Neither the Pollution Control Revenue Bond Act nor anything herein contained shall be construed as a restriction or limitation upon any powers which a municipality might otherwise have under any laws of this state, but shall be construed as cumulative; and the Pollution Control Revenue Bond Act shall not be construed as requiring an election by the voters of a municipality prior to the issuance of bonds hereunder by such municipality, and all other laws of the state relative to public contracts and properties shall have no application to projects or bonds issued under this act.