SECTION 31.  Collection of taxes, fines and assessments..
   Unless otherwise provided, it shall be the duty of the treasurer of the city, or other individual who may be designated by general law, by this Charter or by the common council, to collect and promptly pay into the city treasury all taxes, fines, special assessments and other money due the city.  All such taxes, fines, special assessments (except assessments for permanent or semi-permanent public improvements) and other money due the city are hereby declared to be debts owing to the city, for which the debtor shall be personally liable, and the treasurer, or other individual so designated, may enforce this liability by appropriate civil action in any court of competent jurisdiction, and is hereby vested with the same rights to distrain for the same as is vested in the sheriff for the collection of taxes.  Such treasurer or other individual shall give bond, conditioned according to law, in such penalty and with such security as the common council may require.