Emulsified Oil Bio-Barrier to Remediate CEE in the Distal Portion of a Groundwater Plume - 20210
A non-time critical (NTC) removal action (RA) was designed at the Savannah River Site (SRS) to inject an emulsified oil mixture with a bioaugmentation culture to prevent trichloroethylene (TCE) discharging to surface water above maximum contaminant levels (MCLs). The emulsified oil mixture is expected to sequester the TCE and then be broken down into harmless compounds through microbial biodegradation. At 15 locations 8,290 L (2,190 gal) of oil mixture, buffer and chase water were injected into the subsurface creating two bio-barriers. At each location half of the oil mixture was injected, then 2 L (0.528 gal) of an enriched bioaugmentation culture was injected, and then the second half of the oil mixture was injected into the subsurface. Finally, at each location 151 L (40 gal) of buffer mixed with 575 L (200 gal) of dilution water was then injected followed by 1,135 L (300 gal) of chase water. SRS estimates this created two emulsified oil barriers totaling 73 m (240 ft) long, approximately 3 m (10 ft) high and 4.9 m (16 ft) wide in the subsurface. Similar emulsified oil barriers have been effective for 3 to 5 years, and SRS anticipates a similar longevity for these barriers. (authors)