Description
Historical activity that resulted
in contamination.
| Dry Clean USA (DC USA) is a former PCE drycleaning facility that operated from 1988 to 1998. The site is located in a shopping center in a mixed retail commercial/residential setting. Another drycleaning operation was located in the same shopping center approximately 65 ft east of the DC USA facility and operated from 1957 to 1988. Three public water supply wells are located within a one-mile radius of the site. The shopping center was served by a septic system until the early 1970s.
Soil sampling shows that the contaminant source areas appear to be the soil beneath the building floor slab where the drycleaning machine was formerly located and the sanitary sewer lateral line. Remediation Status: Site closed |
Contaminants
Contaminants present and the highest amount
detected in both soil and groundwater.
| Contaminant |
Media |
Concentration (ppb) |
Nondetect |
| Tetrachloroethene (PCE) |
groundwater |
27,300 ppb |
|
| Tetrachloroethene (PCE) |
soil |
3,900 ppb |
|
Site Hydrology
| Deepest Significant
Groundwater Contamination: |
|
68ft bgs |
| Plume Size: |
|
Plume Length: 800ft
Plume Width: 300ft
|
| Average Depth
to Groundwater: |
|
9ft |
Lithology and Subsurface Geology
|
|
Slightly silty, fine to medium-grained quartz sands
Depth: 0-47ft bgs
47ft thick
Conductivity: 1.9ft/day
Gradient: 0.002ft/ft
|
|
|
slighly sandy clay
Depth: 47-53ft bgs
6ft thick
Conductivity: 0.4ft/day
|
|
|
Fine to medium-grained sand interbedded with clayey sand
Depth: 53-83ft bgs
30ft thick
Conductivity: 0.4ft/day
|
|
|
Sandy, clayey, silt
Depth: 83-89ft bgs
6ft thick
Conductivity: 0.4ft/day
|
|
|
Fine to coarse-grained sand with shell fragments
Depth: 89-93ft bgs
4ft thick
Conductivity: 0.4ft/day
|
|
|
Hard phosphatic limestone
Depth: 93-94ft bgs
1ft thick
|
Pathways and DNAPL Presence
 Groundwater
 Sediments
Soil
DNAPL Present
|
Remediation Scenario
Cleanup
Goals: |
|
Maximum Contaminant Levels Groundwater;PCE = 3.0 mg/L,
Soil - PCE = 30 µg/kg (leachability)
|
Technologies
In Situ Chemical Oxidation |
|
Date implemented:
Chemical Oxidation Injection Event: October 4-5, 2005
Final remediation design:
Low-level PCE concentrations in the source area well (installed beneath the facility floor slab and screened across the water table and the capillary zone) continued to persist, and the decision was made to polish contaminated groundwater using chemical oxidation.
On October 4-5, an additional monitoring well was installed in the source area, and 1,057 gallons of a 1% hydrogen peroxide was injected into the former source area monitoring well.
Next Steps:
PCE concentrations in groundwater have met cleanup target levels for four consecutive quarterly monitoring events. The site has met No Further Action critera and a Site Rehabilitation Completion Order will be issued.
Cost to Design and Implement:
Chemical Oxidation: $28,400
|
In Situ Soil Vapor Extraction |
|
Why the technology was selected:
SVE was chosen to remediate the soils at the site because it is a proven technology for recovering VOCs from permeable unsaturated sediments.
Date implemented:
SVE/Pump & Treat: April 1999
Final remediation design:
SVE: Two 4-inch diameter SDR 11 HDPE laterals with 0.01-inch slot screens, 100 feet in length were installed beneath the facility at a depth of 5 ft BLS. The system was powered by a 10 HP rotary lobe blower. The system was designed to operate at a vacuum of 30 inches of water column and a flow rate of 70 scfm. Off gas was treated with a 1000 lb. G.A.C. unit.
Results to date:
The SVE system was shut down on December 1, 2000. It recovered an estimated 9.8 lbs. of VOCs.
Operation of the SVE system and the groundwater recovery system was successful in reducing contaminant concentrations in groundwater to single digit µg/l levels.
Next Steps:
PCE concentrations in groundwater have met cleanup target levels for four consecutive quarterly monitoring events. The site has met No Further Action critera and a Site Rehabilitation Completion Order will be issued.
Cost to Design and Implement:
SVE/Pump & Treat systems: $221,400
|
Ex Situ Air Stripping |
|
Why the technology was selected:
Groundwater recovery was chosen to contain the contaminant plume and remediate contaminated groundwater.
