What Is The Principle Of Water Level Control For Sewage Pumps

Aug 15, 2025

Sewage pumps, also known as wastewater pumps, are used to transport sewage containing organic, inorganic, or mineral solid components. Sewage pumps are primarily single-stage centrifugal pumps and do not have self-priming capabilities. They operate by using an impeller to draw and discharge sewage and are designed to work submerged in the medium being transported. The pump shaft seal employs a wear-resistant mechanical face seal.

When using various sewage pumps, if there is no dedicated personnel to monitor them, the pumps must operate based on the water level control principle. Otherwise, for example, if a WQ submersible sewage pump continues to run after draining the water and fails to stop promptly, the lack of cooling water may cause the motor to burn out. If the pump malfunctions and cannot shut down automatically, the problem may worsen.

The water level control principle of sewage pumps mainly relies on a float level sensor to send start/stop signals to the control panel. The float is fixed in the pool. For instance, if the pool depth is 6 meters, the preset high water level is set at 5.5 meters and the low water level at 1 meter. When the water level rises to 5.5 meters, the float rises with the water and stands upright, sending a signal to the control panel to start the pump. As the water level drops to the minimum level of 1 meter, the float tilts downward and sends a signal to the control panel to cut off power to the pump. Regardless of the water level control method used, the working principle of sewage pumps is essentially the same.

Sewage pumps can be widely applied in industries such as food processing, construction, papermaking, sugar production, metal processing (e.g., metal electrolysis), mining, and water resource extraction (e.g., cooling water, seawater desalination). Depending on requirements, sewage pumps can be categorized into municipal sewage pumps and industrial sewage pumps. Municipal sewage pumps are mainly used to transport the following mediums: urban sewage (e.g., residential sewage, fecal wastewater), wastewater (e.g., sedimentation tank cleaning water), sludge (e.g., activated sludge, raw sludge, digested sludge, and seeded sludge), and rainwater.

Digested sludge refers to raw sludge that has undergone anaerobic digestion, while seeded sludge refers to externally introduced activated sludge used for new system commissioning. However, for sludge-like liquids, it is more appropriate to use slurry pumps.