Mitchell's Formal Wear (D-19-188), Nashville, Tennessee

State Coalition for Remediation of Drycleaners Site Profiles

Description
Historical activity that resulted in contamination.

Mitchell's Formal Wear is an active facility located in a commercial area of Nashville, Tennessee. Drycleaning operations began at this facility in 1986 and have continued through the present. The facility has always utilized PCE as their drycleaning solvent. There has been no reports of major spills or leaks. The facility did have an AST which was located outside the rear of the building. It was removed in 1999 when the facility purchased new dry-to-dry machines. There are no private wells or municipal drinking water intakes located near the facility.

Remediation Status: In active remediation

Contaminants
Contaminants present and the highest amount detected in both soil and groundwater.

Contaminant	Media	Nondetect
cis-1,2-Dichloroethene	groundwater
cis-1,2-Dichloroethene	soil
Tetrachloroethene (PCE)	groundwater
Tetrachloroethene (PCE)	soil
Trichloroethene (TCE)	groundwater
Trichloroethene (TCE)	soil
Vinyl Chloride	groundwater
Vinyl Chloride	soil	ND

Site Hydrology

Deepest Significant Groundwater Contamination:
Plume Size:
Average Depth to Groundwater:		50ft

Lithology and Subsurface Geology

		fill material consisting of brown, silty clay, which is mixed with crushed stone and rock fragments Depth: 0.5-8ft bgs 7.5ft thick Gradient: 0.0124ft/ft
Leipers and Catheys Formation or the Bigby-Cannon Limestone		weathered limestone with interbedded shale Depth: 8ft bgs

Pathways and DNAPL Presence

Groundwater

Sediments

Soil

DNAPL Present

Vapor Intrusion Pathway

Has the potential for vapor intrusion (VI) been evaluated?		No
Has a vapor mitigation system been installed?		No

Remediation Scenario

Cleanup Goals:		Cleanup goals are EPA MCLs
Remedy Level:		Interim Action

Technologies

In Situ Bioremediation

Why the technology was selected:
Bioremediation was selected because PCE was seen to be degrading to it's daughter constituents within the contaminated groundwater and it was decided to accelerate and increase the breakdown by adding an additional food source for the native bacteria, in this case Slow Release Substrate (SRS) was selected.

Date implemented:
May 22 through 25, 2006

Final remediation design:
- 15 injection points (IP) were advanced into the impacted area near the southwest corner of the building. The IPs were installed into the bedrock approximately 20 to 25 feet bgs. Each point was completed with 10 to 15 feet of 2-inch PVC slotted pipe and finished to the surface with 2-inch PVC riser. Sand was used to fill the annular space between the boring wall and PVC to one foot above the screen and then bentonite was used to seal the borings to the surface. These points were installed to provide a treatment area, in the upper water bearing zone, to act as treatment for both vadose zone leachate prior to reaching the aquifer and also provide substrate available to migrate along existing fractures and solution channels. - Injection Event (May 25, 2006) -1,155 gallons of emulsified (SRS solution), 2,310 gallons of mix water and 2,205 gallons of water were scheduled to be injected into the 15 injection points. Due to problems with the injection pumps the event was halted until they were repaired and then restarted on July 24 and completed on July 26, 2006. At this time all the remaining SRS solution was injected. Three points could not be used to the full extent planned and the solution scheduled to be injected into them was injected into other points able to take the additional liquid volume.

Results to date:
Pre-injection contaminant levels: June 15, 2005 PCE - 3.7 mg/L TCE - 2.7 mg/L DCE - 3.0 mg/L VC - 3.5 mg/l Post-injection contaminant levels: April 25, 2008 PCE - 0.055 mg/L TCE - 0.026 mg/L DCE - 2.9 mg/L VC - 6.7 mg/L

Next Steps:
Design full scale remedy using different amendment.

Cost to Design and Implement:
$99,272.00

Costs

Cost for Assessment:		$123,941.00
Cost for Operation and Maintenance:
Total Costs for Cleanup:

Lessons Learned

Emulsified oil may be problematic,breakdown stalled.

Contacts

Jim Gilbert, PG
TDEC/DOR/DCERP
401 Church Street, Nashville, TN. 37243
615-741-4998

Rick Bruce, PG/PE
S&ME, Inc
1413 Topside Road
Knoxville, Tennessee 37777
865.970.0003

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