Scotch Cleaners, Topeka, Kansas

State Coalition for Remediation of Drycleaners Site Profiles

Description
Historical activity that resulted in contamination.

A soil gas survey at a building in Topeka showed elevated levels of PCE and TCE in the soil gas. Subsequent investigations led to the Scotch Cleaners site as the source. Specifically along the sewer line exiting the building.

Remediation Status: In active remediation

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

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

Site Hydrology

Deepest Significant Groundwater Contamination:		95ft bgs
Plume Size:		Plume Length: 1,400ft Plume Width: 420ft Plume Thickness: 50ft
Average Depth to Groundwater:		36ft

Lithology and Subsurface Geology

		Silty clay with intermittent thin sand and silt lenses Depth: 0-36ft bgs 36ft thick Gradient: 0.001ft/ft
		Silty sand Depth: 36-40ft bgs 4ft thick
		fine to medium sand Depth: 40-60ft bgs 20ft thick
		medium to coarse sand Depth: 60-93ft bgs 33ft thick
		shale bedrock Depth: 93ft bgs

Pathways and DNAPL Presence

Groundwater

Sediments

Soil

Presumptive Evidence of DNAPL

Remediation Scenario

Cleanup Goals:		Reduce soil and groundwater contamination to below EPA MCLs.
Remedy Level:		Full Scale Remedy

Technologies

In Situ Chemical Oxidation

Why the technology was selected:
The type of remediation (chemical oxidation) was selected based on site geology, depth to the source, and cost. The kind of oxidant was chosen based on cost, availability and estimated effectiveness.

Date implemented:
First injection, September-October 2006. Second injection November 2007

Final remediation design:
The chosen oxidant was sodium permanganate. The oxidant was to be applied through direct push rods at 40 locations with a spacing of 5 ft between locations. Approximately 500 gallons of 3% sodium permangante would be injected for a total of 20,000 gallons. A "top down" method was preferred starting at 13 ft and proceeding at 3-5 ft intervals to 36 ft bgs.

Results to date:
19,375.7 gallons of 3% sodium permangante was injected at 39 locations within the source zone. There were some problems with daylighting and the depths were adjusted accordingly. The daylighting was thought to be attributed to creation of preferential pathways, low permiability in the injection area, or over-saturation at a particular interval. PCE concentrations in the soil were reduced by 80% or more in all but one area. Groundwater concentrations remained consistent with pre-injection levels. The treatment was intended as a source zone treatment only. A second injection was completed in November 2007 to remediate the remaining contaminant in the soil. Injections were completed in 20 locations using the same strategy as the first injection. Concentrations in the source area were reduced by an order of magnitude. Groundwater monitoring indicates a decrease in the concentration of PCE and its degradation products in the source zone.

Next Steps:
Continue groundwater monitoring.

Cost to Design and Implement:
$131,551.29