Any municipality that issues bonds under this subtitle for the development of any sewerage facility may appropriate or expend the revenue from the sewerage facility for: Paying, when due, all bonds and the interest on the bonds, for the payment of which the revenue is pledged, charged, or otherwise encumbered; Providing for all expenses of operation and maintenance of the sewerage facility; Paying and discharging the principal and interest on any notes, bonds, or other obligations: Not issued under this subtitle, but for payment of which the revenue of the sewerage facility is pledged, charged, or encumbered; or Issued to finance the development of the sewerage facility, but which do not constitute a lien, charge, or encumbrance on the revenue of the sewerage facility; and Providing a reserve for improvements to the sewerage facility. Any municipality may transfer the revenue of any sewerage facility to the general funds of the municipality only after the municipality has made adequate provision for the purposes set out in subsection (a) of this section.