DNAPL Recovery System July 2010 Progress Meeting McCormick & Baxter Superfund Site Portland, Oregon

DNAPL Recovery System Objectives Previous Efforts at Recovery Proposed Effort –Investigation –Design –Installation –Start-up Schedule –Shallow contour maps –Hydrographs –Gradients

ROD DNAPL RAOs “Removing mobile NAPL to the extent practicable to reduce the continuing source of groundwater contamination and potential for discharge to the Willamette River.” How do you measure extent practicable?

End-Points for Recovery Recovery of NAPL system is reduced to an established value (could be based on the asymptote or NAPL recovery decline method) Concentrations of dissolved phase downgradient of the system are below MCLs NAPL transmissivity is reduced to a given value NAPL saturations are reduced to levels below residual saturations as measured by a given method (such as from cores, or product levels in wells) NAPL chemistry has changed rendering it less mobile or less toxic Containment is in place (works for barrier wall)

Objectives of NAPL System Recover DNAPL outside the barrier wall such that end-point measurements can be evaluated while being protective of the river and the current remedy (specifically the sediment cap). Define “extent practicable” for NAPL removal through end-point technology.

1998: The treatment system in the TFA was modified to that used in the FWDA. 2007: A XITECH skimmer pump was installed in EW-23s to automate LNAPL recovery. The system was unsuccessful. 1991: DEQ expanded recovery efforts by using additional monitoring wells 1993: Extraction wells EW-3 through EW-10 were installed NAPL extraction was automated in selected wells in the TFA and FWDA Manual extraction efforts continued in some wells Interceptor trench was installed Pilot testing was carried out on wastewater treatment, total fluids extraction, and pure-phase extraction 1994: A pilot-scale wastewater treatment system was installed Wells in the FWDA were used for pure-phase NAPL extraction Field data collected between 1992 and 1994 indicated that weekly pumping yielded as much NAPL as automated pumping. Automated system was discontinued because it required constant monitoring 1999 & 2000: The FWDA and TFA NAPL extraction systems were shut down in September 2000 NAPL extraction was continued manually Current: Select wells with NAPL are manually extracted based on thickness. Historic NAPL Recovery

Data Gap Investigation Review previous coring information (primarily the 2004 investigation) Advance up to 8 additional cores to define locations for extraction wells Conduct product mobility testing on select cores for:1) free product mobility, 2) grain size, 3) Amott and USBM Wettability, and NAPL and water fluid properties (interfacial tension, density, and viscosity). Submit recommendation for Extraction Wells (up to 3) and DNAPL Recovery System

DNAPL Recovery System System Design (extraction and separation) –Focus on ability to re-cycle water into barrier wall, recognize historic NAPL recovery failures, use energy efficient technology such as solar panels, and protection of river and sediment cap. System Installation System Start-up

Schedule (Outdated) Draft Detailed Data Gap Investigation Work Plan – beginning of June 2010 Final Detailed Data Gap Investigation Work Plan – end of June 2010 Procurement of Drilling Contractors and Laboratories for the specialized NAPL properties – July 2010 Field Work to occur between August and October Draft Data Gap Results and Detailed DNAPL Recovery System Design – January Final Data Gap Results and Detailed DNAPL Recovery System Design – March Procurement of Contractors for System Installation – April-May Installation of system and start-up– July 2011