The X-701B soil remediation project, including the excavation and treatment of more than 70,000 square feet of soil in a former holding pond area, has dramatically reduced a contamination source for an underlying groundwater plume on the east side of the DOE Portsmouth Site. Above, inset, is the excavation and treatment in progress, and above, the final, very green result.
The completion of the X-701B Interim Remedial Measure marks a significant accomplishment in the soil remediation efforts around the site. The project, which involved excavating and chemically treating more than 70,000 square feet of soil, dramatically reduced what had been an ongoing contamination source for the underlying groundwater plume.
The X-701B is a former holding pond on the east side of the plant which was part of the original construction. During its operation, X-701B became contaminated with a variety of hazardous substances including Trichloroethylene (TCE), radiological material and heavy metals. TCE is a commonly used industrial solvent and was used in large amounts at the plant as a degreasing agent. The pond has been undergoing some level of cleanup since the late 1980s but the high levels of TCE have hampered the effort.
“TCE is a hazardous chemical,” explained Paul Cross, ER Quadrant II Manager. “In this particular plume, the levels of TCE were as high as one million parts per billion. The acceptable level is five parts per billion, so mitigating this source was clearly a priority. The contaminated soil had to be removed so we could move forward with treating the groundwater.”
The area was divided into small cells measuring 21 feet by 42 feet, and the soil from each cell was removed to a depth of 31 feet.
Jodi Crabtree of WAI reviews documentation at the X-701B site where a groundwater plume contamination source of Trichloroethylene was being remediated. Through the team's efforts more than 80 percent of the contamination was removed from the area on the east side of the gaseous diffusion plant.
“We excavated the soil from each cell, treated it, sampled it to make sure it was within acceptable limits and then reinstalled it,” Cross said. “When Fluor-B&W took over, we committed to having the project done by the end of the fiscal year and despite the weather and other challenges, we were able to complete it three weeks ahead of schedule while maintaining strict RCRA and radiological requirements.”
Fluor-B&W Portsmouth, WAI and Geiger Brothers worked together to complete the project, with approximately 45 employees assigned to the task.
“It was a big, technically challenging job that required a lot of coordination,” said Scott Burton, Project Superintendent. “We were able to remove 81 percent of the TCE-contaminated soil from the area. It’s not the final remedy but it’s a great step forward on the path to where we need to be. If the decision is made to proceed with an on-site disposal cell, this soil will go into the cell and that will truly complete the project.”