In-Situ Chemical Oxidation Remediates NASA Site's Soil and Groundwater

The National Aeronautics & Space Administration (NASA) Kennedy Space Center in Cape Canaveral, Fla., has undertaken aggressive groundwater and soil remediation to treat an area of onsite petroleum hydrocarbon contamination. Faced with the challenge of removing the contamination while maintaining the integrity of underground utilities, piping and infrastructure, NASA and its consultant Tetra Tech chose RegenOx, a proven, noncorrosive and cost-effective in-situ chemical oxidation technology developed by Regenesis, San Clemente, Calif.

The Launch Equipment Shop, part of NASA’s famed Vehicle Assembly Building complex, has conducted highly specialized manufacturing, fabrication and assembly work for the space program since the early 1960s. Leaks from a 4,000-gal underground fuel oil tank, subsequently decommissioned and removed, led to notable contamination of soil and groundwater, including a layer of light nonaqueous phase liquid up to 15 in. thick, with total recoverable petroleum hydrocarbon (TRPH) levels as high as 20,000 ppm in soil and 42 ppm in groundwater.

The tank and 178 tons of readily accessible contaminated soil were excavated and properly disposed of early on, but harder-to-reach contaminated soils had to be left in place beneath and near building foundations, where essential underground utilities were located. Although Tetra Tech’s engineering evaluation identified excavation as the preferred approach for remediating the remaining contamination, the cost of excavating the hard-to-reach soils was prohibitive at more than $1 million.

After examining alternative remediation technologies, in-situ chemical oxidation--the application into the subsurface of highly reactive chemicals which chemically oxidize and destroy contaminants on contact--was chosen. Most conventional in-situ chemical oxidation chemistries were ruled out, however, due to their corrosivity and tendency to generate intense heat and explosive pressures.

Tetra Tech injected approximately 50,000 lb of RegenOx into the site via 52 injection wells. After treatment, the area of TRPH-impacted soils was reduced to approximately one-fourth of its original size. Site-wide groundwater contaminant concentrations of TRPH were also reduced substantially, and the thickness of the free-product layer was reduced by 80 percent. The program originally included a more costly soil removal phase to address the free product contamination, but after further investigation, the RegenOx dosing was adjusted to handle the phase separated material.

Source: Regenesis