Client: USACE Omaha
Location: Grand Island, Nebraska
Completion Year: Ongoing
Scope of Work:
- GWTF Remedial Action-Operation (RA-O)
- GWTF Long-term Operations/Long-term Maintenance (LTO/LTM)
Brice is performing Remedial Action – Operation (RA-O) of the Groundwater Treatment Facility (GWTF) and groundwater monitoring at the Cornhusker Army Ammunition Plant (CHAAP) in Grand Island, Nebraska. The project includes long-term operations (LTO), maintenance of a GWTF at Operable Unit 1 (OU-1), and long-term monitoring (LTM) at OU-1 and OU-3. To date, we have successfully maintained operational status of 95%.
One extraction well is being operated at approximately 300 gallons per minute to prevent downgradient migration of contaminated groundwater. The contaminated groundwater is transported to the GWTF to a feed tank upstream of a two-stage granular activated carbon (GAC) treatment train inside the GWTF. Effluent from the GWTF is discharged to a nearby canal.
To execute the work, Brice coordinates with local farmers and commercial facility to gain site access. In addition, because we are working alongside city streets to perform sampling, we have implemented enhanced safety measures.
Recent groundwater monitoring and subsequent analysis has shown that contaminant concentrations at the site (TNT and RDX) are significantly decreasing. Further, numerical modelling has suggested that operation of the extraction well is no longer required to prevent plume migration. Based on these results and simulations, Brice will begin a study in October 2019 that will temporarily discontinue pumping at the extraction well and confirm if the modeling is accurate. Following the shutdown of the extraction well, we will perform quarterly groundwater monitoring for two years to closely monitor potential migration of the explosives plumes. Concurrently, subsurface injections to enhance anaerobic in situ bioremediation processes and cometabolically biodegrade TNT and RDX will be performed in remaining areas of groundwater contamination to help reduce the remedial timeframe, and subsequently, lifecycle costs at the site.
To date, wehave completed the work with no safety incidents.