Tennessee Wastewater Operator Practice Exam

Which of the following best describes what may happen to treated effluent if the flow is too high?

1. It may become overloaded with nutrients

2. It may result in reduced treatment efficiency

3. It will always be acceptable for discharge

4. It will lead to increased biofilm growth

The correct answer is: It may result in reduced treatment efficiency

When the flow of treated effluent is too high, it can lead to reduced treatment efficiency. In wastewater treatment systems, each part of the process is designed to handle a specific volume of inflow at optimal conditions. When the flow exceeds design capacity, the treatment processes—such as biological treatment, sedimentation, and filtration—may not have enough time to effectively remove contaminants. As a result, the overall efficiency drops, impairing the system's ability to adequately treat the wastewater before it is discharged. This can potentially lead to higher levels of pollutants in the effluent, which may not meet regulatory standards for discharge into the environment. In contrast, the other options do not accurately capture the primary concern of high flow situations. While high flow can sometimes lead to nutrient overload, it is the treatment efficiency that is most immediately affected. Increased biofilm growth might occur in some circumstances, but it is not a guaranteed consequence of high flow and does not directly reflect the main issue of efficiency loss. Discharging effluent that is always acceptable is unrealistic, especially when treatment efficiency is compromised. Therefore, the primary issue in situations of excessive flow is the reduction in treatment efficiency.