Background:
In early March 2009, after an evaluation period, AdEdge Technologies was selected and contracted by Elk Point Country Club Community to provide a packaged treatment system for uranium removal that complied with Nevada Department of Environmental Protection (NDEP) regulations. Elk Point Country Club Community is located on the southeast side of Lake Tahoe at Elk Point, Nev., and is served by a well, which initially had a flow rate of 120 gal per minute (gpm). The flow of the well pump was modified to obtain the specified 60 gpm design flow rate with an average uranium concentration of 40 micrograms per liter, exceeding the U.S Environmental Protection Agency (EPA) Maximum Contaminant Level (MCL) of 30 micrograms per liter. AdEdge worked closely with the community’s engineer to provide techical support, drawings and final design of a uranium treatment solution for the community that satisfied the NDEP drinking water regulations.
The Treatment System
The AdEdge AD92 pre-engineered and packaged system provided for Elk Point is composed of twin 30-in.-diameter vessels with a design flow of 60 gpm in a parallel configuration. The system is controlled during normal operation, backwash and onsite regeneration using the Programmable Logic Controller PLC with a control panel. The system was furnished with a regeneration/brine system to regenerate the IX resin periodically on demand. A sodium chloride brine solution is used to regenerate the anion resin. The brine module is a separate system composed of a single polyethylene brine tank with valves, flow restrictors and rotometers, which work during the automatic cycle operation, service, backwash, brining, slow rinse and fast rinse cycles.
The AdEdge AD92 IX regenerative ion exchange approach was the preferred and most cost-effective option for this site, and this technology has been designed to provide high efficiency removal of naturally occurring uranium from groundwater supplies. The AD92 IX media is a strong base-anion exchange resin used to selectively remove naturally occurring uranium from groundwater. It can selectively remove the negatively charged uranium anion to below the state and federal MCL of 30 parts per billion. As uranium passes through the bed, it is removed, allowing the chloride and bicarbonate ions to be exchanged for the uranium. In addition, AD92 IX resin provides superior regeneration efficiency and greater resistance to organic fouling.
System Performance
The complete system was packaged and delivered for site installation in September 2009, and was placed into full operation in early January 2010, processing about 6,000 to 8,000 gal per day. Samples of the treated water were taken in February 2010, and results from a state-certified lab reported excellent performance with uranium levels of less than 0.001 mg per liter (1 microgram per liter).
