The plastics recycling industry is one of the most important sectors in waste management and environmental protection. Given the globally increasing consumption of plastics, recycling these materials is not only an ecological necessity but also an economically sound endeavor. However, one of the biggest challenges in plastics recycling is the presence of fats, emulsions, and organic matter in the waste. These contaminants can reduce the quality of the final product, impair plant performance, and cause numerous problems in the production of extruded, molded, and granulated materials.

Many plastics recycling companies are therefore now relying on dissolved air flotation (DAF) de-oiling instead of conventional settling tanks or simple washing methods. DAF technology is one of the most common and effective methods for removing oil from water and plastic waste and contributes significantly to improving the quality of the final product.

This article analyzes the DAF degreaser for plastics recycling from a professional point of view and discusses its operating principle , its advantages, its importance in the recycling industry, and important aspects of its design.

What is DAF? And how does it work?

The acronym DAF stands for dissolved air flotation . The purpose of this process is the separation of fats, organic substances, emulsions, light suspended solids, microplastics and floating sediments from water streams or sewage sludge produced during plastic waste washing.

A brief overview of how DAF works:

First, wastewater containing fats, suspended solids or polymers enters the water tank.
Some of the water reaches saturation under the pressure of compressed air.
When the pressure drops, air is released in the form of tiny bubbles (microbubbles).
These bubbles adhere to fat molecules and light substances and transport them to the surface of the tank.
Oil and floating particles are collected with a surface scraper.
Clean water flows from the bottom of the tank and enters the next stage.

DAF technology is considered one of the most accurate and efficient methods for separating oils from process water, and its performance significantly surpasses that of simple sedimentation or conventional purification systems.

Why does the plastics recycling industry need a dissolved air flotation system?

In many plastic waste recycling facilities, the following materials are considered plastic waste:

Lesito
Packaging of dairy products
Sauces and food packaging
cosmetic packaging
oil-soaked nylon
Polyethylene and polypropylene contaminated with motor oil.
industrial waste

These waste materials typically contain high levels of fat, stable emulsions, and sticky organic matter . If the fats are not removed:

Decrease in particle quality
The result was a product with an unpleasant odor.
Problems such as burning, contamination, and bubbles can occur in the extruder.
The color of recycled materials fades over time.
The price has dropped.

The DAF system is an important step in waste degreasing to improve the final quality of recycled plastic.

Advantages of using the DAF system on plastic clotheslines

1. Improvement of the quality of the final particles.

Removal of fats and organic substances:

The color of the particles became lighter.
The smell is gone.
Improvement of extrusion quality
The likelihood of exporting finished products has increased.

2. Reduce the use of chemical products.

Many household appliances use highly alkaline cleaning agents for grease removal. DAF technology reduces the amount of these cleaning agents by up to 50% .

3. Increasing the productivity of dryers, mills and flotation machines.

Lubricants can cause malfunctions and blockages in automated systems. Removing the grease can have the following consequences:

Cleaning equipment
Increase production speed
Reduction of production line downtime
To prevent the formation of unpleasant odors in the factory environment.

4. Improving the efficiency of floating and underwater water tanks.

Grease can alter the density of a material and thus affect its buoyancy. Dissolved air flotation (DAF) technology enables the purification of wash water and achieves the following results:

Polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC) can be easily separated.
Reduction of environmental pollution.
Improving the effectiveness of teaching

5. Reduction of the costs for sewage sludge and wastewater treatment.

Sludge that formed at the outlets of a dissolved air flotation plant:

small size
High concentration
It is also waterproof.

Consequently, the costs of waste disposal are reduced.

The coagulation and flocculation process is used to purify water that accumulates in oil fields (an example of this is the Haram oil field).

Main components of the DAF system

The complete DAF system consists of the following components:

1. Main tank (floating tank)

A plant for the flotation and separation of oily and light substances.

2. Saturation pump

Mix water with compressed air and saturate by pressing.

3. Air compressor or blower

Air supply system.

