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Deborah Hyke
Applications Expert

Rotating Biological Contactors (RBC)

Efficient fixed film wastewater treatment technology from the Industry leader

Rotating Biological Contactors are an efficient fixed-film wastewater technology well suited for secondary and/or advanced biological treatment. The long-term reliability of this process is evident in the more than 6,000 units from Evoqua in operation today. Evoqua owns most of the key industry brands of RBCs including Envirex®, Lyco, and Autotrol, and provides OEM (Original Equipment Manufacturer) parts, process expertise, and complete turnkey replacements to help equipment owners maintain equipment performance.

The RBC process consists of a large disc with radial and concentric passages slowly rotating in a concrete tank. During the rotation, 40 percent of the media surface area is in the wastewater. The rotation and subsequent exposure to oxygen allows organisms to multiply and form a thin layer of biomass. This large, active population causes the biological degradation of organic pollutants. Excess biomass shears off at a steady rate and is carried through the system for removal in a clarifier.


 key benefits

  • Consistent process results
  • Stable operation without frequent supervision
  • Lower expansion and retrofit costs due to modular construction and reduced excavation
  • Short wastewater retention time allows for a smaller footprint
  • Minimal head loss through system
  • Low energy consumption (3 kW per 3,000 people)
  • The only maintenance required is simple drive and bearing lubrication
  • Reduced life cycle costs as compared to suspended growth systems
  • Simple operation: no recycle, less lab testing for process control
  • Operator friendly
  • Easily modified for upgrades, retrofits, and multiple applications


  • Municipal wastewater treatment
  • Food and beverage wastewater treatment
  • Landfill leachate
  • Refinery and petrochemical wastewater treatment
  • Pulp and paper wastewater treatment
  • Septage treatment
  • Lagoon effluent polishing
​Click on the tiles below to learn about Evoqua's full-service RBC Retrofit capabilities and more. Rotating Biological Contactors (RBC)