-- The SVE system consists of five 12-ft vapor extraction wells (VEW).
-- The design radius of influence is 15 ft with a design flow rate of 27 cubic feet per minute (cfm).
-- Additional VEWs are being considered for the SVE system.
-- In June 1999, a pilot test was conducted in the source area located at the upgradient edge of the groundwater plume at the site. The test area covered approximately 2,500 square feet (ft²) and consisted of three injections of Fenton's chemistry-based Oxy-Cat™.
-- The full-scale operation for groundwater and dense non-aqueous phase liquid (DNAPL) remediation using Fenton's chemistry-based Oxy-Cat™ began in April 2001. According to the Remedial Action Plan (RAP) for this site, the full-scale remediation will include five phases (I to V).
-- Baseline groundwater samples were collected from selected monitoring and injection wells prior to the first injection event.
-- Phase I, which began in April 2001, focused on two areas — Area IA and Area IB. Area IA was the same as the 2,500 ft² pilot test area which contained a large portion of the contaminant mass. Seven new injection wells were installed in this area at depths ranging from 35 to 45 ft. Area IB was downgradient of area IA and covered 2,000 ft². Thirteen new injection wells were installed in this area.
-- Based on the results of groundwater samples taken after the first two full-scale injection events in areas IA and IB, a third injection was conducted in April 2002 in 11 select injection wells from areas IA and IB.
-- At the end of Phase I, it was determined that implementation of Phases II to V would be less cost effective. As of March 2007, FDEP planned to assess soil and evaluate various options to treat the downgradient PCE plume. Treatment options include enhanced biodegradation with reductive dechlorination, thermal treatment, and excavation of the contaminated soil in the source area.
Bureau of Waste Cleanup (as part of FDEP's Dry Cleaning Solvent Cleanup Program)
Florida Department of Environmental Protection
2600 Blair Stone Road, MS4520
Tallahassee, FL 32399
Golder Associates, Inc.
9428 Baymeadows Road, Suite 400
Jacksonville, FL 32256
Volatiles-halogenated: 1,1-dichloroethene (DCE); cis-1,2-DCE; tetrachloroethene (PCE) DNAPL; trans-1,2-DCE; trichloroethene (TCE); vinyl chloride (VC).
Inappropriately discarded spent filters containing PCE at the drycleaning facility
Type/Quantity of Media Treated:
Soil; Groundwater (quantity not documented)
Purpose/Significance of Application:
Full-scale remediation of PCE in soil and groundwater.
Regulatory Requirements/Cleanup Goals:
Soil cleanup target levels for the site were based on leachability tests while the groundwater cleanup levels were based on the primary standards (maximum contaminant levels (MCLs)). The goal was to use active remediation activities such as chemical oxidation to reduce the contaminant levels to the Natural Attenuation Default Source Concentrations (NADSC) and use monitored natural attenuation (MNA) to lower concentrations below NADSCs to the primary standards.
-- Quarterly monitoring of the SVE system indicated that the system continued to remove PCE from the soil target area.
-- As of August 2006, the SVE system was operational and removing approximately one to four lbs per month and has removed a total of 140.7 lbs.
-- Additional VEWs were being considered for the SVE system.
-- Results of the pilot test indicated that Fenton's chemistry was capable of remediating both the dissolved phase and adsorbed phase PCE at the site. However, the intermediate and deep areas with higher concentrations of PCE would require greater volume of the Fenton's reagent to reduce PCE levels to the groundwater cleanup goals.
-- Samples collected from the source area in September 2001 after the first and second injections for Areas IA and IB showed that PCE concentrations were reduced to below 200 µg/L in most monitoring wells. However, monitoring results from November 2001 revealed that concentrations of PCE in several wells in the source area had increased to levels at, or above, baseline concentrations.
-- A third injection was conducted in March 2002 at 11 selected wells in Areas IA and IB to address the areas where contaminant rebound was identified.
-- Groundwater monitoring results from 2004 indicated that elevated concentrations of PCE are still present at certain locations on the site in the shallow, intermediate and deep zones of the aquifer.
-- Groundwater sampling results from May 2006 indicated that PCE and TCE concentrations had decreased in all three surficial aquifers. The concentrations of cis-1,2-DCE, trans-1,2,DCE, and VC continued to be detected at low concentrations, indicating that the contaminants are not effectively degrading beyond TCE.
Cost for site characterization totaled $164,000. Cost for design and implementation totaled $428,000, which included $110,000 for the ISCO pilot test, $118,000 for SVE construction, and $200,000 for 3 ISCO injection events. The operation and maintenance (O&M) costs for soil and groundwater were $30,000 per year.
Swift Cleaners in Jacksonville, Florida, is an active dry cleaning facility that has been in operation since 1971 and primarily uses PCE as a dry cleaning solvent. Three source areas of contamination were identified at the site, including 1) the area outside the service door of the facility where the spent filters were stored, 2) the soils beneath the building floor slab near the dry cleaning machine, and 3) a former sanitary sewer line leak. The main waste source at the site was found to be inappropriately discarded spent filters containing PCE and an assessment was conducted in 1997 to determine the extent of contamination. Maximum PCE concentration in the source area was approximately 40 milligrams per kilogram (mg/kg), with the highest concentration being near the surface at approximately 1 foot below ground surface (bgs). The groundwater PCE plume appeared to have migrated vertically and laterally westward to a maximum depth of approximately 60 ft in the area downgradient from the source. The highest PCE concentration in groundwater was found to be 10,000 µg/L, at a depth of 40 to 45 ft bgs. This indicated the presence of PCE as DNAPL, with the source zone located behind the Swift Cleaners building. The down gradient edge of the plume could not be determined due to offsite access issues.
The remedial action plan developed for the site included ISCO using Fentons chemistry-based Oxy-Cat™ to treat groundwater and DNAPL contamination and SVE to treat the contaminated soil. A pilot test was conducted in 1999 to determine the viability of chemical oxidation at the site and based on the results, a multiphase approach was developed for the full-scale application. At the time of writing this report, full scale application of the remedial action was still being conducted at the site and approximately 22,500 cubic feet (ft³) of soil