Tennessee Wastewater Operator Practice Exam

What does the difference between soluble BOD in the influent and effluent represent?

1. Total suspended solids

2. Readily biodegradable COD

3. Non-biodegradable BOD

4. Organic matter removal rate

The correct answer is: Readily biodegradable COD

The difference between soluble Biological Oxygen Demand (BOD) in the influent and effluent reflects the amount of readily biodegradable organic matter that has been treated or removed during the wastewater treatment process. Soluble BOD specifically measures the amount of oxygen that microorganisms will consume while decomposing organic matter in a water sample. In this context, the influent represents the BOD of the incoming wastewater, while the effluent represents the BOD of the treated water being discharged. Analyzing the difference allows operators to gauge how effectively the treatment process has broken down easily digestible organic material. Readily biodegradable Chemical Oxygen Demand (COD) encompasses organic compounds that microorganisms can utilize for growth and energy, and this is aligned with the process of biological treatment in wastewater facilities. Therefore, the measurement captures the performance of biological treatment mechanisms, which are aimed at reducing the concentration of organic pollutants that can lead to oxygen depletion in receiving water bodies. Understanding this difference is critical for wastewater treatment operators, as it helps to evaluate not just the efficiency of the treatment system, but also ensures compliance with environmental discharge regulations.