In the daily operation of thermal power plants, oily wastewater treatment has always been a focus of environmental management. Whether it is wash water from fuel oil tank farms, flushing water from leakage of oil pumps and pipelines, or oily wastewater from coal handling systems and transformers. The composition is complex and highly variable. Although the oil content of such wastewater is usually only a few hundred mg/L, improper treatment can place a huge shock load on downstream wastewater treatment plants, causing unstable operation and non-compliant effluent and significantly increasing operating costs and risk.

Addressing this industry pain point, SINOKLE Technology draws on its core patented technology - the CDFU compact swirl dissolved-air flotation system - to provide the power industry with a full-process green solution from pre-treatment to advanced purification.

1. The limits of conventional processes: large footprint, heavy chemical use, heavy sludge

Conventional oily wastewater treatment at thermal power plants mostly uses oil separation tank plus gravity settling. This approach needs long retention times and a large footprint, and performs extremely poorly on fine oil droplets and emulsified oil. To meet standards, plants often have to dose large amounts of chemicals to aid demulsification, which not only drives up operating costs but also produces large quantities of oily sludge (hazardous waste), causing secondary pollution.

2. The SINOKLE CDFU solution: a green revolution led by purely physical technology

SINOKLE's oily wastewater treatment solution for thermal power plants is built around a core process of two-stage CDFU + KFM filters - fully resolving the chronic problems of conventional processes.

1. Core technical advantages:

• Purely physical demulsification with zero chemical addition: CDFU systems combine swirl centrifugation, dissolved-air flotation and ultrafine bubble technology to achieve efficient purely physical oil removal, with single-stage oil removal efficiency of over 90%. It produces no extra sludge, and the recovered crude oil is of high quality and reusable.

• Rapid separation, space saving: the reaction rate is fast and the equipment is compact. Its footprint is only 1/5 of conventional flotation processes, making it ideal for space-constrained power plant environments.

• Intelligent unattended operation: the system runs fully automatically in a closed loop (pressurised and sealed, with no hazardous gas release) under PLC automatic control, with simple operation that greatly reduces labour and maintenance costs.

• Strong shock resistance: it easily handles sharp fluctuations in power plant wastewater quality, ensuring consistently stable compliant effluent.

2. KFM active media filter: the last line of defence for advanced purification

This filter uses silicate-based media modified by atomic deposition technology; its super-hydrophilic nanostructure and filtration mechanism further remove trace oil and suspended solids, ensuring clear, transparent effluent.

3. Benchmark case: heavy oil power plant project in Sierra Leone, Africa

SINOKLE's technical strength has been strongly demonstrated in multiple international projects. Take the Sierra Leone heavy oil power plant in Africa wastewater treatment project as an example:

• Treatment scale: 120 m3/d.

• Process flow: two-stage CDFU + KFM filters, a purely physical process.

• Operating results: with zero chemical addition, influent oil content of 200 mg/L was reduced to below 5 mg/L; influent suspended solids (SS) fell from 972 mg/L to 4.6mg/L.

• Value delivered: commissioned in June 2025, the project not only brought wastewater back within limits but also recovered large amounts of usable crude oil, achieving both environmental and economic benefits.

4. Conclusion

As a leader in refractory industrial wastewater treatment, SINOKLE has successfully provided professional services to major domestic power and energy enterprises. Whether for heavy oil/light oil tank farm wastewater or coal washing and transformer wastewater, SINOKLE can provide efficient, reliable and economical customised solutions.