PaperPure DAF System for Pulp & Paper Mill Effluent

Dissolved air flotation description

Dissolved air flotation is a water treatment process that clarifies wastewater by removal of suspended solids, oils, greases, BOD, COD, and metals. This is achieved by dissolving air in the wastewater under pressure and then releasing the air at atmospheric pressure in a flotation tank. The released air forms tiny bubbles which adhere to the suspended matter causing it to float to the surface of the water where it can then be removed by a skimming device, ready to dewater for proper disposal. To improve solids removal coagulant/flocculants are added to coax suspended solids and colloidal particles into clumping together.

Dissolved air flotation principle

DAF systems depend on fairly simple but sensitive control to allow for maximum removal of pollutants from the inlet flow. In the main tank, water level and recycle flow are the key parameters that determine removal efficiency. Pump operation requires a suitable air flow, pressure, and recycle flow for maximum air saturation of the recycled water flow.

The main tank level is controlled by the rates of outflow and recycle flow. This requires finetuning to ensure that, if the recycle flow rate changes, so does the effluent flow rate (i.e. higher recycle requires lower outflow and vice versa). Usually the pump control system is in charge of the recycle flow, which means the effluent outflow needs to be controlled separately or linked to the pump system control.

Dissolved air flotation technical sheet

Dissolved air flotation process flow

Dissolved air flotation advantage

DAF technology boasts an impressive removal efficiency, often exceeding 90% for suspended solids. This makes it a robust choice for industrial and municipal applications where high cleanliness standards are required. Additionally, its ability to adapt to varying wastewater characteristics ensures reliable performance across different scenarios.

The compact design of DAF units is another significant advantage. Compared to traditional gravity clarification, DAF systems take up less space, making them suitable for facilities with limited footprints. The ability to handle bulking solids and produce higher sludge solids content further distinguishes DAF technology in wastewater treatment.

Moreover, the multitude of applications, ranging from oil and grease removal to biosolids thickening, underlines the flexibility of DAF units. They prove effective in various treatment goals such as product recovery, pretreatment for sewer discharge limits, and polishing of biological treatment effluent.

Dissolved air flotation feature

The environmental impact of DAF systems is generally positive, particularly in minimizing water pollution. By enabling the removal of over 90% of harmful components from industrial effluents, DAF systems contribute to cleaner water bodies and reduced environmental pollution. Moreover, reduced chemical usage and advancements in energy-efficient designs further enhance the sustainability of DAF technology.

Dissolved air flotation application

Make-up water clarification
Wastewater treatment End-of-pipe (EOP) treatment
Cooling water clarification
Caster spray water clarification
Rolling mill contact water clarification

Contact Us for a Consultation

• Company: Wuxi Dajiang Environmental Technology Co., Ltd.  DAGYEE
• Phone/WhatsApp:+8613961861780
• Email: info@dagyee.com
• Website: www.dagyee.com