No application to sanitary district with population over 1,000,000. Nothing contained in the Civil Administrative Code of Illinois shall apply to or be construed in any manner to affect the property, real, personal, or mixed and wherever situated, or the channels, drains, ditches, and outlets and adjuncts and additions thereto and their use, operation, and maintenance and the right to the flow of water therein for sewage dilution, or affect the jurisdiction, rights, power, duties, and obligations of any existing sanitary district that now has a population of 1,000,000 or more within its territorial limits.