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Treating toxic monovalent anions such as NO 3 − or ClO 4 − in drinking water remains challenging due to the high capital and environmental costs associated with common technologies such as reverse osmosis or ion exchange. Capacitive deionization (CDI) is a promising technology for selective ion removal due to high reported ion selectivity for these two contaminants. However, the impacts of ion selectivity and influent water characteristics on CDI life cycle cost have not been considered. In this study we investigate the impact of ion selectivity on CDI system cost with a parameterized process model and technoeconomic analysis framework. Simulations indicate millimolar concentration contaminants such as nitrate can be removed at costs in the range of $0.01–0.30 per m 3 at reported selectivity coefficient ranges ( S = 6–10). Since perchlorate removal involves micromolar scale concentration changes, higher selectivity values than reported in literature ( S > 10 vs. S = 4–6.5) are required for comparable treatment costs. To contextualize simulated results for CDI treatment of NO 3 − , CDI unit operations were sized and costed for three case studies based on existing treatment facilities in Israel, Spain, and the United States, showing that achieving a nitrate selectivity of 10 could reduce life cycle treatment costs below $0.2 per m 3 . 

Abstract Background and objectivesThe coproduct of ethanol industry, dried distiller's grains with solubles (DDGS), has phosphorus content in excess of the animal diet requirement, which leads to excess P in manure and causes environmental concerns. The objective of this study is to determine the technical and economic feasibility of recovering this excess P as a coproduct. FindingsThe amount of P was observed to reduce from 9.26 to 3.25 mg/g (db) of DDGS, which is consistent with the animal diet requirement of 3–4 mg P/g animal diet. For an existing dry grind plant of 40 million gallon ethanol capacity, an additional fixed cost of $5.7 million was estimated, with an operating cost increase of $1.29 million/year. ConclusionsThe total phosphorus recovered from the plant was estimated as 1,676 kg P/day, with an estimated operating cost of $2.33/kg P recovered. Significance and noveltyApproximately 37 million MT of DDGS is produced annually as animal food containing excess P, which is a serious concern for the environment. This study provides with an economically feasible solution to recover the excess P as a coproduct, which has a potential to be used as fertilizer on more than 56,000 acres of land annually, growing corn and soybean.