Drycleaner Site Profiles

Dry Clean USA # 11204, Fort Lauderdale, Florida

Description
Historical activity that resulted in contamination.

Drycleaning using PCE was performed at this site from 1985 to 1996. The facility currently is a dry drop-off location. The facility is located in a mixed commercial/residential setting. The nearest public water supply well is located approximately 2,670 ft east of the facility. An irrigation well is located approximately 120 ft southwest of the facility.

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 202,000 ppb
1,1-Dichloroethene groundwater 1,390 ppb
Tetrachloroethene (PCE) groundwater 87,200 ppb
Tetrachloroethene (PCE) soil 765 ppb
Trichloroethene (TCE) groundwater 28,500 ppb
trans-1,2-Dichloroethene groundwater 6,720 ppb
Vinyl Chloride groundwater 17,300 ppb

Site Hydrology

Deepest Significant Groundwater Contamination:   53ft bgs
Plume Size:   Plume Length: 60ft
Plume Width: 210ft
Plume Thickness: 48ft
Average Depth to Groundwater:   5ft

Lithology and Subsurface Geology

 
  fine-grained sand
Depth: 0-7ft bgs
7ft thick
Conductivity: 44ft/day
Gradient: 0.0015ft/ft
 
  Organic rich soil
Depth: 7-8ft bgs
1ft thick
Conductivity: 44ft/day
 
  Very fine to fine-grained sand
Depth: 8-23ft bgs
15ft thick
Conductivity: 44ft/day
 
  Sandy, oolitic limestone
Depth: 23-34ft bgs
11ft thick
Conductivity: 44ft/day
 
  Very fine-grained sand to medium-grained sand
Depth: 34-50ft bgs
16ft thick
Conductivity: 27ft/day
 
  limestone
Depth: 50-70ft bgs
20ft thick
Conductivity: 27ft/day

Pathways and DNAPL Presence

checkGroundwater
Sediments
checkSoil
checkDNAPL Present

Remediation Scenario

Cleanup Goals:
  Groundwater (MCLs): PCE = 3.0 µg/L, TCE = 3.0 µg/L; cis 1,2-DCE = 70 µg/L; trans 1,2-DCE = 100 µg/L; VC = 1.0 µg/L

Soil: (soil cleanup target leachability standard) PCE = 30 ug/kg
Remedy Level:
  Full Scale Remedy

Technologies

Ex Situ Bioremediation
 

Why the technology was selected:
Bioremediation using Cl Solution's Cl-Out was chosen for the pilot study as a method to enhance degradation of contaminants in groundwater. Reductive dechlorination is occurring in groundwater.

Date implemented:
Excavation & infiltration:- December 17-19, 2001 Cl-Out injection - January 23, 2002 ABC injection: February 15, 2006 ABC injection: September 14, 2008

Final remediation design:
Following a bench-scale study of Cl-out, a pilot test was designed to be implemented concurrently with the soil excavation. A portion of the building floor slab was removed and approximately 5.4 cubic yards of contaminated soil was hand-excavated to a depth of 6 ft. The pilot test consisted of two injection events, conducted a month apart. The Cl-Out treatment was infiltrated into the source removal excavation in December 2001 and then the CL-Out solution was introduced into the subsurface through injection wells installed inside the facility in January 2002. Number of injection events: 2 3 Injection wells: 2 - 1" diameter PVC wells screened 5-10 ft bgs & 1 one and one-half inch diameter PVC well screened 5-10 ft bgs. Quantity per event: 55 gallons of solution (50 lbs. of dextrose & ~ 109 colony forming units (CFU)/milliliter of bacteria (Pseudomonous sp.) Quantity per well: ~ 20 gallons Injected with variable speed peristaltic pump ~ 1 gallon/minute. Subsequently, there have been two additional bioremedial injection events using ABC (Anaerobic BioChem). ABC is a mixture of potassium lactate, soybean oil and a phophate buffer. The same three injection wells were utilized as for the CL-Out injections. Each injection event utilized 420 gallons of a 15% by weight ABC solution (140 gallons per well).

