The backwater lifting station for wastewater with and without sewage is equipped with two submersible pumps, one motor-driven and one mechanical closure system and a backflow preventer. The collection tank made of permanently resistant polymer (PE) has an enclosed pump tank. Quick-release closures enable the integrated components to be removed easily. Normally, draining takes place via the natural fall to the sewer. Backwater is detected by an optical probe, which causes the motor-driven closure system to close automatically and there is no longer free passage to the sewer. During the backwater phase, the water drains via a pressure pipe, which carries the wastewater into the sewer. The pressure pipe must be within a welded PE pipe; in the case of pump SPF 4500 this must be additional enclosed in a pressure relief chamber. The KESSEL modular system provides different upper sections and engineering chamber options as accessories.