Why are BOD samples generally not used for process control?

BOD, or Biochemical Oxygen Demand, measures the amount of oxygen that microorganisms will consume while decomposing organic matter in water. One of the key reasons BOD samples are generally not used for process control in treatment plants is that the test takes a long time to complete, typically five days. This delay in obtaining results makes it impractical for real-time adjustments in the treatment processes, which require immediate feedback to effectively manage operations.

In contrast, other methods for monitoring water quality or organic load, such as COD (Chemical Oxygen Demand) or online sensors, can provide quicker results, allowing for timely process adjustments. The lengthy BOD testing period limits its application in scenarios where rapid intervention is crucial for maintaining optimal operational conditions.