Results to date:
Within the first two years after the CL-Out injections, contaminant concentrations in groundwater samples collected from the source area monitor well showed a drop in PCE concentration to 96 ug/l (three orders of magnitude less than the pre-injection concentration). The TCE concentration also dropped (to 27.9 ug/l). There were corresponding increases in the concentrations of Cis 1,2-DCE and vinyl chloride. However, PCE and TCE concentrations rebounded to 1000s of ug/l in 2005 and 2006, indicating that parent contaminant mass still remained in the source area. Following the first ABC injection event, PCE and TCE concentrations increased in the source area monitor well but then decreased after the second ABC injection event. Concentrations of Cis 1,2-DCE showed an initial increase (to 35,600 ug/l) and then declined. Vinyl chloride concentrations have esentially remained flat (3,890 to 4,000 ug/l). No PCE and very little TCE had been detected in groundwater samples collected from downgradient monitor wells during the site assessment. Cis 1,2-DCE concentrations as high as 3,080 ug/l declined to 67 ug/l after the CL-Out injections and then rebounded. After the ABC injections, Cis 1,2-DCE concentrations have dropped well below the MCL. Vinyl chloride concentrations in downgradient montior wells dropped after the Cl-Out injections and then rebounded. After the ABC injections, vinyl chloride concentrations in downgradient monitor wells have dropped and range from non-detect to 18 ug/l.

Next Steps:
When local permits are approved a soil vapor extraction system will be installed to recover VOC contamination in the unsaturated zone not removed by the excavation.

Cost to Design and Implement:
Feasibility study: $4,658 Cl-Out injection: $7,100 Well installation, sampling & reporting: $20,708

Ex Situ Soil Removal
 

Why the technology was selected:
Excavation was chosen as a more practical removal technology for soil contamination than SVE, because the drycleaning machine had been removed and the source area was accessible. Also, there is little room for a remedial system at the site.

Date implemented:
Excavation & infiltration:- December 17-19, 2001 Cl-Out injection - January 23, 2002

Final remediation design:
A portion of the building floor slab was removed and approximately 5.4 cubic yards of contaminated soil was hand-excavated to a depth of 6 ft.

Next Steps:
When local permits are approved a soil vapor extraction system will be installed to recover VOC contamination in the unsaturated zone not removed by the excavation.

Cost to Design and Implement:
Soil excavation & removal: $18,000

Costs

Cost for Assessment:
  $126,405
Cost for Operation and Maintenance:
 
Total Costs for Cleanup:
 

Lessons Learned

1. PCR testing conducted after the Cl-Out injection events confirmed the presence of DHE. Ethene and ethane have been detected in groundwater samples. Augmenting the dextrose injections with Pseudomonous sp did not aid in reductive dechlorination of PCE to ethene and ethane.

2. The presence of the full range of daughter products and ethene and ethane in groundwater is sufficient evidence that the necessary strain of DHE is present in the groundwater at the site and therefore, PCR testing was not necessary.

3. The source area soil excvation, though useful in removing contaminant mass was not effective in removing sufficient mass in the unsaturated zone to preclude continued sourcing of groundwater contamination from contaminated soil through seasonal rises in the water table. Hence, SVE will be necessary to remove most of the remaining mass in the unsaturated zone.

Contacts

Kelsey Helton, Project Manager
Bureau of Waste Cleanup (MS 4520)
Florida Department of Environmental Protection
2600 Blair Stone Road
Tallahassee, Florida 32399-2400
(850) 245-8969
Kelsey.Helton@dep.state.fl.us

Mike McCoy, PG
Earth Tech
30 South Keller Road, Suite 500
Orlando, Florida 32810-6101
(407) 331-5967
Michael.McCoy@earthtech.com

Site Specific References

1. Site Assessment Report & Remedial Alternatives Analysis: February 2001
2. Bioremediation Feasibility Study: June 2001
3. Cl-out Pilot Study Plan: November 2001
4. Interim Source Removal & Bioremediation Pilot Study Report: March 2001
5. Remedial Action Plan (bioremediation): October 2005
6. Soil Remedial Action Plan (SVE); May 2008.
7. Groundwater monitoring reports