Power Plant Oily Wastewater: Sizing CDFU, KHC and KFM Stages to Tank Farm, Coal-Washing and Leachate Loads
Power generation and oily water go together. Tank farms, coal-washing circuits and miscellaneous drains hand a power plant a wastewater profile that mixes heavy oil, light oil and suspended solids in proportions that swing by the hour, and conventional processes struggle to hold modern discharge limits against that variability. SINOKLE has built its power plant answer around CDFU cyclonic dissolved air flotation and a small family of matching units.
Sampling discipline pays for itself here. A week of composite samples across the three source streams tells an engineer which pollutant sets the design, and the answer differs from plant to plant: one site is an oil problem, another a solids problem, a third a dissolved organics problem that only oxidation can close.
Know the load before sizing the plant
The wastewater arrives mainly from heavy-oil tank farms, light-oil tank farms and coal-washing processes. Heavy-oil tank farm water can carry up to 500,000 ppm of oil, while light-oil tank farm water typically sits around 50 mg/L, and both fluctuate hard with tank turnover and weather. Discharged without proper treatment this load does real damage to receiving waters, which is why the design conversation starts with the pollutant inventory rather than with equipment brochures.
Coal-washing water deserves its own note. It arrives with fine coal fines in suspension alongside the oil, and the combination blinds conventional media filters quickly. The CDFU train handles both pollutants in the same pass, because the bubbles that lift oil droplets also aggregate the fines, and the downstream filter stage then sees a load it can actually polish rather than a slurry it has to survive.
The CDFU core
Developed by SINOKLE, CDFU (cyclonic dissolved air flotation) combines cyclonic separation, dissolved air flotation and catalytic oxidation. Micro and nano bubbles form without any chemical dosing, oil-water separation completes under strong centrifugal force, and one unit can process up to 500 m³/h with oil removal above 90%. Three advantages carry the design: super-oleophilic hydrophobic coalescing fibre materials that merge cyclonic centrifugal separation, wetting coalescence and collision coalescence; purpose-designed coalescing media that remove emulsified oil droplets larger than 0.1 μm; and a purely physical flow that generates no secondary pollution.
The three cases differ in load but share a design logic: put each unit where its mechanism wins. Filtration and coalescing handle the free and coalescible fractions cheaply; the CDFU stages attack the emulsified fraction that neither gravity nor media can touch; the KFM polisher catches the last solids; and CDOF takes over only where dissolved refractory COD demands oxidation. Plants that copy the logic rather than the exact equipment list get the same result at their own concentrations.
Three case patterns worth copying
Case one, high-concentration cogeneration water. At a back-pressure cogeneration project in Shaanxi Province, a filter plus KHC coalescing oil separator combination treated high-oil power plant wastewater and brought effluent oil below 5 ppm, a removal rate over 99%.
Case two, a full three-stage train. The heavy-oil power plant in Sierra Leone runs CDFU+CDFU+KFM, with KFM the active filter media polisher. Influent oil under 50 mg/L and suspended solids under 80 mg/L come out as oil below 10 mg/L and solids below 20 mg/L. Stated with the comparison symbols the designers use, <50 mg/L oil and <80 mg/L solids in, <10 mg/L and <20 mg/L out, all indicators on discharge standard.
Case three, leachate on an ozone train. The waste incineration power plant in Shiyan, Hubei Province, treats landfill leachate with a CDOF integrated unit. Influent COD of 1,300 mg/L or less drops to 400 mg/L or less with colour at 30 or below, and the subsequent biological stage finishes at COD of 20 mg/L or less and ammonia nitrogen of 1 mg/L or less, Class III surface water territory.
The monitoring layer also shortens troubleshooting. Pressure, ozone dose and reaction level stream into one record, so an excursion traces back to its cause in minutes rather than shifts, and the AI layer flags drift before it becomes an exceedance rather than after.
Automation as an operating cost lever
The control layer does more than watch gauges. DCS and PLC systems run fully automatic regulation of ozone dosing, reaction level and pressure, and an AI real-time monitoring layer supports unattended operation, which is where the labour savings actually come from. Operating costs land 20%-30% below conventional processes, the footprint shrinks to one third, skid-mounted equipment deploys quickly, hydraulic retention time is 1-5 minutes, and energy consumption runs more than 30% lower than conventional process trains.
For plant owners facing tightening policy and a genuine need for green transformation, the lesson from these cases is sequencing: match the front-end separation duty to CDFU, put KHC where coalescing pays, reserve CDOF for refractory COD loads, and let KFM polish. SINOKLE keeps refining that toolkit for the global power industry, and the dual goals of green energy development and environmental protection rest on exactly this kind of engineering fit.