All City taxes on real property remaining uncollected by the City Treasurer at the end of the last day for collection of County and School taxes shall be returned to the County Treasurer in the manner and with like effect as provided by statute for returns by township treasurers of township, school and county taxes. Such returns shall include all the additional assessments, charges and fees hereinbefore provided, which shall be added to the amount assessed in said tax roll against each property or person. The taxes thus returned shall be collected in the same manner as other taxes returned to the County Treasurer are collected, in accordance with statute, and shall be and remain a lien upon the property against which they are assessed until paid. If by change in statute or otherwise, the County Treasurer is no longer charged with the collection of delinquent real property taxes, such taxes shall be collected in the manner then provided by statute for the collection of delinquent township, school and county taxes.