Former Gas Station

Project Summary

A former gasoline service station located in St. Albans, WV was contaminated following site operations and releases from former underground storage tanks (USTs). The primary contaminants of concern identified were benzene, toluene, ethylbenzene, xylene (BTEX), methyl tert-butyl ether (MTBE), and tert-butyl alcohol (TBA).

The site geology is primarily clay, and the depth to groundwater was 5 feet below ground surface (ft bgs).

In-situ chemical oxidation (ISCO) and enhanced bioremediation was selected as the remedial approach.

Remedial Plan

Innovative Environmental Technologies, Inc. (IET) applied Provect-OX to the subsurface via a patented injection process and apparatus (US Patent 7,044,152) such that the activation processes occur in a controlled manner. A total of 19 injection points and 7,300 lbs of Provect-OX were utilized to treat the area of concern.

The Provect-OX rapidly oxidizes the organic contaminants present in soil and groundwater and provides long-term, sustained secondary bioremediation to manage residuals and prevent contaminant rebound. This is accomplished by using ferric iron (Fe III) as a safe and effective means of activating persulfate, which quickly yields sulfate and ferrate radicals for chemical oxidation treatment.

Results

• MW-9 exhibited non-detect concentrations for all contaminants of concern, including benzene, toluene, ethylbenzene, total xylenes, MTBE, and tert-butyl alcohol.
• MW-5R showed significant reductions in BTEX and MTBE concentrations with benzene decreasing from 12.2 µg/L to 7.48 µg/L.
• Chemical oxidative conditions confirmed in first post-treatment sampling event with ORP of +171.7 mV.
• Transition to reducing conditions with iron and sulfate-enhanced bioremediation supporting additional contaminant decreases.