Basic Wastewater Operator Practice Exam

What should never be done when placing a positive displacement sludge pump into operation?

1. The discharge valve should be closed

2. The discharge valve should be open

3. It should always be operated at maximum speed

4. The inlet valve should be closed

The correct answer is: The discharge valve should be closed

When placing a positive displacement sludge pump into operation, it is critical that the discharge valve is open. This type of pump operates by moving a fixed volume of fluid with each cycle; therefore, if the discharge valve is closed, it can create excessive pressure in the pump, leading to potential damage or failure. Opening the discharge valve allows the pumped material to flow freely, preventing undue stress on the pump mechanisms and facilitating proper functioning. The other options highlight actions that would not be appropriate under operational guidelines. When closed, the inlet valve prevents fluid from entering the pump, which is necessary for it to function. Operating at maximum speed is not advisable, as each pump has an optimal operating range and going beyond that can lead to performance issues. Thus, ensuring the discharge valve is open is a fundamental safety and operational standard in the use of positive displacement sludge pumps.