An Ordinance providing for the construction of a sub-sewer on the center line of East State Street from a point 280 feet west of the west line of Main Avenue to the main sewer at the center line of Spring Avenue in the City of Ballard, and to assess the cost thereof to the abutting property and property benefited by the construction of said sub-sewer and providing for the payment of said cost and expense and establishing a sub-sewer district No. 21.