Pumped medium in wastewater technology
During dimensioning, care must be taken to ensure that explosion-proof units are used to convey sewage containing faeces from shafts connected to the public sewer system.
See for example also UVV 54.Kanalisationswerke:
§2 The sewer system, its access points, wells, shafts and rainwater inlets as well as collection points and venting valves in the pressure pipe system are considered to be potentially explosive in their entirety ...
resp. explosion protection guidelines (Ex-RL) of the professional association (GUV 19.8) edition 06.96, example collection no. 184.108.40.206.
There are, however, other regulations that may have to be taken into account. You can obtain more detailed information for your specific case from the trade association, the trade supervisory authority, the TÜV or the building authority.