In Situ bioremediation of contaminated groundwater is made technologically challenging by the physically, chemically, and biologically heterogeneous subsurface environment. Subsurface heterogeneities are important because of influences on interfacial mass transfer processes which impact the availability of substrates to microorganisms. The goal was to develop a quantitative understanding of the impact of interfacial heterogeneities effecting contaminant biodegradation. A quantitative framework of dimensionless parameters was developed to capture the effects of competing physiochemical and biokinetic processes. Two numerical modeling experiments were completed, demonstrating the framework, and how it can be used to determine what engineered enhancements will alleviate the rate-limiting process. Baseline conditions were established to examine intrinsic biodegradation with a set rate-limiting process (either dispersion or biokinetics). Three different engineering controls were then examined. In each case, the control predicted to be appropriate based on the quantitative framework more successfully alleviated the limitation and enhanced biodegradation more than the alternative enhancements.