Description
Historical activity that resulted
in contamination.
| Drycleaning was conducted at this facility from 1972 until 1978. The facility was located in a strip shopping mall in a mixed commercial/residential setting. A laundromat that ran a coin-operated perchloroethylene (PCE) drycleaning machine was located in the same strip mall.
In 1977, a valve failed on an above-ground storage tank (AST) that contained perchloroethylene (PCE) at the Big B facility, releasing approximately 275 gal of PCE. In 1983, PCE was detected in a public water supply well located approximately 400 ft hydraulically downgradient of the facility. Wellhead treatment (granular activated carbon) has been installed at the water supply well.
A consulting firm conducted a contamination assessment and installed a 3-well groundwater pump-and-treat system for the property owner that operated from 1993-1995 and treated approximately 8 million gal of water. The site became eligible for the Florida Drycleaning Solvent Cleanup Program in 1997. Remediation Status: In groundwater monitoring |
Contaminants
Contaminants present and the highest amount
detected in both soil and groundwater.
| Contaminant |
Media |
Concentration (ppb) |
Nondetect |
| Tetrachloroethene (PCE) |
groundwater |
|
|
| Tetrachloroethene (PCE) |
soil |
|
|
Site Hydrology
| Deepest Significant
Groundwater Contamination: |
|
200ft bgs |
| Plume Size: |
|
Plume Length: 2,650ft
Plume Width: 1,100ft
|
| Average Depth
to Groundwater: |
|
8ft |
Lithology and Subsurface Geology
Shallow Zone
|
|
very fine to medium-grained sand
Depth: 0-77ft bgs
77ft thick
Conductivity: 32.3ft/day
Gradient: 0.0035ft/ft
|
Low Permeability Zone
|
|
very fine to fine-grained sands interbedded with clays and sandy clays
Depth: 77-195ft bgs
118ft thick
Conductivity: 3.3ft/day
Gradient: 0.001ft/ft
|
Main Producing Zone
|
|
fine to coarse sand with some clay lenses
Depth: 195-228ft bgs
33ft thick
Conductivity: 70ft/day
Gradient: 0.007ft/ft
|
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? |
|
Yes |
Type of Vapor Mitigation System(s): |
|
Soil Vapor Extraction
|
Remediation Scenario
Cleanup
Goals: |
|
Groundwater (MCL): PCE = 3 µg/L
Soils - Leachability-based levels (SCTLs): PCE = 30 µg/kg
|
Remedy Level: |
|
Full Scale Remedy |
Technologies
In Situ Chemical Oxidation |
|
Why the technology was selected:
Chemical oxidation was selected to address high contaminant concentration in groundwater in a deeper lower permeability zone between 90 and 115 feet BLS. Fenton's Reagent was chosen because of the proximity of the site to a public water supply well.
Total organic carbon concentrations in the aquifer ranged from less than 500 mg/kg to 720 mg/kg (0.72%).
Date implemented:
First chemical oxidation injection event: June 18- July 24, 2004
2nd chemical oxidation injection event: July 18 - August 4, 2005
Final remediation design:
Two chemical oxidation injection events (Fenton's Reagent) were conducted at the site, the first from June 22-July 12, 2004 and the second one from July 18-August 4, 2005. Injection occurred in fifteen (15) injection wells constructed of 2-inch diameter Schedule 80 PVC. Eight (8) of the wells were screened 95-105 ft BLS. Five wells were screened 85-95 ft BLS. One well was screened 100-115 ft BLs and one well was screened 85-95 ft BLS.
One day prior to chemical oxidant injeciton 100 gallons of a ferrous iron sulfate, sodum persulfate and hydrochloric acid solution conditioner was injected into each well to promote generation of hydroxyl radicals by Fenton's Reaction and to lower the pH. The chemical oxidant was a 11.7% hydrogen peroxide solution. Approximately 600 gallons of this solution was injected into each of 20 injeciton interval for a total injection volume of 12,000 gallons per each of the two injection event.
