Uncertainty quantification and global sensitivity analysis for reactive transport models, application to uranium remediation

Jef Caers Kate Maher
In addressing subsurface contamination, it is important to understand the efficacy of remediation practices. Do these practices achieve what they are intended for? How can we monitor this by means of sensors or geophysics? A major challenge is to address complexities in both geological heterogeneity as well as uncertainties about the biogeochemical system. In this research, we developed a general workflow to address such questions and demonstrate it on the uranium remediation experiment at the rifle site, Colorado. Groundwater contamination caused by the leftover uranium mill tailings after the cold war is a vital environmental concern in the United States. In Colorado, attention has been given to a number of hazardous sites adjacent to the Colorado River because the elevated concentrations of contaminants that can be harmful to young-of-year fish using backwater channels as habitat during late summer. Over the last couple of years, acetate injection has been proposed and tested at the Rifle pilot site to examine the effectiveness of in-situ bio-remediation.  Our research addresses how both geological as well as geochemical (reactions) uncertainties can be integrated to quantify the efficacy of acetate injection as a remediation practice.

Dissertation: Holistic strategies for prediction uncertainty quantification of contaminant transport and reservoir production in field cases