Lessard Environmental Incorporated: Case Study #7

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Remedial Case Study

Overview:

Chlorinated Solvents including TCE, PCE and vinyl chloride along with fuel oil constituents were identified in several discrete areas at this fire arms manufacturing plant. A dual phase extraction (DPE) system was employed at the property from 1998-2001 under the auspices of a Release Abatement Measure (RAM). Following a significant reduction in contaminant levels, a combined Method 1 & 2 risk assessment was performed, resulting in the determination that a permanent solution had been achieved.

Assessment:

The following assessment activities were performed by LEI to assess the performance of the DPE treatment system and to support a risk evaluation of the improved site conditions:

Developed health and safety plan
Advanced ~20 soil borings, including several into bedrock, and completed borings as groundwater monitoring wells screened at varying intervals to delineate the vertical extent of impact
Collected, field screened, and lab analyzed select soil and groundwater samples
Developed groundwater flow model
Conducted soil vapor survey and indoor air quality assessment

Response Activities:

A series of integrated response activities were performed to address residual constituents in soil and groundwater. These activities included the following:

Supervised the excavation and recycling/disposal of approximately 1,200 tons of soil
Maintained and operated DPE system utilizing vapor phase carbon to polish extracted air and glucose/hydrogen peroxide treatment for recovered groundwater. Over 1.6 million gallons of groundwater was recovered, treated and re-circulated during system operation.
Performed a combined Method 1 & 2 risk evaluation. Established site specific groundwater standards and employed soil averaging techniques.
Submitted a Response Action Outcome concluding that No Further Remedial Actions were needed at this property

Key Monitoring Results:

Current Site Status:

Site Closed — No Further Remedial Actions required