The Deionized Water System shall include regeneration units for the ion exchange beds. The cation regeneration unit shall supply dilute acid to the cation units during regeneration and the anion regeneration unit shall provide a heated dilute caustic solution to the anion units during regeneration. The units shall also supply acid and caustic to the neutralization tank for pH control (refer to the Waste Neutralization System section of this specification for neutralization tank pH control requirements). Each unit shall consist of a chemical day tank, regeneration chemical feed pumps, neutralization chemical feed pumps, regeneration dilution water flow control valves, and mixing tees. The anion regeneration unit shall also be supplied with a heat exchanger for heating the caustic regeneration dilution water.