumulation of dirt that could impair equipment performance.

Lubrication: Regularly lubricate the rotating parts of the DAF machine to reduce wear and tear.

As a plastic product manufacturer, we can produce various plastic components required for DAF machines, such as:

Dissolution tanks

Mixers

Skimming devices

By providing high-quality plastic components, you can contribute to the advancement of the water treatment industry.