Dewatering is the process of getting rid of unwanted water in any material. Dewatering can be done in two ways; either by pumping out groundwater or by draining off excessive surface water. The most common uses of dewater pumps include trench shoring, reservoir dewatering, basement dewatering, site wetland restoration, and oil field production wells. There are four types of pumps used for dewatering:
1) Jet Pumps
Jet Pumps are best for pumping out shallow groundwater. This type of pump is also used in removing solids and scum from water and wastewater. The main components of a jet pump include:
- Discharge head: The most important component because it determines the total energy available for lifting water
- A nozzle: Creates a high-speed stream of fluid that entrains (draws into or catches in something) atmospheric air, allowing more efficient transportation
- Suction pipe: Submerged below the surface to create suction, which draws fluid into the pump
- Intake strainer basket: Collects debris; there may be multiple baskets
2) Centrifugal Pumps
Centrifugal pumps are best used for high-volume pumping. They are often used in construction to dewater foundations, basements, and excavations. The main parts of a centrifugal pump include:
- Impeller/impellors: The rotating part that moves water through the pump by exerting force on it
- Shaft: The driveshaft that transfers power to the impeller assembly
- Casing: Houses all components within its outer shell
3) Diaphragm Pumps
A diaphragm is a flexible membrane or sheet which separates fluids with different properties. These types of pumps are often found where noise must be kept to a minimum. The main components of a diaphragm pump include:
- Housing: Carries the inlet and outlet ports
- Shaft: Transfers power to the diaphragm assembly
- Diaphragm (seal): Moves up and down inside the housing, creating suction for drawing in fluid
4) Submersible Pumps
Submersible or deep-well pumps are commonly used when there is not enough room for standard borehole pumps. They can also be used in small diameters with additional benefits, including easier installation, lower maintenance requirements, and greater protection against freezing. The main parts of a submersible pump include the impellers. The impellers are the rotating part that moves fluid through the pump.
