70 ILCS 2805/9
In providing works for the disposal of industrial sewage, commonly called industrial wastes, in the manner above provided whether said industrial sewage is disposed of in combination with municipal sewage or independently, said sanitary district shall have power to apportion and collect therefor, from the producer thereof, fair additional construction, maintenance and operating costs over and above those covered by normal taxes, and in case of dispute as to the fairness of such additional construction, maintenance and operating costs, then the same shall be determined by a board of three engineers, one appointed by such producer or producers, one by said sanitary district, and the third by the two selected as above described. In the event the two so selected shall fail to agree upon a third then upon the petition of either of the parties the circuit judge shall appoint such third engineer. A decision of a majority of said board shall be binding on both parties and the cost of the services of said board shall be shared by both parties equally.
70 ILCS 2805/9