Tennessee Wastewater Operator Practice Exam

Which issue is commonly associated with a high surface overflow rate in a clarifier?

1. Increased solids removal

2. Poor effluent quality

3. Enhanced biological treatment

4. Stabilized sludge production

The correct answer is: Poor effluent quality

A high surface overflow rate in a clarifier is commonly associated with poor effluent quality. When the surface overflow rate is too high, it can lead to inadequate settling of solids, causing those solids to be carried over into the effluent. This condition results in an increased concentration of suspended solids in the treated water, ultimately diminishing the quality of the effluent that is being released. In contrast, the other options would not typically result from a high surface overflow rate. Increased solids removal is generally associated with lower overflow rates that allow more time for settling. Enhanced biological treatment is linked to processes that promote effective microbial activity, which is not directly impacted by high overflow rates. Stabilized sludge production is also a function of the treatment process rather than a direct consequence of the overflow rate in the clarifier. Thus, poor effluent quality is the primary issue that arises when high surface overflow rates occur in clarifiers.