Texas Wastewater Class B Practice Exam

Which type of pump is most likely used for discharging into a 10-inch diameter pressure sewer main?

1. Diaphragm pump

2. Positive displacement pump

3. Centrifugal pump

4. Screw pump

The correct answer is: Centrifugal pump

The correct answer is a centrifugal pump, which is commonly used in applications like discharging into a pressure sewer main. Centrifugal pumps are designed to move fluids by converting rotational energy, usually from a motor or engine, into hydrodynamic energy. This makes them suitable for transferring large volumes of liquids through relatively large diameters of pipes, such as a 10-inch pressure sewer main. Centrifugal pumps are especially efficient and effective at handling relatively low-viscosity fluids, which is typical for wastewater, making them a favored choice in wastewater applications. Their ability to provide a continuous flow, combined with the capacity to handle changing conditions, equips them well for the operational demands of pressure sewer systems. In comparison, diaphragm and positive displacement pumps are often used for applications that require precise control over the flow rate or the handling of more viscous fluids, which may not be necessary for all pressure sewer applications. Screw pumps, while beneficial for specific circumstances (like handling thick or viscous materials), are generally less common in pressure sewer systems than centrifugal pumps due to their design and operational nuances. This context helps to clarify why centrifugal pumps are typically the ideal choice for discharging into a pressure sewer main of that size.