Former Giant Wash, McPherson, Kansas

State Coalition for Remediation of Drycleaners Site Profiles

Description
Historical activity that resulted in contamination.

The site operated as a dry cleaning and laundry facility from 1963 to 1965. An investigations of tetrachloroethylene (PCE) detected in two public water supply (PWS) wells in 1987 and 1989 revealed one source of PCE in the groundwater was attributed to the Tidy Laundry Site but that there was another unidentified contributing site. A directory search in 2000 showed the Giant Wash Laundry located upgradient from one PWS well. In 1995, the City of McPherson installed a Packed tower air stripper system that remediates contaminated water from the PWS wells. The Kansas Department of Health and Environment (KDHE) conducted the site investigation and remediation under the authority of the Kansas Drycleaner Environmental Response Act (DERA).

Remediation Status: In active remediation

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

Contaminant	Media	Concentration (ppb)	Nondetect
chloroform	groundwater
cis-1,2-Dichloroethene	groundwater
1,2-Dichloroethane	groundwater
Tetrachloroethene (PCE)	groundwater
Tetrachloroethene (PCE)	soil
Trichloroethene (TCE)	groundwater
trans-1,2-Dichloroethene	groundwater

Site Hydrology

Deepest Significant Groundwater Contamination:		105ft bgs
Plume Size:		Plume Length: 900ft Plume Width: 200ft Plume Thickness: 15ft
Average Depth to Groundwater:		87.5ft

Lithology and Subsurface Geology

		Fine to coarse sands with interbedded silty clay layers Depth: 0-28.5ft bgs 28.5ft thick
		Light red lean clay Depth: 28.5-51ft bgs 22.5ft thick
		Fine to coarse sand Depth: 51-55ft bgs 4ft thick
		silty clay Depth: 55-70ft bgs 15ft thick
		weathered shale bedrock Depth: 70-152ft bgs 82ft thick

Pathways and DNAPL Presence

Groundwater

Sediments

Soil

DNAPL Present

Vapor Intrusion Pathway

Has the potential for vapor intrusion (VI) been evaluated?		Yes
How was the site evaluated?		Soil vapor and/or Sub-slab vapor sampling,Groundwater sampling
Results of VI evaluation:		The VI pathway was ruled out (or does not exist)
Has a vapor mitigation system been installed?		No

Remediation Scenario

Cleanup Goals:		Reduce PCE and TCE groundwater contamination to below EPA Maximum Contaminant Level (MCL) of 5 µg/L.
Remedy Level:		Full Scale Remedy

Technologies

In Situ Air Sparging

Why the technology was selected:
O&M cost, effectiveness of the technology, and expected duration of cleanup.

Date implemented:
System start-up, August 2008.

Final remediation design:
A cluster of three vertical SVE wells were planned at three different depths to a total depth of approximately 70 ft bgs. The wells were screened at 10-30 ft bgs, 35-50 ft bgs, and 55-70 ft bgs. Universal RAI Model 24URAI, rotary lobe blower with a design capacity of approximately 70 scfm airflow at 80 in. H2O vacuum.

Results to date:
Due to difficulty in drilling and reaching total depth during installation, only two SVE wells were installed. One is screened from 9-30 ft bgs and the other is screened from 35-60 ft bgs. Roughly 1000 lbs of VOC's have been rememoved from the soil since system start-up, the system is currently in operation.

Next Steps:
Continue with soil remediation and groundwater monitoring.

Cost to Design and Implement:
$47,591.00

Costs

Cost for Assessment:		$85,661.72
Cost for Operation and Maintenance:		$17,063.50
Total Costs for Cleanup:

Lessons Learned

Limited access drilling equipment was functional when conditions are favorable. However, due to significant rainfall during the installation of the deep SVE well, surface runoff entered the borehole and caused the annulus to smear off. Installation contractor attempted to rehab the well through the addition of water, surging, and purging of the well screen. Well rehab assisted in cleaning fines from the filter pack, but system needed to operate for a year before the screened interval dried out enough to allow flow-paths to develop and obtain recordable flow at the header.