Any project shall be deemed self-liquidating if, in the judgment of the authority, the revenues and earnings of the authority or of the project or from the terminal or facilities of which the project shall become a part will be sufficient to pay the cost of constructing, maintaining, repairing, and operating the project and to pay the principal and interest of revenue bonds which may be issued for the cost of such project. Any buildings or facilities acquired by the authority under this chapter which are to be utilized in the manufacturing, processing, assembling, storing, or handling of any agricultural or manufactured produce or products or produce and products of mining or industry, which may be acquired by the authority for operation by a corporation, entity, or persons other than the authority, as distinguished from facilities acquired by the authority for operation by it as a port and allied facilities for the direct use of the public, shall be acquired and financed under this chapter only if, prior to the issuance of bonds therefor, the authority shall have entered into a lease or leases thereof or an agreement or agreements for the sale thereof pursuant to the terms of which the lessees or purchasers shall pay to the authority such rentals or installment purchase payments, or both, as upon the basis of determinations and findings to be made by the authority will be fully sufficient to pay principal of and interest on the bonds issued by the financing thereof, to build up and maintain any reserves deemed by the authority to be advisable in connection therewith, and to pay the cost of maintaining the buildings and facilities in good repair and of keeping them properly insured, unless the leases or agreements obligate the lessees or purchasers to pay for such insurance or maintenance. The authority is given full power and discretion to enter into any such agreements or leases as may in its judgment be desirable for the best interests of the authority. Any such agreement or lease may provide that any surplus capacity of the buildings or facilities which are the subject matter thereof may be utilized by and for the benefit of the general public, in which event, such surplus capacity may be maintained or operated, or both, by either the authority or by the lessee or purchaser under the lease or agreement, or in part by each, all as may be provided in the lease or agreement. Any project may include in part one or more buildings or facilities or combinations thereof to be leased or sold as provided in this Code section and in part other facilities described in paragraph (6) of Code Section 52-2-2, the revenues of the whole being allocated and pledged to the financing of the project as a whole; and in such event, the requirements of this Code section applicable to buildings or facilities to be leased or sold shall be applicable only to the part of the project which consists of the buildings or facilities to be so leased or sold.