The U.S. Army spends millions of dollars each year to operate and maintain major groundwater pump-and-treat systems, but most of the systems have no defined measures of effectiveness. The Groundwater Extraction and Treatment Effectiveness Reviews will help installations determine how well a system is performing, when the system has reached the end of its usefulness, or whether another method could meet remediation goals at lower costs.
To institute an Armywide program for developing clear remediation objectives and measures of effectiveness for planned and installed groundwater pump-and-treat systems. For systems where remedial objectives cannot yet be obtained, the program will reevaluate and renegotiate the objectives using risk-based approaches and reasonable land-use scenarios.
Optimization of existing systems and the proper setting of objectives could help the Army potentially avoid costs of $100 million in the next 10 years.
Major Army commands and installations with operating or proposed pump-and-treat systems.
The U.S. Army operates major groundwater pump-and-treat systems at 35 installations, with a yearly operations and maintenance cost of approximately $25 million. Each major system costs about $3 million to build and is expected to last at least 30 years. Of the systems with a definable objective, more than half were designed to contain plumes, not restore aquifers. Most of the systems have no defined measures of effectiveness; the Army therefore has little or no ability to determine how well a system is performing or when a system has reached the end of its usefulness. In addition, approximately 70 major pump-and-treat systems are in the planning stages within the Installation Restoration, Base Realignment and Closure (BRAC) and Formerly Used Defense Sites (FUDS) programs.
An Army Science Board study on the effectiveness of groundwater and soil treatments recommended that a team of independent experts review the Army's largest groundwater pump-and-treat remediation programs (according to cost-to-complete estimates). The study also recommended implementing a groundwater cleanup strategy to reduce the number of pump-and-treat systems being proposed in the Army's environmental program.
The Groundwater Extraction and Treatment Effectiveness Reviews will:
An effectiveness review team is made up of individuals experienced in the design, operation and optimization of pump-and-treat systems, as well as in the regulatory aspects of Record of Decision (ROD) development and modification. Depending on the installation's technical and regulatory situations, the team uses different mixes of in-house and outside experts. The disciplines that might be required include:
A contractor handles the team's administrative requirements, such as data collection, preparing the site for the visit and preparing reports. Team members could be drawn from the U.S. Army Environmental Command, the Army Center for Health Promotion and Preventive Medicine, the Groundwater Modeling Support Program at the U.S. Army Engineer Research and Development Center-Waterways Experiment Station, the U.S. Army Corps of Engineers Hazardous, Toxic, and Radioactive Waste Center of Expertise, the Department of Geography and Environmental Engineering at the U.S. Military Academy, the U.S. Geological Survey, Environmental Protection Agency laboratories, the Department of Energy and nongovernment entities. Local regulatory agencies and community representatives may be involved in the later stages of a site visit.
A team examined a proposed pump-and-treat system at Hunter Army Airfield in Savannah, Georgia. The system was proposed to contain a petroleum plume (mainly benzene) emanating from a former underground storage tank site near a runway. The team recommended ways to handle the problem without constructing a pump-and-treat system. The recommendations were well received by the installation and the U.S. Army Corps of Engineers' Savannah District.
Based on the team's visit, the proposal for a $1.8 million (capital cost) system is on hold. The team's recommendation for approximately $100,000 worth of sampling and analysis during the next year will lead to the selection of a monitored natural attenuation remedy. Use of monitored natural attenuation instead of the proposed pump-and-treat and soil vapor extraction system will save approximately $5 million over the life of the project.
Reviews are labor intensive and only a few can be accomplished each year.