By: Bill Johnston, PG
Linebach Funkhouser, Inc. (LFI) personnel performed permanent closure, assessment and corrective action activities on (UST) systems at a former retail petroleum facility located in Louisville, KY. Three gasoline/diesel USTs were removed from the subject site in 1997. During the removal of the USTs, a large amount separate phase product was observed leaching into the common tank pit area. Product recovery procedures were immediately initiated to mitigate the contamination concurrent with notifying the appropriate agencies including the Kentucky Department for Environmental Protection (KDEP), Division of Waste Management, Emergency Response Section and the State Fire Marshal’s Office. Following the completion of the removal and initial abatement procedures, several documents including Initial Abatement, Product Recovery and UST Permanent Closure reports were filed with the KDEP, DWM, and Underground Storage Tank Branch (USTB) on our client’s behalf. Several assessments were completed to define the horizontal and vertical extent of the separate phase and dissolved petroleum contaminant plumes identified in the shallow groundwater. LFI personnel enrolled our client in the USTB Petroleum Storage Tank Environmental Assurance Fund (PSTEAF) in an effort to recover eligible costs for assessment and remediation.
A corrective action plan (CAP) was written for the site with the assistance of AST Environmental (AST) of Midway, Kentucky that proposed utilizing a “cutting edge” in-situ remediation technology. The technology developed by Remediation Products, Inc. (RPI) of Golden, Colorado known as BOS 200® is a Trap & Treat® Bacteria Concentrate applied with a high velocity/high pressure delivery system designed and implemented by AST. This combined product-delivery remediation technology was outlined in the CAP that was submitted and approved by the USTB.
Prior to implementation of the CAP, subsurface impacts consisted of petroleum hydrocarbons in soils, accumulation of light non-aqueous phase liquids (LNAPL) in three monitoring wells and aqueous phase (dissolved) benzene in groundwater as high as 11 milligrams per liter (mg/L). The impacted area immediately surrounding the former tank pit, occupied approximately 7,000 square feet of the approximately 3-acre site.
LFI and AST teamed to develop a remedial approach to address the LNAPL and dissolved phase petroleum hydrocarbon impacts at the site. Specifically, an injection design was prepared and implemented to address LNAPL and dissolved phase petroleum hydrocarbons. The goal was to inject BOS 200® to remediate the site for removal all the LNAPL and reduce benzene concentration to below 0.005 mg/L in the on-site monitoring wells.
On Friday, August 19, 2011, 20,400 lbs of BOS 200® was delivered to the subject site. On the morning of August 22, 2011, AST mobilized personnel and equipment to the site and setup for the injection effort to begin that day. The injections were completed in 8 workdays with AST injecting the 20,400 pounds (lbs) in 150 injection points to approximately 14′ below grade surface. AST prepared BOS 200® slurries and injected it into the subsurface through probe rods. The slurry is pumped through the probe rods using a positive displacement diaphragm pump capable of delivering 1,200 pounds per square inch (psi) at 35 gallon per minute (gpm). The injection pressure varied from 200 to 600 psi. The pressure injection scheme created extensive “fracturing or soil lifting” of the soil to create preferential pathways within the fine grain clay which are filled with BOS 200®. The injection effort was completed on 8/31/2011.
The post injection monitoring reports from July and October 2012 reveal that the full list of analytes and all constituents of concern (COCs) were well below the CAP and EPA defined clean-up goals. Based on these results KY-USTB issued a No Further Action for the site on December 20, 2012
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