Three Field Cases: How CDFU Plus CDOF Performs on Real Oily Wastewater
Technology earns its reputation on site, not in a specification sheet. SINOKLE provides oily wastewater treatment based on a CDFU plus CDOF pure-physical process, and the three projects below show what that process does when it meets real influent. Each case involves a different stream profile, a different capacity and a different definition of success.
Case 1: refining and chemical produced water, 1,000 m3/d
The problem. Produced water with high oil content and severe emulsification. The previous process — oil separation, flotation then biological treatment — removed oil inefficiently, generated large amounts of sludge, could not reliably meet standard, and left the plant carrying heavy sludge disposal costs.
The process. A full-flow pure-physical train combining CDFU cyclonic dissolved-air flotation with CDOF ozone catalytic oxidation.
The result. Effluent oil content is stable below 5 mg/L, COD below 100 mg/L and SS below 30 mg/L, meeting Grade 1 of the Integrated Wastewater Discharge Standard. Part of the effluent is reused in the circulating cooling water system at a reuse rate of 60%. With no chemical addition and no oily sludge generated anywhere in the process, the sludge disposal problem disappears entirely rather than being reduced.
The benefit. Annual savings on chemical procurement and sludge disposal are significant, and total operating cost fell by more than 50%. Water is reused on site, cutting fresh water consumption, and environmental compliance is now a reliable position instead of a recurring risk.
Case 2: thermal power plant, 500 m3/d
The problem. Oily wastewater whose oil content fluctuated widely and which was highly emulsified. The conventional process had weak shock resistance and unstable effluent, and it occupied a large footprint with high operation and maintenance costs.
The process. A combined train of a high-efficiency coalescing de-oiler plus CDFU cyclonic dissolved-air flotation, paired with an intelligent control system.
The result. Effluent oil content is stable below 3 mg/L, meeting the reuse standard, and the whole flow is reused for plant landscaping and road washing — genuine zero discharge. The equipment footprint is small and the installation and commissioning period short, while the control system enables automatic operation and remote monitoring with no dedicated staffing.
The benefit. Annual savings in fresh water and sludge disposal costs are noticeable, equipment failure rates are lower, and O&M labour costs fall accordingly. Zero discharge also helped the plant meet its environmental assessment targets and gain recognition from the local environmental authority.
Case 3: ship bilge water, 30 m3/d per vessel
The problem. Severely emulsified bilge water with high oil content. Conventional equipment was inefficient and awkward to maintain, making the IMO discharge standard difficult to meet and exposing the operator to voyage restrictions and penalty risk.
The process. A three-stage compact arrangement of CDFU, KFM filtration and CDOF, with skid-mounted equipment.
The result. Effluent oil content is stable below 15 mg/L, meeting the IMO MEPC.107(49) standard and suitable for direct discharge or reuse. The package is small and light enough to install in a corner of the engine room without taking core space, and the pure-physical process means no chemicals, no sludge and simple maintenance — which is what decides whether shipboard equipment survives long-term use.
The benefit. The discharge compliance problem is fully solved, removing the risk of international environmental penalties. Equipment service life is long and annual maintenance cost low, which strengthens the fleet's environmental credentials and its market position.
Reading the cases together
The capacity range is worth noting on its own. Capacities of 1,000 m3/d, 500 m3/d and 30 m3/d are not variations on a theme; they are three different engineering problems. At the small end, packaging and maintenance simplicity dominate every other consideration. At the large end, reuse and the elimination of sludge drive the economics. Building all three on the same two core technologies is what allows the process to be specified from the water analysis rather than from a fixed catalogue.
In each instance the binding constraint turned out not to be removal efficiency but what happened to the separated material, and to the sludge that was no longer being produced. That is where the customer benefit actually landed.
What the three cases have in common
The streams differ, but the same two properties recur: no chemicals are added at any stage, and no sludge is produced. Those two facts drive most of the customer benefit — lower operating cost, fewer regulatory exposure points, and recovered oil or reused water that offsets the capital outlay.
SINOKLE brings three things to that pattern. The technical base is the in-house CDFU and CDOF core technology, a pure-physical process with high treatment efficiency and stable effluent. The customisation base is the ability to tailor the arrangement to different industries and water qualities, meeting discharge compliance and reuse requirements as separate cases rather than assuming one answers the other. The benefit base is the combination of lower operating cost, water savings and avoided environmental risk, which is what turns a compliance project into an investment that keeps paying.