Florida Wastewater Practice Test

Which test is typically recommended for determining the strength of influent wastewater in activated sludge control?

1. BOD

2. COD

3. TSS

4. pH

The correct answer is: COD

The recommended test for determining the strength of influent wastewater in activated sludge control is the Chemical Oxygen Demand, or COD. COD measures the total amount of oxygen that is required to chemically oxidize organic compounds in water. This provides a robust indicator of the organic strength of the influent, as it accounts for both biodegradable and non-biodegradable material present in the wastewater. Monitoring COD is crucial in activated sludge systems because it helps operators understand the influent characteristics. High COD levels could indicate a greater quantity of organic material, which may require adjustments in aeration and retention times to optimize the treatment process. Furthermore, COD testing can be performed more quickly than biochemical oxygen demand (BOD) tests, allowing for more timely management decisions regarding the aeration and treatment processes. In contrast, while BOD is also important in assessing organic strength, it only measures the amount of organic material that can be biologically decomposed over a specific period, typically five days. This makes BOD less suitable for quick evaluations in activated sludge control, where timely information is key. Total suspended solids (TSS) and pH measurements are also relevant in wastewater treatment but serve different purposes. TSS indicates the solid pollutants that could affect the system’s operation and efficiency, while