The cost of the assessment of any such nuisance paid by the city and not reimbursed by the owner on or before September 1 of each year shall be reported by the City Forester to the Council and the Council shall assess and levy and cause to be collected the amount of such costs as a special assessment upon and against the premises and property upon which said nuisance existed in like manner as such other special assessments, payable in one sum.
('69 Code, § 6.71, Subd. 8)