CDFU and CDOF Explained: What Two Patented Units Can Do for Hard Industrial Wastewater

Industrial wastewater rarely fails for a single reason. In petrochemicals, pharmaceuticals, metallurgy, oilfield extraction and landfill leachate treatment, the streams are complex in composition and carry large amounts of recalcitrant organics, dissolved oil and toxic substances. Traditional treatment routes tend to fail on one of three fronts: unstable results, high energy and material consumption, or sludge and secondary pollution that simply move the problem elsewhere. SINOKLE has built its technology matrix around two patented units that attack the problem from opposite directions.

Why the Traditional Path Stalls

Biological treatment needs biodegradable material. When hard-to-degrade organics dominate and dissolved oil is present, biology struggles and operators compensate with longer residence times and more chemicals. Physicochemical routes then generate sludge, and the sludge becomes the new cost centre. The high-carbon, high-consumption character of that model is difficult to defend on either financial or environmental grounds.

CDFU: Efficient Physical Separation

The CDFU (compact cyclonic dissolved gas flotation) unit is one of the core patented technologies from SINOKLE. It brings cyclonic centrifugal separation and dissolved gas flotation into a single vessel, so the treatment is purely physical.

High-speed cyclonic demulsification

Wastewater enters the unit tangentially and forms a stable cyclone. Under centrifugal force, micro-bubbles and emulsified oil droplets rapidly gather toward the centre, where they collide and merge. Oil-water separation efficiency rises accordingly.

Micro-nano bubble enhancement

The micro-nano bubbles generated by the system are only 5-30 μm in diameter. Their enormous specific surface area lets them adsorb tiny oil droplets and suspended particles efficiently and float them upward quickly.

Measured performance

Single-stage oil removal efficiency exceeds 90%, with good removal of oil droplets as small as 2 μm or below. No chemical agents are needed, which reduces sludge and secondary pollution at the source. Retention time is only 1-5 minutes, and the footprint is only 10% of traditional dissolved gas flotation.

CDOF: Deep Oxidative Degradation

CDOF (ozone advanced oxidation cyclonic flotation integrated unit) is another core patent from SINOKLE, aimed squarely at recalcitrant organic pollutants. It combines ozone advanced oxidation and flotation separation in one unit.

Ultra-fast catalytic oxidation

With a dedicated catalyst, ozone is converted efficiently into hydroxyl radicals (·OH). Oxidation efficiency rises several times over, and the process rapidly breaks chains and degrades macromolecular organic matter and polymers, which is precisely what biological methods handle poorly.

Synergistic deep treatment

Oxidation and flotation separation complete in the same vessel, so degradation and separation happen simultaneously. Retention time is short, under 15 minutes, and treatment is thorough.

Chaining the Two Units

The practical advantage lies in flexible combination according to water quality. For high-oil, high-emulsification wastewater, the usual arrangement is CDFU front-end oil removal followed by CDOF back-end oxidation. Where specific recalcitrant substances dominate, CDOF can be deployed directly for the hard task. This modular, customisable approach keeps the full chain from pretreatment through to compliant discharge or reuse both efficient and reliable.

What Makes the Units Credible

SINOKLE was founded in 2014 and has grown into a national high-tech enterprise with more than 30 patents, including 7 invention patents, 1 PCT international patent and multiple utility model patents. Research and development spans the full chain from reaction engineering and separation technology to intelligent control. That breadth is what allows CDFU and CDOF to be specified as a system rather than as isolated equipment.

Choosing Between Them

The decision usually comes down to two questions. How much of the problem is separable oil that can be lifted out physically, and how much is dissolved or recalcitrant material that needs chemical attack? CDFU handles the first question and removes the oil before it can burden the second stage. CDOF addresses the second. Used together in the right order, they reduce both the operating cost and the residual risk of the discharge, which is what makes the sequence worth designing carefully rather than buying off the shelf.

The Engineering Logic Behind the Pairing

Oxidation and separation are usually treated as separate disciplines, which is why they are usually paid for separately. Ozone oxidation needs contact time, and contact time needs tank volume. Flotation separation needs a quiescent zone, and a quiescent zone needs space. Combining them in a single vessel means the same volume serves both duties, and the oxidant attacks material that has already been concentrated rather than diluted through the whole stream.

That concentration effect is easy to underestimate. When oil is first removed physically, the residual organic load entering the oxidative step is both smaller and more uniform, so the ozone dosing ratio can be tuned to a narrow band instead of being sized for worst-case peaks. The savings compound across the operating year, particularly where electricity and oxygen supply make up a large share of the running budget.

There is also a reliability argument. Two smaller, purpose-built units with defined duties are easier to troubleshoot than one general-purpose unit asked to do both jobs. When performance drifts, the operator can see which duty has moved and adjust accordingly, rather than guessing at the cause.

Where the Approach Fits Best

Sites with high-emulsification oily streams and rising hazardous waste fees see the fastest return. Sites where dissolved or biologically resistant organics dominate the discharge limit benefit more from starting with the oxidative unit. In both cases, the practical step is to characterise the stream properly first, because the split between separable oil and dissolved load determines which unit leads the train.