In order to comply with applicable state and federal water pollution control standards and to be eligible for grants-in-aid or other allotments, notwithstanding any provision of law to the contrary, each municipal corporation and each county of this state is authorized, in the discretion of its governing authority, to enter into valid and binding contracts with each other and with private persons, firms, associations, or corporations, for any period of time not to exceed 50 years, to provide industrial waste water treatment services to such private persons, firms, associations, or corporations, provided that such contracts shall provide that the charge for the services shall never be less than the actual cost to the municipal corporation or county for providing the services.