The accomplishment of the purposes stated in Sections 29-3-151 through 29-3-183 being for the benefit of the people of the county and for the improvement of their properties, the authority, in carrying out the purposes of Sections 29-3-151 through 29-3-183, will be performing an essential public function and shall not be required to pay any tax or assessment on the project and related facilities or any part thereof except as provided herein, and the interest on the bonds issued hereunder shall at all times be free from taxation within this state; and the state hereby covenants with the holders of any bonds to be issued hereunder that the authority shall not be required to pay any taxes or assessments imposed by the state or any of its political subdivisions or taxing districts on improvements funded from the avails of the issue except assessments for municipal utilities benefiting the property.