Pilot Study Data Evaluation: Enhanced Attenuation of PFAS and VOCs in Groundwater
Presented on Monday, December 3, 2018
Jeffrey Holden, PE, LSP, LEP1, Bruce Thompson2 and David Peterson, PG, HG3, (1)GEI Consultants, Inc., Ithaca, NY, (2)de maximis inc., Windsor, CT, (3)Regenesis, Red Hook, NY
The SRSNE facility operated between the 1950s and 1991 distilling and re-distributing spent industrial solvents. Releases resulted in the presence of non-aqueous phase liquids (NAPL) in overburden and bedrock. In the 1990s, two groundwater pump-and-treat systems were installed to capture the plume originating from the source area. The first (NTCRA 1) captured source area groundwater with a sheetpile wall and overburden recovery wells. The second (NTCRA 2) is downgradient of the sheetpile wall and uses overburden and bedrock extraction wells to hydraulically control the groundwater plume exceeding MCLs.
Between 2013 and 2015, thermal remediation of the overburden source zone removed ~500,000 pounds of VOCs and a RCRA cap was installed over the source area in 2016-2017. Expecting these measures would eliminate the need for long-term NTCRA 1 extraction, three valved penetrations were installed through the sheetpile wall, collection and redistribution trenches were constructed on the up- and downgradient sides of the wall, and fill was placed to account for predicted groundwater rise downgradient of the wall.
Despite orders of magnitude VOC concentration reductions in source zone soil and groundwater, and significant ongoing MNA, groundwater within the sheetpile wall remains more impacted than downgradient of the wall. PFOS and PFOA were also detected in NTCRA 1 groundwater at concentrations higher than in NTCRA 2 groundwater. Regulators expressed concern that allowing groundwater flow through the penetrations would degrade the downgradient water quality.
A pilot study was implemented to evaluate using zero-valent iron (ZVI) and PlumeStop® to treat groundwater within the trenches and minimize the potential for adverse downgradient water quality impacts. This presentation will provide an overview of the pilot study approach, summarize the monitoring performed to date, and preliminarily evaluate the materials’ effectiveness at attenuating PFAS migration in groundwater.
Jeffrey Holden, PE, LSP, LEP
GEI Consultants, Inc., Ithaca, NY
Mr. Holden is a Senior Engineer with GEI located in the Ithaca, NY office. He has over 25 years of experience in the investigation and remediation of industrial sites under various regulatory programs including Superfund, RCRA, TSCA, and the Massachusetts Contingency Plan. He is a registered Professional Engineer in NY, CT and MA, a Licensed Site Professional in MA, and a Licensed Environmental Professional in CT. He holds degrees in Mechanical/Aeronautical and Civil/Environmental Engineering from Clarkson University.
Bruce Thompson
de maximis inc., Windsor, CT
Bruce Thompson is a Project Director for de maximis, inc., where for the past 14 years he has coordinated environmental projects for industry as required by federal and state regulatory agencies. Responsibilities include managing the technical, administrative and financial aspects of Superfund site investigations, feasibility evaluations, remedial designs, clean-ups, and long-term monitoring work. Mr. Thompson graduated from the US Naval Academy in 1985 with a B.S. in Oceanography, and prior to working for de maximis, inc., he served as a division officer onboard the battleship USS IOWA, and as a leadership and management instructor at the Navy Supply Corps School in Athens, GA.
David Peterson, PG, HG
Regenesis, Red Hook, NY
Mr. Peterson is a Principal Hydrologist with Regenesis located in their Red Hook, NY location. He had extensive experience with modeling, design, and implementation of in-situ applications of various remedial additives to facilitate groundwater remediation.
