Description
Historical activity that resulted
in contamination.
| Bruce Cleaners is an active PCE drycleaning facility that has been in operation since 1991. The identified contaminant source was the area outside the serivce door of the facility. Groundwater flow at the site is toward a small lake located west of the site. The chlorinated solvent groundwater contaminant plume runs from the facility toward the lake and is comingled with a BTEX plume from a service station located approximately 240 feet northeast of the drycleaning facility. Remediation Status: Site closed |
Contaminants
Contaminants present and the highest amount
detected in both soil and groundwater.
| Contaminant |
Media |
Concentration (ppb) |
Nondetect |
| Benzene |
groundwater |
1,120 ppb |
|
| cis-1,2-Dichloroethene |
groundwater |
1.8 ppb |
|
| ethylbenzene |
groundwater |
664 ppb |
|
| Tetrachloroethene (PCE) |
groundwater |
2,600 ppb |
|
| Tetrachloroethene (PCE) |
soil |
5,900 ppb |
|
| Trichloroethene (TCE) |
groundwater |
13 ppb |
|
| Trichloroethene (TCE) |
soil |
6 ppb |
|
| toluene |
groundwater |
4,600 ppb |
|
| p-Xylene |
groundwater |
4.92 ppb |
|
Site Hydrology
| Deepest Significant
Groundwater Contamination: |
|
55ft bgs |
| Plume Size: |
|
Plume Length: 840ft
Plume Width: 130ft
Plume Thickness: 55ft |
| Average Depth
to Groundwater: |
|
6.52ft |
Lithology and Subsurface Geology
|
|
silty, very fine to fine-grained sand
Depth: 0-30ft bgs
30ft thick
Conductivity: 13ft/day
Gradient: 0.17ft/ft
|
|
|
very fine to fine-grained sand with clay
Depth: 30-32ft bgs
2ft thick
|
|
|
fine-grained sand
Depth: 32-37ft bgs
5ft thick
|
|
|
very fine to fine-grained sand with clay
Depth: 37-56ft bgs
19ft thick
|
Pathways and DNAPL Presence
 Groundwater
 Sediments
Soil
DNAPL Present
|
Remediation Scenario
Cleanup
Goals: |
|
Soil: PCE = 30 ug/kg; TCE = 30 ug/kg
Groundwater: PCE = 3 ug/l, TCE = 3 ug/l, cis 1,2=DCE = 70 ug/l; benzene= 1 ug/l, ethylbenzene = 700 ug/l, toluene = 1,000 ug/l, xylenes = 10,000 ug/l, MTBE = 20 ug/l
|
Technologies
In Situ Bioremediation |
|
Why the technology was selected:
Biostimulation was selected to polish low concentrations of PCE remaining in the contaminant source area because Aquifer conditions were fairly strongly anaerobic (dissolved oxygen concentrations generally ranged from 0.20 to 0.44 mg/L). However, many of the groundwater samples collected from monitor wells had a pH of less than 5 standard units. Therefore the decision was made to buffer the groundwater (raise the pH) to create a more favorable environment for reductive dechlorination.
Date implemented:
Biostimulation (K-lactate injection): November 6, 2006.
Final remediation design:
Biostimulation: Six gallons of 60% potassium lactate was mixed with 600 gallons of groundwater extracted onsite. The solution was buffered with 1.6 pounds of food-grade calcium carbonate to a pH of approximately 8 standard units. Injection was via three direct push boreholes advaced to 16 ft BLS. A centrifugal pump was used inject the amendment at 15 p.s.i. The direct push pipe was pulled back during the injection until it was within 5 feet of the water table.
Other technologies used:
Buffered groundwater with potassium carbonate to facilitate biodegradation
Results to date:
The SVE system was operated through June of 2001 and recovered an estimated 3.5 lbs. of VOCs. Confirmation soil sampling showed that the unsaturated zone has been sucessfully remediated. PCE concentrations in groundwater had decreased to single digit ppb but still exceeded the MCL so the decision was made to inject a carbon amendment to polish the low concentrations of PCE.
PCE concentrations in the groundwater were non-detect after the one-time K-lactate event and have reamined so for the past year. The first post-injection monitoring event, conducted three months after the injection event showed only a slight increase in pH from the baseline sampling event in groundwater samples collected from teh source area monitor well (4.12 to 4.72). PCE concentrations in groundwater collected from the source area monitor well we below cleanup target levels. No PCE degradation products were detected in these groundwater samples.
Next Steps:
The site has met the No Further Action, without engineering and institutional controls. A Site Rehabilitation Completion Order will be issued.
