Drycleaner Site Profiles

Former Prestonwood Specialty Cleaners, Dallas, Texas

Description
Historical activity that resulted in contamination.

Prestonwood Specialty Cleaners formerly operated in a one-story shopping center. Investigations conducted in 1995 identified this former operation as a contaminant source.

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
1,1-Dichloroethene groundwater
Tetrachloroethene (PCE) groundwater
Tetrachloroethene (PCE) soil
1,1,1-Trichloroethane groundwater
Trichloroethene (TCE) groundwater
trans-1,2-Dichloroethene groundwater

Site Hydrology

Deepest Significant Groundwater Contamination:   25ft bgs
Plume Size:   Plume Length: 120ft
Plume Width: 70ft
Average Depth to Groundwater:   5ft

Lithology and Subsurface Geology

 
  Fill material, clay lenses, limestone

Gradient: 0.13ft/ft

Pathways and DNAPL Presence

checkGroundwater
Sediments
checkSoil
DNAPL Present

Remediation Scenario

Cleanup Goals:
  Groundwater: PCE = 500 µg/l
Soil: PCE = 50,000 µg/kg

Technologies

Ex Situ Soil Removal
 

Why the technology was selected:
Since PCE degradation products were present in groundwater, HRC was proposed to enhance biodegradation by fueling reductive dechlorination in an offsite source area (50 ft x 70 ft) Exacation was recommended to remove contaminated soils - onsite and offsite.

Date implemented:
Excavation: 1999 HRC Injection: June 2001

Final remediation design:
Approximately 146 cubic yards of contaminated soil were excavated in two areas: beneath the floor slab of the former drycleaning facility (2-3 ft in depth) and at an offsite location in the vicinity of a monitor well. A total of 25 injection points (open-hole) were installed on a 10-ft spacing at an offsite location. A straddle packer was used to isolate the injection zone (limestone). The limestone was fractured by injecting HRC at high pressure in a zone 15-25 ft bgs. Slightly less pressure (40-60 psi) was used to inject HRC at shallower depths (5-15 ft bgs). On average, 136 pounds of HRC was injected per borehole. A total of 3,400 pounds of HRC was injected at the site or an average of 6.7 lb/ft/borehole.

Results to date:
Between June 2001 (injection event) and April 2002 monitoring indicated that groundwater wells located proximate to the injection area had not been significantly influenced by the HRC application. Nearly two years after treatment, PCE concentrations in one monitoring well located in the injeciton zone have increased from 15,000 µg/l to 23,500 µg/l.

Next Steps:
No groundwater monitoring required anymore. Excarvation performed and site eventually closed. A certificate of completion was issued on November 12,2007.

Costs

Cost for Assessment:
  No costs were available.
Cost for Operation and Maintenance:
 
Total Costs for Cleanup:
 

Lessons Learned

1. Fracturing at high pressures resulted in unseating of straddle packers at some locations.

Contacts

Joe Bell
Texas Commission on Environmental Quality (TCEQ)
Voluntary Cleanup Program
12100 Park Circle, Bldg. D
Austin, Texas 78753

Contractor:
Dames & Moore
5151 Beltline Road, Suite 700
Dallas, Texas 75240
Phone (972) 980-4961