CDOF Explained: One Skid for Multi-Catalytic Ozone Oxidation and Cyclonic Dissolved-Air Flotation

The CDOF (Cyclonic Dissolved Ozone Flotation) unit is a proprietary patented product of SINOKLE. It integrates advanced ozone oxidation, cyclonic separation and dissolved-air flotation technology into one machine, and it does so to attack several pollutant classes at once rather than in a train of separate vessels.

What Gets Integrated, Specifically

The technology stack is unusually deep for a single skid: ozone multi-catalytic oxidation (homogeneous plus heterogeneous) combined with cyclonic dissolved-air flotation, fully enclosed pressurized catalytic oxidation, supercritical catalytic oxidation, hydrodynamic cavitation catalysis and high-efficiency flocculation — multiple patented technologies working synergistically.

The design intent is compression in both senses: compression of the reaction into a pressurised vessel, and compression of the treatment train into a single skid. Pressurisation raises the driving force for ozone transfer into the liquid; skid-mounting removes most of the civil work that usually dominates a retrofit schedule. The unit is described as domestically original and internationally leading, and the claim that matters operationally is this: it can rapidly and efficiently remove petroleum, suspended solids, colloids, COD, bacteria and various other pollutants from wastewater in one pass.

Four Stages in Sequence

The working principle is a multi-stage, multi-dimensional, multi-catalytic oxidation reaction system:

• Ozone generation and dosing — the oxygen generation system produces high-purity oxygen, the ozone generator converts it to ozone, and the efficient dosing system mixes the ozone gas with the wastewater.
• Multi-catalytic oxidation — homogeneous and heterogeneous catalysts work in synergy to generate abundant hydroxyl radicals (OH) with an oxidation potential of 2.80 V, efficiently degrading organic matter.
• Cyclonic flotation separation — cyclonic centrifugal force and micro-nano bubbles work synergistically to rapidly separate and remove suspended solids, colloids and scum.
• Exhaust gas destruction and discharge — ozone-containing tail gas is treated by the tail-gas destructor to meet standards before discharge; the unit operates fully enclosed with zero leakage.

A typical process flow runs: influent wastewater, then CDFU for cyclonic de-oiling and SS removal, then the ozone generator for O2 to O3 conversion, then CDOF for catalytic oxidation flotation, then compliant discharge with COD and colour within limits.

Performance Headlines

The figures that define the unit:

• 99.98% ozone utilisation rate.
• Retention time <15min, against 90 min for traditional processes.
• Ozone dosing ratio 0.5~1.2, against 2-4 traditionally.
• Decolourisation rate 90%+.

The patented reactor structure improves efficiency by over 4x, and operating cost lands at only 1/3-1/2 of traditional processes. DCS/PLC systems precisely control ozone dosing, liquid level and pressure, automatically optimising based on water quality to reduce cost. The unit runs fully enclosed and pressurized with no ozone leakage, requires zero chemicals, and reduces sludge by over 90%.

Against Fenton Plus Flocculation Sedimentation

The head-to-head comparison is stark across eight dimensions:

• Treatment effect: slightly yellow effluent with unstable COD removal, versus colourless, odourless effluent with high and stable COD removal using CDFU+CDOF.
• Stability: complex operation and poor adaptability to water-quality fluctuations, versus fully automatic operation with real-time multi-parameter monitoring.
• Reaction rate: slow, needing >=60 min, versus high-efficiency at <=15 min.
• Treatment cost per ton: >=25 CNY/ton, versus <=15 CNY/ton.
• Sludge volume: 4kg/t, versus 0.1 kg/t — one fortieth.
• Decolourisation: poor and prone to re-colouration, versus thorough decolouration with no re-colouration.
• Safety and environment: exhaust gas leakage and high secondary-pollution risk, versus fully enclosed pressurized operation with zero leakage.
• Footprint: many tanks and a large footprint, versus a skid-mounted design.

The sludge line is the one that changes the project economics most. A fortieth of the sludge volume removes a disposal contract, a transport arrangement and a permitting conversation.

Against Traditional Catalytic Ozonation

Even measured against catalytic ozonation rather than Fenton, the gaps hold up:

• Principle: single catalyst or no catalyst, versus homogeneous plus heterogeneous plus supercritical cavitation plus cyclonic flotation multi-catalysis.
• Technology level: conventional, versus PCT international patent plus 2 invention patents.
• Retention time: 60~90min versus 10~15min — TOP.
• Footprint: large, versus only 1/5 of traditional.
• Catalyst stability: prone to clogging and scaling and almost ineffective long-term, versus fully automatic backwash activation and regeneration with long-term high efficiency — OK.
• Ozone utilisation: O3/COD at 1.5~4, versus O3/COD at 0.5-1.2, an improvement of 2-4x — TOP.
• Operating cost: high ozone dosing and high energy consumption, versus only 2/3 or even lower than traditional — OK.
• Safety and environment: atmospheric-pressure reaction with high ozone-leakage risk, versus enclosed pressurized operation with zero leakage.

The catalyst stability row is the one to interrogate during specification. Automatic backwash activation and regeneration is what turns a catalyst from a consumable into an asset, and it is precisely where traditional catalytic ozonation tends to decay.

Where CDOF Fits

Adopting the integrated patented technology of ozone multi-catalytic oxidation and cyclonic dissolved-air flotation, with 99.98% ozone utilization, retention time <15min (1/6 of traditional) and treatment cost per ton of water only 1/3~1/2 of traditional, with sludge reduced by over 90%, the unit is aimed squarely at advanced wastewater treatment and upgrading retrofits. Where land is tight, where sludge disposal is expensive, and where an enclosed process is preferred over an open tank farm, it is the configuration worth costing first. It is not, however, a universal substitute: streams with very high suspended solids still need removal ahead of the oxidation stage, which is exactly why the CDFU stage sits at the front of the flow.