What are the two types of lifting devices used for automatic discharge in sump or ejector basins?

The correct choice highlights the two primary systems used in sump or ejector basins for lifting and discharging wastewater or effluent. Centrifugal pumps are designed to move fluid by converting rotational kinetic energy into hydrodynamic energy, making them suitable for transporting large volumes of liquid effectively, which is often required in sump applications where significant water accumulation occurs.

Pneumatic ejectors, on the other hand, utilize compressed air to facilitate the movement of liquids, particularly in scenarios where electric pumps might not be practical or desired due to potential submerged conditions or electrical hazards. This makes them ideal for applications in sewage and effluent systems where solids might be present in the liquid.

Together, these devices complement each other in functionality and application: centrifugal pumps are effective for continuous flow, while pneumatic ejectors provide an alternative for specific situations requiring less maintenance or different operational parameters. The combination reflects a comprehensive approach to managing wastewater in various environments.