Drycleaner Site Profiles

One Hour Valet Cleaners, Chattanooga, Tennessee

Description
Historical activity that resulted in contamination.

The site, the former One Hour Valet Cleaners, in Chattanooga, TN was an operating drycleaner from 1957 until 1981. The building was demolished in 1982 and a utility company and an attached parking garage was constructed on the site in 2007. The contaminants associated with the drycleaner are the drycleaner solvent PCE. A former gas station was also remediated as part of a Brownfield's agreement. A soil removal was conducted to remove BTEX contaminated soil from the southwest corner of the block.

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


Contaminant Media Concentration (ppb) Nondetect
cis-1,2-Dichloroethene groundwater 59 ppb
Tetrachloroethene (PCE) groundwater 158,000 ppb
Tetrachloroethene (PCE) soil 205,000 ppb
Trichloroethene (TCE) groundwater 5,600 ppb
Trichloroethene (TCE) soil 4,830 ppb

Site Hydrology

Deepest Significant Groundwater Contamination:   50ft bgs
Plume Size:   Plume Length: 100ft
Plume Width: 40ft
Average Depth to Groundwater:   8.5ft

Lithology and Subsurface Geology

 
  fill material made up of cherty clay, silty clay, building debris and foundry sand

Conductivity: 0.002834646ft/day
Gradient: 0.025ft/ft
 
  residual clay and silty clay with chert fragments
 
  floating limestone boulders within a clay matrix
(Chickamauga Supergroup
  bedrock consisting of gray micritic, medium bedded, weathered to crystalline limestone (Chickamauga Supergroup) and thin gray and maroon interbedded shale beds

Pathways and DNAPL Presence

checkGroundwater
Sediments
checkSoil
checkPresumptive Evidence of DNAPL

Vapor Intrusion Pathway

Has the potential for vapor intrusion (VI) been evaluated?
  Yes
How was the site evaluated?
  Indoor air sampling
Results of VI evaluation:
  The VI pathway was ruled out (or does not exist)
Has a vapor mitigation system been installed?
  No 

Remediation Scenario

Cleanup Goals:
  The Remedial Action Objective for this site is 10 mg/L. Other remedial goals are plume contraction and continuing to ensure that the plume remains on-site.
Remedy Level:
  Full Scale Remedy

Technologies

In Situ Air Sparging
 

Why the technology was selected:
An excavation was conducted on the site to remove the BTEX contamination present at the former gas station. Chemical oxidation in the form of sodium permanganate was chosen due to the high concentrations of PCE on the site. Air sparging was activated in Spring 2009 to further remediate the concentrations of PCE.

Date implemented:
Spring 2009- Air Sparging System Activated

Results to date:
Concentrations of PCE have decreased in most of the monitoring wells across the site, most notably in the deep well OW 1-1 where concentrations decreased from 158 mg/L PCE in May 2002 to 27 mg/L in April 2009. OW 1-1 is a deep monitoring well on the site. The other deep monitoring well MW-7 decreased to below the RAO for the site from 71 mg/L in May 2002. The shallow monitoring wells (25-30 feet bgs) MW-3B, MW-6, and OW1-2 have had mixed results. MW-3B and MW-6 have decreased from 38 mg/L and 18 mg/L respectively in May 2002 to 13 mg/L and 10 mg/L PCE, respectively. OW1-2, however, has increased significantly since the remedial design was implemented with the concentration of PCE increasing from 18 mg/L in November 2002 to 59 mg/L during the April 2009 sampling event. This increase can be attributed to the mobilization of the sorbed PCE present on the soil particles.

Next Steps:
Quarterly groundwater monitoring events scheduled for 2009 to June 2010.

Cost to Design and Implement:
All technologies: Soil: $840,482.00 GW: $173,501

In Situ Chemical Oxidation
 

Why the technology was selected:
An excavation was conducted on the site to remove the BTEX contamination present at the former gas station. Chemical oxidation in the form of sodium permanganate was chosen due to the high concentrations of PCE on the site. Air sparging was activated in Spring 2009 to further remediate the concentrations of PCE.

Date implemented:
Spring 2006- Chemical Oxidation Spring 2007- Chemical Oxidation Winter 2007- Chemical Oxidation

Final remediation design:
Three chemical oxidation injections were conducted between the spring of 2006 and the winter of 2007, introducing over 15,000 pounds of sodium permanganate into the subsurface via direct push points.

Results to date:
Concentrations of PCE have decreased in most of the monitoring wells across the site, most notably in the deep well OW 1-1 where concentrations decreased from 158 mg/L PCE in May 2002 to 27 mg/L in April 2009. OW 1-1 is a deep monitoring well on the site. The other deep monitoring well MW-7 decreased to below the RAO for the site from 71 mg/L in May 2002. The shallow monitoring wells (25-30 feet bgs) MW-3B, MW-6, and OW1-2 have had mixed results. MW-3B and MW-6 have decreased from 38 mg/L and 18 mg/L respectively in May 2002 to 13 mg/L and 10 mg/L PCE, respectively. OW1-2, however, has increased significantly since the remedial design was implemented with the concentration of PCE increasing from 18 mg/L in November 2002 to 59 mg/L during the April 2009 sampling event. This increase can be attributed to the mobilization of the sorbed PCE present on the soil particles.

Next Steps:
Quarterly groundwater monitoring events scheduled for 2009 to June 2010.

Cost to Design and Implement:
All technologies: Soil: $840,482.00 GW: $173,501

Ex Situ Soil Removal
 

Why the technology was selected:
An excavation was conducted on the site to remove the BTEX contamination present at the former gas station. Chemical oxidation in the form of sodium permanganate was chosen due to the high concentrations of PCE on the site. Air sparging was activated in Spring 2009 to further remediate the concentrations of PCE.

Date implemented:
Spring 2002- Excavation

Final remediation design:
In the spring of 2002, 593 tons of PCE contaminated soil was removed and disposed of as hazardous waste.

Results to date:
Concentrations of PCE have decreased in most of the monitoring wells across the site, most notably in the deep well OW 1-1 where concentrations decreased from 158 mg/L PCE in May 2002 to 27 mg/L in April 2009. OW 1-1 is a deep monitoring well on the site. The other deep monitoring well MW-7 decreased to below the RAO for the site from 71 mg/L in May 2002. The shallow monitoring wells (25-30 feet bgs) MW-3B, MW-6, and OW1-2 have had mixed results. MW-3B and MW-6 have decreased from 38 mg/L and 18 mg/L respectively in May 2002 to 13 mg/L and 10 mg/L PCE, respectively. OW1-2, however, has increased significantly since the remedial design was implemented with the concentration of PCE increasing from 18 mg/L in November 2002 to 59 mg/L during the April 2009 sampling event. This increase can be attributed to the mobilization of the sorbed PCE present on the soil particles.

Next Steps:
Quarterly groundwater monitoring events scheduled for 2009 to June 2010.

Cost to Design and Implement:
All technologies: Soil: $840,482.00 GW: $173,501

Costs

Cost for Assessment:
  $180,263.00
Cost for Operation and Maintenance:
 
Total Costs for Cleanup:
  Total costs (to June 2009): $1,194,246.00

Contacts

Nancy Boisvert
DCERP
L&C Annex, 4th Floor
401 Church Street
Nashville, Tennessee 37243
615-253-3876