Drycleaner Site Profiles

Former Alpine Cleaners, Friendswood, Texas

Description
Historical activity that resulted in contamination.

Alpine Cleaners operated as a PCE drycleaner from 1989 to 1998. A sewer line break was reportedly one of the pathways for contaminant migration into the subsurface. Spills at the facility and discharges to a storm sewer were also identified as possible source areas.

Remediation Status: In groundwater monitoring


Contaminants
Contaminants present and the highest amount detected in both soil and groundwater.


Contaminant Media Concentration (ppb) Nondetect
Benzene groundwater
cis-1,2-Dichloroethene groundwater
1,1-Dichloroethene groundwater
Tetrachloroethene (PCE) groundwater
Trichloroethene (TCE) groundwater
trans-1,2-Dichloroethene groundwater
Vinyl Chloride groundwater

Site Hydrology

Deepest Significant Groundwater Contamination:   16ft bgs
Plume Size:   Plume Length: 160ft
Plume Width: 80ft
Average Depth to Groundwater:   10ft

Lithology and Subsurface Geology

 
  silty clay
Depth: 0-10ft bgs
10ft thick
Conductivity: 0.283ft/day
Gradient: 0.0055ft/ft
 
  fine-grained clayey sand
Depth: 10-15ft bgs
5ft thick

Pathways and DNAPL Presence

checkGroundwater
Sediments
Soil
checkPresumptive Evidence of DNAPL

Vapor Intrusion Pathway

Has the potential for vapor intrusion (VI) been evaluated?
  No
Has a vapor mitigation system been installed?
  No 
Additional VI Information:
  None as of present.

Remediation Scenario

Cleanup Goals:
  *Shallow Groundwater zone:
PCE = 5 µg/l
TCE = 5 µg/l
cis 1,2-DCE = 70 µg/l
vinyl chloride = 2 µg/l

*2nd Groundwater zone:
PCE = 500 µg/l
TCE = 500 µg/l
cis 1,2-DCE = 7,000 µg/l
vinyl chloride = 200 µg/l
Remedy Level:
  Interim Action

Technologies

In Situ Chemical Oxidation
 

Why the technology was selected:
Based on bench scale testing,in-situ chemical oxidation was selected.

Date implemented:
1999

Final remediation design:
In 1999, there were two five-day injection events utilizing hydrogen peroxide, in three injection wells. The volume of treated groundwater was estimated to be approximately 17,000 gallons. Initially, an aqueous solution of ferrous sulfate and hydrochloric acid was injected. This was followed by hydrochloric acid and finally by a 35% solution of hydrogen peroxide (495 gallons in the first event and 605 gallons in the second injection event). In August and September of 2001, a total of 135 gallons of a 5.5% solution of potassium permanganate was injected at the site.

Results to date:
*The 1999-2001 In-situ chemical oxidation events resulted in only minor reductions in chlorinated solvent concentrations. Since those events, the source area and plume have been better characterized. The size and concentration of the plume are greater than was thought when the remediation events were conducted. Groundwater analytical results in 2007 indicated concentrations of PCE and its daughter products exceeding Tier 1 PCLs in the samples collected from wells MW-1 and MW-6. Daughter products exceeding their Tier 1 PCLs included TCE, cis- and trans-1,2-DCE, 1,1-dichloroethene (1,1-DCE), and vinyl chloride. The highest concentration of PCE (8.1 mg/L) and its daughter products were reported in well MW-6. *Groundwater analytical results in 2008 continue to indicate concentrations of PCE and its daughter products exceeding Tier 1 PCLs. PCE, TCE, Cis-1,2-DCE, Trans-1,2-DCE, and 1,1-DCE have shown an increase in concentrations since last sampled in December, 2007, with vinyl chloride showing the only decrease in concentration. The increase in daughter products indicates that reductive dechlorination continues to occur at the site.

Next Steps:
* In 2006, this site transfered from an RP-lead program to a state lead program. * Continue Monitoring of existing monitor wells to obtain additional groundwater data and evaluate any trends. * Investigation of second groundwater unit is ongoing. *In 2009, a pilot study will evaluate the applicability and/or effectiveness of in-situ chemical oxidation (ISCO) with regards to the site's geologic conditions and in terms of the reduction of chlorinated solvent contaminant concentrations currently above TRRP Tier 1 PCLs in the shallow groundwater bearing unit. As part of the study, a sodium percarbonate based chemical oxidant will be injected into the subsurface to treat COCs. This oxidant will be utilized in the study because it will exist in the subsurface over a longer period than the previously injected oxidant.

Costs

Cost for Assessment:
  Costs for the 1999-2001 Remediation is not available
Cost for Operation and Maintenance:
 
Total Costs for Cleanup:
 

Lessons Learned

*Source area should be fully characterized before conducting remediation.

*A review of data results from the October 1999 response action showed concentration reductions, with later site data showing a return of concentration levels. Based on soil types at the site (silty clay to silty sand), it appeared that the delivery system may not have been adequate to provide a sufficient radius of coverage. In addition, hydrogen peroxide based oxidants are fast acting oxidants, reducing the overall area of influence, that require a lower pH concentration, which is not typical of the site. Although a pH adjustor was included, the site pH is not generally compatible with the oxidant and the overall effectiveness may have been reduced.

Contacts

Richard Scharlach
Texas Commission on Environmental Quality (TCEQ)
Voluntary Clean-up Program
12100 Park Circle, Bldg. D
Austin, Texas 78753

ERM Southwest, Inc.
Paul Stefan
15810 Park Ten Place, Suite 300
Houston, Texas 77084
Phone: 281-600-1000