Drycleaner Site Profiles

Blue Ribbon Cleaners, Tallahassee, Florida

Description
Historical activity that resulted in contamination.

Blue Ribbon Cleaners is an active PCE drycleaning facility that has been operating since 1991. It is located in a shopping center in retail commercial setting. The contaminant source area is the soil beneath the facility floor slab.

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
Tetrachloroethene (PCE) soil
Trichloroethene (TCE) groundwater

Site Hydrology

Deepest Significant Groundwater Contamination:   42ft bgs
Plume Size:   Plume Length: 220ft
Plume Width: 155ft
Plume Thickness: 19ft
Average Depth to Groundwater:   23ft

Lithology and Subsurface Geology

 
  very fine-grained to fine-grained sand
Depth: 0-23ft bgs
23ft thick
Conductivity: 2.69ft/day
Gradient: 0.067ft/ft
 
  silty, very fine to fine-grained sand
Depth: 23-31ft bgs
8ft thick
 
  dry plastic clay
Depth: 31-40ft bgs
9ft thick
 
  clayey, silty, fine-grained sand
Depth: 40-42ft bgs
2ft thick
 
  silty fine-grained sand with minor clay and limes
Depth: 42-44ft bgs
2ft thick

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:
  Soil: PCE = 30 ug/kg (leachability)

Groundwater: PCE = 3 ug/L
Remedy Level:
  Full Scale Remedy

Technologies

In Situ Monitored Natural Attenuation
 

Why the technology was selected:
Monitored natural attenuation was selected for the groundwater remedy because Program experience with similar sites (low contaminant concentraitons in groundwater) shows that remediation of the unsaturated zone source will generally result in site closure.

Next Steps:
A Site Rehabilitation Completion Report will be issued.

Cost to Design and Implement:
$ 183,900 for all technologies

In Situ Soil Vapor Extraction
 

Why the technology was selected:
Soil vapor extraction was selected because it is an effective technology for removal of VOCs from permeable unsaturated soils.

Date implemented:
September 29, 2009

Final remediation design:
The soil vapor extraction system consists of seven (7) vapor extraction wells screened 2-22 ft BLS. Four (4)of these wells were installed beneath the facility floor slab; two wells were installed outside the west wall of the building that houses the drycleaning operation and one well was installed outside the south wall of the building. The system is powered by a 15 HP Ametek Rotron regenerative blower. Off gas is treated via one 500 lb.G.A.C. vessel. Design flow rate is 319 scfm at a wellhead vacuum of 25 inches w.c.

Results to date:
The soil vapor extraction system was shut down on May 2, 2012 after operating for approximately nineteen (19)months. Four post-active remedial monitoring events conducted from November 2011 to August 2012 did not detect contaminant concentrations in groundwater that exeeded any cleanup target levels.

Next Steps:
A Site Rehabilitation Completion Report will be issued.

Cost to Design and Implement:
$ 183,900 for all technologies

Ex Situ Carbon Adsorption
 

Date implemented:
September 29, 2009

Final remediation design:
The soil vapor extraction system consists of seven (7) vapor extraction wells screened 2-22 ft BLS. Four (4)of these wells were installed beneath the facility floor slab; two wells were installed outside the west wall of the building that houses the drycleaning operation and one well was installed outside the south wall of the building. The system is powered by a 15 HP Ametek Rotron regenerative blower. Off gas is treated via one 500 lb.G.A.C. vessel. Design flow rate is 319 scfm at a wellhead vacuum of 25 inches w.c.

Results to date:
The soil vapor extraction system was shut down on May 2, 2012 after operating for approximately nineteen (19)months. Four post-active remedial monitoring events conducted from November 2011 to August 2012 did not detect contaminant concentrations in groundwater that exeeded any cleanup target levels.

Next Steps:
A Site Rehabilitation Completion Report will be issued.

Cost to Design and Implement:
$ 183,900 for all technologies

Costs

Cost for Assessment:
  $ 172,500
Cost for Operation and Maintenance:
  O&M + Site Restoration: $139,200
Total Costs for Cleanup:
  $495,600

Lessons Learned

1. Although over 100 soil samples were collected at this site and analyzed, very little contamination was found. However an active soil gas survey was conducted (MAGS)and PCE concentrations in soil gas samples ranged as high as 257 milligrams per cubic meter, which lead to the decision to install a soil vapor extraction system at the site.

2. In order to evaluate the possible contribution of PCE vapors from the ongoing drycleaning operations to the VOCs recovered by the SVE system, some field research was conducted and for a period of nineteen (19)consecutive days in April 2011. PCE concentrations in air were monitored at three different areas: inside the building near the back of the drycleaning machine; at a vapor extraction well installed beneath the facility floor slab near the drycleaning machine and the SVE system influent.

Air was monitored using a ppbRAE PID (continuous monitoring), time weighted samples were collected using Waterloo Membrane Samplers (passive soil gas device) and some grab samples were collected utilizing Summa cannisters.

The highest PCE concentrations detected in the monitored vapor extraction well and the SVE influent was on days drycleaning was being conducted at the site. However, the highest VOC concentrations were detected after the building was shut down for the day. During the day, three doors to the building were genreally open and an interior fan and a large exhaust fan mounted in the back wall of the building were generally running. The interpretation of the data is that during the day, VOC vapors are being exhausted from the building through the open doors and the vent fan. When the facility is shut down at night and the doors are closed and the fans are turned off, the operating SVE system captures PCE vapors in the the drycleaning facility.

This phenomenon should be taken into consideration when evaluating when to shut down an SVE system that has vapor recovery wells installed beneath the facility floor slab of an active drycleaning facility.

Contacts

Aaron Cohen, Project Manager
Division of Waste Management
Florida DEP
2600 Blair Stone Road
Tallahassee, Florida 32301-2400

Phone (850)245-8962
E-Mail: Aaron.Cohen@dep.state.fl.us

Dave Riotte, P.E.
Geosyntec Inc.
1200 Riverplace Boulevard #710
Phone: (904) 858-1818
E-Mail: DRiotte@Geosyntec.com

Site Specific References

Site Assessment Report: 2005
Remedial Action Plan: 2008
Operation & Maintenance Reports: 2009 - 2011.
Groundwater Monitoring Reports: 2006 - 2012