The governing authorities shall annually certify to the tax collector, or other officer charged with the duty of collecting taxes in the municipality, the annual installment of assessment due from each tract of land against which an assessment has been levied, together with the amount of the interest upon all unpaid installments at the same rate as that fixed in the bonds issued to raise money to pay the cost of the said improvements, which is to be paid in whole or in part by the owners of property abutting to the proposed improvements. In the event no bonds are issued to raise money to pay the cost of the said improvements, which is to be paid in whole or in part by the owners of property abutting to the proposed improvements, then the said assessments shall bear a rate of interest not to exceed six per centum per annum, and shall be fixed by the governing authorities of the municipality making such improvements at the time when the said assessments are made final. In the event any municipality has made assessments for special improvements authorized by law and there are special improvement bonds outstanding which are paid by special assessments levied against property abutting the streets so improved, the governing authorities of such municipality shall change the interest on such assessments to equal the rate of interest fixed in such bonds and such change shall become effective on the date the governing authorities take such action and shall not be retroactive. Any property owner who has elected to pay his assessment in installments shall have the right at any time to pay the balance of the assessment against his property in full, but in so doing he shall be required to pay all interest which would have accrued thereon had same not been paid until its maturity.

The collector shall thereupon enter upon the annual tax roll of the municipality, in a separate column, the amount of the installment and interest to be collected from each tract of land assessed, and said collector shall collect said installment, together with the interest upon all unpaid installments, together with, and at the same time he collects the annual municipal tax.