USACE Groundwater Treatment Systems O&M, former Fort Ord
Ahtna has provided remediation and engineering support for USACE at the Former Fort Ord (FFO) for various phases of the CERCLA BRAC cleanup program since 2002 under multiple consecutive contracts. FFO is in the remedial design and remedial action phase of the CERCLA process and the property transfer phase of the BRAC process. The basewide purpose is to complete the full investigation, design, and remediation required for the National Priorities List (NPL) sites and non-NPL environmental compliance sites (former UST locations) at FFO to facilitate property transfer for the benefit of the surrounding communities.
As prime contractor, Ahtna operates and maintains the GWTS and connected subsystems at Operable Unit 2 and Sites 2 and 12 to ensure compliance with the respective CERCLA decision documents. These GWTS are operated using SCADA and remove VOCs through granular-activated carbon (GAC) adsorption and air stripping. Under Ahtna’s oversight, the GWTS have achieved the operational goal of being on line at least 95% of the time with a total flow rate of approximately 1,000 gallons per minute. As of 2013, combined, these GWTS have treated approximately 7.8 billion cumulative gallons of groundwater and are containing two large and diffuse groundwater plumes.
In coordination with USACE, Ahtna schedules and leads quarterly optimization meetings to discuss the status of hydraulic containment, remediation progress, sampling optimization, analytical methods, and additional cost-saving measures. For example, Ahtna developed new decision rules in the QAPP for determining discharge limit compliance; GAC change-outs; hydraulic containment; plume remediation; and sampling frequency. These decision rules were designed to introduce efficiencies and cost savings to GWTS operations by codifying decisional parameters, which allowed for maximizing usage of GAC and reducing sampling and analysis costs.
Ahtna completed a cost-benefit analysis and conceptual design to assess the feasibility of moving the OU2 GWTP to the plume area with the highest concentrations of COCs. Ahtna determined that moving the GWTP, along with installing new extraction wells, would achieve RAOs 10 years earlier and reduce RA costs by 50% ($38M) over the life of the project. Ahtna also collaborated on design and installation of a post-GAC air stripper at Sites 2/12, which maximized GAC capacity and reduced GAC change-outs by 90%, saving USACE approximately $60K/yr.
Ahtna performs quarterly groundwater sampling at over 200 wells across 5,000 acres using passive diffusion bag samplers, the Westbay sampling system, and HydraSleeves. Groundwater samples are analyzed for organic and inorganic compounds in accordance with the approved SAP and QAPP. In addition, we measure and record water level elevations with respect to established survey control points, and water quality parameters, including dissolved oxygen and oxygen reduction potential, to evaluate the effectiveness of enhanced in-situ bioremediation at OUCTP.
We manage the analytical data collected as part of GWTS O&M and groundwater monitoring. This includes uploading data to the Fort Ord Data Integration System and the GeoTracker database per State Water Resources Control Board requirements. Ahtna compiles the data for inclusion in technical reports and also performs a comprehensive assessment of the data to evaluate the performance of the GWTS and provide recommendations for optimization.
Ahtna provides community relations support consisting of developing and submitting correspondence and reports for regulatory and public review, submitting documents to the Administrative Record, and supporting other outreach activities as required. Because of our knowledge, expertise and communications abilities, the U.S. Army Fort Ord BRAC Office specifically requests that Ahtna make regular presentations on the status of the groundwater remediation program to the public, at the U.S. Army’s Community Involvement Workshops, Technical Review Committee meetings, and Open House events.
- Community relations
- Groundwater monitoring
- Operations and maintenance