Search: Site This Page
1-888-4ECOVAC
| Ecovac Services / Projects / Gasoline / SURFAC Projects / |
Nashville, Tennessee
|
SITE LOCATION: |
Nashville, Tennessee |
|
CONTAMINATION: |
Historically, separate-phase hydrocarbons (SPH) thicknesses up to approximately five feet had been present in two monitor wells |
|
GEOLOGY: |
Fractured Limestone Bedrock |
|
HYDROGEOLOGY: |
Groundwater is present in limestone at approximately 3 to 35 feet below grade. |
|
SURFAC® EFFECTIVENESS: |
SITE CLOSURE |
Background
The subject site was selected by the Tennessee Department of Environment and Conservation to test the effectiveness of EcoVac Services’ patented SURFAC® process and remove gasoline/diesel fuel. Little background information was obtained prior to SURFAC® due to the client’s computer files being destroyed. Mobile-phase extraction events and SPH skimmers had been previously utilized to remove SPH from the site.
The object of EcoVac Services’ patented SURFAC® process was to remove all SPH from the site.
Geology/Hydrogeology
Groundwater is present in limestone at depths ranging from 3 to 35 feet below grade. Limestone is present at approximately 2 feet below grade.
Treatment Methodology
EcoVac Services was contacted to implement SURFAC® at this site due to the challenging subsurface conditions (i.e. fractured limestone bedrock) and the failure of previous remedial activities.
EcoVac Services’ patented SURFAC® process is the combination of dual-phase/multi-phase extraction and surfactant injection. The process described herein is patent-protected and represents the intellectual property of EcoVac Services, Inc.
SURFAC® Pilot Test
A one-day SURFAC® pilot test was conducted at the site to: (1) achieve contaminant removal, (2) reduce the aerial/vertical extent of the plume, (3) locate fractures/joints and depth(s) of contamination for proper placement of the surfactant, (4) determine the surfactant injection volumes/locations/sequence, and (6) determine the duration of the surfactant injection/capture events.
Historically, SPH had been present in two monitor wells ranging up to 5 feet in thickness. The SURFAC® pilot test was conducted at two monitor wells. Stinger (drop tube) depths were increased throughout the event to identify fractures/joints and depth(s) of contamination. Fractures/joints were identified during the test by higher flow rates and lower in-well vacuums at certain stinger depths. Hydrocarbon removal rates increased when these fracture/joints were contacted, indicating these fracture/joints acted as preferential pathways for fuel migration and accumulation in the subsurface. The dewatering of the aquifer during the pilot test exposed “trapped” SPH and mobilized it to MW-9.
SURFAC® Treatment Program
SURFAC® was conducted at the subject site during a one week period in September 2005. The pilot test had mobilized SPH (0.25 feet) into one well prior to SURFAC®. The aquifer was dewatered during SURFAC® to expose the SPH “trapped” in the fractures/joints identified during the pilot test and ensure the injected surfactant came into contact with the SPH. Mobilized SPH was subsequently “captured” with mobile dual-phase/multi-phase extraction.
Results
SITE CLOSURE WAS ACHIEVED.
Complimentary Site Evaluation
Please provide us with the details of your site so we can evaluate the costs of the job. CLICK HERE
Brown Bag Request
Click here for a free lunch & presentation.