Any and all bonds issued under the provisions of this act, and the interest coupons attached thereto, shall be paid by revenue derived from an annual ad valorem assessment and levy upon all of the real property within the district, which real property shall be and remain liable to be assessed for the payment of such bonds until such bonds, both principal and interest, are fully paid, and said assessment shall be made, levied and collected in the same manner as are general county and state taxes. Said bonds, interest coupons and the assessments made for their payment shall be and remain a perpetual lien upon all of the real property located within said district until said bonds and all interest coupons thereto appurtenant have been paid in full. The sale of any land within the district for general or other taxes [shall] in no manner divest said real property so sold of the lien of said bonds, interest coupons and assessments.