Innovative Technology Solves the Oily Wastewater Challenge at Thermal Power Plants

In the field of industrial wastewater treatment, oily wastewater from thermal power plants has long been a "hard nut" for the industry because of its complex composition, high degree of emulsification and difficult treatment. As a national high-tech enterprise focused on difficult industrial wastewater treatment, SINOKLE has drawn on nearly a decade of technological accumulation and innovation to build a full-process solution for oily wastewater at thermal power plants. Centered on purely physical separation technology, it overcomes the pain points of conventional processes and offers the power industry an efficient, environmentally sound and economical new option for water environment management.

Oily wastewater at thermal power plants arises in many settings, mainly including fuel oil tank cleaning water, flushing water from oil pump and pipeline leakage, and water contaminated by grease in coal handling systems. Its composition is complex and treatment is notably difficult, chiefly in the following three respects:

• Emulsified oil is hard to separate: the wastewater contains large amounts of emulsified oil, and conventional settling and centrifugation cannot effectively break the emulsified state, resulting in low oil removal efficiency and effluent that struggles to meet standards;

• Poor adaptability to operating conditions: the oil content of the wastewater fluctuates widely (from a few hundred mg/L to hundreds of thousands of mg/L), while conventional processes have weak shock resistance, unstable effluent quality and a tendency to burden downstream wastewater treatment plants;

• Secondary pollution and high cost: conventional processes rely on chemical reagents for demulsification, which not only raises treatment costs but also produces large amounts of oily sludge (hazardous waste) that is difficult to dispose of and poses environmental risks; at the same time, the equipment occupies a large area, has a low degree of automation, and incurs high manual O&M costs.

Taking the conventional "oil-intercepting pond + flotation tank + filtration" process commonly used at thermal power plants as an example, its removal rate for emulsified oil droplets is below 60%, and the filters clog easily and need periodic manual cleaning — which not only undermines treatment efficiency but also increases safety risks, and can no longer satisfy current environmental standards and the industry's cost-reduction needs.

Breaking the Deadlock: Purely Physical Separation Achieving "Efficiency + Environmental Protection + Economy"

Addressing the pain points of oily wastewater at thermal power plants, SINOKLE has drawn on its core technologies to tailor three categories of solutions covering different scenarios such as heavy oil tank farms, light oil tank farms and coal-washing wastewater. All are built around "purely physical separation", achieving simultaneous gains in treatment efficiency, environmental performance and cost-effectiveness.

(1) Core Process Schemes: Customized by Scenario to Solve Different Wastewater Challenges Precisely

Heavy oil tank farm oily wastewater pretreatment scheme: it adopts a combined process of "CDFU (cyclonic dissolved air flotation) + KFM active filter media filter". Through the dual action of cyclonic centrifugal separation and ultrafine bubble adsorption, it efficiently breaks emulsified oil droplets, achieving an oil removal rate above 95%. The process requires no chemical reagents at all; the recovered waste oil can be returned directly to the crude oil tank for reuse, with no oily sludge generated. The equipment is skid-mounted, occupying only 1/3 the area of conventional processes, with a high degree of automation enabling remote monitoring and O&M, and a construction cycle shortened by 50%.

Light oil tank farm oily wastewater treatment scheme: centered on "pre-filter + KHC high-efficiency coalescing oil separator", it uses the super-oleophilic, hydrophobic fiber material of the KHC separator. Through multiple mechanisms such as wetting coalescence and collision coalescence, it removes emulsified oil with droplet sizes above 0.1 μm, with oil removal consistently above 95%. The process runs fully enclosed with no odorous gas leakage, and the modular filter elements are easy to replace with a service life 2-5 times that of conventional coalescing elements, greatly reducing O&M costs.

Discharge process: advanced treatment to meet the strictest discharge standards. For wastewater requiring discharge, SINOKLE adds "CDOF (integrated ozone advanced oxidation and flotation unit)" on top of pretreatment. Integrating multi-stage ozone catalytic oxidation, hydrodynamic cavitation and cyclonic flotation, it rapidly degrades COD and removes color and odor, with a reaction residence time of only 15 minutes (1/3 that of conventional processes). The final effluent has oil content ≤10 mg/L, suspended solids ≤20 mg/L and COD ≤100 mg/L — far better than the Class I limits of the "Integrated Wastewater Discharge Standard" (GB8978-1996) — while sludge volume is reduced by more than 90%, thoroughly eliminating secondary pollution.

(2) Core Technical Advantages: Four Key Technologies Building a Competitive Moat

SINOKLE's solution achieves its breakthrough thanks to four core technologies, all of which reach internationally leading levels and have been verified at industrial scale:

CDFU Cyclonic Dissolved Air Flotation Technology : it integrates cyclonic centrifugation, ultrafine bubble generation and dissolved air flotation. Bubble diameter is only 5-30 μm (versus 300-1,000 μm for conventional flotation), giving more than 10 times the contact area with oil droplets, a single-stage oil removal rate above 90% and a suspended solids removal rate above 85%; the recycle ratio is only 20-30% (versus 30-100% for conventional processes) and energy consumption drops by 40%.

KHC High-Efficiency Coalescing Oil Removal Technology: atomic layer deposition is used to modify the surface of the fiber material, improving coalescing efficiency and tolerance to impurities. Even when suspended solids in the wastewater exceed 1,000 mg/L, it still runs stably — far more adaptable than conventional coalescing equipment.

CDOF Ozone Advanced Oxidation Technology : a domestically pioneered integrated unit that boosts ozone oxidation efficiency by more than 4 times and rapidly degrades refractory organics. It also provides flotation, so "oxidation + separation" proceed simultaneously, occupying only 1/5 the space of conventional oxidation processes.

KFM Active Filter Media Filtration Technology: the media is made from silicate material through 60 processing steps. Its surface carries a negative charge and it has a self-sterilizing function; it does not compact and is easy to rinse. Filtration precision reaches below 1.5 μm, effluent oil content is ≤6 ppm, and the media lasts more than 5 years, keeping O&M costs low.

(3) Technical Comparison: Outperforming Conventional Processes Across the Board