Stable Compliance for Tank Washing Wastewater: An In-Depth Analysis of the "Two-Stage CDFU + CDOF" Advanced Treatment Process

Stable Compliance for Tank Washing Wastewater

Tank washing wastewater is an environmental compliance challenge that has troubled oil depots for years: the washing wastewater contains large amounts of oil, COD and BOD, with complex pollution factors; simple gravity oil separation cannot meet the tertiary discharge standard of the Integrated Wastewater Discharge Standard (GB 8978-1996), making compliant discharge difficult. With its internationally pioneered integrated CDOF and CDFU units as the core, SINOKLE's overall solution delivers stable compliance — the effluent stably meets the integrated wastewater discharge standard and has won praise from domestic and overseas customers.

1. Process Route — Separation + Oxidation, Two Steps to Tackle the Hard Parts

The difficulties of tank washing wastewater treatment can be split into two categories: oil is removed by physical separation, while COD is reduced by advanced oxidation; neither can be omitted. SINOKLE's core technical route is: two-stage CDFU cyclonic dissolved air flotation for purely physical separation + CDOF ozone catalytic oxidation flotation for deep COD degradation, in an integrated skid-mounted unit, with stable compliant effluent.

2. Main Equipment 1: Two-Stage CDFU — Purely Physical, Efficient Oil Removal

CDFU (Cyclonic Dissolved Gas Flotation Unit) is a patented technology independently developed by SINOKLE with internationally advanced technical levels — a new-generation, domestically pioneered, high-efficiency, compact, enclosed, pressurized flotation technology.

Technology fusion:

- Cyclonic centrifugal separation: the centrifugal force field accelerates oil droplet coalescence
- Ultrafine bubble generation: micro-bubbles adhere to oil droplets for efficient rising
- Dissolved air flotation: uniform bubble release in an enclosed, pressurized environment

Treatment targets: efficient, rapid separation of waste oil, emulsified oil and suspended solids; purely physical action, with oil recoverable.

Two-stage design logic: the first stage bears the main load for coarse separation, while the second stage treats difficult-to-separate components such as emulsified oil, with gradient purification ensuring oil-removal performance.

3. Main Equipment 2: CDOF — Ozone Catalytic Oxidation for Deep COD Reduction

CDOF (Cyclonic Dissolved Ozone Flotation Unit, an integrated ozone advanced catalytic oxidation and flotation device) is SINOKLE's patented technology — a domestically original, internationally leading high-efficiency integrated oxidation and flotation unit holding a PCT international patent.

Five-system composition:

Multi-mechanism synergistic enhancement: six core technologies — homogeneous/heterogeneous catalysis, cyclonic flow, dissolved air flotation, cavitation, supercritical catalytic oxidation and fully enclosed pressurized oxidation — work in concert to efficiently and rapidly remove petroleum, suspended solids, colloids, COD, bacteria and other pollutants.

4. Scheme Comparison: Simple Gravity Separation vs. SINOKLE Overall Solution

5. Cases and Market Validation

With its CDOF and CDFU integrated units as the core, SINOKLE's overall solution has been implemented in the oil-depot wastewater treatment field, with stable compliant effluent and praise from domestic and overseas customers. The internationally pioneered equipment technical route, combined with the integrated skid-mounted delivery form, is becoming a reliable choice for tank washing wastewater treatment.