At 38,000 acres, Redstone Arsenal (RSA) in north-central Alabama represents one of the largest and most successful cleanup programs in the Army. Approximately 40,000 people work there--about 90 percent of them are civilian or contract employees. The installation is partially bordered by the Tennessee River; and some of its land is forest, wetlands, and flood plains. Two things make groundwater cleanup a challenge at RSA: tight clay soil and the underlying geology's complex fractures.
"We are proud to conduct the environmental restoration this historical site deserves," said Clint Howard, installation restoration branch chief from Redstone Arsenal's Directorate of Public Works Environmental Management Division. "The War Department purchased RSA in 1941 for manufacturing weapons and ammunition. After WWII, the military stored, destroyed, or buried chemical weapons in trenches there. The installation later became an engineering center and made notable contributions to the American space program. Today it hosts more than 28 tenant organizations, including the Department of Defense, NASA, and others."
Of the 400 RSA cleanup sites originally identified, the installation remediated 182 of them. Remediation of the 17 chemical warfare material (CWM) cleanup sites will take years, as there are almost six miles of trenches. The investigation phase for CWM work started in 2015, but digging won't begin until 2019. Even then, only six munitions can be removed per day safely, as they are likely intact, meaning they are relatively stable in the ground but volatile once disturbed. To date, no chemical agents have been detected in groundwater at RSA.
Other cleanup areas associated with the everyday operations of an Army installation (e.g., training ranges, motor pools, landfills) can pollute groundwater and pose a risk to humans. RSA is planning for cleanup using the latest technology available, but some areas may require monitoring for many years.
One remediation tool used at RSA is electrical resistance heating (ERH), which consists of constructing electrodes in the ground, applying electricity to the electrodes, and heating the subsurface to temperatures that promote evaporation of contaminants. Then, a vapor recovery system captures contaminants, which moves them to the surface where they are separated and treated. This method works in tight clay soil and has removed about 47,000 pounds of volatile organic compounds at four sites within the last two years. If left in the soil, however, the material could have contaminated more than a trillion gallons of groundwater.
Excavation and proper disposal have a tremendous impact on removing contaminates. During the last two years, more than 72,000 cubic yards of contaminated soils were excavated and disposed of in approved offsite landfills; more than 60,000 cubic yards were excavated, moved to higher ground, and covered with an approved landfill cover. This work saved hundreds of millions of gallons of surface and groundwater from continued contamination--potentially at sites adjacent to wetlands, flood plains, or creeks.
RSA staff strategically planned cleanups to expedite the return of land for mission use and reduced the amount of contamination migrating off post. Additionally, a top priority was stakeholder involvement, demonstrated by regular contact with Alabama Department of Environmental Management to ensure transparency. RSA representatives also visit community and school groups, and their outreach at conferences and community events help dispel rumors and relieve anxiety about the types and severity of contamination, as well as the cleanup.
Other military installations can learn from RSA efforts. For example, innovative groundwater investigation technologies used there are now widely available. ERH methods yielded lessons applicable to sites with similar geology and contaminants. Also, the Environmental Restoration Branch developed (and shares) a data management system; its data deliverable abilities were vital to RSA's success. Another component of their success was skillfully maintaining installation-wide protocols to ensure consistency between contractors.
A 10-person team--comprised of contracting officer representatives, project managers, civil and chemical engineers, and geologists--manages the estimated $1.5 billion Installation Restoration Program.