Effect of Speed Variation on Clogging of Sewage Pumps

Pump clogging is a well-known problem due to the increasing amount of nonwoven wet wipes in the wastewater system. In addition, the usage of water decreases which causes higher concentration of solids in the wastewater. Based on the high variation of sewage flow many operators of sewer systems and sewage pumping stations were motivated to act that the wastewater is pumped as needed. It means that with reducing costs of frequency-controlled drives the usage of pumps with speed variation became a more state of the art application. The current operation mode when speed variation in wastewater pumps are used, affects the pumping of sewage water depending on inflow and the minimum velocity in the pipes. Until now, there is no answer which functionality and clogging occurs in the pump when speed changes. The study investigates how speed influences the clogging phenomena of wastewater pumps. The pumps have been approved at a test stand in a laboratory that is designed for proving wastewater pumps. The test includes several speeds with different quantities of wipes in a short-time and long-time functional performance test. The effects on the pumps and their clogging behavior are very different.