ISCO-EFR

Norman, Oklahoma

 Releases from two former UST sites created a very large plume beneath multiple businesses, a state highway, and threatened nearby residences. The SPH plume (~550 feet by 250 feet - > 2 acres) was completely remediated using EcoVac Services’ patented SURFAC® process in 37 days. The resultant benzene plume was ~700 feet by 400 feet (>5 acres). ISCO-EFR^® was subsequently implemented to reduce dissolved benzene concentrations. Dissolved benzene has been reduced >90%, below corrective action levels nearly across the entire >5 acre plume.

 

Newnan, Georgia

 SITE CHARACTERISTICS

Site Use: Prior fueling area (gasoline)

Geology: fine grained saprolite

Depth to Water: 27 – 30 feet

Initial Plume Dimensions (dissolved benzene >CALs): 85 ft x 110 ft

No. of Wells > CALs: 12

Benzene Concentrations: 34,600 ug/l maximum (5 wells above 20,000 ug/l)

SITE BACKGROUND

EcoVac Services has successfully reduced the dissolved benzene concentrations to below CALs at a former fuel dispensing site using our patented ISCO-EFR® process. This former fueling area previously contained a substantial separate phase hydrocarbons (SPH) gasoline plume with individual well thicknesses ranging from a maximum of 7.45 feet to 0.45 feet/well (aggregate maximum thickness of 29.54 feet in eight wells). The SPH was successfully removed from all wells using EcoVac Services’ enhanced fluid recovery (EFR® - mobile dual-phase/multi-phase extraction) process.

RESULTS

The residual dissolved benzene plume measured 85 feet by 110 feet with maximum baseline benzene levels of up to 34,600 ppb and having five of the wells at levels over 20,000 ppb. EFR® was initially implemented to reduce contaminant mass prior to injecting chemical oxidants, which resulted in a 38% reduction in dissolved benzene (relative to the 6,500 ppb closure criterion). Sodium Persulfate (Klozur™) with multiple activation chemistries was subsequently used successfully in combination with dual-phase/multi-phase extraction to reduce dissolved benzene below the closure criterion.  Approximately 10,000 gallons of activated solution was emplaced with this technique into 16 wells.

EcoVac Services has engaged to remove dissolved benzene concentrations below the site corrective action level on a pay-for-performance (PFP) basis at this site. It is noted that our fixed price to clean up this site was 42% less than the projected cost of a fixed system (that did not offer a guarantee of a successful clean up).

 Opelika, Alabama

 SITE CHARACTERISTICS

Site Location: Opelika, Alabama

Site Use: Prior fueling area (gasoline)

Geology: silty clay grading downward to a sandy silt

Depth to Water: 8 – 10 feet

No. of Wells > CALs: 2

Max. Benzene Concentrations: 5,690 ug/l

SITE BACKGROUND

A DOT maintenance garage was plagued with a resistant dissolved benzene plume residual to fueling operations (gasoline). Two monitor wells contained dissolved benzene in excess of the site CALs, as high as 5,690 ug/l.

RESULTS

EcoVac Services implemented a single ISCO-EFR® injection using sodium persulfate (Klozur™) activated with sodium hydroxide. Dissolved benzene concentrations in the treatment area were reduced to below detection limits (BDL).

 

Macon, Georgia

SITE CHARACTERISTICS

Site Location: Macon, Georgia

Site Use: Prior dry cleaners site

Geology: clayey-silty sand on top of bedrock

Depth to Water: 35 – 50 feet

Initial Plume Dimensions (dissolved PCE >MCLs): ~300 ft x 500 ft

No. of Wells > MCLs: ~10

PCE Concentrations: 1,200 ug/l maximum

SITE BACKGROUND

A plume from a former dry cleaners site from decades ago has emanated a ~300 feet by ~500 feet PCE plume. Remediating the plume will be complicated by topographic differences, access, and the existence of several roads and buildings.

RESULTS

EcoVac Services implemented a two day ISCO-EFR® pilot test in advance of full ISCO-EFR® implementation. This short term pilot test yielded a 37% to >95% reduction in PCE concentrations within the test area. Additional treatment/injection wells are to be installed prior to full ISCO-EFR® implementation.