The Northern Virginia Daily

Article Date: February 15, 2008

Site cleanup continues with sewer work

By: Jessica Coleman

A long trench is being dug at the Avtex Superfund site to remove about 7,200 linear feet of the plant’s sewers. 

Christened “the big dig” by workers on the site, the trench will be 1,200 feet long, 100 feet wide and about 10 feet deep when it is completed.  It will allow workers to extract six known sewer lines that run side-by-side through the trench at different elevations.

The 90 day excavation is part of the second phase of the sewer removal process on the Avtex site.  It should be completed by the end of the spring, said John Torrence, site manager for FMC Corp., one of the plant’s former owners that is funding and leading the cleanup.  Avtex was declared a Superfund site in 1986.

The first phase of the sewer removal was completed in 2005, and centered on lines in the northern part of the site. The Third and final phase will probably begin in 2009, Torrence said, and will focus on the sewers on the other side of the railroad that runs through the site.

As the sewer lines are pulled out any sludge found in the pipes is removed by hand and stored in two plastic bags before being transported to permanent landfills.

“That’s one level of effort we use to be as effective and as cost-effective as possible,” Torrence said.  “It’s cleaner and less expensive.  It’s a more prudent way of doing it.  It’s a more responsible way.”

Three sets of soil samples are also collected around the pipes, one from directly underneath the pipe, one from the floor of the excavation and one from the side of the pipe.  If the soil is found to be contaminated by any chemicals, the soils are remove and retested until the tests come back clean, Torrence said.

“So when we’re done, we’ll have three sets of data all analyzed for the same things,” Torrence said.

The sewers in “the big dig” are being tested for metals, PCB’s and semi- volatile organic compounds, but each section of sewers might be tested for something different.

“Other sewers and soils might be tested for other things, as well, depending on what they were used for and what they expect to fine there.” Torrence said.  “We predetermine what we’ll analyze for in our work plans for [the Environmental Protection Agency]”.

So by the time all the sewers are removed, Torrence said, the soils should have been tested several times to ensure they are clean.

“Everything we do we test to give FMC and the EPA a level of comfort that what we’re doing was effective,” he said.