ARCHIVED REPORTS_2011 REVISED FEASABILITY STUDY

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APPENDIX A Summary of Remedial Technologies Tested/Used at the 230 Industrial Avenue Site Former Nestle USA, Inc. Facility — Ripon, CA 1 INTRODUCTION ECM submitted the 2009 Revised Feasibility Study Report (FS) in October 2009. The focus of the 2009 Revised FS was to address the areas of highest constituent of concern (COC) concentrations at the Site through containment and source removal. Groundwater characterization activities' identified an area of high COC concentrations in the subsurface between 40 feet and 60 feet (upper A zone) below ground surface (bgs) at the Site. Since this area is acting as a continual source of dilute COCs downgradient of the Site, the 2009 Revised FS recommended remedial alternative centered on groundwater extraction from the Upper Aquifer source area at the Site. Evaluation of in- situ treatment, or subsurface barrier technologies, would be considered, if dissolved COC concentrations were not sufficiently reduced after a three-year period. Because the areal extent of affected groundwater is large (over two hundred acres), institutional controls and monitoring were recommended for the greater Study Area. Following the submittal of the 2009 Revised FS, the RWQCB requested information regarding the evaluation of remediation technologies used for all zones impacted by the presence of COCs onsite and offsite. This appendix presents a description and evaluation of previous remediation technologies and remedial approaches tested or applied within the Study Area in all zones impacted by CDCs. Three attachments are included, Attachment A.1, Attachment A.2, and Attachment A.3, which present the field activities, results, conclusions and analysis of two in-situ pilot tests and the implementation of soil vapor extraction at the Site. 2 BACKGROUND INFORMATION FOR REMEDIAL ACTIONS The effectiveness of a remedial action is dependent upon the age of the release, the regional and local hydrogeology, and the type and distribution of CDCs. These factors are discussed in Section 3 and Section 4 of the body of the 2011 Revised Feasibility Study. Remediation efforts have targeted removal of COC mass in soil, soil vapor, and groundwater. Groundwater extraction and treatment has been conducted at the Site since 1986 and is on-going. Nestle provides a summary of the groundwater remediation activities annually; therefore, groundwater extraction and treatment will not be discussed in Appendix A. Pilot tests of multiple technologies were conducted to assess additional mass removal from the source areas in the northeast area of the Site (near the extraction wells EI-1 and EW-1, and monitoring wells M-1A and M-1 B). These included injection of microbes and nutrients in 19892, potassium permanganate in 2 0003, and a carbohydrate substrate (molasses) in 20054. Detailed discussions of the potassium permanganate and the carbohydrate substrate pilot tests are included in attachments A.1 and A.2, respectively. 2