Treatment Of Perchlorate Contaminated Groundwater Using Highly Selective Regenerable Anion Exchange Resins At Edwards Air Force Base

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ISBN 13 :
Total Pages : 5 pages
Book Rating : 4.:/5 (16 download)

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Download or read book Treatment of Perchlorate-Contaminated Groundwater Using Highly-Selective, Regenerable Anion-Exchange Resins at Edwards Air Force Base written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Selective ion exchange is one of the most effective treatment technologies for removing low levels of perchlorate (ClO4−) from contaminated water because of its high efficiency without adverse impacts on the water quality caused by adding or removing any chemicals or nutrients. This report summarizes both the laboratory and a field pilot-scale studies to determine the ability and efficiency of the bifunctional synthetic resins to remove ClO4− from the contaminated groundwater at the Edwards Air Force Base in California. Regeneration of the resins after groundwater treatment was also evaluated using the FeCl3-HCl regeneration technique recently developed at Oak Ridge National Laboratory. On the basis of this study, the bifunctional resin, D-3696 was found to be highly selective toward ClO4− and performed much better than one of the best commercial nitrate-selective resins (Purolite A-520E) and more than an order of magnitude better than the Purolite A-500 resin (with a relatively low selectivity). At an influent concentration of ≈ 450 {micro}g/L ClO4− in groundwater, the bifunctional resin bed treated ≈ 40,000 empty bed volumes of groundwater before a significant breakthrough of ClO4− occurred. The presence of relatively high concentrations of chloride and sulfate in site groundwater did not appear to affect the ability of the bifunctional resin to remove ClO4−. However, the presence of high iron or iron oxyhydroxides and/or biomass in groundwater caused a significant fouling of the resin beds and greatly influenced the effectiveness in regenerating the resins sorbed with ClO4−. Under such circumstances, a prefilter (≈ 0.5-1 {micro}m) was found to be necessary to remove these particulates and to reduce the risk of fouling of the resin beds. Without significant fouling, the resin bed could be effectively regenerated by the FeCl3 displacement technique. Nearly 100% of the sorbed ClO4− was displaced or recovered after elution with only ≈ 2-5 bed volumes of the FeCl3-HCl regenerant solution. On the basis of both the laboratory and field pilot-scale studies, they therefore anticipate that a combination of the selective ion exchange and the FeCl3-regeneration technologies may offer a cost-effective means to remove ClO4− from contaminated groundwater with significantly reduced waste generation and operational cost.