OU III Groundwater Contingency Remedy Optimization System. The groundwater contingency remedy has been optimized by an expanded pump-and-treat remediation in the AOA, where hydrogeologic boundaries and elevated concentrations of uranium in the alluvial groundwater are both well defined. The contingency remedy optimization is consistent in concept with the requirements of the Record of Decision and the Explanation of Significant Difference. The optimized system, which became operational during the quarter, uses a network of eight vertical extraction xxxxx (well numbers OR-1 through OR-8) strategically placed in the AOA to extract contaminated groundwater. The water is transmitted in buried pipelines to the Groundwater Transfer Building where it is batched in an aboveground tank and pumped via a buried pipeline to Pond 4, located about 1 mile south of the AOA, for evaporative treatment. Sixteen monitoring xxxxx (well numbers MW-1, MW-3 through MW-17) were installed to monitor groundwater levels and quality in the AOA. A fixed time water right appropriation (number 09-2347) was obtained from the Utah Department of Natural Resources, Division of Water Rights for this system because evaporation is considered a consumptive use. Water use is limited under this water right to 16 acre-feet per year, which equates to approximately 5,213,600 gallons per year. Major OU III groundwater contingency remedy optimization system activities occurring this quarter include: • Phased system operations start-up began on January 14, 2015. • Full system, continuous operations began on February 14, 2015. • System operation refinement continues. • Some minor, follow-up construction associated with the new system occurred during the quarter. Similar follow-up activities are scheduled for spring 2015, and revegetation of land disturbed during system construction is scheduled for July 2015. • As shown on Table 1, the system removed approximately 2 million gallons of groundwater from the alluvial aquifer during the quarter. Table 1 provides approximate monthly quantities of pumped groundwater and average monthly pumping rates.
OU III Groundwater Contingency Remedy Optimization System. The GRO system, which began full operation in January 2015, includes eight vertical extraction xxxxx strategically placed in the AOA to extract contaminated groundwater and an associated monitoring system. The water from the extraction xxxxx is transmitted in buried pipelines to an aboveground holding tank in the groundwater transfer building; from there it is pumped through a buried water transmission line for about 1 mile to Pond 4 for evaporation. The associated monitoring system consists of 22 xxxxx installed in the AOA. Sixteen of the 22 xxxxx were installed south of Montezuma Creek in 2014, and 6 xxxxx were installed north of U.S. Department of Energy Monticello NPL Sites FFA Quarterly Report: January 1–March 31, 2019 May 2019 Doc. No. S25044 Montezuma Creek in 2017. Beginning in 2017, sampling of the extraction and monitoring xxxxx occurred on a monthly basis for approximately 1 year. As of October 2018, sampling will occur following the extraction of approximately every 1 million gallons from the GRO system. The extraction and monitoring xxxxx were last sampled during the October 2018 semiannual sampling event.
OU III Groundwater Contingency Remedy Optimization System. The groundwater remedy optimization system began full operation in February 2015. Eight vertical extraction xxxxx are strategically placed in the AOA to extract contaminated groundwater. The water is transmitted in buried pipelines to an aboveground holding tank in the groundwater transfer building; from there it is pumped through a buried water transmission line for about 1 mile to Pond 4 for evaporation. The associated monitoring system consists of the 16 monitoring xxxxx that were installed in the AOA. These xxxxx are sampled on a frequency of approximately every 1-million gallons of water extracted by the treatment system. Consumptive use (evaporation of the extracted groundwater in Pond 4) is allowed under a fixed-time water right appropriation (number 09-2347) and a temporary water right appropriation (number 09-2422) that LM obtained from the Utah Department of Natural Resources, Division of Water Rights.
