Fluor-Idaho engineers rehabilitate monitoring well

A deep aquifer monitoring well, known as Middle-2051, has been rehabilitated and will be returned to service, according to Fluor Idaho’s Environmental Restoration Program.

The well tested positive for an industrial solvent called perchloroethylene (PCE) in November 2015. It is located in the south-central portion of the Idaho National Laboratory site.

Fluor Idaho scientists determined the solvent originated in the well’s tubing fluid and was not present in groundwater.

Researchers also determined two similar wells in different areas had similar problems. Again, engineers found that only the tubing fluid isolated within the wells was contaminated.

Fluor developed a stainless steel, screened sleeve filled with granulated, activated carbon. The “filter-swab” was lowered more than 1,000 feet into the wells and the PCE attached to the carbon as water passed through the sleeve.

Rehabilitation of the other two wells is expected to be completed this summer.

“With each pass in the well column, PCE concentrations were reduced,” said Fluor Idaho ER Program Director Marc Jewett. “Tubing fluid samples that were analyzed by an independent lab showed that PCE levels in Middle-2051 were reduced to such a level that we can return the well to service and begin collecting aquifer samples in the immediate future.”

The wells are used to help scientists understand how deep site-generated contaminants are located within the aquifer and the speed at which they move in water.