As you proceed through the stages of the RBC system, the dissolved oxygen concentration should normally:

In a rotating biological contactor (RBC) system, the introduction of microorganisms to break down organic matter typically requires adequate dissolved oxygen for optimal microbial respiration and metabolism. As water moves through the RBC system, the dissolved oxygen concentration is expected to increase due to the aeration provided by the rotating disks that are partially submerged in the wastewater.

As the disks rotate, they intermittently lift the biofilm (a layer of microorganisms) out of the wastewater into the air, where oxygen can diffuse into the biofilm. This process allows the microorganisms to utilize the dissolved oxygen for their metabolic processes, resulting in an overall increase in the dissolved oxygen concentration as wastewater is treated. The increase signifies effective oxygen transfer from the air to the microorganisms, enhancing the performance of the biological treatment process.

An increase in dissolved oxygen concentration supports the breakdown of organic pollutants more effectively, leading to improved effluent quality as it progresses through the stages of treatment within the RBC system. Understanding this behavior is critical for monitoring the performance of wastewater treatment systems and ensuring that they function efficiently.