Slashing O&M Costs by 50%: How SINOKLE’s Patented CDOF Technology Solves Refinery Wastewater COD and Membrane Fouling Crisis

In the petroleum refining and petrochemical industry, wastewater treatment is a critical link to achieving green, low-carbon development, as well as one of the core challenges enterprises face. As global environmental standards become increasingly strict, refining wastewater presents two prominent technical pain points due to its complex composition and high concentration of refractory organic matter (such as aromatics, phenols, and petroleum hydrocarbons): the difficulty of stabilizing Chemical Oxygen Demand (COD) compliance, and the severe fouling of subsequent membrane systems, which drives up operation and maintenance (O&M) costs. Traditional processes often rely on heavy chemical dosing, which not only incurs high operating expenses but can also cause secondary pollution.

As a leader in environmental governance technology and equipment, Shenzhen Clear Science & Technology Co., Ltd (SINOKLE) is driven by its mission to solve industry challenges through technological innovation. The company's independently developed CDOF - Ozone Catalytic Oxidation - Cyclonic Dissolved Gas Flotation Integrated Device is a powerful tool designed to directly eliminate these pain points. This technology creatively integrates advanced ozone oxidation with high-efficiency physical separation, opening a highly efficient, economical, green, and intelligent new pathway for the advanced treatment and resource reuse of refinery wastewater.

I. The Dilemma of Traditional Processes: High Costs, Low Efficiency, and Secondary Pollution

Traditional advanced treatment of refinery wastewater usually employs a combined process of "Biochemical Treatment + Fenton Oxidation + Membrane Filtration." However, this system possesses clear limitations:

· Fenton Oxidation: Although it can degrade a portion of organic matter, it requires dosing large amounts of iron salts and hydrogen peroxide. This generates massive quantities of iron-containing sludge (hazardous waste), leading to high disposal costs, while chemical residues can negatively impact downstream membrane systems.

· Ozone Oxidation: Traditional ozone contact reaction towers require long hydraulic retention times (typically over 90 minutes), resulting in low ozone utilization and high dosing ratios (the O₃/COD weight ratio is usually between 2 and 4). This keeps energy consumption and operating expenses high.

· Membrane System Bottlenecks: Colloids, emulsified oils, and macromolecular organic matter that have not been completely broken down can easily cause irreversible fouling and clogging of ultrafiltration (UF) and reverse osmosis (RO) membranes. This shortens membrane lifespan, necessitates frequent cleaning, and decreases water yield—becoming the Achilles' heel of stable system operations.

II. SINOKLE’s CDOF Process: A Synergistic Revolution of Advanced Oxidation and High-Efficiency Separation

The core of SINOKLE’s CDOF technology lies in its systematic innovation. Rather than a single equipment upgrade, it utilizes a patented structural design to integrate ozone multiple catalytic oxidation technology, cyclone dissolved gas flotation technology, and high-efficiency coagulation into a single, closed, pressurized reactor.

1. Efficient Degradation of Refractory COD: Advanced Oxidation Based on Hydroxyl Radicals

The CDOF device delivers powerful oxidation capabilities, substantially boosting ozone utilization and oxidation efficiency through the following mechanisms:

· Synergy of Homogeneous and Heterogeneous Catalysis: The system simultaneously utilizes a liquid homogeneous catalyst and a patented reactor loaded with solid heterogeneous catalysts. The catalysts efficiently trigger ozone decomposition to generate hydroxyl radicals (·OH, with an oxidation potential of 2.80V) possessing extreme oxidation capabilities. Its oxidation efficiency is 2 to 5 times higher than that of traditional ozone oxidation.

· Mass Transfer Enhanced by Micro-Bubbles: Utilizing patented high-efficiency jet aeration technology, ozone gas is sheared into micro-nano bubbles. This dramatically increases the gas-liquid contact area, allowing ozone to rapidly dissolve and disperse in the water to react fully with pollutants.

· Cyclonic Fluidized Reaction: The specialized cyclonic design inside the reactor keeps the catalyst in a fluidized state. This causes violent collisions and mixing among the catalyst, micro-bubbles, and pollutants, which significantly enhances the mass transfer process. The reaction rate is exceptionally fast, reducing the effective hydraulic retention time to < 15 minutes. The footprint of the device is reduced by approximately 70% compared to traditional ozone towers.

2. Guarding Membrane Systems: A Purely Physical Separation Pre-Barrier

While performing highly efficient oxidation, the integrated cyclone dissolved gas flotation unit plays a vital role:

· Simultaneous Separation: During the oxidation reaction, generated intermediate products, demulsified oil droplets, suspended solids, and colloids are rapidly carried to the water surface by the combined forces of cyclonic centrifugation and the buoyancy of a massive volume of micro-bubbles, forming a scum layer that is promptly removed.

· Reducing Membrane Load: This "simultaneous oxidation and separation" model fundamentally improves the water quality entering downstream membrane systems. With extremely low levels of suspended solids and colloids, it mitigates the risk and frequency of membrane fouling at the source, effectively extending membrane service life.

3. Intelligent and Green: Radical Reductions in Operating Costs

· Precise Intelligent Control: Utilizing a fully automated DCS/PLC control system, the unit monitors parameters such as off-gas ozone concentration and effluent ORP in real time. This feedback allows for the precise regulation of ozone dosing, optimizing ozone consumption while ensuring stable COD compliance. Its ozone utilization rate exceeds 99.98%, and the ozone dosing ratio (O₃/COD) can be lowered to 0.5-1.2, reducing operating costs to just 1/3 to 1/2 of traditional ozone oxidation technologies.

· Eco-Friendly Operations: The entire process operates with nearly "zero chemical dosing" (requiring only a trace amount of catalyst). This eliminates the generation of large volumes of chemical sludge typically caused by flocculants, reducing sludge volume by more than 90% and achieving true pollution and carbon reduction.

III. Proven Performance: Data from Benchmark Projects

Taking the Chinese market as an example, SINOKLE’s CDOF technology has been successfully deployed across multiple large-scale refining and chemical enterprises, including Sinopec and PetroChina. Its excellent performance has been thoroughly validated under complex, real-world operating conditions.

IV. Beyond Treatment: Reshaping the Value Dimensions of Refining Wastewater Management

The value of SINOKLE’s CDOF ozone catalytic oxidation technology extends far beyond a standard wastewater treatment process upgrade; it represents a strategic investment oriented toward the sustainable future of the refining and chemical sector.

· Economic Value: Through an exceptionally high ozone utilization rate and intelligent controls, it directly cuts chemical costs and energy consumption. By protecting downstream membrane systems, it indirectly saves on expensive membrane replacement fees and frequent cleaning maintenance costs, offering a prominent lifecycle cost advantage.

· Operational Value: The device features a modular, skid-mounted design with high automation. It supports unmanned operations, significantly reducing labor intensity and safety risks while enhancing the convenience and reliability of production management.

· Environmental and Social Value: By utilizing green chemistry, the technology minimizes hazardous waste generation and secondary pollution. This helps enterprises achieve deeper pollutant reductions, fulfill environmental responsibilities, and build a green corporate image aligned with global "Net-Zero" strategic targets.

V. Conclusion

In the face of industry-wide challenges where refinery wastewater exhibits hard-to-degrade COD and causes frequent membrane fouling, SINOKLE's CDOF technology provides a comprehensive solution featuring high-efficiency oxidation, high-efficiency separation, intelligent control, and a low-carbon footprint. It not only overcomes deep technical bottlenecks but has also proven its dual value in boosting environmental performance and economic returns through the long-term, stable operation of multiple benchmark projects.