|Twenty-Year Remediation Project Completed at JSC
Since 1988, the Johnson Space Center Environmental Office has been working on a groundwater remediation project. After more than twenty years of sustained remediation efforts in partnership with area regulators, the site now meets regulatory requirements. So, what does this all mean?
It all began a couple decades ago when investigations showed groundwater and soil beneath the Energy Systems Testing Area (ESTA) site, formerly known as the Thermochemical Testing Area (TTA), were found to contain Freon and other volatile organic compounds (VOCs), mainly trichloroethene. Freon is not generally labeled as a health hazard, but releases of the other VOCs into the atmosphere exceeded regulatory protection levels.
Pictured is the groundwater contamination site including large white tanks and two stripping towers behind Building 383.
The contamination was caused by a leaking, underground process sewer line emerging from Building 356. Small rocket engine testing was conducted at the ESTA area between the 1960s and 1994, specifically the Auxiliary Power Units and Orbital Maneuvering Systems for the space shuttle. Freon 113 was used as a substitute propellant for the test.In an effort to contain and prevent continued releases, NASA slip-lined the sewer in 1991 by installing a plastic liner inside of a sewer line made of vitrified clay and installed a groundwater extraction and treatment system. The sewer lines were originally clay, so they cracked when the soil shifted, which caused the contamination to leak out into the groundwater. By slip-lining with the plastic, it prevented the material from leaking out through the cracks.
After the contamination was discovered
Sandy Parker, Environmental Specialist, began her career in JSC’s Environmental Office in 1989, and just days after she started, Parker was assigned the first building blocks for what would become the 20-year remediation project.
“The group of folks who built this center had the foresight to install groundwater monitoring wells in the area, probably because hypergolic propellants were handled in this area,” Parker said.
After the contamination was discovered, the Environmental Office conducted a soil and groundwater investigation to outline the vertical and horizontal extent of the groundwater plume. Additional groundwater monitoring wells were installed to define the extent of the contamination.
“My assignment was to have a groundwater extraction and treatment system (also known as a groundwater pump and treat system) designed and built to clean up the contaminated groundwater,” Parker said.
As the years went by, Parker and her team worked to resolve the issue and bring it up to standard.
“In 2004, this system was shut down to facilitate further site remediation using in-situ chemical oxidation,” Parker said. “Sodium and potassium permanganate injections were conducted between 2006 and 2008, followed by additional testing.”
Park said the results showed that the remaining concentrations exceeding cleanup standards remain in a small area and were not a threat to human health or the environment. There is no reasonable expectation that the affected groundwater zone will ever be developed as a source of drinking water.
“Contamination was found at a fairly shallow depth, and at this depth, it is highly unlikely that water would be ever used for drinking water. Drinking water is found 400 feet below the ground, and this was 10 to15 feet below in one spot and 60 to 80 below in the other,” Parker said. Clean up is required by the state, and although remediation has been completed, restrictions on groundwater use will continue to be enforced.
How to get assistance with environmental issues
For more details on environmental topics, training or any other environmental issues, contact the JSC Environmental Office at: Environmental Information Line at x36207; visit the http://www6.jsc.nasa.gov/ja/ja13/index.cfm”>JSC Environmental Web page or via email at JSC-Environmental-Office@nasa.gov
Johnson Space Center, Houston