Tennessee Wastewater Operator Practice Exam

What operational practice can help mitigate bulking conditions in an aeration tank?

1. Decrease aeration intensity

2. Increase organic loading

3. Monitor pH levels

4. Adjust wasting rates

The correct answer is: Adjust wasting rates

Adjusting wasting rates is an effective operational practice for mitigating bulking conditions in an aeration tank. Bulking refers to the excessive growth of floc-forming bacteria, which can lead to poor settling characteristics of the sludge during the clarification process. By managing the wasting rates, operators can effectively control the amount of biomass that remains in the system, thereby reducing the proliferation of the filamentous organisms that contribute to bulking. When the wasting rates are appropriately adjusted, it can help maintain a balanced mixed liquor suspended solids (MLSS) concentration. This balance is crucial as it influences the competition for nutrients and oxygen among the microbial populations. Properly managing the wasting rates allows for the removal of excess biomass while retaining enough microorganisms in the system to ensure efficient treatment of wastewater. In contrast, options like decreasing aeration intensity or increasing organic loading may exacerbate bulking problems by creating conditions that favor filamentous bacteria over floc-forming bacteria. Monitoring pH levels is important for overall process control but does not directly address the issue of bulking as effectively as adjusting wasting rates.