Which pump type uses pneumatic injection to lift wastewater?

• A. Pneumatic Injectors (Air Lift)
• B. Centrifugal
• C. Progressive Cavity
• D. Jet Pump

Answer: (A)

Air-lift pumping uses compressed air injected into the wastewater at the bottom of a lift tube. The air forms bubbles that mix with the liquid, lowering its apparent density and creating buoyant forces that drive the mixture upward through the pipe. This pneumatic injection is the defining feature of Pneumatic Injectors (Air Lift), making them the choice for lifting wastewater in setups where solids or slurries might clog other pump types.

Centrifugal pumps rely on an impeller to impart velocity and move fluid, not on air injection. Progressive cavity pumps use a rotating rotor inside a stator to displace fluid, a positive-displacement mechanism without injecting air. Jet pumps use a high-velocity water jet to entrain more water and create suction, without introducing air into the pumped stream.