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Because of naturally occurring levels of uranium that reached 76 ug/L—nearly three times the acceptable level—the village of Marshfield, Vt.’s municipal system had not utilized two supply wells for several years. Following a successful pilot test, the village and the project engineer, Forcier, Aldrich & Associates (FA&A) selected AdEdge Technologies in 2007 to supply and install a full-scale uranium treatment system using its AD92 regenerative ion exchange (IX) technology .
Bottled water was being provided to residents while waiting for a solution. The affected wells serve a portion of the town and can produce up to 80 gpm, with an expected average daily demand of 28,500 gal per day. Contracted to fabricate and install the treatment system by FA&A and the village, the AdEdge team prepared the design documents to install a twin vessel parallel treatment system to reduce the high uranium levels below MCLs. Both regenerative and throwaway options were explored. It was concluded that the regenerative AD92 IX approach was the preferred and most cost-effective option for the site.
Designed to provide high-efficiency removal of naturally occurring uranium from groundwater supplies, the packaged, pre-engineered system featured a twin vessel configuration flowing 160 gpm in parallel or 80 gpm per vessel. The system came complete with a manual regeneration/brine system to regenerate the IX resin periodically on demand.
The complete system was packaged and delivered for site installation in July 2007. AD92 IX media is a specialty strong base anion resin with a high capacity for uranium removal. It provides superior removal efficiency for uranium and greater resistance to organic fouling than other media. The negatively charged uranium species binds to the anion resin as it passes through the bed and is periodically regenerated with salt brine solution as the resin reaches a certain loading level. The system was permitted by the Vermont Water Supply Division and utilizes a local discharge permit for the periodic wastewater.
The system was placed into full-time operation in early July 2007 and was processing 80 gpm. Initial results, reported by the site’s State Certified Laboratory to the State of Vermont Water Supply Division, show uranium reduction from 75 ug/L to below 2 ug/L (nondetectable) in the treated water. The system will be monitored regularly according to the terms of the operating permit.