Crews digging for oil around courthouse circle

Lazaro Aleman, ECB Publishing, Inc.

If you noticed the crews and rigs that were partially blocking the courthouse circle last week and drilling in the area, it wasn't petroleum that they were after; or at least not petroleum in the traditional sense, but rather in the form of contamination.
Chris Crevello, a staff geologist with the Tallahassee-based Advanced Environmental Technologies LLC. (AET), which is doing the drilling, explained that his group's purpose is to establish the depth and extent of the underground oil contamination in the area.
“We're trying to determine how far the contamination spread and the direction of the groundwater flow,” Crevello said, pointing out that it was generally slow and gentle here and traveled in a southeasterly direction, from the area of the Monticello News toward the Rev Cafe and under and around the courthouse proper.
He said the drilling served to install wells, which were used to monitor and map the makeup of the contamination. He described the contamination as an underground plume that was both dissolved in the groundwater and floated on its surface.
As for the origin of the plume, he said, it was created by leakage from the buried fuel tanks of the several gasoline stations in the area at one time.
Crevello said there the remediation effort entailed two basic methods. If the contamination was floating on the groundwater surface as a free product, it would be extracted via the well and disposed of appropriately, he said. And if it was dissolved in the water, then the process entailed pumping air into the groundwater and causing the contamination to volatilize, so that the vapors could be captured and extracted by another well.
Fortunately, he said, most of the contamination was in the groundwater rather than the soil, which facilitated the work.
“We won't have to dig up the ground,” Crevello said, adding that such a measure would be particularly disruptive in the area, given the heavy motor traffic around the courthouse circle.
For the time being, Crevello said that the aim was simply to monitor the wells. He said that for the next six months or more, AET personnel will take periodic groundwater samples and send these to the lab for analysis. Based on the lab result, he said, AET will map the plume and develop a remediation plan.
“We'll then talk to the state and come up with the best option for getting rid of the contamination,” Crevello said, noting that the Florida Department of Environmental Protection (FDEP) is funding the cleanup project.