|Ecovac Services / Projects / Diesel Fuel /
South Bend, Indiana (Railroad site)
Separate-phase hydrocarbons (SPH) present in 7 monitor/recovery wells ranging in thicknesses from 0.02 to 1.17 feet
Fine to medium sand with some fine to coarse gravel
SURFAC® PILOT/TREATABILITY TESTING:
SURFAC® Pilot Testing was conducted to collect data to implement EcoVac Services’ patented SURFAC® process. SURFAC® is proposed due to its proven cost effective results, the site’s limited access, and failure of fixed system remediation activities to remove SPH. EcoVac’s treatability study predicts that SURFAC® will remove 96% of diesel fuel at this site. Diesel fuel recovery during the pilot test exceeded the annual recovery from the site’s remediation system.
A subsurface investigation of this site was prompted by a sheen on the St. Joseph River observed and reported by the Notre Dame rowing team. A remediation system consisting of two recovery wells containing skimmer pumps was installed and operated for a number of years at an approximate annual O&M cost of $100,000/year.
EcoVac Services was retained to remove SPH from the site after the Indiana Department of Environmental Management (IDEM) required a more aggressive cleanup approach.
The site consists of fine to coarse sand with some fine to coarse gravel. The aquifer is present at ~7 to 20 feet bgs over most of the site; however, groundwater is present at approximately 45 feet bgs beneath a very steep railroad embankment. The treatment area is largely inaccessible due to railroad lines, 25-foot high embankment, and dense vegetation
EcoVac Services was contracted to implement patented SURFAC® process (the combination of dual-phase/multi-phase extraction and surfactant injection) at this site due to the challenging conditions (i.e. geology/hydrogeology conditions, extent of SPH plume, ongoing presence of SPH despite previous and current remedial activities, limited site access, and exceptionally steep topography).
A three-day SURFAC® Pilot Test was conducted at the site to (1) determine the surfactant injection volumes and sequencing, (2) achieve contaminant removal by the multi-phase/dual-phase extraction process, (3) reduce the aerial and vertical extent of the plumes, (4) assess the potential need for additional injection wells, (5) determine if additional mobile dual-phase/multi-phase extraction (EFR®) events are necessary prior to surfactant injection, and (6) determine the duration of the surfactant injection.
A greater volume of SPH was removed during the three-day SURFAC® pilot test than what the fixed remediation system was recovering annually.
EcoVac Services also conducted a treatability and SURFAC® simulation study using site media. The treatability study indicated that SURFAC® will remove 96% of diesel fuel at this site.
Additional EFR® (mobile dual-phase/multi-phase extraction) events are proposed for the site until SPH thicknesses are reduced to approximately <0.5 feet/well. SURFAC® will be implemented at this site once SPH thicknesses have decreased and the SPH plume has been further delineated.