For the purpose of Sections 11-144-2 and 11-144-3, "sewerage system" means a sewage treatment plant or plants, collecting, intercepting and outlet sewers, force mains, conduits, lateral sewers and extensions, pumping stations, ejector stations and all other appurtenances, extensions, or improvements necessary or useful and convenient for the collection, treatment, and disposal, in a sanitary manner, of sewage and industrial wastes.
65 ILCS 5/11-144-1