70 ILCS 2605/4a
The chairman of the committee on finance of the board of trustees of any sanitary district organized under this Act may designate in writing one or more persons who shall have authority to affix his signature as chairman to any written instrument which is required to be signed by the chairman. The chairman shall send written notice of this designation to the board of trustees of the sanitary district, stating the name or names of such person or persons whom he has selected and what instrument or instruments such person or persons will have authority to sign. The written signature of the chairman executed by such person or persons so designated with the signature of the person so designated underneath shall be attached to the notice. The notice with the signatures attached shall be recorded in the journal of the proceedings of the board of trustees. When the signature of the chairman is placed on a written instrument at the direction of the chairman in the specified manner, the instrument in all respects shall be as binding on the sanitary district as if signed by the chairman in person.
70 ILCS 2605/4a