a valve for diluting and activating polymer molecules used in wastewater treatment is designed to divert a desired amount of dilution water around the primary dilution and activation apparatus to the inlet of the secondary dilution apparatus . water in the valve passes through a slot which extends through about 180 degrees . the ends of the slots have square corners , so that the total volume of water which passes through the valve and the relative proportion of water which passes through the primary and secondary activation apparatus can be adjusted independently of each other . in this manner , a control system can be used which only requires information regarding the total amount of water supplied to the system in order to execute operator instructions as to the total volume of water required and the proportions of water to be supplied to the primary and secondary dilution apparatus .