Ship Wastewater and Port Terminal Oily Wastewater Treatment Solution

The ocean is the foundation of the shipping industry, and ship oily wastewater (such as engine room bilge water and tank washing water) poses a potential threat to the marine ecosystem because of its high degree of emulsification and complex composition. Conventional processes generally suffer from low deoiling efficiency and a tendency to cause secondary pollution, making compliant discharge a core challenge for shipping companies.

To address these pain points, Shenzhen SINOKLE has developed the combined process of 'CDFU pretreatment deoiling + KFM filter + CDOF catalytic ozone oxidation'. Through three-stage synergistic treatment it stably meets the Grade 3 requirements of the Integrated Wastewater Discharge Standard, providing reliable technical support for ships to achieve environmental compliance.

Process System Explained: Full-Flow Control from Pretreatment to Advanced Purification

Step 1: CDFU pretreatment deoiling unit - the core of front-end high-efficiency separation

As the core of front-end pretreatment, the CDFU (compact swirl dissolved-air flotation) unit combines centrifugal separation with ultra-fine bubble technology to generate 5-30 μm ultra-fine bubbles (a specific surface area 10 times that of conventional bubbles). With a dual-zone flotation structure, single-stage deoiling efficiency exceeds 90% and suspended solids removal exceeds 85%.

The unit uses a purely physical demulsification principle and requires no chemicals, effectively eliminating oily sludge (hazardous waste); the recovered oil can be reused as a resource, balancing environmental performance and economy. The equipment is skid-mounted and occupies only one third of the footprint of conventional flotation units, with a hydraulic retention time of just 1-5 minutes, suiting applications with limited ship space and large operating fluctuations.

Step 2: KFM filter - the key link in fine filtration

Wastewater pre-treated by CDFU then enters the KFM activated filter media filter for fine filtration. The filter uses super-hydrophilic modified media prepared through 60 process steps; the media surface carries a negative charge and efficiently adsorbs pollutants, with self-inhibiting antibacterial properties, resistance to compaction and easy backwashing.

Its filtration precision is outstanding: wastewater with influent oil content ≤ 50 ppm and suspended solids (SS) ≤ 50 mg/L can be treated to oil content ≤ 6 ppm, SS ≤ 2 mg/L and a median particle size ≤ 1.5 μm, providing high-quality influent for the downstream advanced treatment unit, avoiding clogging of terminal equipment and reducing overall O&M costs.

Step 3: CDOF catalytic ozone oxidation unit - the advanced purification terminal

As the core of terminal advanced treatment, the CDOF (integrated catalytic ozone oxidation and flotation unit) couples catalytic ozonation deeply with dissolved-air flotation. A proprietary catalyst efficiently activates ozone to generate highly oxidative hydroxyl radicals that non-selectively mineralise refractory organics in wastewater.

The unit achieves COD removal above 85% and simultaneously removes colour, odour and toxic substances; with built-in flotation it efficiently separates the flocculent impurities produced by oxidation. Compared with conventional ozonation, reaction time is only 10-30 minutes and operating costs are 20%-30% lower; the equipment runs fully enclosed with no odour leakage, combining operating efficiency with safety.

Three-Stage Compliance Guarantee: Core Indicators Fully Meet the Standard

The combined process has been verified in real projects: for ship oily wastewater with influent oil content of about 1,000 mg/L and suspended solids of about 1,000 mg/L, the final effluent stably meets the Grade 3 requirements of the Integrated Wastewater Discharge Standard (GB 8978-1996), namely COD ≤ 400 mg/L, petroleum substances ≤ 10 mg/L and SS ≤ 50 mg/L, with key indicators better than the standard limits. The process also has strong shock-load tolerance, adapting to fluctuations in oil type and concentration with good effluent stability.

Advantages Tailored to Ships: Compliance Needs and Shipping Conditions Combined

· Outstanding environmental performance: mainly a purely physical process with no chemicals, no secondary pollution and a 90% reduction in sludge generation, significantly lowering hazardous waste disposal costs;

· Simple, efficient O&M: a PLC/DCS control system supports remote monitoring and unattended operation, with few moving parts and maintenance costs only one third of conventional processes;

· Strong scenario adaptability: the fully enclosed pressurised design prevents leakage of hydrogen sulphide and other oil vapours, suits the special conditions of ship motion and limited space, and is easy to install with online retrofit capability.

Protecting the marine ecosystem and practising compliant shipping. The combined process 'CDFU+KFM+CDOF' from Shenzhen SINOKLE solves the ship oily wastewater challenge with its core strengths of high efficiency, low carbon and stability, helping shipping companies achieve Grade 3 compliant discharge and driving the green upgrade of the shipping industry.