Breaking the Coal Chemical Bottleneck: How SINOKLE’s Patented CDOF Technology Revolutionizes Zero Liquid Discharge (ZLD) Wastewater Treatment

Driven by the dual forces of global "Net-Zero" carbon targets and increasingly strict environmental regulations, Zero Liquid Discharge (ZLD) for industrial wastewater has become a baseline requirement for high-quality development in the coal chemical industry. As a major water consumer and prominent polluter, the industry faces complex, highly toxic, and poorly biodegradable wastewater. In particular, treating coal gasification wastewater has long been recognized as a major bottleneck across the sector.

Faced with stringent environmental standards and water resource constraints, Shenzhen Clear Science & Technology Co., Ltd (SINOKLE) leverages its independently developed core technologies to directly address the pain points of coal gasification wastewater treatment. The company delivers highly efficient, stable, and commercially viable ZLD solutions to the industry.

I. High Water Consumption and High Emissions: Overcoming Environmental Bottlenecks

The coal chemical industry uses coal as a primary raw material, converting it through chemical processing into gaseous, liquid, and solid fuels, as well as various chemical products. It encompasses three main processes—coal gasification, coal coking, and coal liquefaction—which support the production of vital commodities such as synthetic ammonia, methanol, olefins, and oil products.

However, behind the industry's rapid growth lie severe challenges regarding water consumption and pollution:

· Coal-to-gas production consumes approximately 10 tons of water per 1,000 Nm³.

· Coal-to-olefins production consumes up to 30 tons of water per ton of product.

· Coal chemical wastewater is rich in phenols, cyanides, oils, ammonia nitrogen, and a high concentration of refractory (hard-to-degrade) organic matter, resulting in high toxicity and low biodegradability.

Taking China as an example, the country's per capita water resources are less than 25% of the global average. Consequently, water pollution has become a critical bottleneck restricting the growth of modern coal chemical projects. From the initial promotion of industrial wastewater zero-discharge during China's 11th Five-Year Plan to the subsequent rollouts of the Water Pollution Prevention and Control Action Plan and the Environmental Access Conditions for Modern Coal Chemical Construction Projects, a clear path has been mandated. Clean/wastewater separation, advanced treatment, fractional water reuse, and ZLD have become absolute environmental rules that coal chemical enterprises must follow.

II. The ZLD Framework: Why is Coal Gasification Wastewater So Difficult to Treat?

Through years of industry practice, a standard process route has emerged for coal chemical wastewater: "Pretreatment → Biochemical Treatment → Advanced Treatment → Brine Treatment → Solidification & Zero Liquid Discharge." However, coal gasification wastewater—especially fixed-bed (Lurgi) gasification wastewater—still faces three major treatment pain points:

1. Incomplete Pretreatment Leading to Biochemical System "Poisoning"

Even after ammonia stripping and dephenolation, the oil content in the wastewater often remains as high as 100 to 200 mg/L. This far exceeds the biochemical influent requirement of less than 50 mg/L. Residual oils and toxic substances directly inhibit microbial activity, causing a sharp decline in biochemical treatment efficiency.

2. Stubborn Refractory Organics Failing Advanced Treatment Standards

Large quantities of macromolecular COD remain in the biochemical effluent. Conventional processes cannot fully break down these structures, easily leading to excess COD and ammonia nitrogen in the discharged water. This makes it difficult to meet reuse and zero-discharge standards.

3. Frequent Component Fouling and Unstable System Operations

Colloids, organic matter, and bacteria easily cause fouling in membrane modules and reaction equipment. This significantly increases operation and maintenance (O&M) costs and can even cause the entire treatment system to break down.

III. Overcoming the Limitations of Traditional Processes with Advanced Oxidation

To eliminate refractory organic matter, the industry widely adopts a "Advanced Oxidation Processes (AOPs) + Secondary Biochemical Treatment + Membrane Separation" process. Advanced oxidation cracks and opens the chains of macromolecular organics to improve their biodegradability (B/C ratio), which are then deeply degraded via secondary biochemical treatment.

A comparison of mainstream Advanced Oxidation Processes currently in use highlights their pros and cons:

Among these, ozone oxidation has become a preferred direction due to its clean and efficient nature. However, traditional ozone processes suffer from two fatal flaws: low ozone solubility in water and low conversion efficiency of hydroxyl radicals (·OH). These limitations restrict its overall treatment performance and large-scale application.

IV. Technical Breakthrough: SINOKLE's Patented Technology Solves Industry Challenges

Targeting the shortcomings of traditional ozone oxidation, SINOKLE has introduced comprehensive innovations across three dimensions: mass transfer efficiency, catalytic efficiency, and system integration. The company developed its core Ozone Catalytic Oxidation - Cyclonic Dissolved Gas Flotation Integrated Technology (CDOF), completely solving the challenges of coal gasification wastewater treatment.

1. Dual Technical Upgrades to Break the Ozone Bottleneck

· Maximizing Solubility: By coupling highly efficient dissolved gas release with pressurized cooling technology, the dissolution efficiency of ozone in water is substantially increased.

· Maximizing Conversion Rates: Through the synergistic action of heterogeneous catalysts, hydraulic cavitation, and high-gravity cyclone technology, the hydroxyl radical conversion rate reaches up to 99.98%, exponentially boosting the system's oxidation capacity.

2. Specialized Catalysts Engineered for High-Difficulty Wastewater

To address macromolecular organic wastewater from coal gasification, SINOKLE developed a new Highly Loaded Ozone Catalyst (N-HLC). Featuring dual-site catalysis, high-porosity micro-pore molding, and hydrophilic anti-fouling technologies, it adapts perfectly to complex water qualities and ensures long-term, stable operation.

3. Streamlined System Integration for Highly Stable Compliance

The CDOF technology integrates multiple catalytic oxidations, hydraulic cavitation, and cyclone flotation into a single system. It achieves a hydraulic retention time (HRT) of less than 15 minutes and an ozone utilization rate near 100%. The system efficiently degrades COD, removes oil, and eliminates toxicity, providing robust protection for subsequent biochemical and membrane treatment stages.

V. SINOKLE: Guarding Industrial Water Quality Through Technical Innovation

As a National High-Tech Enterprise dedicated to industrial wastewater treatment, SINOKLE has long been deeply rooted in the field of high-difficulty wastewater management. With patented technologies such as CDOF and CDFU at its core, the company provides customized, integrated, and zero-liquid-discharge wastewater treatment solutions for the petrochemical, coal chemical, and oil & gas industries.

Moving forward, SINOKLE will continue to drive innovation in water treatment technology. By tackling industrial wastewater challenges with advanced engineering, we help enterprises achieve green production and regulatory compliance—contributing technological strength to water resource protection and the realization of global "Net-Zero" goals.