Results to date:
The chemical oxidation injections resulted in a reduction of PCE concentrations in groundwater samples collected from source area monitor wells. Based on groundwater monitoring, the highest pre-injection PCE concentration detected in groundwater was 1,500 ug/l. The highest PCE concentration detected in the contaminant source area in the first monitoring event conducted after the second chemical oxidaiton injection event was 357 ug/l PCE.
Next Steps:
The site is currently in groundwater monitoring. A monitoring event conducted in December 2008 found that the highest contaminiant concentration in a groundwater sample collected on the property where the drycleaning facility was formerly located and where remediation occurred was 42.1 ug/l PCE. Two off property wells had PCE concentrations of 531 ug/l and 758 ug/l. Groundwater produced from the nearby water supply well is still being treated via G.A.C.
Cost to Design and Implement:
Pilot Chem-Ox Design: 27,900
Pilot Chem-ox implementation & Full-scale Remedial Action Plan: $78,200
Implement Chem-ox (njection well installation & 2 injection events: $479,700
|
In Situ Multi Phase Extraction |
|
Why the technology was selected:
Multiphase extraction was utilized to depress the water table and expose the shallow sediments for VOC extraction via the soil vapor extraction system.
Date implemented:
Multiphase Extraction/Soil Vapor Extraction: March 1, 2000.
Final remediation design:
The multiphase extraction system consisted of one 4-inch diameter PVC well screened 3-38 ft BLS. Design pumping rate was 10 gpm. Estimated radius of influence was 59 feet. Groundwater recovery is via a 1/2 HP Grunfos submersible pump. Extracted groundwater is treated in a low profile air stripper. The water is then treated via two liquid phase Carbtrol HP-200 carbon filters and discharged to an injection well.
Results to date:
The multiphase extraction/SVE systems operated for approximatley 8.25 months and were shut down on January 17, 2001. An estimated 214.6 pounds of VOCs were recovered in vapor phase. The multiphase system produced and treated an estiamted 889,795 gallons of groundwter recoverying an estimated 1.15 pounds of VOCs.
Next Steps:
The site is currently in groundwater monitoring. A monitoring event conducted in December 2008 found that the highest contaminiant concentration in a groundwater sample collected on the property where the drycleaning facility was formerly located and where remediation occurred was 42.1 ug/l PCE. Two off property wells had PCE concentrations of 531 ug/l and 758 ug/l. Groundwater produced from the nearby water supply well is still being treated via G.A.C.
Cost to Design and Implement:
SVE/MPE: $141,000
|
In Situ Soil Vapor Extraction |
|
Why the technology was selected:
Multiphase extraction was utilized to depress the water table and expose the shallow sediments for VOC extraction via the soil vapor extraction system.
Date implemented:
Multiphase Extraction/Soil Vapor Extraction: March 1, 2000.
Final remediation design:
The SVE system consisted of two horizontal vapor recovery wells with 10 foot screen lengths installed one and one-half feet BLS. The system was powered by a 4 HP Ametek Rotron regenerative blower. Off gas was treated via two Carbtrol G-1S vapor-phase carbon canisters piped in series.
Results to date:
The multiphase extraction/SVE systems operated for approximately 8.25 months and were shut down on January 17, 2001. An estimated 214.6 pounds of VOCs were recovered in vapor phase. The multiphase system produced and treated an estiamted 889,795 gallons of groundwter recoverying an estimated 1.15 pounds of VOCs.
Next Steps:
The site is currently in groundwater monitoring. A monitoring event conducted in December 2008 found that the highest contaminiant concentration in a groundwater sample collected on the property where the drycleaning facility was formerly located and where remediation occurred was 42.1 ug/l PCE. Two off property wells had PCE concentrations of 531 ug/l and 758 ug/l. Groundwater produced from the nearby water supply well is still being treated via G.A.C.
Cost to Design and Implement:
SVE/MPE: $141,000
|
Ex Situ Air Stripping |
|
Date implemented:
Multiphase Extraction/Soil Vapor Extraction: March 1, 2000.
