RBC stands for Rotating Biological Contactor.

• A. Rotating Contactor
• B. Rotating Biological Contactor
• C. Rotating Biochemical Contactor
• D. Biological Contactor

Answer: (B)

RBC stands for Rotating Biological Contactor. The idea behind this process is that wastewater treatment is achieved by a biofilm—microorganisms living on media such as plastic discs—that rotates partially submerged in the wastewater. As the discs rotate, the biofilm alternates between contact with the wastewater and exposure to air, giving the microorganisms oxygen and substrate to break down organic matter. This rotating, fixed-film setup makes oxygen transfer and biofilm refreshment more efficient, helping to treat the water as it flows by.

The name highlights three elements: rotation (the discs or carriers spin), biological (the treatment relies on living microorganisms), and contac tor (the media where contact and treatment occur). Dropping any of these changes the meaning: a term like Rotating Contactor omits the biological aspect, a term like Rotating Biochemical Contactor isn’t the standard terminology, and Biological Contactor without rotation would describe a different, non-rotating fixed-film system.