For the purpose of carrying the foregoing provisions of this chapter into effect, it shall be the duty of the Director of Community Development from time to time to ascertain and cause all nuisances arising under this chapter to be abated. In all cases when a nuisance shall be found in any building, or upon any grounds or other premises which can be charged by assessment with the expense of removal, notice shall be given to the owner or occupant of the building or other premises, when known and can be found, to remove the nuisance; and in case of his refusal or neglect to comply with such notice, the Director of Community Development shall have the same abated and report the expenses thereof to the City Council. (1956 Code ch. 21 art. V)