Wastewater Collection Process
Wastewater is collected through 55 miles of underground sewer pipes from
homes and businesses to the Wastewater Treatment Facility.
Pumping stations in sewage collection systems, also called lift stations, are normally designed to handle raw sewage that is fed from underground gravity pipelines (pipes that are sloped so that a liquid can flow in one direction under gravity). The City of Saint Peter has four lift stations: South Lift, Traverse des Sioux Lift, Main Lift, and Kasota Lift. Sewage is fed into and stored in an underground pit, commonly known as a wet well. The well is equipped with electrical instrumentation to detect the level of sewage present. When the sewage level rises to a predetermined point, a pump will be started to lift the sewage upward through a pressurized pipe system called a sewer force main or rising main from where the sewage is discharged into a gravity manhole. From here the cycle starts all over again until the sewage reaches its point of destination—usually a treatment plant. By this method, pumping stations are used to move waste to higher elevations. In the case of high sewage flows into the well (for example during peak flow periods and wet weather) additional pumps will be used.
Liquid Assets – The Story of Our Water Infrastructure (video link)
Vactoring, Jetting, Televising
Cleaning and inspecting sewer lines are essential for maintaining a properly functioning system. Jetting directs high velocities of water against pipe walls. The process removes debris and grease build-up, clears blockages, and cuts roots within small diameter pipes. Televising equipment helps staff inspect and identify problem areas within the collection system.