In the countryside most of the sewer pipelines carried runoff with flows of pluvial or drainage origin. Domestic wastewater treatment was solved with individual containers per household. Hence in many places a new pipeline and facilities are needed for a more efficient, collective sewage treatment.
I have been setting up a sanitary sewer system in an village close to a nature reserve zone. Later I moved to an area where new industry buildings are to be built, for the setting up of the sanitary sewer pipelines. I have been working mainly with the manholes, and concrete & mortar related steps rather than the positioning of pipes, a task I dealt with some years ago, with such a good topography team as I haven't seen again.