Wastewater Treatment for Heavy-Fuel Power Plants

Oily wastewater treatment at heavy-fuel power plants

Under the ongoing 'dual-carbon' goals, standards for water conservation, emission reduction and wastewater treatment at thermal power plants keep rising. Among them, oily wastewater treatment at heavy-fuel power plants has long been a recognized technical difficulty in the industry. In heavy oily wastewater, high-concentration emulsified oil, resins/asphaltenes and suspended solids interweave into a stable system; the traditional oil-skimming + air-flotation process commonly suffers from large footprint, high chemical dosing, fluctuating effluent and cumbersome O&M, making it hard to stably meet discharge and reuse requirements.

To address this common industry challenge, SINOKLE, leveraging years of industrial water-treatment expertise, launched a 'two-stageCDFUhigh-efficiency cyclone air flotation + KFM deep filtration' integrated process. With core advantages such as high-efficiency demulsification coalescence, compact footprint, low operating cost and strong shock-load resistance, it provides a mature and reliable technical solution for heavy-fuel power-plant oily wastewater treatment.

Where are the difficulties in treating heavy-fuel power-plant oily wastewater?

Oily wastewater at heavy-fuel power plants mainly comes from tank-bottom draw-off water, equipment wash water, site wash water and turbine condensate drainage. The water composition is complex and far more difficult to treat than ordinary industrial oily wastewater; the core difficulties concentrate in four aspects:

First, the oil fraction is complex and highly emulsified. Heavy oil itself has high viscosity and density; once mixed with water it easily forms a stable emulsified-oil system. Conventional gravity separation is almost ineffective, and traditional processes often need large amounts of demulsifier to achieve preliminary separation;

Second, large fluctuations in flow and quality create strong shock loads. Plant inflow is uneven, and during peak periods flow and oil content can fluctuate several-fold; traditional processes have weak shock resistance and effluent indicators easily exceed limits;

Third, tightening discharge standards raise treatment requirements. Whether for compliant discharge or recycle, current plant wastewater demands lower oil content and suspended solids; traditional processes lack effluent stability and struggle to meet high standards long-term;

Fourth, limited site space makes retrofits difficult. Plant layouts are compact and wastewater areas often cramped; traditional processes need large oil-skimming and flotation tanks, pushing civil-construction costs and schedules high.

Two-stageCDFU+ KFM process: precisely cracking the treatment challenge

SINOKLE couples its proprietaryCDFUhigh-efficiency cyclone air-flotation technology with KFM deep-filtration technology to form a three-tier 'rough separation – fine treatment – deep filtration' chain that precisely fits the complex conditions of heavy-fuel power-plant oily wastewater.

First stageCDFUcyclone air flotation: high-efficiency demulsification, rapid removal of bulk oil

CDFUHigh-efficiency cyclone air flotation is SINOKLE's core patented technology, innovatively integrating swirl centrifugation, micro-nano bubble flotation and coalescence demulsification to achieve highly efficient, rapid oil separation. After wastewater enters the unit, a high-speed centrifugal field forms in the swirl chamber; relying on the oil-water density difference, large oil droplets rapidly gather toward the center and rise. Meanwhile, large numbers of micro-nano bubbles released inside fully collide with and adhere to oil droplets and suspended solids, carrying pollutants quickly up to the top oil-collection zone. Internal coalescing media further merge fine emulsified droplets into large ones, strengthening demulsification. The first stageCDFUcan rapidly remove over 90% of free oil, dispersed oil and large suspended solids, greatly reducing the load on downstream units—equivalent to an efficient 'rough purification' of the wastewater.

Second stageCDFUcyclone air flotation: deep purification, capturing fine emulsified oil

After first-stage treatment, what remains is mostly stable emulsified oil and fine suspended solids—the hardest part for traditional processes. The second stageCDFUuses a finer swirl-channel structure and smaller micro-bubbles to specifically break the remaining stable emulsion and further coalesce and remove micron-scale fine oil droplets. The two-stage series design ensures treatment efficiency under high loads while greatly improving effluent stability—even if incoming oil content fluctuates sharply over a short time, effluent oil stays low and stable, perfectly matching power-plant wastewater's strong shock-load character.

KFM high-efficiency filter: deep safeguard for stable compliant effluent

Effluent from the two-stage flotation still contains trace residual oil and fine suspended solids, failing high-standard discharge or reuse. The KFM high-efficiency filter uses modified composite media combining oleophilic-hydrophobic traits with adsorption-capture ability to deeply intercept residual micron-scale oil droplets and suspended solids. Its media has high dirt-holding capacity and easy backwash regeneration, with little hardening or clogging, delivering stable long-term performance. After KFM deep filtration, effluent oil content stably drops below 10 mg/L and suspended solids within 10 mg/L, fully meeting plant discharge or reuse standards.

Four core advantages that fit plants' real needs

Compared with the traditional 'oil-skimming tank + dissolved-air flotation + quartz-sand filtration' process, SINOKLE's two-stageCDFU+ KFM process offers irreplaceable advantages in heavy-fuel power-plant applications:

High treatment efficiency and strong shock resistance. Traditional dissolved-air flotation typically needs over 30 minutes of hydraulic retention, whereasCDFUcyclone air flotation needs only 3–5 minutes—several times more efficient. The two-stage series design further strengthens shock-load resistance, delivering stable effluent even under large inflow fluctuations, matching plant operating characteristics.

Second, compact footprint and short construction cycle. The process is highly integrated, needs no large settling tanks, and can use skid-mounted layout—occupying only 1/3–1/5 of the traditional footprint. Whether new construction or old-system retrofit, it flexibly fits compact plant sites, greatly cutting civil works and shortening the project schedule.

Third, low operating cost and easier O&M. Traditional processes rely on heavy dosing of demulsifiers and flocculants—high chemical cost and large sludge volume drive up hazardous-waste disposal fees.CDFUThis process achieves demulsification through physical swirl and coalescence, greatly reducing chemical dosing and cutting operating cost by 30%–50%; high automation enables unattended operation, markedly lowering plant O&M workload.

Fourth, high oil-phase recovery with economic benefit. A dedicated oil-collection zone at the top centrally collects separated slop oil with low water content, directly reusable in production—reducing hazardous waste while creating extra economic value, aligning with plant energy-saving goals.

Conclusion

For heavy-fuel power plants, oily wastewater treatment is both a hard environmental-compliance requirement and a key lever for water savings, efficiency and green transformation. SINOKLE's two-stageCDFU+ KFM process overcomes the severe-emulsification, high-difficulty pain points of heavy oily wastewater while meeting plants' needs for small footprint, stable operation and low cost. It has been verified in multiple industrial oily-wastewater projects with effluent stably better than national standards. As the power sector's water-conservation demands keep rising, this highly integrated process will provide solid technical support for the green, low-carbon development of the heavy-fuel power industry.