Hamilton County School Board

SSAR/RAPM Preparation
 

GLE serves as the Contractor and environmental consultant for a multiple-work order (term contract) for the Hamilton County School Board (HCSB). GLE performed sub-surface investigations at the property in support of the closure of an underground storage tank, which identified petroleum-related impacts. Based upon the results of the Closure Assessment, GLE performed and completed a Site Assessment Report (SAR), a Remedial Action Plan (RAP) and implemented a remedial action consisting of multiple injection of oxygen release compound (ORC) at the site to complete the remediation through bio-augmentation. Due to the drought conditions in the State of Florida and the gradual decline of the water table at the site, the smear zone at the site was exposed and the ORC injections failed to significantly impact the contamination at the site.
 
Recent supplemental site investigations in 2007 revealed that petroleum impacts are now exposed above the water table.  GLE was authorized by HCSB to prepare a Remedial Action Plan Modification (RAPM) to address the site.  The RAP Mod was approved by FDEP on February 27, 2008.  The RAPM included the installation of shoring around the excavation area, due to the location of the contaminated soil in between a gymnasium and a classroom building, and the depth to groundwater at the site (17 ft-bls).
 
GLE was authorized to proceed with the Source Removal by HCSB and immediately prepared a Bid Package, and solicited bids from qualified contractors. The bid results were significantly higher than estimated, due to extremely high costs for shoring.  GLE negotiated an alternative scope of work with the successful bidder, substituting the underpinning of the gymnasium for the shoring, resulting in a significant cost savings for HCSB.
 
GLE implemented the Source Removal activities on August 4, 2008.  High levels of petroleum impacted soil were identified in the former tank farm area from depths of 8 – 17 ft-bls.  Over 800 tons of petroleum-impacted clay were removed from the site for thermal treatment. The underpinning of the gymnasium was a crucial component of the project, since the excavation reached to within 8 feet of the gymnasium.  Once the excavation was completed into the groundwater at the site, GLE applied a bioremediation innoculum to the bottom of the excavation to speed the polishing of the residual groundwater contamination at the site.

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