7 Machines and mechanical apparatus for sewer cleaning, gully cleaning, road cleaning, emptying of cesspits, emptying of oil separators, emptying of fat traps, in each case with or without water recycling, as well as for cleaning and disposing of substrates resulting from sewer cleaning, gully cleaning, road cleaning, emptying of cesspits, emptying of oil separators, emptying of fat traps, in particular for the recovery of purified sand, oil or fat from such substrates, and structural parts therefor