Industry Background & Challenge

In petrochemical plants, discharged brine is characterized by high salinity, low B/C ratio, and poor biodegradability.

Biofilters have long been the mainstream biological treatment for such brine – but they come with complex equipment, complicated controls, significant head loss, and frequent backwashing.

Why Hybrid MBBR?

Hybrid MBBR (Moving Bed Biofilm Reactor) is a biofilm process that offers simple operation, easy control, and low maintenance.

However, it has traditionally faced three technical hurdles in petrochemical brine applications:

• Difficult flow regime design

• Slow biofilm attachment

• Long commissioning cycles

That's why it has rarely been used in this sector – until now.

The Project: Space & Function Constraints

A revamp project at an integrated refining–chemical site required a new biological treatment unit to be inserted between two existing units, removing ammonia‑N, total nitrogen, and COD simultaneously.

With conventional biofilters, both elevation and footprint were too restricted.

Hanqi Environment designed a custom hybrid MBBR system that integrates nitrification, denitrification, and carbon removal – successfully breaking through the space and performance bottlenecks.

Core Technology: Zoned Design + Flexible Control

Hanqi's proprietary zoned reactor design ensures:

• Proper hydraulic flow

• Even carrier fluidization without accumulation

• Flexible adjustment of nitrification, denitrification, and COD removal functions according to water quality changes

The result: a reliable, adaptable system that handles varying influent conditions.

Breakthrough: Biofilm Attachment Cut from 6 Months to 15 Days

The biggest commissioning challenge was denitrification biofilm formation.

Hanqi's R&D team worked side‑by‑side with the project site, applied targeted technical improvements, and dramatically shortened the attachment period – from the industry‑typical 6 months down to just 15 days.

Proven Performance – 4 Key Results (after >1 year of operation)

• High Efficiency, Saves 2/3 Footprint

  The hybrid MBBR removes NH₃‑N, TN, and COD in one integrated unit. Compared to building new biofilters, it cuts footprint by two‑thirds – a game‑changer for space‑limited revamps.

• Strong Nitrogen Removal – Load up to 1 kg/m³·d

  The system achieves NH₃‑N and TN loading rates of 1 kg/m³·d, and still meets discharge standards even with high‑strength nitrogen wastewater.

• Excellent Shock Resistance – Stable Effluent

  Microorganisms grow on protected carriers, giving the system strong tolerance to water quality swings. Even when acrylonitrile‑laden wastewater was introduced, the hybrid MBBR effluent remained consistently compliant – proven in real‑world conditions.

• Simple Operation – Essentially Maintenance‑Free

  The system is self‑balancing – no frequent manual intervention required. Equipment is minimal, and no dedicated maintenance is needed.

Through continuous R&D and field practice, Hanqi Environment has expanded MBBR's application boundaries – offering the petrochemical industry a new, reliable, and compact biological treatment option for brine discharge compliance.