Drycleaner Site Profiles

Colonial Cleaners (SC), Denmark, South Carolina

Description
Historical activity that resulted in contamination.

The drycleaner is a stand-alone building in a commercial area of Denmark. The contamination has been greatly influence by the pumping of multiple public wells. Levels of PCE below the MCL have been detected in one of the public wells.

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 178 ppb
Tetrachloroethene (PCE) groundwater 39,300 ppb
Trichloroethene (TCE) groundwater 51.1 ppb

Site Hydrology

Deepest Significant Groundwater Contamination:   168ft bgs
Plume Size:   Plume Length: 300ft
Plume Width: 175ft
Plume Thickness: 110ft
Average Depth to Groundwater:   20ft

Lithology and Subsurface Geology

Sand and Clay Zone
  sand and clay
Depth: 0-128ft bgs
128ft thick
Conductivity: 4.472135955ft/day
Gradient: 0.337ft/ft
Upper Limestone Zone
  limestone
Depth: 128-148ft bgs
20ft thick
Conductivity: 74.4ft/day
Lower Limestone Zone
  limestone
Depth: 155-185ft bgs
30ft thick
Conductivity: 81.6ft/day

Pathways and DNAPL Presence

checkGroundwater
Sediments
Soil
DNAPL Present

Remediation Scenario

Cleanup Goals:
  MCLs
Remedy Level:
  Full Scale Remedy

Technologies

In Situ Bioremediation
 

Why the technology was selected:
Success with ozone sparging at another site had been observed. It was decided to use it at this site, which is a different environment than the previous site, to see how it would work.

Date implemented:
The system was installed in August 2003. However, due to a series of functional problems, it was not started until October 2003.

Final remediation design:
A package Ozone Sparging System was purchased from ARCE Systems of Natick, Massachusetts. The system was installed and turned on, but it never became fully functional. By that time, however, ARCE Systems had gone bankrupt. The system has since been rebuilt by Engineered Products and Services (EPS). The re-built system was installed and started in June 2005. There are 28 injection points some of which have duel injection depths.

Results to date:
At the first sampling since the system was rebuilt, contamination had been reduced an order of magnitude in most locations. There were, however, some wells where the levels rose. It is not certain if contamination from upper layers is moving down and causing the levels to rise or if the pressure of the injection is just forcing it deeper. The contaminant levels were reduced by the order of magnitude shortly after the ozone system sart-up. However, after reaching certain concentrations (between 1,000 to 4,000ppb) reduction has ceased. After observing no reduction for several years, the program decided to shut the system down in 2010. The contaminant levels have not responded in a significant manner to the shutdown.

Next Steps:
After the next quarterly sampling event, we will determine if the ozone sparging schedule needs to be changed. We have the ability to redirect the ozone to different sparge points or to lengthen or lessen the amount of time spent sparging the various points. Currently, the Program is conducting a couple of low cost pilot studies for shallow sand-clay and deeper limestone acquifers.

Cost to Design and Implement:
$567,161

Costs

Cost for Assessment:
  $477,978
Cost for Operation and Maintenance:
  $50,000
Total Costs for Cleanup:
 

Lessons Learned

1. You have to have a system designer/manufacturer that understands what you are trying to accomplish. The designer/manufacturer also needs to be able to stand behind their system.

2. The two systems that EPS built have an average of 97% up-time.

3. A more thorough study of remedial alternatives is necessary before remedial system is selected.

4. If remedial system remains ineffective for at least two years, a decision must be made about it's further viability.

Contacts

Konstantin Akhvlediani
South Carolina DHEC
803-896-4045
appellr@dhec.sc.gov

Contractor:
Vasi Kourlas or Walter Gerald
AECOM
864-234-8925

Site Specific References

1. Site Assessment Report January 2003
2. Feasibility Study January 2003
3. Record of Decision April 2003
4. Remedial Action Design October 2003
5. Remedial Action Report November 2005