The locality making assessments under the provisions of this article may provide that the persons against whom the assessments have been made may pay such assessments in equal installments over a period not exceeding 20 years, together with interest on the unpaid balances at an annual interest rate not to exceed the rate of the index of average yield on United States Treasury securities adjusted to a constant maturity of one year as made available by the Federal Reserve Bank at the time the assessment ordinance was adopted. Such installments shall become due at the same time that real estate taxes become due and payable in the locality in which the assessment was made, and the amount of each installment, including principal and interest, shall be shown on a bill mailed, not later than 14 days prior to the installment due date, to each such person by the treasurer. In cities, the council, in its discretion, may cause the payment of the amount assessed or apportioned against each landowner, or fixed by agreement with him, for improving sidewalks upon streets or for improving and paving alleys to be made in such manner divided into such installments as shall be determined by the council, bearing interest at such rate as shall be fixed by the council. If an assessment is made under the provisions of this article for the installation of street lights, the locality making the assessment may provide by ordinance that the actual costs of installing, maintaining and operating such street lights be charged to and collected from each landowner as a separate component of the locality’s billing system for any public utility.