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WASTEWATER DEMINERALIZATION BY TWO-STAGE FIXED-BED ION EXCHANGE PROCESS
Citation:
Chen, C. AND R. Miehle. WASTEWATER DEMINERALIZATION BY TWO-STAGE FIXED-BED ION EXCHANGE PROCESS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/2-77/146.
Description:
A 9.5 l/min (2.5 gpm) two-stage fixed bed ion exchange process (primary cation - primary anion - secondary cation - secondary anion) was operated on a feed of carbon treated secondary effluent for 48 months at Pomona, California. To achieve high levels of regeneration efficiency regenerant was passed counter current to the feed, and regenerant levels were held to 17.6 g H2SO4 per liter of cation resin (1.1 lb/cu ft) and 9.6 g NH3 per liter of anion resin (0.6 lb/cu ft). At this level regenerant efficiency was 85% for the cation resin and 90% for the anion resin. TDS removal for feed range of 600 mg/l to 1700 mg/l was in excess of 90% despite the low level of regenerant used. A single stage system (primary cation - primary anion) was set us to determine resin lifetime performance. The same feed and regenerant was used as in the two-stage system. During a 32 month period the cation resin was regenerated over 7,000 times and the anion resin was regenerated almost 2,000 times. No evidence of any deterioration was observed. The system consistently achieved 70% TDS removal. Estimates are presented on treatment costs as a function of plant capacity and feed TDS based on the data generated.