Notwithstanding the restrictions and limitations prescribed by the act to which this act is a supplement, the commissioners may enter into a lease with a lessee at such minimum annual rental and with such other terms as to the flow and discharge to be received and the computation of the quantities thereof as may be approved by the commissioners; provided, such lessee shall be a municipality, or a sewer district created under the provisions of section 40:63-32 of the Revised Statutes, which for more than ten years past shall have had a contract or arrangement with a contracting agency for the discharge of sewage into the intercepting sewer of not more than one hundred thousand gallons average daily flow. L.1944, c. 214, p. 752, s. 1.