Date implemented:
SVE/Pump & Treat: April 1999
Final remediation design:
The groundwater recovery system consisted of one six-inch diameter PVC recovery well screened 5-25 ft BLS. A Grundfos submersible pump was utilized. The design pumping rate was 7-10 gpm. Recovered groundwater was treated in a low profile air stripper and then discharged to an infiltration gallery.
Results to date:
The groundwater recovery system was shut down on January 17, 2001. Due to a rebound in contaminant concentrations, however, it was restarted on February 26, 2001 and ran until November 2002. The groundwater recovery system recovered an estimated 7.1 million gallons of water and recovered a negligible amount of VOCs.
Operation of the SVE system and the groundwater recovery system was successful in reducing contaminant concentrations in groundwater to single digit µg/l levels.
Next Steps:
PCE concentrations in groundwater have met cleanup target levels for four consecutive quarterly monitoring events. The site has met No Further Action critera and a Site Rehabilitation Completion Order will be issued.
Cost to Design and Implement:
SVE/Pump & Treat systems: $221,400
|
Ex Situ Carbon Adsorption |
|
Why the technology was selected:
SVE was chosen to remediate the soils at the site because it is a proven technology for recovering VOCs from permeable unsaturated sediments.
Groundwater recovery was chosen to contain the contaminant plume and remediate contaminated groundwater.
Date implemented:
SVE/Pump & Treat: April 1999
Chemical Oxidation Injection Event: October 4-5, 2005
Final remediation design:
SVE: Two 4-inch diameter SDR 11 HDPE laterals with 0.01-inch slot screens, 100 feet in length were installed beneath the facility at a depth of 5 ft BLS. The system was powered by a 10 HP rotary lobe blower. The system was designed to operate at a vacuum of 30 inches of water column and a flow rate of 70 scfm. Off gas was treated with a 1000 lb. G.A.C. unit.
Results to date:
The SVE system was shut down on December 1, 2000. It recovered an estimated 9.8 lbs. of VOCs.
Operation of the SVE system and the groundwater recovery system was successful in reducing contaminant concentrations in groundwater to single digit µg/l levels.
Next Steps:
PCE concentrations in groundwater have met cleanup target levels for four consecutive quarterly monitoring events. The site has met No Further Action critera and a Site Rehabilitation Completion Order will be issued.
Cost to Design and Implement:
SVE/Pump & Treat systems: $221,400
|
Ex Situ Pump and Treat |
|
Why the technology was selected:
Groundwater recovery was chosen to contain the contaminant plume and remediate contaminated groundwater.
Date implemented:
SVE/Pump & Treat: April 1999
Final remediation design:
The groundwater recovery system consisted of one six-inch diameter PVC recovery well screened 5-25 ft BLS. A Grundfos submersible pump was utilized. The design pumping rate was 7-10 gpm. Recovered groundwater was treated in a low profile air stpper and then discharged to an infiltration gallery.
Results to date:
The groundwater recovery system was shut down on January 17, 2001. Due to a rebound in contaminant concentrations, however, it was restarted on February 26, 2001 and ran until November 2002. The groundwater recovery system recovered an estimated 7.1 million gallons of water and recovered a negligible amount of VOCs.
Operation of the SVE system and the groundwater recovery system was successful in reducing contaminant concentrations in groundwater to single digit µg/l levels.
Next Steps:
PCE concentrations in groundwater have met cleanup target levels for four consecutive quarterly monitoring events. The site has met No Further Action critera and a Site Rehabilitation Completion Order will be issued.
Cost to Design and Implement:
SVE/Pump & Treat systems: $221,400
|
Costs
Cost
for Assessment:
|
|
$97,700 |
Cost
for Operation and Maintenance:
|
|
$147,800 (includes monitoring) |
Total
Costs for Cleanup:
|
|
$503,300 |
Lessons Learned
1. Numerical groundwater modeling was very valuable in siting the recovery well on location.
2. The injection of a low concentration of a chemical oxidant in the upper portion of the surficial aquifer and the capillary fringe was successful in polishing low concentrations of contaminants and closing the site.
|
Contacts
Karen Milcic, Project Manager
Bureau of Waste Cleanup (MS4520)
Florida Dept. of Environmental Protection
2600 Blair Stone Road
Tallahassee, FL 32399-2400
(850) 245-8931
Karen.Milicic@dep.state.fl.us
Mike Lodato, PG
GeoSyntec
14055 River Edge Drive, Suite 300
Tampa, FL 33637
(813) 558-9829
mLodato@GeoSyntec.com
|
Site Specific References
Contamination Assessment Report-9/97
Remedial Action Plan-8/98
System Start-up Report and Record Drawings Submittal 8/4/99
Operation & Maintenance Reports
Ground Water Monitoring Reports
|
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