No municipality shall have the power to pay out of its general funds or otherwise contribute any part of the costs of acquiring a project and shall not have the power to use land already owned by the municipality, or in which the municipality has an equity, for construction thereon of a project or any part thereof, unless the municipality is fully reimbursed for the value of the land as may be determined by a current appraisal, or unless the city leases the land at an annual rental fee of not less than five percent of the appraised value. The entire cost of acquiring any project must be paid out of the proceeds from the sale of bonds issued under the authority of the Pollution Control Revenue Bond Act; provided, that this provision shall not be construed to prevent a municipality from accepting donations of property to be used as a part of any project or money to be used for defraying any part of the cost of any project.