CDOF Ozone Catalytic Oxidation Technology: Overcoming the Dual Challenges of Excessive COD and Membrane Fouling in Refinery Wastewater
In the refining and petrochemical industry, wastewater treatment is a key link in achieving green and low-carbon development and one of the core challenges facing enterprises. As environmental standards become increasingly stringent, refinery wastewater - because of its complex composition and high content of refractory organics (such as aromatic hydrocarbons, phenols, and petroleum substances) - commonly suffers from two major technical pain points: chemical oxygen demand (COD) is difficult to keep consistently compliant, and the downstream membrane system is prone to fouling with high O&M costs. Traditional processes often rely on treating water with chemicals, which not only incurs high operating costs but may also cause secondary pollution.
As a leader in environmental governance technology and equipment, Shenzhen SINOKLE Technology shoulders the mission of solving industry problems through technological innovation. The company's independently developed CDOFintegrated ozone advanced catalytic oxidation and swirl dissolved air flotation unit is precisely a powerful tool that targets the above pain points. This technology creatively combines ozone advanced oxidation with high-efficiency physical separation, opening up a new path that is efficient, economical, green, and intelligent for advanced refinery wastewater treatment and resource reuse.
1. The Dilemma of Traditional Processes: High Cost, Low Efficiency, and Secondary Pollution
Traditional advanced refinery wastewater treatment often adopts the combined process of biological treatment + Fenton oxidation + membrane filtration. However, this system has obvious limitations:
Fenton oxidation: Although it can degrade some organics, it requires large amounts of iron salts and hydrogen peroxide, generating huge quantities of iron-containing sludge (hazardous waste), with high treatment costs; moreover, residual chemicals may affect the downstream membrane system.
Ozone oxidation: Traditional ozone contact reaction towers require long residence times (usually more than 90 minutes) and have low ozone utilization and a high dosing ratio (the O3/COD weight ratio is usually between 2 and 4), resulting in persistently high energy consumption and operating costs.
Membrane system bottleneck: Colloids, emulsified oil, and macromolecular organics that have not been thoroughly cracked readily cause irreversible fouling and blockage of ultrafiltration and reverse osmosis membranes, shortening membrane life, requiring frequent cleaning, and reducing water production - the Achilles' heel of stable operation.
2. SINOKLE's CDOF Process: A Synergistic Revolution of Advanced Oxidation and High-Efficiency Separation
SINOKLE's CDOF technology lies in its systematic innovation. It is not an improvement of a single piece of equipment; rather, through a patented structural design it integrates multi-stage ozone catalytic oxidation, swirl dissolved air flotation, and high-efficiency coagulation into one sealed, pressurized reactor,
1. Efficiently Cracking Refractory COD: Advanced Oxidation Based on Hydroxyl Radicals
CDOFThe core of the unit is its powerful oxidizing capability. It greatly improves ozone utilization and oxidation efficiency through the following mechanisms:
Synergy of homogeneous and heterogeneous catalysis: The system simultaneously doses a liquid homogeneous catalyst and a patented reactor loaded with a solid heterogeneous catalyst. The catalyst efficiently catalyzes the decomposition of ozone to produce hydroxyl radicals (OH, oxidation potential 2.80 V) with extremely strong oxidizing power, raising oxidation efficiency by 2-5 times compared with traditional ozone oxidation.
Ultra-fine bubbles enhance mass transfer: Using a patented high-efficiency jet aeration technology, ozone gas is cut into ultra-fine bubbles, greatly increasing the gas-liquid contact area so that ozone dissolves rapidly, disperses in the water, and fully reacts with pollutants.
Swirl fluidized reaction: The special swirl design inside the reactor keeps the catalyst in a fluidized state, causing violent collision and mixing with ultra-fine bubbles and pollutants. This strengthens mass transfer, makes the reaction extremely fast, and shortens the effective residence time to within 15 minutes.
A strong swirl forms inside the reactor so that the catalyst, pollutants, and ozone micro-bubbles fully mix and collide, giving extremely high mass-transfer efficiency; the hydraulic residence time is shortened to within 15 minutes, and compared with a traditional ozone tower the unit volume is reduced by about 70%.
2. Safeguarding the Membrane System: A Pure-Physical Separation Upstream Barrier
CDOF technology, while performing efficient oxidation, has its integrated swirl dissolved air flotation unit playing a vital role:
Simultaneous separation: During the oxidation reaction, the intermediate products generated, the demulsified oil droplets, suspended solids, and colloids are quickly carried to the water surface by the swirling centrifugal force and the buoyancy of numerous ultra-fine bubbles, forming scum that is removed.
Reducing membrane load: This oxidize-while-separating mode fundamentally improves the water quality entering the downstream membrane system, with extremely low suspended solids and colloid content, significantly reducing the risk and frequency of membrane fouling at the source and effectively extending membrane service life.
3. Intelligence and Greenness: A Fundamental Reduction in Operating Costs
Precise intelligent control: adopting a DCS/PLC fully automatic control system that monitors the ozone concentration in the tail gas and parameters such as effluent ORP online, feeding back in real time and precisely adjusting the ozone dosing rate to ensure stable COD compliance while optimizing ozone dosing. Its ozone utilization rate reaches as high as 99.98% or more, and the ozone dosing ratio (O₃/COD) can be reduced to 0.5-1.2, with operating costs far lower than those of traditional ozone oxidation technology.
Green and environmentally friendly: the whole process involves almost zero chemical dosing (only a trace of catalyst is needed), eliminating at the source the large amount of chemical sludge produced by adding flocculants, and reducing sludge volume by 90% or more, achieving genuine pollution and carbon reduction.
3. Proven in Practice: Results and Data from Benchmark Projects
SINOKLE's CDOFtechnology has been successfully applied by many large refining and petrochemical enterprises such as Sinopec and PetroChina, and its outstanding performance has withstood the test of complex operating conditions.
4. Beyond Treatment: Reshaping the Value Dimensions of Refinery Wastewater Treatment
SINOKLE's CDOFozone catalytic oxidation technology is far more than an upgrade of a wastewater treatment process. It is a strategic investment in a sustainable future for the refining industry.
Economic value: Through extremely high ozone utilization and intelligent control, it directly and greatly reduces chemical and energy costs; by protecting the membrane system, it indirectly saves expensive membrane replacement costs and frequent cleaning maintenance costs, delivering a significant lifecycle cost advantage.
Operational value: the unit is skid-mounted and highly automated and can operate unattended, greatly reducing manual operating intensity and safety risks while improving the convenience and reliability of production management.
Environmental and social value: Using green chemistry, this technology minimizes hazardous waste generation and secondary pollution, helping enterprises achieve more thorough pollutant reduction, fulfill environmental responsibilities, and build a green corporate image, in line with the national dual carbon strategic goals.
5. Conclusion
Facing the common problems of refinery wastewater such as “CODbeing difficult to degrade and membranes being prone to fouling”, SINOKLE's CDOFtechnology provides a complete solution featuring efficient oxidation, efficient separation, intelligent control, and green low-carbon performance. It not only overcomes technical bottlenecks but also, through long-term stable operation of multiple benchmark projects, verifies its dual value in improving both environmental performance and economic benefits.
Choosing SINOKLE's CDOFmeans choosing to drive wastewater treatment toward a cleaner, more economical, and smarter future through technological innovation.
