Drycleaner Site Profiles

Dixie Cleaners, Jacksonville, Florida

Description
Historical activity that resulted in contamination.

Dixie Cleaners is an inactive perchloroethylene (PCE) drycleaning facility that operated from 1956 to 1995. The facility is located in a strip shopping center in a commercial/residntial setting. Identified contaminant source areas include the soils beneath the facility floor slab and a sanitary sewer lift station located near 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
cis-1,2-Dichloroethene soil
Tetrachloroethene (PCE) groundwater
Tetrachloroethene (PCE) soil
Trichloroethene (TCE) groundwater
Trichloroethene (TCE) soil
trans-1,2-Dichloroethene groundwater
Vinyl Chloride groundwater

Site Hydrology

Deepest Significant Groundwater Contamination:   33ft bgs
Plume Size:   Plume Length: 175ft
Plume Width: 350ft
Plume Thickness: 31ft
Average Depth to Groundwater:   2.5ft

Lithology and Subsurface Geology

 
  silty, fine-grained sand
Depth: 0-18ft bgs
18ft thick
Conductivity: 0.31ft/day
Gradient: 0.009ft/ft
 
  clayey fine-grained sand
Depth: 18-30ft bgs
12ft thick
Conductivity: 0.23ft/day
 
  limestone
Depth: 30-32ft bgs
2ft thick
 
  stiff clay
Depth: 32ft bgs

Pathways and DNAPL Presence

checkGroundwater
Sediments
checkSoil
checkDNAPL 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):
  Passive Venting

Remediation Scenario

Cleanup Goals:
  Maximum Contaminant Levels (MCLs) for groundwater- PCE= 3.0 ug/l, TCE= 3.0 ug/l, cis 1,2-DCE= 70 ug/l , trans 1,2-DCE= 100 ug/l, VC= 1.0 ug/l
Soil Cleanup Target Levels- PCE= 0.03 mg/kg, TCE= 0.03 mg/kg, cis1,2-DCE= 0.4 mg/kg
Remedy Level:
  Full Scale Remedy

Technologies

In Situ Bioremediation
 

Why the technology was selected:
In situ bioremediation was chosen as the groundwater remedy because groundwater analytical and geochemical data indicated that reductive dechlorination was occurring at the site. Conditions were amenable to injection of HRC as a passive low-cost enhancement to naturally occurring biodegradation of contaminants. EOS was subsequently selected for injection under the facility floor slab. The bay that formerly housed the drycleaning operation had been vacated and was accessible for injection. It was not known when there woule be another opportunity for injection in the main source area. EOS was selected to as a long-lived carbon source. Aquifer or groundwater buffering was attempted in the intermediate surficial aquifer to raise the groundwater pH from approximatley 4.5 standard units to a higher pH (near neutral) to facilitate biodegradation.

Date implemented:
1st HRC injection: June 2000; 2nd HRC: April 2002 HRC-X injection; May 2003; Bioaugmentation: Injection of Bio-Dechlor Inoculum: May 2004. Biostimulation using EOS & Vitamin B12: September 6-9. 2005. Buffering: magnesium hydroxide pilot test: Februar

Final remediation design:
During the first bioremediation injection event Approximately 22,000 lbs. of HRC were injected via 175 direct push borings located behind the drycleaning facility on 10-foot centers, points were shifted 5 ft on every other north south transect. the HRC was injected at from 25-30 feet bls (or 5 lbs of HRC/foot). The second bioremediation injection event utilized 3,000 lbs of HRC injected in 48 direct push borings located on 10 foot centers. The HRC was injected at depths ranging from 20-30 ft bls. This amounted to from 3-7 lbs of HRC/foot During the third injection event approximatley 3,200 lbs of HRC-X was utilized. There were two separate injection areas. Area 1 (20 feet by 100 feet with 20 injection points Depth: 2 to 25 feet bgs Volume: 4lbs/ft) Area 2 (40 feet by 70 feet with 28 injection points, Depth 2 to 22 feet bgs, Volume: 2bls/ft) A bioaugmentation pilot study was conducted also in May 2003 using Bio-Dechlor INOCULUM (BDI). BDI was injected into 7 injection points near a source area well at from 10 to 20 feet bls. Injection volume was was 0.1 Liter/ft (1 Liter/point). The fourth bioremediation injection event was conducted from September 6-9, 2005. A total of 29 drums (1,595 gallons of emulsified oil substrate (EOS) mixed with 4,700 gallons of water and 64 ounces of EOS B12 supplement was injected into the eight wells installed beneath the facility floor slab (screened 5-25 ft bls). Magnesium hydroxide buffering pilot test consisted of the injection of the a 110 lbs. of magnesium hydroxide mixed with 200 gallons of water into a singe injection well (screened 15-25 ft BLS). The second buffering event was from April 3-5, 2006 when a solution of 100 kilograms of ammonium carbonate mixed with 150 gallons of water was injected into each of 7 intermediate surficial aquifer injeciton wells.

Other technologies used:
Bioaugmentation: using Bio-Dechlor Inoculum. Groundwater buffering: using magnesium hydroxide and ammonium bicarbonate.

