DNAPL Recovery System

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

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

3. 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?

4. 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)

5. 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.

6. Historic NAPL Recovery • 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 • 2004 - Current: • Select wells with NAPL are manually • extracted based on thickness. • 1991: • DEQ expanded recovery • efforts by using additional • monitoring wells • 2007: • A XITECH skimmer pump was installed • in EW-23s to automate LNAPL recovery. • The system was unsuccessful. • 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 • 1998: • The treatment system in the TFA was • modified to that used in the FWDA. • 1999 & 2000: • The FWDA and TFA NAPL extraction • systems were shut down in September 2000 • NAPL extraction was continued manually

7. 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

8. 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

9. 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 2010. • Draft Data Gap Results and Detailed DNAPL Recovery System Design – January 2011. • Final Data Gap Results and Detailed DNAPL Recovery System Design – March 2011. • Procurement of Contractors for System Installation – April-May 2011. • Installation of system and start-up– July 2011