BTEX and MTBE Remediation
Retail Gas Station in Florida
Acceptance into the Florida State cleanup program, was the driver for remedial action at this petroleum contaminated (gasoline) site in Northwest Florida. To mitigate gasoline released by leaking UST’s, a remedial solution consisting of two systems was constructed. Air stripping and granular activated carbon absorption was employed to address groundwater contaminants. Attempts to mitigate soil contaminants employed a soil washing, water infiltration system with nutrient enhanced biodegradation. These were operated from 1993 through May 1995, when it was concluded that they were ineffective because of the low permeability of the heavy soils and bio-fouling of equipment. In 2002, a RAP Addendum was approved incorporating a new hydrogen peroxide based ISCO remedial process. This proved to be very successful at reducing the contaminant mass due to its ability to penetrate the heavy soil matrix.
PROJECT AT A GLANCE
Type of Site: Retail Gasoline Station
Location: Northwest Florida
Contaminants: BTEX, MTBE
Work Scope: Inject Cool-Ox® Reagent
Media Treated: Soil & Groundwater
Soil Type: Clayey Sand to Sandy Clay
Groundwater Depth: 3 fbgs
Remedial Objectives (Phase 1): Natural Attenuation default levels
Application Method: DPT Probe Rig
Area Treated: 3,525 square Feet
Vertical Interval: 3 to 12 feet bgs
Injection Point (IP) Spacing: 5 feet
Media Volume Treated: 1,174 cubic yards
Number of Injection Points: 223
Cool-Ox® Volume: 13,027 gallons
Cool-Ox® per IP: 58 gal
The blue area on the site map depicts the extent of the groundwater contaminant plume prior to the ISCO injection. The red area shows the higher concentrations where the release occurred. Note the reduction in the size of the plume and GW concentrations after the ISCO injections. Because of a potential real estate transaction, an additional application is planned.
Because of the significant reductions in contaminant concentrations, the site was placed Post Remedial Action Monitoring Status pending determination of natural attenuation activity.