Waste water gathered in the sewer system cannot always be led to a sewage treatment plant over a falling terrain. In other cases, purified waste water has to be elevated when high water occurs in the sewage treatment plant. For these reasons, the Ruhrverband owns and runs a total of 117 pump stations for creating the required run-off capacity (set date: August 1st, 2011). Inlet and high water pump stations, like intermediate pump stations, are usually located on the premises of the sewage treatment plant. Booster pump stations transferring sewage from individual settlement areas are sometimes at a distance of several kilometres from the sewage treatment plant. Storm water pump stations ensure transfer of the increased flow caused by precipitation.
Sewers and pressure pipelines
Besides its sewage treatment plants, the Ruhrverband operates around 325 km of sewers and pressure pipelines as connecting conduits. They are normally used for connecting individual settlement areas to the sewer network which would otherwise have to be served by their own sewage treatment plant. Apart from transferring sewage, some of these conduits are also used for gathering waste water. In most of those cases, the Ruhrverband has only acquired the right to use such networks as a third party. Besides inlet installations, the Ruhrverband also operates the outlet canals of its sewage treatment plants and runs overflow channels in and around rainwater treatment plants. These can be several hundred metres in length. Some of the Ruhrverband sewage treatment plants do not have their own, fully-fledged sludge treatment installations. Here, the sewage sludge is transferred to neighbouring plants in pressure pipelines for further treatment.