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BTEX AND MTBE BIOREMEDIATION: BIONETS™ CONTAINING SOS, PM1 AND ISOLITE®
DavisHoover*, W J. BTEX AND MTBE BIOREMEDIATION: BIONETS™ CONTAINING SOS, PM1 AND ISOLITE®. Presented at University of Oxford Research Institute (Informal Meeting), OXFORD, UK, September 20, 2004.
To determine if biologically active in situ BioNets could bioremediate MTBE and BTEX contaminated groundwater.
MTBE and BTEX (benzene, toluene, ethylbenzene, and xylenes) are major problems of many sites in the United States. The objective of this study was to determine if biologically active in situ BioNets could bioremediate MTBE and BTEX contaminated groundwater. Seven BioNets were placed in a site on the Flathead Indian Reservation in Montana. The MTBE and BTEX plume from a retail gasoline station was contaminating farmland and threatening Native American owned surface waters. The BioNets contained: 1) sand or Isolite® as a fracture material, which created bioremediation zones by facilitating inoculation, allowing attachment of the bacteria, presenting a zone for addition of oxygen by way of aeration or addition of Solid Oxygen Source (SOS) and enhancing the porosity/permeability of the subsurface; 2) PM1, an aerobic bacteria known to degrade MTBE, which can be monitored with a genetic probe; 3) nutrients; and 4) oxygen as air or SOS.
Results indicate that after 22 months of treatment the reductions of MTBE in the groundwater samples were as high as 85 percent under the same conditions as above. The use of SOS stimulates more reduction than supplied air. Results indicate that after 22 months of treatment the reductions of BTEX in the groundwater samples were as high as 99.7 percent where optimum conditions existed for biodegradation, which included MTBE degrading PM1 inoculated Isolite with SOS or air. The use of SOS stimulates more reduction than supplied air.
After 12 months, DNA of PM1 was isolated from soils from the inoculated BioNets, but not the un-inoculated BioNet. PM1 was consistently identified in proximity to fracture locations on subsurface soil samples using Taqman PCR assay and standard microbial techniques. MTBE degraders and PM1 were also found from fractures and soils four (4) inches below the fractures. Material was inoculated onto Bushnell-Haas medium containing 750 ppm MTBE and incubated at 8oC in an atmosphere supplemented with MTBE.