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Seneca’s Environmental Services (SES) division utilized subsurface Laser-Induced Fluorescence (LIF) probing to identify residual gasoline and diesel fuel contaminated soil and groundwater up to 50 feet below a former truck fueling station. SES presented the resulting 3D plume model to the client, Iowa Department of Natural Resources (DNR) and State Funding Agency, which identified the spatial extent of the contamination. Following the meeting, SES proposed conducting a vapor and groundwater pilot test in the heart of the identified plumes to gather necessary data to assess remediation options.
SES designed and implemented the pilot test which included installing four extraction wells, running a vacuum truck vapor recovery test and a groundwater pumping test. In October 2013, vacuum was applied separately to each extraction well during soil vapor testing by one of Seneca Waste Solutions’ vacuum trucks. During the testing, an SES field scientist collected detailed vapor recovery data including airflow, vacuum, radius of influence, depth to groundwater and resulting volatile organic compound removal rates. Following the vapor recovery tests, a groundwater pumping test was completed to assess groundwater extraction rates and free product removal. An SES senior hydrogeologist, along with several field scientists, outfitted the extraction well with a variable frequency drive (VFD) controlled submersible pump, groundwater level transducers, and flow meter to enable data capturing and real-time monitoring. The contaminated groundwater was pumped into a Seneca tanker truck and later disposed of at a proper treatment facility.
In November 2013, Seneca compiled the results into a pilot test report and presented to the client, Iowa DNR and State Funding Agency. Pilot test results were favorable for remediation, and SES is currently working on a Corrective Action Design Report (CADR) to effectively and efficiently remove the remaining contaminates to below Iowa DNR guidelines.
SES’s precise and thorough testing of soils and groundwater has significantly increased the probability that this site will be permanently remediated in a relatively short amount of time.