Client: USACE Seattle
Location: Mountain Home AFB, ID
Completion Year: 2021
Scope of Work:
- Updated FFS and Proposed Plan
- Operations and Maintenance
Brice, as managing partner of Brice-AECOM JV1, is completing a supplemental Remedial Investigation (RI)/data gap investigation to delineate the nature and extent of PFAS at Restoration Site FT008, a former fire training pit, at Mountain Home Air Force Base (MHAFB) installation. At FT008, PFAS is comingled with VOC contamination in soil. The selected remedy for VOCs at the site was an Air Sparging/Soil Vapor Extraction (AS/SVE) system. The SVE system has effectively treated most of the VOC soil contamination, but some VOCs remain in shallow soils.
We are conducting environmental contaminant control/treatment of solvents (VOCs) and investigation of emerging contaminants (PFAS) in soil. The project includes monthly O&M of the AS/SVE system, data gap soil sampling, data interpretation, statistical evaluation, the completion of a Focused Feasibility Study (FFS) update supported by the data interpretation and statistical evaluation, and completion of a Proposed Plan (PP), public notice, and public meetings.
Brice-AECOM prepared a work plan and a streamlined UFP-QAPP for obtaining 16 soil samples from FT008 to include analysis for 16 PFAS compounds as part of the supplemental RI/data gap investigation. The purpose is to better understand the extent of PFAS contamination at the site before implementing a revised remedy for VOCs in soil. Samples were obtained from depths between the surface and 12 feet below ground surface. The team then prepared a Data Gap Soil Sampling Report, following Idaho and federal requirements, presenting the results of the soil sample analysis to refine new and existing alternatives for the updated FFS. The investigation/inspection also involved a review of historical records and current documents to verify conditions at FT008 as they relate to PFAS. The UFP-QAPP, field work, and Supplemental RI Report received very few comments from the regulators and, as a result, were completed ahead of schedule.
Brice prepared an O&M Manual for the SVE system at FT008 and performs monthly O&M of the system. Monthly O&M included system inspections, data recording, purging of condensate water from SVE lines, repair of any disconnected lines, and checking for accumulation of condensate in the moisture separator/holding tank. Brice prepares quarterly status reports that outline maintenance and other significant findings of the O&M visits. After taking over O&M of the system, Brice and AECOM made several major repairs to the vacuum lines, replaced numerous fittings, and added a condensate overflow tank to maximize system run time before the knock-out tank fills. After these repairs, the system has been near-100% operational with limited down time to maintain the treatment activities for VOCs.
To maximize the run-time of the AS/SVE system between monthly O&M site visits, Brice and AECOM designed and installed a condensate overflow system which doubled the condensate capacity of the system and increased operational run-time to nearly 100%. The modification satisfied EPA/IDEQ regulators that were concerned with previous operational capacity.
- Designed/implemented numerous upgrades to existing SVE system to ensure system remains 100% operational with limited downtime
- Completed UFP-QAPP, Supplemental RI Report, FFS, and PP on schedule with a high-level of quality with few regulator comments