Naval Facilities Engineering Command Southeast, 149 pp, 2018

Building 780 is located at the north end of OU 3 and sits atop a chlorinated solvent plume caused by a closed-loop solvent recycling facility that previously operated in the building. A soil vapor extraction (SVE) system to remove VOCs from the subsurface and a groundwater pump and treat system (GWT) operated from 2000 until 2005 when it was shut down. A 2015 remedial investigation found CVOCs (primarily chlorinated ethanes and, to a lesser extent, chlorinated ethenes, both parent and byproducts) in both shallow (5-10 ft below ground surface [bgs]) and deep (10 ft-20 ft bgs) zones. A pilot test was initiated to design and implement emulsified vegetable oil (EVO) injections and evaluate the effectiveness of enhanced reductive dechlorination. About 205 gals of neat CoBupH-Mg^™ pH buffer was first injected, followed by 2,173 gals of neat EOS Pro into shallow and deep injection wells. Both injections were followed by chase water to distribute the products into the aquifer uniformly. High CVOC concentrations in two monitoring wells indicated the presence of sorbed DNAPL. Results indicate that the DNAPL should aerobically degrade as it partitions into the dissolved phase. Reductive dechlorination was effective in remediating CVOCs to daughter products. However, further conversion to non-toxic end products was limited by low pH, high contaminant concentrations, and low amounts of the fermentable organic substrate. The total amount of colloidal buffer injected was not sufficient to maintain the pH in an appropriate range for efficient conversion to non-toxic end products. https://www.navfac.navy.mil/niris/SOUTHEAST/JACKSONVILLE_NAS/N00207_004410.pdf