Drycleaner Site Profiles

Spring Cleaners, Longwood, Florida

Description
Historical activity that resulted in contamination.

At the time of site assessment, Spring Cleaners was an active PCE drycleaning facility that had been in operation since 1988. The facility was housed in a small strip shopping center located in a retail commercial/residential setting. The facility was served by a septic tank/drainfield. There is a shallow (43 feet) 2-inch diameter water well located just off the northeast corner of the facility. A small pond is located approximatley 15 feet south of the strip shopping center that houses the drycleaning operation. The identified contaminant source areas at the site were the septic tank/drainfield and the soils located beneath the facility floor slab and just outside the service door of the facility.

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 16.5 ppb
Tetrachloroethene (PCE) groundwater 22.3 ppb
Tetrachloroethene (PCE) soil 17,000 ppb
Trichloroethene (TCE) groundwater 5.8 ppb
Trichloroethene (TCE) soil 200 ppb

Site Hydrology

Deepest Significant Groundwater Contamination:   13ft bgs
Plume Size:   Plume Length: 90ft
Plume Width: 60ft
Plume Thickness: 10ft
Average Depth to Groundwater:   4.52ft

Lithology and Subsurface Geology

 
  fine-grained sand
Depth: 0-3ft bgs
3ft thick
Conductivity: 5.7ft/day
Gradient: 0.0045ft/ft
 
  organic-rich fine-grained sand
Depth: 3-4ft bgs
1ft thick
 
  fine-grained sand
Depth: 4-25ft bgs
21ft thick
 
  silty, fine-grained sand
Depth: 25-26ft bgs
1ft thick
 
  fine-grained sand
Depth: 26-30ft bgs
4ft thick
 
  clayey, fine-grained sand
Depth: 30-32ft bgs
2ft thick
 
  silty, fine-grained sand
Depth: 32-35ft bgs
3ft thick
 
  limestone
Depth: 35-37ft bgs
2ft thick

Pathways and DNAPL Presence

checkGroundwater
Sediments
checkSoil
DNAPL Present

Remediation Scenario

Cleanup Goals:
  Groundwater: PCE = 3 ug/l, TCE = 3 ug/l, cis 1,2-DCE = 70 ug/l

Soil: PCE = 30 ug/kg, TCE = 30 ug/kg

Technologies

In Situ Monitored Natural Attenuation
 

Why the technology was selected:
Due to the low contaminant concentrations present in groundwater, monitored natural attenuation was selected as the groundwater remedy. It was believed that contaminant source removal (excavation of contaminated soil and septic tank cleanout) would result in a drop in contaminant concentrations in groundwater and that groundwater remediation would not be necessary.

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

Cost to Design and Implement:
All technologies: Design: $9,700 Implementation: $136,800

Ex Situ Soil Removal
 

Why the technology was selected:
The decision was made to clean out the septic tank because PCE, TCE and cis 1,2-DCE were detected in a wastewater sample collected from the tank and most of the groundwater contaminant plume was located in the area under and downgradient of the drainfield. The decision was made to excavate soil because drycleaning operations had ceased in early 2005 and the building that formerly housed the drycleaning operation was accessible. Also, there is a shallow water table at the site and most of the contaminant mass was sorbed on an organic-rich sand at 3-4 ft BLS.

Date implemented:
November 2006.

Final remediation design:
Clean out septic tank. Excavate contaminated soil beneath facility floor slab and from area outside service door.

Results to date:
Approximately 1000 gallons of sludge/wastewater were vacuumed from the septic tank and hauled offsite for property disposal. The concrete floor was removed from the inside of the building and mini-excavator and mini-front end loader were used to first excavate a trench 3 feet wide by 5 feet deep along the southern and eastern extent of contamination and the trench was filled with flowable concrete (5-to-1 sand-to-cement mixture to stablize the building structure. After the flowable fill was allowed to cure overnight, the excavation inside the building continued. Approximately 65 tons of soil were removed from the area beneath the facility floor slab and the excavation was backfilled with clean fill and a new floor slab was poured. The soil excavation area outside the service door was approximately 6 feet by 6 feet. Contaminated soil was excavated to a depth of 5 ft BLS. Because of the presence of numerous utility lines, much of the soil had to be hand excavated. Approximately 68 tons of contaminated soil was excavated from this area and the area was backfilled with clean fill. Confirmatory soil sampling and groundwater monitoring have demonstrated that the site has met the No Further Action criteria (without institutional or engineering controls).

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

Cost to Design and Implement:
All technologies: Design: $9,700 Implementation: $136,800

Costs

Cost for Assessment:
  $68,600
Cost for Operation and Maintenance:
  Monitoring & Reporting; $22,700 Site Restoration: $5,000
Total Costs for Cleanup:
  $242,800

Lessons Learned

1. If a building that housed a drycleaning business is vacated, it is an opportunity for source removal, particularly at sites with shallow water tables. Todays mini-excavators and mini-front end loaders can readily access many buildings and complete excavation work in a short period of time.

2. Most of the contaminant mass at this site was sorbed onto the organic-rich sand located at the water table at this site. Removal of this source resulted in a drop in contaminant concentrations in groundwater and enabled the site to be closed without groundwater remediation.

Contacts

Jennifer Farrell, Project Manager
Bureau of Waste Cleanup (MS4520)
Florida Department of Environmental Protection
2600 Blair Stone Road
Tallahassee, Florida 32399-2400
Phone: (850) 245-8937
E-mail: Jennifer.Farrell@dep.state.fl.us

Kevin Warner, PE
LFR Levine-Gricke, Inc.
3382 Capital Circle Northeast
Tallahassee, Florida 32308-2400

Phone: 8850) 422-2555
E-mail: Kevin.Warner@LFR.com

Site Specific References

Site Assessment Report - March 2005

Interim Source Removal Plan - September 2006

Interim Source Removal Report - January 2007

Groundwater Monitoring Reports