Drycleaner Site Profiles

Inwood Shopping Center / Bell Cleaners, Houston, Texas

Description
Historical activity that resulted in contamination.

Various onsite dry cleaners have operated in the shopping center since it was first constructed in 1982. Bell Cleaners, the subject of this dry cleaner investigation, was the last dry cleaning tenant of the Inwood Shopping Center. Dry cleaning operations have not been conducted on the property since September 2002. Site investigations conducted at the property determined that soil and groundwater impact occurred as a result of historical dry cleaning operations at concentrations above the applicable cleanup standards. To date, a network of 40 groundwater monitoring wells has been installed at the property in three groundwater bearing units (GWBUs). The first GWBU plume is centered on-site beneath the former dry cleaning facility extending to the southwest along the northern property boundary. The migration of the plume in this direction is believed to have been caused by the release of contaminants into the on-site storm sewer system which acted as a preferential migration pathway. The plume has been documented extending off-site on the adjacent apartment complex property to the west.

Remediation Status: In groundwater monitoring


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


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

Site Hydrology

Deepest Significant Groundwater Contamination:  
Plume Size:  
Average Depth to Groundwater:   ft

Lithology and Subsurface Geology

 
  Silty Clay

Conductivity: 6.68E-005ft/day

Pathways and DNAPL Presence

Groundwater
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 

Remediation Scenario

Cleanup Goals:
  GW Clean up goals: MCLs x100

Remedy Level:
  Full Scale Remedy

Technologies

In Situ Biostimulation
 

Date implemented:
*FY11 Biostimulation

Final remediation design:
Two in-situ treatment events were conducted during fiscal year 2011. The first event involved chemical oxidation with the injection of 400 gallons of potassium permanganate (KMnO4) through 21 injection points. The second event, completed approximately two months after the first, consisted of bioaugmentation with the injection of 200 gallons of Cl-Out® through 20 injection points. On December 13, 2011, additional in-situ groundwater treatment was conducted at the property. During this event, 200 gallons of KMnO4 was injected into the first GWBU through 13 temporary injection points located in approximately the same locations as the FY 2011 injections.

Results to date:
The analytical results of this post-treatment groundwater monitoring event indicate decreasing concentrations across the site within the first groundwater bearing unit. The decreasing trends are attributable to the in-situ response actions completed between May 2011 and December 2011.

Next Steps:
Since this type of groundwater response action typically requires multiple injection iterations to achieve the target goals; additional in-situ injection events could be warranted in the future. However the contractor proposed monitoring the first GWBU to determine if any concentration rebound occurs. It should be noted that additional groundwater response actions are warranted for the second groundwater bearing unit in the future.

In Situ Chemical Oxidation
 

Why the technology was selected:
In-situ oxidation for the first GWBU. By reducing the concentrations in the first GWBU, vertical migration to the second and third GWBUs could be reduced if not eliminated.

Date implemented:
FY11 Chem-Ox (2 events)

Final remediation design:
Two in-situ treatment events were conducted during fiscal year 2011. The first event involved chemical oxidation with the injection of 400 gallons of potassium permanganate (KMnO4) through 21 injection points. The second event, completed approximately two months after the first, consisted of bioaugmentation with the injection of 200 gallons of Cl-Out® through 20 injection points. On December 13, 2011, additional in-situ groundwater treatment was conducted at the property. During this event, 200 gallons of KMnO4 was injected into the first GWBU through 13 temporary injection points located in approximately the same locations as the FY 2011 injections.

Results to date:
The analytical results of this post-treatment groundwater monitoring event indicate decreasing concentrations across the site within the first groundwater bearing unit. The decreasing trends are attributable to the in-situ response actions completed between May 2011 and December 2011.

Next Steps:
Since this type of groundwater response action typically requires multiple injection iterations to achieve the target goals; additional in-situ injection events could be warranted in the future. However the contractor proposed monitoring the first GWBU to determine if any concentration rebound occurs. It should be noted that additional groundwater response actions are warranted for the second groundwater bearing unit in the future.

Ex Situ Pump and Treat
 

Date implemented:
*FY11 Biostimulation and FY11 Chem-Ox (2 events)

Final remediation design:
Two in-situ treatment events were conducted during fiscal year 2011. The first event involved chemical oxidation with the injection of 400 gallons of potassium permanganate (KMnO4) through 21 injection points. The second event, completed approximately two months after the first, consisted of bioaugmentation with the injection of 200 gallons of Cl-Out® through 20 injection points. On December 13, 2011, additional in-situ groundwater treatment was conducted at the property. During this event, 200 gallons of KMnO4 was injected into the first GWBU through 13 temporary injection points located in approximately the same locations as the FY 2011 injections.

Results to date:
The analytical results of this post-treatment groundwater monitoring event indicate decreasing concentrations across the site within the first groundwater bearing unit. The decreasing trends are attributable to the in-situ response actions completed between May 2011 and December 2011.

Next Steps:
Since this type of groundwater response action typically requires multiple injection iterations to achieve the target goals; additional in-situ injection events could be warranted in the future. However the contractor proposed monitoring the first GWBU to determine if any concentration rebound occurs. It should be noted that additional groundwater response actions are warranted for the second groundwater bearing unit in the future.

Costs

Cost for Assessment:
 
Cost for Operation and Maintenance:
 
Total Costs for Cleanup:
  $71,027 (cost includes all biostimulation and chem-ox events in FY11); DPHVE Pilot costs about $38,800 Total Costs on remdiation are approximately: $109,827

Lessons Learned

*Multiple groundwater bearing units (GWBU) must be considered individually when doing remediation, but also the most effective way to remediate all the GWBUs as cost effective as possible is another key issue to consider. It depends on the site conditions concerning how to go about remediation on multiple GWBUs.

Contacts

Dan Switek
PST / DCRP Section
Remediation Division
Texas Commission on Environmental Quality (TCEQ)
dan.switek@tceq.texas.gov
512-239-4132