(a) All amounts received from the sale of bonds under this subchapter shall be deposited with the county or municipal treasurer, as appropriate. The county or municipal treasurer shall hold the amounts in trust exclusively for the purposes prescribed by this subchapter.
(b) The county or municipality shall hold all taxes collected to pay the interest on and principal of bonds issued under this subchapter in trust for the payment of the interest and principal. Any amount that exceeds the amount required to pay the annual interest on the bonds may be invested for the benefit of the sinking fund in:
(1) bonds issued under this subchapter;
(2) bonds of the state; or
(3) bonds of the United States.