Numerical methods for reactive transport and biodegradation

The microbial degradation of organic contaminants in the subsurface holds significant potential as a mechanism for in-situ remediation strategies. Numerical methods are presented for a conceptual model that incorporates both aerobic and anaerobic reactions. Nutrient uptake is described using Michaelis-Menten expressions, which are incorporated into a multiple nutrient uptake model. The resulting mathematical models form a series of advective-diffusive-reactive transport equations. There is nonlinear coupling of the different equations for conservation of the various species through the nonlinear reaction terms, which may involve reactions with all of the species and are themselves coupled to growth equations for the subsurface bacterial populations. First, discretization procedures and numerical results will be presented for equations written as Localized Adjoint Methods with spatially weighted test functions. Then techniques utilizing Eulerian-Lagrangian Localized Adjoint Methods are discussed and compared with other formulations.