Tetrachloroethylene Groundwater Remediation In A Dolomitic Limestone Aquifer Using Injectable Zero Valent Iron

Thursday, December 6, 2018: 11:40 a.m.
Exhibit Hall- C4 & C5 (Las Vegas Convention Center)
Dawn Knipe, L.P.G. , August Mack Environmental, Inc., Indianapolis, IN
Timothy DeWitt, P.E, P.G. , August Mack Environmental, Inc., Indianapolis, IN

Tetrachloroethylene (PCE) and its daughter products were detected in the shallow portion of a fractured dolomitic aquifer system between five (5) and 30 feet below ground surface (ft bgs) at a former dry cleaning facility located in Indiana. Geophysical surveys were conducted to guide investigation activities and subsequently used to direct monitoring well placement. Zero valent iron (ZVI) along with a carbon substrate was chosen as the remedial technology. A Pilot Test was completed to evaluate the chemical selection/injection technology and the ability of the fractured bedrock to accept the chemical injections. Based on the Pilot Test results, the combination of ZVI and carbon substrate was selected for the full-scale chemical injection. Full-scale injections were subsequently implemented at 21 injection locations. Following full-scale injection, a methane survey was completed to alleviate state agency concerns over production of excessive levels of methane. The remedial strategy has been a success at the Site with substantial contaminant reduction in a challenging fractured bedrock media, a strategy that can be used at other impacted bedrock Sites.
Dawn Knipe, L.P.G., August Mack Environmental, Inc., Indianapolis, IN
Dawn Knipe is a Licensed Professional Geologist at August Mack Environmental, Inc. Her experience includes managing environmental investigations and remediation efforts at sites in Indiana and Wisconsin through various state programs where contaminants of concern are petroleum and chlorinated solvents. She has managed the technical execution of various remediation efforts including: excavations, chemical injections, enhanced fluid recovery events, and installation of soil vapor extraction and air sparge treatment systems.


Timothy DeWitt, P.E, P.G., August Mack Environmental, Inc., Indianapolis, IN
Tim DeWitt is a senior engineer at August Mack Environmental, Inc. in the Indianapolis office. He has more than 24 years of experience in Construction Inspection & Management, Cap Design, Remedial Investigation, Remedial System Design and Installation, Groundwater Recovery and Treatment, Subsurface Geological Remedial Investigations, Litigation support and Remedial Scoping & Estimating. Tim received a Bachelor of Science in engineering, a Bachelor of Science in geology and a Master of Science in geotechnical engineering from Purdue University. He is both a registered Professional Engineer and a registered Professional Geologist.