Tennessee Wastewater Operator Practice Exam

Why is the control of filamentous organisms important in activated sludge systems?

1. To reduce effluent pH

2. To prevent foaming and settling issues

3. To increase nutrient intake

4. To minimize energy use

The correct answer is: To prevent foaming and settling issues

Control of filamentous organisms in activated sludge systems is vital primarily to prevent foaming and settling issues. Filamentous bacteria can proliferate excessively under certain conditions, leading to the formation of long, stringy clumps that do not settle well during the sedimentation process. This can result in poor settling of the sludge and the potential for scum or foam formation at the surface of the tanks. When foaming occurs, it can negatively impact the treatment process by allowing untreated wastewater to escape with the effluent or by causing operational difficulties that may require additional management interventions. Furthermore, poor settling of activated sludge can lead to an increase in total suspended solids (TSS) in the treated effluent, which may violate discharge permits and result in environmental issues. Therefore, maintaining the balance of filamentous organisms is crucial for ensuring efficient operation of the treatment process, achieving compliance with regulatory standards, and ensuring the overall effectiveness of wastewater treatment.