Drycleaner Site Profiles

Comet Cleaners, Vero Beach, Florida

Description
Historical activity that resulted in contamination.

Drycleaning using PCE was performed at this site from 1967 until May of 1981. The facility is currently a dry drop-off. It is located in a mixed commercial/residential setting. The nearest water supply well is located approximately 2000 feet south-southeast of the site. Only low concentrations of PCE (up to 7 ug/kg) were found in the unsaturated zone. These detections were in soil samples collected beneath the facility floor slab.

Remediation Status: In active remediation


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


Contaminant Media Concentration (ppb) Nondetect
cis-1,2-Dichloroethene groundwater 7 ppb
Tetrachloroethene (PCE) groundwater 1,930 ppb
Tetrachloroethene (PCE) soil 7 ppb
Trichloroethene (TCE) groundwater 1,130 ppb
toluene groundwater 235 ppb
trans-1,2-Dichloroethene groundwater 18 ppb

Site Hydrology

Deepest Significant Groundwater Contamination:   70ft bgs
Plume Size:   Plume Length: 950ft
Plume Width: 100ft
Plume Thickness: 62ft
Average Depth to Groundwater:   8ft

Lithology and Subsurface Geology

 
  silty, fine to medium-grained sand
Depth: 0-13ft bgs
13ft thick
Conductivity: 14.27ft/day
Gradient: 0.005ft/ft
 
  silty clay gradient to clayey fine-grained sand
Depth: 13-15ft bgs
2ft thick
 
  fine-grained sand
Depth: 15-18ft bgs
3ft thick
 
  silty fine-grained sand with shells
Depth: 18-45ft bgs
27ft thick
 
  silty, very fine to medium-grained sand
Depth: 45-50ft bgs
5ft thick
 
  clayey fine-grained sand with shells
Depth: 50-55ft bgs
5ft thick
 
  shell has with silty fine-grained sands
Depth: 55-76ft bgs
21ft thick

Pathways and DNAPL Presence

checkGroundwater
Sediments
checkSoil
DNAPL Present

Remediation Scenario

Cleanup Goals:
  Groundwater: PCE = 3 ug/l, TCE = 3 ug/l, cis 1,2-DCE = 70 ug/l, trans 1,2-DCE = 100 ug/l

Soil: PCE = 30 ug/kg
Remedy Level:
  Full Scale Remedy

Technologies

In Situ Bioremediation
 

Why the technology was selected:
Bioremediation was selected as the groundwater remedy because PCE daughter products are present in groundwater and aquifer and geochemical conditions are favorable for reductive dechlorination: disolved oxygen concentrations range from 0.5 to 0.9 mg/l, Redox values range from -152 to -266 millivolts; Total organic carbon concentrations detected in groundwater range from 27 to 59 mg/l. Potassium lactate was chosen an an amendmenment because it is a relatively cheap carbon source.

Date implemented:
On site injection: Decemeber 14-28, 2005 Off site injection: January 4-13, 2006

Final remediation design:
A total of 10 injection wells were installed. Six of these wells (1.5-inch diameter PVC), were installed around the building that formerly housed the drycleaning operation using a direct push unit. Three wells were installed hydraulically upgradient of the facility and three wells were installed downgradient of the facility. A seventh 2-inch diameter injection well was later added downgradient of the facility. These wells were screened as follows: two wells 18-32 ft BLS, two wells 20-34 ft BLS, and three wells 12-29 ft BLS. Additionally, three injection wells (2-inch diameter PVC) were installed on the property immediately downgradient (across the street) of the former drycleaning facility. These wells were screened as follows: one well 18-32 ft BLS, two wells 19-34 ft BLS.

Results to date:
A total of 158,000 gallons of a 0.17% (w/w) potassium lactate solution (207 gallons or 3.8 drums of a 60% K-lactate solution) were injected in onsite injection wells over a 14 day period. Average injection flow rate was 1.2 gpm. 46,000 gallons of a 0.20% (w/w) potassium lactate solution (68 gallons or 1.2 drums of a 60% K-lactate solution),were injected in the four offsite injection wells. Average injection flow rate was 1.5 gpm. As of the February 15, 2008 monitoring event, PCE is no longer being detected. TCE has been largely converted to Cis 1,2-DCE (highest TCE concentration was 15.4 ug/L. The highest Cis 1,2-DCE concentration was 230 ug/l. After the injections, concentrations of Cis 1,2-DCE rose and have subequently declined. No vinyl chloride has yet been detected in groundwater at the site. An active soil gas survey was recently conducted. Of soil gas samples collected from five vapor extraction points, incluidng three installed beneatht the floor slab of the facility, only one soil gas sample had detectable concentrations of a contaminant: 1.4 mg/cubic meter.

Next Steps:
An addtional potassium lactate injection event is being considered.

Cost to Design and Implement:
Design: $13,300 Implementation:

Costs

Cost for Assessment:
  $152,200
Cost for Operation and Maintenance:
 
Total Costs for Cleanup:
 

Contacts

Nancy Murchison, Project Manager
Bureau of Waste Cleanup (MS4520)
Florida Department of Environmental Protection
2600 Blair Stone Road
Tallahassee, Florida 32399-2400
Phone: (850) 245-8990
E-mail: Nancy.Murchison@DEP.state.fl.us

Gregg Roberts, PG
725 U.S. Highway 301 South
Tampa, Florida 33619-4349
Phone: (813) 612-3687
E-mail: gregg.roberts@shawgrp.com

Site Specific References

Site Assessment Report - Decemeber 2001

Remedial Action Plan - December 2003

Remedial Action Construction/Startup Report - May 2006

Groundwater Monitoring Reports