Drycleaner Site Profiles

Excel Dry Cleaners, Plantation, Florida

Description
Historical activity that resulted in contamination.

Drycleaning, using PCE, was performed at this site from 1978 until 2003 when it converted to a drop-off store. The facility is located in a small strip mall in a retail commercial/residential setting.

Remediation Status: Site closed


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


Contaminant Media Concentration (ppb) Nondetect
cis-1,2-Dichloroethene groundwater 11.8 ppb
Tetrachloroethene (PCE) groundwater 88.1 ppb
Tetrachloroethene (PCE) soil 78 ppb
Trichloroethene (TCE) groundwater 2 ppb
trans-1,2-Dichloroethene groundwater 8.1 ppb

Site Hydrology

Deepest Significant Groundwater Contamination:   20ft bgs
Plume Size:   Plume Length: 145ft
Plume Width: 50ft
Plume Thickness: 16ft
Average Depth to Groundwater:   4.02ft

Lithology and Subsurface Geology

 
  very fine to fine-grained sand
Depth: 0-30ft bgs
30ft thick
Conductivity: 2.45ft/day
Gradient: 0.0003ft/ft

Pathways and DNAPL Presence

checkGroundwater
Sediments
checkSoil
DNAPL Present

Remediation Scenario

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

Soil: PCE = 30 µg/kg

Technologies

In Situ Monitored Natural Attenuation
 

Why the technology was selected:
Monitored natural attenuation was the remedy selected for this site after completion of a contamination assessment in 1997. This was based on the low contaminant concentrations detected in groundwater and (at the time) the lack of significant contamination found in the unsaturated zone at the site. After approximately six years of monitoring and the detection of PCE in a downgradient monitoring well, soil samples were collected beneath the facility floor slab. PCE was detected in these soil samples, and the decision was made to actively remediate contaminated soil at the site. Soil vapor extraction was chosen as the soil remedial technology, because it is an effective technology for removing VOCs from permeable unsaturated sediments.

Next Steps:
A Site Rehabilitation Completion Order will be issued for the site.

Cost to Design and Implement:
$57,200 for all technologies

In Situ Soil Vapor Extraction
 

Why the technology was selected:
Monitored natural attenuation was the remedy selected for this site after completion of a contamination assessment in 1997. This was based on the low contaminant concentrations detected in groundwater and (at the time) the lack of significant contamination found in the unsaturated zone at the site. After approximately six years of monitoring and the detection of PCE in a downgradient monitoring well, soil samples were collected beneath the facility floor slab. PCE was detected in these soil samples, and the decision was made to actively remediate contaminated soil at the site. Soil vapor extraction was chosen as the soil remedial technology, because it is an effective technology for removing VOCs from permeable unsaturated sediments.

Date implemented:
February 3, 2005

Final remediation design:
Two lateral vapor extraction wells were installed at the site. Since drycleaning operations had ceased, one lateral was installed beneath the floor slab at the former location of the drycleaning machine. The other lateral was installed outside the service door of the facility. The laterals were constructed of 1-inch diameter Schedule 40 PVC with 0.020-inch slit. They were installed 28 inches below grade. A 3 HP rotary lobe blower was utilized. Off gas was treated with two 175 lb. G.A.C. units. The system was operated at 77 scfm with an applied vacuum of 28 - 30 inches w.c.

Results to date:
The SVE system was shut down on August 24, 2005. Although a negligible amount of VOCs (less than one pound) was recovered by the sytem, contaminant concentrations in groundwater dropped below cleanup target levels in June 2005 and remained below cleanup target levels for over a year. Low VOC recovery was likely due to excavation of contaminated soil during installation of SVE laterals.

Next Steps:
A Site Rehabilitation Completion Order will be issued for the site.

Cost to Design and Implement:
$57,200 for all technologies

Ex Situ Carbon Adsorption
 

Date implemented:
February 3, 2005

Final remediation design:
Two lateral vapor extraction wells were installed at the site. Since drycleaning operations had ceased, one lateral was installed beneath the floor slab at the former location of the drycleaning machine. The other lateral was installed outside the service door of the facility. The laterals were constructed of 1-inch diameter Schedule 40 PVC with 0.020-inch slit. They were installed 28 inches below grade. A 3 HP rotary lobe blower was utilized. Off gas was treated with two 175 lb. G.A.C. units. The system was operated at 77 scfm with an applied vacuum of 28 - 30 inches w.c.

Results to date:
The SVE system was shut down on August 24, 2005. Although a negligible amount of VOCs (less than one pound) was recovered by the sytem, contaminant concentrations in groundwater dropped below cleanup target levels in June 2005 and remained below cleanup target levels for over a year. Low VOC recovery was likely due to excavation of contaminated soil during installation of SVE laterals.

Next Steps:
A Site Rehabilitation Completion Order will be issued for the site.

Cost to Design and Implement:
$57,200 for all technologies

Costs

Cost for Assessment:
  $56,500
Cost for Operation and Maintenance:
  $94,700 (includes monitored natural attenutation)
Total Costs for Cleanup:
  $217,500 (includes site restoration)

Lessons Learned

Early in Florida's Drycleaning Solvent Cleanup Program, a number of drycleaning sites with low VOC concentrations in groundwater were placed in monitored natural attenuation. Since that time, SVE systems have been installed to removed VOCs from soil at many of these sites resulting in site closures. Given Florida's cleanup target levels and shallow groundwater tables, most drycleaning sites will not achieve closure unless contaminated soil is addressed.

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

Contractor:
Gregg Roberts, PG, Consultant
Shaw Environmental & Infrastructure, Inc.
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 - 1997
Remedial Action Plan - 2004
Construction Completion & Startup Report 2005
Monitoring Reports: 1998 - 2005