In a centrifugal wastewater pump, which component primarily transfers energy to the fluid?

• A. Impeller
• B. Drive Shaft
• C. Volute
• D. Check Valve

Answer: (A)

The energy is added to the fluid by the impeller blades as the rotor turns. As the impeller spins, it grabs incoming wastewater and throws it outward, increasing its velocity and imparting kinetic energy. When that high-velocity flow enters the volute, some of that energy is converted into pressure head, delivering higher discharge pressure. The drive shaft simply transfers mechanical power from the motor to the impeller and does not itself transfer energy to the fluid. The volute’s role is to collect and smooth the flow while aiding the conversion of velocity energy to pressure, not to add energy directly. The check valve prevents backflow and is not involved in energy transfer.