Efficient Oil-Contaminated Wastewater Treatment with CDFU Cyclonic Dissolved-gas Flotation Technology
Oil-contaminated wastewater primarily contains pollutants such as floating oil, emulsified oil, dissolved oil, and suspended solids. Direct discharge can lead to issues such as eutrophication, ecological damage, and pipeline blockages. Traditional treatment technologies (such as gravity separation, standalone flotation, and biochemical treatment) have limitations including low oil removal efficiency (especially for emulsified and dissolved oils), weak resistance to shock loads, and long treatment cycles.
CDFU (Cyclonic Dissolved-gas Flotation Unit) technology, based on cyclonic-enhanced dissolved air flotation, achieves efficient oil separation through the combined effects of cyclonic shear and micro-bubble adsorption, providing an efficient solution for oil-contaminated wastewater treatment.
1. Cyclonic Dissolved-gas Flotation Unit Overview
Pre-treated wastewater enters the cyclonic dissolved air flotation tank, where pressurized dissolved-gas generates micro-bubbles with diameters of 5-30 μm. The centrifugal force created by the cyclone enhances the collision and adsorption of oil droplets with the bubbles, forming a gas-solid-liquid composite with a density lower than water. Under the combined effects of cyclonic shear and buoyancy, the oil droplets quickly rise to the surface, where they are skimmed off, achieving efficient oil-water separation.
2. CDFU Process Treatment Effect Analysis
(1) Oil Removal Efficiency: The overall oil removal rate of the CDFU process can reach 90%-95%.
(2) COD Removal Efficiency: The COD removal rate of the CDFU process can reach 30%-50%, and through optimization of cyclonic intensity and dissolved air parameters, the COD removal rate can be further improved.
(3) Removal of Suspended Solids and Other Pollutants: Suspended solid (SS) removal rates exceed 90%. Additionally, the CDFU process shows good removal efficiency for petroleum hydrocarbons, volatile phenols, and other characteristic pollutants, demonstrating its broad purification capability for complex oily wastewater.
3. Key Influencing Factors Optimization
· By adjusting dissolved-gas pressure and time, the bubble diameter distribution can be altered. Optimizing the cyclone speed strengthens the collision and coalescence of oil droplets, improving bubble adsorption efficiency.
· Adding coagulants (e.g., PAC) can enhance the aggregation of flocs and bubbles, further improving the separation efficiency of the cyclonic flotation process.
· An integrated intelligent control system, with online monitoring (e.g., oil content, COD sensors), allows real-time adjustments to process parameters.
4. Comparison with Traditional Processes
Compared to traditional flotation methods (oil removal rate of 70%-85%) and biochemical methods (treatment cycle >24 hours), the CDFU process offers the following advantages:
(1) High Oil Removal Efficiency: The combined effect of cyclonic shear and bubble adsorption enables efficient separation of emulsified and floating oils, with an oil removal rate of 90%-95%.
(2) Strong Shock Load Resistance: The process can handle fluctuations in influent oil content (±30%) while maintaining stable effluent quality.
(3) Shorter Treatment Cycle: The treatment cycle is only 1/5 to 1/10 of traditional biochemical methods.
5. Conclusion
In conclusion, the CDFU cyclonic dissolved-gas flotation process offers an efficient, stable, and low-cost solution for oil-contaminated wastewater treatment. It provides technical support for achieving compliant industrial wastewater discharge.
