Lincoln County, MT, Dept. of Health, 402 pp, 2018

International Paper Company (Memphis, TN) completed this feasibility study to develop and evaluate alternatives to remediate contaminants in the Upper Aquifer at the Libby Groundwater Site, a former lumber mill and wood treater. Prior remedial efforts at the site have been unsuccessful in meeting cleanup goals in certain portions of the Upper Aquifer that contain DNAPL (coal tar creosote). This report addresses portions of the Upper Aquifer affected by both creosote and LNAPL. An in situ biosparging (ISB) pilot-scale test was conducted in 2014-2017 in the Upper Aquifer soil and groundwater. A source area treatment system removed ~40,546 gal of NAPL from the Upper Aquifer (1991-2016) and currently consists of 3 extraction wells, 2 oil/water separators, a bioreactor, an infiltration trench, and an injection well. A study to evaluate natural source-zone depletion was conducted to identify and quantify NAPL mass depletion processes and support remediation timeframe estimates (2016-2018). Establishment of a Controlled Groundwater Area is currently being considered to consolidate existing institutional controls and provide a comprehensive and consistent way to address future potential groundwater consumption and plume stability until full cleanup occurs. http://lincolncountymt.us/images/departments/health_department/Board_of_Health/Groundwater/documents/Final_FFS_Report_UA_April_25_2018.pdf A potential bio-oxidation treatment for the site is described in a slide presentation by R. Sillan, "New Approach with an Old Tool: Aerobic Biooxidation to Effectively Deplete Groundwater Contaminants from Creosote," one of 4 presentations at https://uofi.app.box.com/s/qn3f39wln9w4wlecpskdsra5yqx33su5/file/358121714520. Use the mid-page arrow to move among the 4 presentations.