INVERSE MODELING OF BTEX DISSOLUTION AND BIODEGRADATION AT THE BEMIDJI, MN CRUDE-OIL SPILL SITE

Oil phase and aerobic and anaerobic degradation processes are assumed in BTEX degradation. Map and cross-sectional views of experimental field used in model formulation showing oil saturation distribution and flow lines. Description of basic conceptual model including rate-controlled dissolution of BTEX from a stationary oil phase with first-order degradation. Presentation of BIOMOC flow and transport model and UCODE inverse model. Reaction coefficients used in simulation to represent dissolution and biodegradation of BTEX are discussed. Comparison of estimated rates to analytical estimates and literature values. Distribution of normalised observed and simulated BTEX and oxygen concentrations. Composite scaled sensivity of estimated and fixed parameters for the basic simulation and hydrocarbon remaining in the oil body at the end of the simulation period and iron reduction conceptual models.