Basic Wastewater Operator Practice Exam

Why are check valves used with centrifugal pumps?

1. To increase head pressure

2. To cause more work for the installers

3. To prevent wastewater in the discharge line from flowing back through the pump

4. To allow for less water to leave the pump

The correct answer is: To prevent wastewater in the discharge line from flowing back through the pump

Check valves are essential components in the operation of centrifugal pumps, primarily due to their role in preventing backflow. When a centrifugal pump is in operation, it creates a pressure difference that pushes water through the discharge line. If the pump were to turn off or if there were a drop in system pressure, without a check valve, the water in the discharge line could flow back into the pump. This backflow could lead to several issues, including potential damage to the pump components, increased wear, or even the introduction of contaminants back into the system. By installing a check valve in the discharge line, the valve allows water to flow in one direction—away from the pump—while effectively blocking any reverse flow. This ensures that the system remains pressurized and operational without having to deal with fluctuations caused by backflow, improving efficiency and protecting the integrity of the pump and the entire wastewater system. Thus, the function of the check valve is critical to the reliability of pumps in wastewater treatment applications.