Wastewater volume activated flushing system consists of sealing devices that are especially arranged perpendicularly to the flow direction in order to backup the wastewater upstream of the section to be cleaned.

Depending on the type of sealing device, the sewer cross section is blocked entirely or partly. The flush gate, arched flush gate, flushing weir, flush sluice, inflatable pipe plug and rotating elbow are among the wastewater volume activated flushing systems [Dettm2005a].