Upon the confirmation of each special assessment roll, the special assessments thereon shall become a debt to the city from the persons to whom they are assessed and, until paid shall be a lien upon the property assessed for the amount of such assessments and all interest and charges which may accrue thereon. Such lien shall be of the same character and effect as that created by this Charter for city taxes and shall be treated as such in all procedures for the collection of special assessments and all collection fees or charges and interest which may have been added or accumulated thereto.