Final remediation design:
The multiphase extraction system consisted of one 4-inch diameter PVC well screened 3-38 ft BLS. Design pumping rate was 10 gpm. Estimated radius of influence was 59 feet. Groundwater recovery is via a 1/2 HP Grunfos submersible pump. Extracted groundwater is treated in a low profile air stripper. The water is then treated via two liquid phase Carbtrol HP-200 carbon filters and discharged to an injection well.
Results to date:
The multiphase extraction/SVE systems operated for approximately 8.25 months and were shut down on January 17, 2001. An estimated 214.6 pounds of VOCs were recovered in vapor phase. The multiphase system produced and treated an estiamted 889,795 gallons of groundwter recoverying an estimated 1.15 pounds of VOCs.
Next Steps:
The site is currently in groundwater monitoring. A monitoring event conducted in December 2008 found that the highest contaminiant concentration in a groundwater sample collected on the property where the drycleaning facility was formerly located and where remediation occurred was 42.1 ug/l PCE. Two off property wells had PCE concentrations of 531 ug/l and 758 ug/l. Groundwater produced from the nearby water supply well is still being treated via G.A.C.
Cost to Design and Implement:
SVE/MPE: $141,000
|
Ex Situ Carbon Adsorption |
|
Date implemented:
Multiphase Extraction/Soil Vapor Extraction: March 1, 2000.
Final remediation design:
The multiphase extraction system consisted of one 4-inch diameter PVC well screened 3-38 ft BLS. Design pumping rate was 10 gpm. Estimated radius of influence was 59 feet. Groundwater recovery is via a 1/2 HP Grunfos submersible pump. Extracted groundwater is treated in a low profile air stripper. The water is then treated via two liquid phase Carbtrol HP-200 carbon filters and discharged to an injection well.
Results to date:
The multiphase extraction/SVE systems operated for approximately 8.25 months and were shut down on January 17, 2001. An estimated 214.6 pounds of VOCs were recovered in vapor phase. The multiphase system produced and treated an estiamted 889,795 gallons of groundwter recoverying an estimated 1.15 pounds of VOCs.
Next Steps:
The site is currently in groundwater monitoring. A monitoring event conducted in December 2008 found that the highest contaminiant concentration in a groundwater sample collected on the property where the drycleaning facility was formerly located and where remediation occurred was 42.1 ug/l PCE. Two off property wells had PCE concentrations of 531 ug/l and 758 ug/l. Groundwater produced from the nearby water supply well is still being treated via G.A.C.
Cost to Design and Implement:
SVE/MPE: $141,000
|
Costs
Cost
for Assessment:
|
|
$47,389 |
Cost
for Operation and Maintenance:
|
|
Two semi-annual groundwater monitoring events: $18,000/year |
Total
Costs for Cleanup:
|
|
|
Lessons Learned
1. Although PCE had been the only contaminant detected in both soil and groundwater samples collected at the site, TCE and Cis 1,2-DCE was detected in source area groundwater samples following the two chemical oxidation injection events.
2. The Schedule 80 PVC casing/screen used for the injection wells proved to be servcicable for the chemical oxidant injections. No warping was noted.
3. Due to the number of monitoring wells and their depths (to over 200 feet), passive difusion bags are being utilized to reduce monitoring costs.
|
Contacts
Aaron Cohen
Florida Dept. of Environmental Protection
Bureau of Waste Cleanup, MS 4500
2600 Blair Stone Road
Tallahassee, Florida 32399
850-245-8974
Aaron.Cohen@dep.state.fl.us
Brian Moore, PE, Contractor
HAS Environmental Engineers & Scientists
4019 East Fowler Ave.
Tampa, FL 33617
813-971-3882
Bmoore@hsa-env.com
|
Site Specific References
Interim Remedial Action Plan - March 1997
Remedial Alternatives Analysis - February 1999
Interim Remedial Action Plan - Feb. 1999
SVE Summary Closure Report - Feb. 2001
Pilot Study Plan - March 2002
Remedial Action Plan - Jan. 2004
Remedial Action Plan Implementation Report Phase I - October 2004
Remedial Action Plan Implementation Report Phase II - October 2005
Groundwater Monitoring Reports- 1998- present
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