The Innovative CDOF Process: A Detailed Look at High-Efficiency Enclosed Pressurized Tank Ozone Catalytic Oxidation
Enclosed pressurized tank ozone catalytic oxidation
(1) CDOF(swirl dissolved-ozone flotation unit) is an innovative process that systematically integrates three technologies—advanced ozone oxidation, swirl separation and dissolved-air flotation—to achieve efficient comprehensive purification of various refractory wastewaters.
(2) Structure: adopts an enclosed pressurized vertical tank design, mainly comprising the main reaction tank, secondary reaction tank, jet ozone injection device, homogeneous/heterogeneous catalysts, pressure-reducing hydrodynamic cavitation device, tail-gas treatment unit and ozone generator.
(3) Process description: after pressurization, the wastewater enters the jet ozone injection device and is thoroughly mixed with the ozone-containing gas. Under the cutting action of the high-velocity water flow, the ozone gas is dispersed into a large number of microbubbles. The microbubble-rich wastewater is then rapidly re-pressurized, causing the ozone to dissolve quickly into the water. Undissolved oxygen microbubbles are further compressed into micro/nano bubbles and enter the main reaction tank.
Inside the tank, dissolved ozone contacts the catalyst and rapidly generates hydroxyl radicals (·OH), which react quickly with the organic pollutants in the wastewater (measured as COD), breaking macromolecular organics into small molecules that are ultimately converted into carbon dioxide and water. In this process, the micro/nano oxygen bubbles continuously scour and agitate the catalyst, which not only strengthens the contact reaction and raises the reaction rate between ozone and catalyst, but also effectively prevents catalyst caking and blockage. Meanwhile, the microbubbles adsorb and remove suspended solids, colloids and oils from the water, reducing non-dissolvable COD and lowering ozone consumption.
The wastewater treated in the main reaction tank is depressurized through the pressure-reducing hydrodynamic cavitation device, releasing a large number of microbubbles into the secondary reaction tank. Previously unreacted dissolved ozone precipitates out here, forming new microbubbles that continue contacting the catalyst for catalytic reaction and further reduce COD. The micro/nano bubbles also continue to remove residual non-dissolvable pollutants (such as oils, suspended solids and colloids), ensuring the final effluent meets the required quality before it is discharged to downstream processes.
To maintain catalyst activity and prevent blockage, CDOF the skid-mounted equipment features a periodic automatic backwash and activation program (about 1-2 times per week) and an acid-washing regeneration program (about once a month) to ensure long-term stable operation of the catalyst.
(4) Technical features:
Efficient reaction and low-consumption operation:Ozone is highly dispersed in the water in dissolved form and as micro/nano bubbles, giving fast ozone reaction rates and fully enhanced contact with the catalyst, with high ·OH conversion efficiency. Ozone consumption is only 1/4-1/3 of conventional systems and operating costs are only 1/3-1/4 of conventional ones.
Enclosed safety and environmental friendliness:The main reaction tank operates at 0.3-0.6 MPa and the secondary reaction tank at 0.03-0.1 MPa. With enclosed pressurized operation, there is zero ozone leakage, making the site environment friendly, safe and green.
Anti-clogging design and long-term stability:Floating-bed catalytic reaction means the catalyst is not prone to caking and blockage; combined with automatic backwashing, activation and regeneration procedures, the catalyst remains stable and effective over the long term, ensuring consistent treatment performance.
Intelligent control and easy operation:Fully automatic DCS/PLC control with intelligent automatic optimization and early-warning systems requires no manual intervention, making the equipment easy to operate and maintain, with high operational stability and safety.
Compact, efficient and quick to deploy:The reaction time is only 15 minutes—1/6 of conventional processes. The skid-mounted design features a small footprint, few auxiliary facilities and a short construction period.
