BP wastewater—high-concentration phenolic and aromatic organic wastewater—has long posed a formidable challenge in environmental treatment. It mainly originates from processes such as bisphenol A (BPA) production, pesticide and pharmaceutical intermediate synthesis, and coal tar processing. Its “four highs and one difficulty” profile often renders conventional treatment methods ineffective:

High concentration: COD ranges widely from 5,000 mg/L to 100,000 mg/L, with consistently elevated phenol levels.
High toxicity: Contains phenols, polycyclic aromatic hydrocarbons (PAHs), halogenated compounds, and other highly toxic substances that directly inhibit biological systems, often leading to process failure.
Poor biodegradability: Stable aromatic ring structures result in very low biodegradability (B/C < 0.2). Conventional biological processes struggle to break them down, causing accumulation in the environment.
High corrosivity / high salinity: Typically exhibits strong acidity/alkalinity and high salt content, imposing stringent corrosion-resistance requirements on equipment.
Difficult compliance: Even after traditional pretreatment, effluent often fails to meet influent standards for biological treatment, increasing regulatory pressure and driving up treatment costs year by year.

Centrifugal Extraction Process for BP Wastewater Treatment

1.Extraction: BP wastewater is brought into intensive contact with a specialized extractant (such as TBP–white oil or N235) inside a high-speed centrifugal extractor for a few to several tens of seconds. Organic compounds are rapidly transferred from the aqueous phase into the extractant, leaving the aqueous phase significantly purified and ready for downstream biological treatment.
2.Stripping: The loaded extractant is then contacted with an alkaline solution, where the target compounds are stripped out and converted into sodium phenolate solution. This product can be reused in production or further refined into crude phenol. The extractant is regenerated, achieving a recovery rate of ≥98%, and is recycled back into the extraction stage.
3.Closed-loop Operation: The extractant experiences minimal loss and is continuously reused. The system supports automated monitoring with only minor replenishment required, resulting in very low long-term operating costs.

Case Study

In a BP high-strength wastewater recovery project at a chemical plant, with a treatment capacity of 12 m³/day, a CWL50-M centrifugal extractor was employed at pilot scale. After five-stage counter-current extraction:
Residual BP content in the raffinate was reduced to <0.1%
BP recovery efficiency exceeded 99%
The treated wastewater could be directly fed into the biological treatment system

Why Choose Tiei Extraction CWL-M Centrifugal Extractor for BP Wastewater Treatment

Traditional equipment such as mixer-settlers and extraction columns often suffer from slow phase separation, large footprint, and a high tendency for emulsification. The CWL-M centrifugal extractor is specifically optimized for BP wastewater characteristics. With five core advantages, it delivers more efficient, cost-effective, and reliable performance:

1.High Separation Efficiency and Outstanding Throughput
The intensified mass transfer under a high-gravity field enables a single-stage extraction efficiency of ≥90%. Deep separation can be achieved with just three stages in series. Phase separation time is reduced from tens of minutes in conventional processes to mere seconds. A single unit can handle 5–50 m³/h, making it well-suited for large-scale industrial applications and capable of efficiently treating high-strength BP wastewater.

2.Enclosed, Environmentally Friendly, and Cost-Effective
The fully enclosed design prevents VOC emissions. Extractant loss is less than 0.5% (compared to 3%–5% in traditional systems), saving over 60% in annual solvent costs. The compact structure requires only 1/3 to 1/5 of the space of conventional equipment, reducing plant footprint and capital investment. Direct motor drive further lowers energy consumption to just 1/3–1/10 of traditional systems, significantly cutting operating costs.

3.Strong Anti-Emulsification for More Complete Separation
BP wastewater is prone to emulsification and often exhibits a small density difference between the two phases, leading to entrainment and poor separation in conventional equipment. The CWL-M centrifugal extractor features a proprietary internal flow-channel design. Under the strong centrifugal force within the rotating drum, the unit inherently breaks emulsions, ensuring more complete phase separation. The treated effluent is clear, with no residual oil phase, effectively preventing downstream process blockages.

4.Superior Corrosion Resistance for Complex Operating Conditions
All wetted parts can be fabricated from 316L stainless steel, duplex stainless steel, or high-performance polymer materials. This provides excellent resistance to the strong acidity/alkalinity and high salinity typical of BP wastewater. The equipment offers a service life of over 10 years with a low failure rate, minimizing maintenance costs and downtime.

5.Intelligent Operation with Low O&M Costs
The system is equipped with an integrated PLC-based control platform that continuously monitors key parameters such as rotational speed, flow rate, temperature, and phase ratio. Operating conditions are automatically adjusted to accommodate fluctuations in wastewater quality. Continuous operation, easy start-up and shutdown, and no need for rebalancing reduce labor costs by up to 70%, making operation simpler and more efficient.

BP wastewater is not an untreatable burden—it is simply a resource in the wrong place. Centered on high-efficiency separation, resource recovery, and environmentally responsible operation, the Tiei Extraction CWL-M centrifugal extractor breaks through the industry bottlenecks of “difficult treatment, high cost, and non-compliance.” It has become the preferred solution for BP wastewater pretreatment in industries such as bisphenol A production, fine chemicals, and coal chemical processing.
Email: sales@tieiextraction.com
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