Tennessee Wastewater Operator Practice Exam

What is the purpose of the last pond in a pond treatment system?

1. To aerate the wastewater

2. To remove biological solids produced in the first two ponds

3. To disinfect the effluent

4. To increase the retention time

The correct answer is: To remove biological solids produced in the first two ponds

In a pond treatment system, the last pond plays a critical role in the treatment process. Specifically, its primary purpose is to remove biological solids, also known as sludge, that have been produced in the earlier ponds of the system. During the treatment process, organic material is broken down by microorganisms, and as a result, biological solids accumulate. The last pond acts as a settling or maturation area, where the remaining solids can settle out of the water column, allowing for clearer effluent to be discharged or further treated. This settling process is essential for ensuring that the water released from the system meets environmental discharge standards and is safe for its intended use, such as irrigation or returning to natural water bodies. While other functions such as aeration, disinfection, or increasing retention time are important aspects of wastewater treatment systems, the specific role of the last pond is primarily focused on the removal of biological solids to improve the quality of the treated effluent.