Lazaro Aleman
ECB Publishing, Inc.
The underground oil contamination plume on the west side of courthouse circle that geologists have been monitoring for more than a year is beginning to diminish in part.
Chris Crevello, a staff geologist with Advanced Environmental Technologies (AET), reported last week that the underground contamination on the south side of U.S. 90 was beginning to clear up. But not so on the north side of U.S. 90, he said.
“The north side is still contaminated,” Crevello said on Friday, Feb. 22.
He said the sucessful cleanup on the south side was largely due to the use of technology that involves pumping air into the groundwater, thus allowing microorganisms to eat up the contamination, which is then extracted via another pump.
So why not use the same method on the north side of U.S. 90?
The problem, Crevello said, was that to install the necessary piping and trenching to pump the air into the groundwater would take a couple of weeks and would be quite disruptive to the nearby businesses.
“We're still trying to decide what to do on the north side”, he said.
Early last year, AET crews used rigs to drill holes at different spots around the courthouse circle and install monitoring wells to determine the depth and extent of the contamination, as well as map the direction of the groundwater flow.
Which flow, as Crevello then described it, was traveling slowly and gently in a southeasterly direction, away from the area of the Monticello News and towards the Rev Cafe and under and around the courthouse.
Crevello described the contamination as a huge underground plume that was both dissolved in the groundwater and floating on its surface. As for the plume's origin, he attributed it to leaks from buried fuel tanks when the area had several gasoline stations.
Remediation efforts generally entail two basic methods. If the contamination is floating atop the groundwater surface as a free product, it is extracted via the use of wells and appropriately disposed of. Or if it dissolved in the water, air is pumped into the groundwater, causing the contamination to volatilize, so that the vapors can be captured and extracted via another well.
Facilitating the cleanup around the courthouse, Crevello said, was that the contamination was in the groundwater rather than in the soil. Had the contamination been in the soil, he said, it would have required excavation, which would have proven especially disruptive for the area businesses and the roundabout traffic.
The Florida Department of Environmental Protection (FDEP) is funding the cleanup project.