Record of Decision System (RODS)
NORTH PENN - AREA 6
|Site Name:||NORTH PENN - AREA 6|
|Address:||W 3RD ST|
|City & State:||LANSDALE PA 19446|
|NPL Status:||Currently on the Final NPL|
|ROD Type:||Record of Decision|
The site was discovered in 1979 when the NPWA discovered elevated levels of contamination in its wells. The wells were immediately taken out of service because of the high levels of TCE in the ground water. The NPWA began sampling of several wells in the area in 1979, to determine the types and levels of contamination in the ground water. An examination of this data showed that in all municipal wells containing detectable volatile organics, the major contaminant was TCE.
After the ground water contamination was identified, potentially responsible party (PRP) searches by EPA and others, identified 26 facilities in the area that may have contributed to the contamination. On August 5, 1991, EPA issued general notice letters to the owners and/or operators of each of the properties to inform them of their potential Superfund liability as owners or operators of these properties. On June 30, 1992, EPA again notified the owners and/or operators of these properties of their potential liability for the site. After several discussions with them concerning the nature and extent of EPA's work to be performed, the owners and operators of 20 of the properties indicated that they were not
willing and/or able to perform or finance the Remedial Investigation for the site. Therefore, EPA decided to perform the response action for these 20 properties from the Superfund. EPA grouped these 20 properties into Operable Unit 1 (OU1). The six properties whose owners or operators were willing and able to do the work themselves, were grouped in Operable Unit 2 (OU2).
In August 1993, EPA began a Source Control Remedial Investigation/Feasibility Study (RI/FS) for contaminated soils at the 20 properties in OU1. Ten properties had soils that did not contain the contaminants of concern, and the remaining properties were found to have contaminated soils. On September 29, 1995, EPA issued a ROD that required the treatment or excavation and offsite disposal at four of these ten properties. This action has been completed by EPA at three properties, and negotiations are ongoing with the current and
previous owners at a fourth property to determine whether or not they will complete the cleanup. No remedial actions for soil were recommended at the remaining six properties, because the levels of contamination were not significantly impacting ground water.
The PRP lead investigation at the final six properties forms OU2. Under this operable unit, the owners or operators of these properties conducted the investigation of soil contamination in accordance with an Administrative Order on Consent (AOC) under EPA. Three of the properties are currently at various stages of remedial investigations. The remaining three properties have completed the AOC requirements, and were found to have none of the target contaminants in soils as specified in the AOC.
Extraction Wells, Air Stripping and Off-gas Treatment, Surface Water Discharge, Public Water Connection
The remedy specifically includes the following:
1. Extraction wells shall be installed to remove the contamination at the 10 identified source locations. An air stripping system shall be installed to treat the ground water by stripping volatile organic compounds at each of the locations. The contaminants shall then be removed using a vapor phase (granular activated carbon) GAC or (ultraviolet) UV oxidation unit. If necessary, after the air stripping, the water may receive additional liquid phase treatment to achieve discharge standards. The treated water shall then be discharged to storm sewer or surface
water. The extraction and treatment system shall operate until cleanup standards are achieved for all COPCs identified in this ROD at the points of compliance.
2. Pump houses shall be constructed to enclose the treatment system at each of the locations. Trenches and associated piping shall be installed to discharge the treated ground water to a storm sewer, or directly to surface water. At the low concentration area outside the source locations, this alternative relies on four new extraction wells and treatment systems, in conjunction with existing pumping and treatment operated by the local water authority and industrial and commercial facility owners. These pumping and/or treatment locations shall include L-10, L-23, L-25, J.W. Rex, and Lehigh Valley Dairies.
3. Homes with wells that are contaminated above maximum containment levels (MCLs) and used for drinking water shall be connected to public water. The number of homes to be connected will vary depending on whether the contamination plume continues to migrate.
4. Long term monitoring in accordance with the terms of the EPA approved Operation and Maintenance Plan, at approximately 50 locations shall be performed for a length of 30 years.
Estimated Capital Cost: $ 2,117,428.00
Estimated Annual O&M Costs: Not Documented
Estimated O&M Costs: $ 9,557,965.00
Estimated Present Worth Costs: $ 20,402,692.00
Estimated Long Term Monitoring: $ 2,472,406.00
Extraction Wells, Liquid Phase GAC Treatment, Surface Water Discharge Public Water Connection
Extraction Wells, Liquid Phase GAC Treatment, Re-injection, Public Water Connection
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