In Situ Chemical Oxidation and Aerobic Bioremediation Decreases Petroleum Contaminants in Inaccessible Aquifer
Jenna Martin, P.E., Project Engineer, GHD
The subject UST site is an active convenience store located in Tallahassee, Florida. GHD performed initial onsite in situ chemical oxidation (ISCO) and aerobic bioremediation (AB) injection events in January and May 2016 followed by one year of quarterly post active remedial monitoring (PARM) in June 2016 through March 2017. Based on the significant groundwater impacts that remained on and offsite, GHD recommended additional remedial action in 2019. GHD performed two additional ISCO/AB injection events using direct push technology (DPT) to deliver alkaline activated Klozur SP and Klozur CR in July and September 2019. Injections were performed both onsite and offsite to target the downgradient plume. The injection points were angled at approximately 40 degrees from vertical in order to target the previously inaccessible areas due the presence of overhead/underground utilities and the inaccessible areas beneath the adjoining roadways. PARM activities over several events reported petroleum-related constituents of concern at concentrations slightly above groundwater cleanup target levels (GCTLs) in several monitoring wells. However, compared to the August 2018 analytical results, petroleum constituents of concern have exhibited overall decreasing trends. Also, there appears to be a historical relationship between petroleum constituent concentrations and groundwater elevation. These trends may indicate an adsorbed contaminant mass exists on soils that may contribute periodically to the dissolved phase during the annual hydrologic cycle. This presentation will summarize the PARM results in graphic form and discuss potential implications for site closure.
Jenna has over 12 years of progressive experience in the field of environmental engineering. Jenna is a registered Professional Engineer and has been with GHD for 12 years. She received her Bachelor of Science in Environmental Engineering from Florida Gulf Coast University in 2009 and Master of Environmental Engineering from the University of South Florida in 2009. Jenna began her career with GHD performing Phase I and II Environmental Site Assessments and currently provides project management activities over a range of projects, including management of over 60 petroleum hydrocarbon impacted facilities under State cleanup contracts throughout Florida. Jenna’s experience includes the remedial design and implementation of air sparge and soil vapor extraction systems, in-situ chemical oxidation, and source removals.