The discharge pump, also called waste water pump, enables the transport of rough polluted water often containing organic, inorganic or mineral solids. The discharge pumps are mostly single stage versions and are not selfpriming. For the shaft sealing the wear resistant mechanical seals are used. The discharge pumps are available in a real dry well installation as a base plate pump or a close-coupled pump in a horizontal version - or as a vertical close-coupled pump, as a submersible dry well installation as a submersible pump with a surface cooling, with less power - or with a fluid-filled cooling jacket with higher performance, and a submersible pump completely submerged in the pumped medium, as stationary wet well installation. For the correct use as a pump for raw water, as a wastewater pump, as a sewerage pump, as a faeces pump or as a mud pump: to select the suitable materials, to select the appropriate design of the impeller shape as well, is of an enormous importance.