Pinnacle Engineering was hired to examine the effectiveness of several bioremediation products on various components of Bakken crude oil following a crude oil leak onto a rail line that saturated an adjacent complex mixture of railroad ballast and sandy heterogeneous soil. The spill occurred in frozen soil conditions, with significant subsurface transport over several weeks, and the crude oil underwent some degree of weathering through the spring thaw.
The 99-day field study employed gas chromatography-mass spectrometry (GC-MS) analysis to evaluate and quantify the presence/degree of weathering of crude oil and analyze the final contamination composition after biodegradation. Biodegradation of benzene, toluene, ethylbenzene, and xylenes (BTEX), total petroleum hydrocarbon-gasoline range organics (TPH-GRO), total petroleum hydrocarbon-diesel range organics (TPH-DRO), and total petroleum hydrocarbon–motor oil range organics (TPH-MOR) compounds was tracked in the shallow soil subsurface with respect to an untreated control. Data was collected on natural attenuation, fertilized (high and low dosages), and unfertilized rates for each selected Oppenheimer Biotechnology remediation product. Oppenheimer Biotechnology products utilize highly concentrated, naturally occurring communities of selective hydrocarbon degrading archaea within a mineral matrix.
Total hydrocarbon reductions observed in the highly heterogeneous matrix were 95.6% of BTEX compounds and 61.5% in the heavier TPH-DRO and TPH-MOR compounds, as compared to natural attenuation reductions of 72.6% (BTEX) and only 7% (DRO, MOR) in the control plots. Soil temperatures and % moisture ranged between 63 °F – 114 °F and 8.1% - 14.7%, respectively. Greater hydrocarbon losses were not observed in the higher fertilizer dose plots compared to low dose plots, but fertilizer application in general resulted in a 17.7% average reduction in BTEX-GRO compounds and a 31.5% average reduction in DRO, MOR compounds, demonstrating a successful use of bioremediation under complex field conditions.