The Director of Public Service shall be appointed by the Mayor for a term concurrent with that for which the Mayor is elected and shall be the head of the Department of Public Service, and shall be charged with the construction, improvement, repair and maintenance of streets, sidewalks, alleys, lanes and bridges, the cleaning, re-surfacing, repairing, sprinkling and lighting of streets and public places, the collection and disposal of waste, and the preservation of all property belonging to the Municipality and pertaining to the functions thereof.