Finite volume/mixed finite element analysis of pollutant transport and bioremediation in heterogeneous saturated aquifers

The adoption of a suitable pumping-injecting well network and the human enhancement of the activity of soil bacteria, whose metabolism contributes to degrade and transform many pollutants in non-toxic substances, may be crucial in the process of remediation of contaminated soils. Organic contaminant transport in a subsurface aquifer and its biological degradation kinetics is numerically addressed by using a four contaminant species model. A numerical approach is proposed, that is based on a cellcentre finite volume method for the system of advection-dispersion equations of contaminants with a mixed-hybrid finite element method for the solution of a single-phase Darcyʹs equation. The effectiveness of the method and its accuracy in retaining the main physical properties of the continuous mathematical model is illustrated by simulating the time evolution of contaminant concentrations in a set of realistic scenarios.