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NIGHTHAWK - A Program for Modeling Saturated Batch and Column Experiments Incorporating Equilibrium and Kinetic Biogeochemistry
Citation:
MATOTT, L. S. AND A. J. RABIDEAU. NIGHTHAWK - A Program for Modeling Saturated Batch and Column Experiments Incorporating Equilibrium and Kinetic Biogeochemistry . COMPUTERS & GEOSCIENCES. Elsevier Science Ltd, New York, NY, 36(2):253-256, (2010).
Impact/Purpose:
Development of the NIGHTHAWK software was motivated by an interest in simulating saturated subsurface biodegradation processes while accounting for the effects of interrelated inorganic geochemical reactions.
Description:
NIGHTHAWK simulates the fate and transport of biogeochemically reactive contaminants in the saturated subsurface. Version 1.2 supports batch and one- dimensional advective-dispersive-reactive transport involving a number of biogeochemical processes, including: microbially-mediated degradation, inorganic redox chemistry, aqueous-phase equilibrium speciation, kinetic and equilibrium precipitation and dissolution of minerals, and a variety of sorption processes, including surface complexation, competitive ion exchange, and linear/nonlinear isotherms. Governing equations are solved using finite-differences and a fully kinetic operator-splitting technique. To demonstrate NIGHTHAWK and evaluate its performance, the program was applied to scenarios involving nitrate biodegradation and sequential parent-daughter decay. NIGHTHAWK simulation results and computational performance compared favorably to two alternative modeling codes.