(a) The principal of and interest on the bonds shall be payable when due and payable from money appropriated from time to time by New Castle County.
(b) The County Council in fixing the rate of taxation shall annually provide for a sum equal to the amount of such bonds in addition to the amount necessary to pay the interest upon the unpaid bonds as before provided, which shall, when collected and paid to the Department of Finance be set apart by it in a separate account to be opened for that purpose; and the Department of Finance shall apply the said sum annually to the payment of such part of said loan and interest thereon as may from time to time become due under this chapter.