Page 9 - Simplified Wastewater Treatment Fundementals\Pumps and Pumping

Pumps and their Applications

Pumps move liquids, sludge, biosolids and air. There are two major categories of pumps,

Centrifugal and Positive Displacement.

Centrifugal pumps behave like fans. The fluid enters the pump along, or near to the

rotating axis and is accelerated outward and exits. A centrifugal pump impeller provides

rotational force. The volute serves as the encasement around the impeller, turning the

rotational force into hydraulic energy.

A centrifugal pump can operate against a throttled, or even closed discharge valve,

because there is a wide tolerance or gap between the impeller and volute. Centrifugal

pumps move large volumes of liquids with a shallow suction lift and discharge head

pressure.

Examples of centrifugal pumps include: large volume blowers and high-volume lift pumps

like raw water or wastewater influent flow pumps, RAS pumps, or aeration basin

recirculation pumps. Smaller examples include WAS pumps, sump pumps, HVAC air

circulation units, and vent fans.