TERRY completed the Corrective Action Plan (CAP) in September 2001 and submitted it to the SCDHEC for review and approval. The CAP included the use of multiple remedial technologies in a “treatment train” approach. The inclusion of multiple remedial technologies in a single CAP significantly reduced the time required to switch between remedial processes during the project, thereby increasing the overall efficiency.
Implementation of the corrective action was approved by the SCDHEC in November 2001. TERRY implemented the CAP by excavating 96 tons of contaminated “source area” soil and remediating it off-site at a thermal treatment/recycling facility. These initial activities resulted in a decrease of contaminant mass on the order of approximately 10,000,000 parts per billion!
INITIAL EXCAVATION ACTIVITIES
The excavation was filled and compacted with clean material. Simultaneously, a permanent injection well was installed in the source area to provide re-useable access to the contaminant plume for the application of a proprietary mixture of hydrocarbon degrading microorganisms and nutrients. Periodic injections of the microorganism and nutrient solution were performed as needed between 2001 and 2004 to maintain a healthy microbial population and the desired rate of contaminant destruction.
LNAPL (PRODUCT) FLOATING ON WATER-TABLE
During this period, the store was renovated and the UST system was replaced and/or upgraded. In February of 2005 the remedial goals were achieved and the site entered the verification process. Two verification wells were installed in June 2005 in locations chosen by the SCDHEC to verify complete site remediation. Final closure of the site (including the abandonment of all remedial equipment) was completed in September 2005.
Due to the effectiveness of combining multiple remediation technologies, TERRY was able to reduce contaminant levels not only below the site specific target levels for a risk based closure, but also below the US EPA drinking water standards. This resulted in the SCDHEC issuing a “No Further Action” letter for the site. Though the project took longer than anticipated (for a number of reasons including a remodel of the store and replacement of the entire UST system during the remediation project) it was still completed within the original budget.