70 ILCS 2605/7c
The Sanitary District, in addition to the other powers vested in it, is empowered to pledge, as collateral security for the payment of principal and interest of any securities heretofore or hereafter sold to the United States of America, or any instrumentality thereof, under an act of Congress entitled, "An Act to encourage national industrial recovery, to foster fair competition, and to provide for the construction of certain useful public works, and for other purposes," any judgment heretofore or hereafter rendered by any court in favor of said sanitary district, all open accounts, bills receivable, and the proceeds thereof, now or hereafter existing in favor of such sanitary district, and revenue derived from the sale of electrical energy by said sanitary district, upon such terms as may be mutually agreed upon between the said sanitary district and the purchaser of said securities, or as may be provided by contract previously entered into between said sanitary district and such purchaser.
70 ILCS 2605/7c