narrower concept activated sludge plant Concept aeration basin Concept conduit-type sewer Concept drainage line Concept drainage network Concept drainage system Concept equalizing tank Concept intake structure Concept intercepting sewer Concept main sewer Concept main sewer Concept outlet structure Concept pipe network Concept pipeline Concept pressure drainage Concept pumping plant Concept pumping station Concept rain retention basin Concept recipient Concept retention basin Concept road drainage Concept sag pipe Concept sediment bucket Concept sedimentation tank Concept service trench Concept sewage disposal Concept sewage inlet Concept sewage law Concept sewage purification Concept sewage purification plant Concept sewage purification plant Concept sewage purification plant Concept sewer Concept sewer pipe Concept sewer tunnel Concept sewerage Concept small sewage treatment plant Concept storage basin Concept surface drainage Concept town drainage Concept water treatment plant Concept