American Uniform, Hutchinson, Kansas

State Coalition for Remediation of Drycleaners Site Profiles

Description
Historical activity that resulted in contamination.

The former American Uniform drycleaner facility operated in this commercial area from 1960-1974. The property is currently occupied by various commercial businesses in the original buildings. Testing of local public water supplies in 1982 revealed the presence of volatile organic compounds (VOCs) due to contamination from this drycleaning facility. 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).

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

Contaminant	Media	Concentration (ppb)	Nondetect
Tetrachloroethene (PCE)	groundwater	80.4 ppb
Tetrachloroethene (PCE)	soil	239 ppb

Site Hydrology

Deepest Significant Groundwater Contamination:		65ft bgs
Plume Size:		Plume Length: 14,256ft Plume Width: 600ft Plume Thickness: 53ft
Average Depth to Groundwater:		20ft

Lithology and Subsurface Geology

		silt and clay Depth: 0-5ft bgs 5ft thick Conductivity: 644ft/day Gradient: 0.001ft/ft
		Fine grained, silty sand grading to medium- to coarse-grained sand Depth: 5-68ft bgs 63ft thick

Pathways and DNAPL Presence

Groundwater

Sediments

Soil

DNAPL Present

Remediation Scenario

Cleanup Goals:

Reduce PCE groundwater contamination to below EPA Maximum Contaminant Level (MCL) of 5 µg/L. Reduce PCE soil contamination in accordance with KDHE Risk-Based Standards of 180 µg/kg.

Technologies

In Situ Air Sparging

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

Date implemented:
Ozone sparge wells - treatment fence approach - Oct, 1998

Final remediation design:
A downgradient aquifer air sparging treatment fence used standard C-Sparger® technology, except without the ozone injection. The C-Sparger® treatment fence used six sparge wells spaced 65 ft.

Results to date:
KVA C-Sparger system was removed due to maintenance issues.

Next Steps:
Source area soil sampling to determine if source area cleanup is complete. Installation of additional downgradient monitoring wells to further track a contaminant plume that appears to be attenuating since the source area has been remediated.

Cost to Design and Implement:
$293,728 for all technologies

In Situ Soil Vapor Extraction

Why the technology was selected:
O&M cost, effectiveness of the technology, and expected duration of cleanup. KDHE selected the SVE system in order to reduce the PCE soil impacts, which would facilitate natural attenuation of the groundwater.

Date implemented:
Source area SVE - Oct 1999

Final remediation design:
At the source area, contractor installed nine SVE wells and four monitoring wells at or near the site, associated above and sub-grade piping, and remediation equipment. The remediation equipment was placed within an 8-by-12-foot enclosure. The SVE remediation system consists of two regenerative blowers, a 5-horsepower (HP) Rotron Model DR6D89 and a 10-HP Rotron Model DR823BB72, which together have a maximum combined design capacity of approximately 265 ft3/min (cfm) at 60 in of water vacuum. Each blower is powered by a 230-volt (V), 3-phase motor. The SVE wells range in depths from 12.5-15 ft bgs, and each one contains a 5-foot screened section at the bottom. The contractor also installed 15 drip legs along the pipe runs to allow condensate water to drain away from the SVE piping. Piping installation cost was high due to trenching in concrete parking lots.

Results to date:
The SVE system achieved cleanup goals to remediate the source area vadose zone and enhance natural attenuation of the groundwater. Sampling events conducted from May-October 2000 revealed significant reduction in groundwater solvent concentrations. Overall PCE concentrations decreased, but samples showed rebounding PCE concentrations during the 6-month period. October 2003 groundwater PCE analytical result were <5 µg/L for all source area MWs. All SVE wells were non-detect for VOC vapors and the system has been shut down. Soil sampling will be conducted to evaluate cleanup progress.

Cost to Design and Implement:
$293,728 for all technologies

Costs

Cost for Assessment:		$16,161
Cost for Operation and Maintenance:		$51,558 (2+ years)
Total Costs for Cleanup:

Lessons Learned

1. SVE system removed available vapors very quickly, but clay soils prevented significant capture zone in some SVE wells. Continued operation of SVE over time appears to have cleaned up the source area.
2. Improper installation of a SVE line allowed blockage of air flow, even though drip legs were designed to prevent fluid build up.
3. C-Sparger® well spacing was over-optimistic and was not able to adequately treat the groundwater to below EPA MCLs.
4. Incorporating the ozone injection vs. air only probably would have enhanced the reduction of contaminant.
5. C-Sparger® equipment had significant maintenance problems and was not able to operate an extended period of time. Therefore, utility savings were negated by extra O&M costs. KV Associates has repaired the equipment, but KDHE has decided not to reinstall the system due to GW contamination dropping below MCLs (source area cleanup).
6. Once source was remediated the plume appears to be rapidly attenuating. Plume size reduced from 2.7 miles to 1.75 miles in length. New MWs will help determine attenuation rates and concentrations.