DAF System Wastewater Treatment — How Dissolved Air Flotation Improves Industrial Effluent Quality
The DAF system wastewater treatment (Dissolved Air Flotation) is a highly efficient clarification technology used to remove oil, grease (FOG), suspended solids (TSS), and colloidal materials from industrial wastewater. Its compact design and impressive removal efficiency make DAF one of the most widely used technologies across industries such as food processing, hotels, palm oil mills, fisheries, textile, and manufacturing.
Industries in Indonesia increasingly rely on DAF systems to meet strict discharge requirements and improve the effectiveness of downstream treatment processes.
What Is a DAF System in Wastewater Treatment?
DAF stands for Dissolved Air Flotation, a proven method in wastewater treatment that removes oil, grease, suspended solids (TSS), and fine particles from industrial effluent. Thanks to its compact design and strong removal results, DAF is one of the most widely used technologies in industries such as food processing, hotels, palm oil mills, fisheries, textiles, and manufacturing.
A DAF system works by injecting microbubbles into wastewater. These bubbles attach to suspended particles such as oil, grease, solids, and sludge. Consequently, the particles float to the surface, where a skimmer removes them easily.
DAF is especially effective in industries with high FOG content. In such cases, sedimentation alone is not enough.
This process also works together with chemicals, such as our Special Coagulant. These chemicals neutralize the charge on particles before flotation, which allows higher efficiency.
How the DAF System Wastewater Treatment Works
The DAF wastewater treatment process follows four main stages:
1. Coagulation & Flocculation
First, operators add coagulants and flocculants to the water. These chemicals bond small particles together into larger, floatable flocs.
2. Air Saturation
Next, the system pressurizes part of the treated water and dissolves it with air.
3. Microbubble Release & Flotation
Third, when the pressure releases in the DAF tank, microbubbles (30–50 microns) form. These microbubbles attach to pollutants and lift them to the surface.
4. Skimming
Finally, a mechanical skimmer removes the floating sludge, while clear water exits at the bottom.
After DAF, RO systems often provide the final polish. You can read more about this in our article on Reverse Osmosis Cleaning Agent.
Why Industries Prefer DAF for Wastewater Treatment
DAF removes up to 90–95% of oil, grease, and suspended solids. In fact, that is a much better result than sedimentation tanks can deliver.
In addition, DAF units need far less space, so they suit hotels, resorts, and industrial estates.
Moreover, removing solids early reduces the load on aeration systems and membranes.
Furthermore, DAF has minimal moving parts and uses chemicals efficiently, which lowers operational costs.
Even better, DAF stays effective when wastewater quality changes between production cycles.
Industries that benefit most from DAF include:
- Food & beverage industries
- Hotels and resorts dealing with kitchen and laundry effluent
- Palm oil mills (POME pretreatment)
- Seafood processing plants
- Industrial parks & central WWTP facilities
- Textile and dyeing industries
Each application uses DAF to remove contaminant loads quickly before filtration or biological processes.
To support DAF performance, GLS also offers complementary chemicals and filtration products. For example, explore our Liqua-Zen Z468 collection for scale control and system optimization.
References
Researchers around the world have studied technologies like Dissolved Air Flotation. Authoritative references include:
- U.S. EPA guidance on Dissolved Air Flotation
- Water Environment Federation on industrial wastewater treatment
- WaterWorld magazine on DAF system applications
These sources discuss the principles, performance, and case studies of flotation systems across industries.
Conclusion
In summary, DAF is one of the most reliable and versatile technologies for industrial effluent treatment in Indonesia. It removes high concentrations of oil, grease, and solids, so it serves as a crucial pre-treatment step that improves overall plant performance.
With PT. Gapura Liqua Solutions (GLS), industries can implement tailored DAF systems. As a result, they gain compliance, lower operational costs, and stronger downstream processes.
Oil and grease: 90–99%; TSS: 80–95%; COD/BOD: 30–50% for the particulate fraction only. In contrast, soluble COD requires biological treatment after DAF.F systems that ensure compliance, lower operational costs, and enhance downstream processes.
Oil and grease: 90–99%; TSS: 80–95%; COD/BOD: 30–50% (particulate fraction only).Soluble COD needs biological treatment after DAF.
Surface loading rate 10–20 m³/m²·h (conventional) or 30–50 m³/m²·h (high-rate withlamella). Recycle ratio 15–30% of feed. GLS provides a free sizing calculator.
Standard DAF is limited to 40 °C because air solubility drops. For hot streams useinduced air flotation or cool the feed first. GLS designs heat-exchanger plus DAFpackages.
Coagulant (PAC/alum 20–100 ppm), flocculant (anionic polymer 0,5–2 ppm), and pHadjustment (6–8 optimum). Jar test is required; GLS includes it in the design package.
API relies on gravity with a large footprint and handles oil above 150 ppm. DAF usesmicro-bubbles, is 10× smaller, and removes emulsified oil at 50–150 ppm. GLS oftencombines API → DAF → polishing.