Results to date:
The latest groundwater monitoring event conducted at the site was from March 19-20, 2009. This is over three and one-half years after the EOS injection event. Only two monitor wells, a shallow (5-15 ft BLS) and an intermediate zone (15-25 ft BLS) well produced detectable concentrations of PCE (1,000 and 2,800 ug/l, respectively. Both of these wells are installed under the floor slab of the former drycleaning facility. The primary contaminants in the shallow and intermediate zones are cis 1,2-DCE (up to 31,000 ug/l) and viny chloride (to 14,000 ug/l). In the deep zone (25-30 ft BLS) the only contaminant detected in groundwater samples in concentrations exceeding an MCL was vinyl chloride (to 3.0 ug/l). Chloride has been a good indicator of biodegradation activity. Background chloride is 6-20 mg/l). Chloride has been detected in concentrations ranging to 5,900 mg/l. Chloride concentrations during this monitor event have been as high as 400 mg/l.

Next Steps:
An additional injection of a long-lived carbon amendment under the facility floor slab is planned.

Cost to Design and Implement:
Well Installation & Baseline Sampling: $32,000
HRC Product (1st injection): $150,000
1st Injection Implementation: $80,000
HRC Product (2nd injection): $25,000
2nd Injection Implementation: $25,000
Monitoring, Reporting (both events): $42,000
HRC-X Product (3rd injection): $29,000
3rd Injection Implementation: $36,000

Ex Situ Soil Removal
 

Why the technology was selected:
Source removal was selected because of the shallow water table (2-3 feet bls) that precluded SVE as a soil remedial technology and there was an oppotunity to excavate below the building floor slab where the primary contaminant source area was located. Piping was installed in the open excavation for a passive venting system.

Date implemented:
Interim Source Removal & installation of passive venting system: August 2005

Final remediation design:
From August 4-8 an interim source removal was conducted. An area of the facility floor slab approximatley 70 ft x 30 ft was removed and approximatley 110 cubic yards of contaminated soil was removed to a depth of 3 feet using a mini-trackhoe. The excavation was back-filled with pea gravel to a depth of 18 inches and then seven (7)4-inch diameter PVC laterals with 0.01-inch slot screens were installed on top the pea gravel. The lateral vapor recovery wells were piped out through a wall of the builidng and then extended upward along the exterior wall to the roof. Each pipe was capped with a neck turbine ventilator. Eight 2-inch diameter vertical injection wells, screened 5-25 feet were installed inside the facility. The remainng excvation was backfilled and the floor slab was poured.

Next Steps:
An additional injection of a long-lived carbon amendment under the facility floor slab is planned.

Ex Situ Other
 

Why the technology was selected:
Piping was installed in the open excavation for a passive venting system.

Date implemented:
Interim Source Removal & installation of passive venting system: August 2005

Final remediation design:
From August 4-8 an interim source removal was conducted. An area of the facility floor slab approximatley 70 ft x 30 ft was removed and approximatley 110 cubic yards of contaminated soil was removed to a depth of 3 feet using a mini-trackhoe. The excavation was back-filled with pea gravel to a depth of 18 inches and then seven (7)4-inch diameter PVC laterals with 0.01-inch slot screens were installed on top the pea gravel. The lateral vapor recovery wells were piped out through a wall of the builidng and then extended upward along the exterior wall to the roof. Each pipe was capped with a neck turbine ventilator. Eight 2-inch diameter vertical injection wells, screened 5-25 feet were installed inside the facility. The remainng excvation was backfilled and the floor slab was poured.

Other technologies used:
passive venting

Next Steps:
An additional injection of a long-lived carbon amendment under the facility floor slab is planned.

Costs

Cost for Assessment:
  $55,000
Cost for Operation and Maintenance:
  Semi-annual Monitoring and Reporting $7,000 Annual Montioring and Reporting $12,000
Total Costs for Cleanup:
 

Lessons Learned

1. Given a similar site, we would perform the source area excavation (contaminated soil under the floor slab) first and then proceed with the biostimulation injections in the source areas (area beneath the floor slab and around the sanitary sewer lift station) rather than treating the area immediately down gradient of the facility.

2. Because of its low solubility, Magnesium hydroxide is not suitable as a buffering agent.

3. Although the injection of ammonium bicarbonate was successful in raising the groundwater pH to as high as 8.0 standard units, groundwater pH in the intermediate surficial aquifer dropped to approximately 4.5 within 16 days of the buffering event.

Contacts

Melissa Garvin, Environmental Specialist
Florida Department of Environmental Protection, Bureau of Waste Cleanup
2600 Blair Stone Road (MS4520)
Phone: 850) 245-8994
E-Mail: Melissa.Garvin@dep.state.fl.us

Kelly Baltz, P.E.
Golder Associates
9428 Baymeadows Road, Suite 400
Jacksonville, FL 32256
Phone: (904)-363-3430
Kelly.Baltz@golder.com

Site Specific References

Contamination Assessment Report 12/97
Remedial Action Plan (biostimulation) 12/99
HRC Injection Report 7/00
Remedial Action Plan (excavtion): 6/04
Remedial Implementation Report: 4/06
Groundwater Monitoring Reports: 1998-2009