4. Pressure regulating valve

It is used for real-time monitoring of tank pressure and for controlling bubble release.

5. Surface skimmer

Skim off the layer of fat that floats on the surface of the water.

6. Pure water storage tank

The wastewater produced during flotation is used, along with dissolved air, to clean the materials.

7. Chemical injection system (if required)

Electrolytic polymers (sintering agents)
Coagulants such as PAC.
Alkaline substances destroy emulsions.

What is the difference between a plastic waste flotation plant (DAF) and a degassing plant (DAF)?

Dissolved air flotation (DAF) technology is widely used in the food and industrial sectors for processing light fats and edible oils.
However, the following requirements must be met for this plastics recycling technology:

This helps to reduce excess fat.
Compatible with stabilized motor oil emulsions.
Antimicrobial
It is characterized by high speed and high computing power .
Materials that are resistant to acids and alkalis due to the use of detergents.

These differences have led to the development of specific models for the plastics recycling industry.

The process of grease cleaning in a closed production line using DAF technology.

Step 1: Sanding and pre-cleaning

Plastic parts are placed in a cleaning machine where grease is removed from their surface.

Step two: Separate the heavy object from the light one.

The separation of plastic materials takes place in flotation and settling tanks.

Step 3: Transfer the oil-water mixture into a dissolved air flotation device.

The water produced during these phases contains a high fat content.

Step four: Addition of chemicals (if necessary)

Split the fat emulsion.

Step 5: Release of dissolved air

Water bubbles carry oil to the surface .

Step six: Fat accumulation

Remove grease and floating particles with a ladle .

Step 7: Fill the clothesline with clean water.

This would allow for significant water savings .

Features of a standard DAF degreaser in a recirculating air system

1. The bubbles form in the correct order.

The amount of fat removed depends on the quality of the blisters.

2. Durable main construction material

Best variety:

thick polyethylene
Fiberglass
Stainless steel 304 or 316

3. Powerful and adjustable skimmer

4. Option to work around the clock.

5. Optimal energy consumption

6. Easy to clean and does not clog.

Economic advantages of applying dissolved air flotation technology in plastics recycling

1. Increase the value of the terminal particles.

Fat-free granules ≈ price increase:
The economic value of polypropylene and polyethylene materials increases significantly after grease removal.

2. Reduction of water consumption by up to 70 %

Because liquid waste is recycled.

3. Reduction of equipment maintenance costs.

4. Improvement of hygienic conditions in factories.

5. Avoid fines for environmental pollution .

Design capacity of the DAF plastics recycling plant

Production capacity typically depends on the following factors:

Water for washing clothes
Waste type
Fat content
Production line in Dubai
Air pollution level at the inlet

That’s obvious.

On average, small systems require 1 to 3 cubic meters of dissolved air per hour, while industrial systems require 5 to 30 cubic meters of dissolved air per hour .

Which is better: DAF degreaser or conventional degreaser ?

Special feature	normal degreaser	Daf
Ability to remove fat	A little	Very
Emulsion removal capability	practically nothing.	Very large
speed	A little	many
Wastewater quality	half	very good.
Suitable for plastic recycling.	NO	Yes

The results are clear:
DAF technology is the best industrial degreasing method in plastics processing plants.

Problems and possible solutions for DAF

1. The foam separator is clogged.

Solution: Regular cleaning + use of a filter at the water inlet.

2. Fluctuations in fat production levels.

Solution: Adjust the flow rate of the saturation pump.

3. Increased energy consumption

Solution: Use a high-efficiency compressor.

In conclusion

The DAF system (degreasing additive) for plastics processing is one of the most important systems in the recycling industry and significantly improves the quality of the final product. This system:

Grease and emulsion are completely removed.
The process water can be fully recycled.
The quality of the molecules and their economic value have improved.
The level of environmental pollution has decreased.
The plant’s operating costs were significantly reduced.

In short, a dissolved air flotation system is more than just a piece of equipment; it is a long-term investment for any plastics recycling plant.