Cost to Design and Implement:
All technologies: Design; $30,300
Implementation: $81,300
|
In Situ Soil Vapor Extraction |
|
Why the technology was selected:
SVE was selected to remediate contaminants in (soil) the unsaturated zone because it is an effective technology for removing VOCs from permeable soils.
Date implemented:
SVE: March 1, 2001
Final remediation design:
SVE: Two 2-inch diameter PVC lateral vapor recovery wells with 0.010-inch slot screens 55 feet in length. These wells were installed at a depth of 3 feet, parallel, approximately 13 feet apart in the sevice area behind the strip mall in which the drycleaning facility is located. The system is powered by a 5-HP Rotron blower. Off gas is treated by 2-250 lb. G.A.C. units.
The design flow rate for the system was 172 scfm under a vacuum of 55.75 inches w.c. The estimated radius of influence was 35 ft. The system operared 142-182 scfm under 40-41 inches w.c.
Results to date:
The SVE system was operated through June of 2001 and recovered an estimated 3.5 lbs. of VOCs. Confirmation soil sampling showed that the unsaturated zone has been sucessfully remediated. PCE concentrations in groundwater had decreased to single digit ppb but still exceeded the MCL so the decision was made to inject a carbon amendment to polish the low concentrations of PCE.
PCE concentrations in the groundwater were non-detect after the one-time K-lactate event and have reamined so for the past year. The first post-injection monitoring event, conducted three months after the injection event showed only a slight increase in pH from the baseline sampling event in groundwater samples collected from teh source area monitor well (4.12 to 4.72). PCE concentrations in groundwater collected from the source area monitor well we below cleanup target levels. No PCE degradation products were detected in these groundwater samples.
Next Steps:
The site has met the No Further Action, without engineering and institutional controls. A Site Rehabilitation Completion Order will be issued.
Cost to Design and Implement:
All technologies: Design; $30,300
Implementation: $81,300
|
Ex Situ Carbon Adsorption |
|
Date implemented:
SVE: March 1, 2001
Final remediation design:
SVE: Two 2-inch diameter PVC lateral vapor recovery wells with 0.010-inch slot screens 55 feet in length. These wells were installed at a depth of 3 feet, parallel, approximately 13 feet apart in the sevice area behind the strip mall in which the drycleaning facility is located. The system is powered by a 5-HP Rotron blower. Off gas is treated by 2-250 lb. G.A.C. units.
The design flow rate for the system was 172 scfm under a vacuum of 55.75 inches w.c. The estimated radius of influence was 35 ft. The system operared 142-182 scfm under 40-41 inches w.c.
Results to date:
The SVE system was operated through June of 2001 and recovered an estimated 3.5 lbs. of VOCs. Confirmation soil sampling showed that the unsaturated zone has been sucessfully remediated. PCE concentrations in groundwater had decreased to single digit ppb but still exceeded the MCL so the decision was made to inject a carbon amendment to polish the low concentrations of PCE.
PCE concentrations in the groundwater were non-detect after the one-time K-lactate event and have reamined so for the past year. The first post-injection monitoring event, conducted three months after the injection event showed only a slight increase in pH from the baseline sampling event in groundwater samples collected from teh source area monitor well (4.12 to 4.72). PCE concentrations in groundwater collected from the source area monitor well we below cleanup target levels. No PCE degradation products were detected in these groundwater samples.
Next Steps:
The site has met the No Further Action, without engineering and institutional controls. A Site Rehabilitation Completion Order will be issued.
Cost to Design and Implement:
All technologies: Design; $30,300
Implementation: $81,300
|
Costs
Cost
for Assessment:
|
|
$ 119,000 |
Cost
for Operation and Maintenance:
|
|
Operation & Maintenance: $17,200
Monitoring: $18,500
Site Restoration: $5,000 |
Total
Costs for Cleanup:
|
|
$253,800 |
Lessons Learned
|
1. Operation of the soil vapor extraction system at this site was largely responsible for achieving of groundwater cleanup target levels. The k-lactate injections did not result in the degradation of PCE and the injection of calcium carbonate did not appear to raise the pH of the groundwater in the contaminant source area for any appreciable period of time.
|
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
Mike McCoy, PG, consultant
Earth Tech Consulting, Inc.
30 South Keller Road, Suite 500
Orlando, Florida 32810-6101
Phone: (407)262-2911
E-Mail: Michael.McCoy@earthtech.com
|
Site Specific References
Contamination Assessment Report; December 1997
Remedial Action Plan (SVE): April 2000
Construction Completion Report: March 2001
Limited Remedial Action Plan: April 2006
Operartion & Maintenance Reports
Groundwater Monitoring Reports
|
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