Keyhole Source Treatment to Remediate PCE in Ground Water Plume

CL-Out bioremediation was used in a keyhole treatment to remediate PCE.  The source treatment also reduced the mass of contamination down gradient in the plume.  At a former manufacturing facility in Ohio the concentration of PCE near the source was over 100,000 ug/L.  Down gradient of the source the PCE concentrations were less than 10% of the source concentration.  Aggressive treatment in the source area reduced the source concentration and in the down gradient plume.

After one treatment with CL-Out bioremediation, the concentrations decreased as follows:

PCE remediation from 120,000 to 12 ug/L.

TCE remediation from 2,000 to 12 ug/L

Cis 1,2-DCE remediation 9,500 to 8,100 ug/L.

Vinyl chloride, however, increased from 1,200 to 22,000 ug/L.

The vinyl chloride increased as the aggressive cometabolic treatment stimulated some incomplete reductive dechlorination.

Down gradient from the source, the concentrations decreased with slight to no increase in daughter products.  The following results were measured in the down gradient plume:

PCE remediation from 5,000 to 1,600 ug/L.

TCE remediation from 43 ug/L to BDL.

Cis 1,2-DCE remediation from 140 to 23 ug/L.

Vinyl chloride  was not detected before or after treatment.

Keyhole treatment was a cost effective approach to remediate  PCE and other contaminanats by focusing aggressive treatment on the source area.  Concentrations of PCE and other contaminants in the rest of the plume decreased as the microbes and treated water dispersed through the plume.