Modelagem computacional aplicada ao transporte de contaminantes em águas subterrâneas

Abstract

Groundwater contamination generates large concern related with public health and environmental conservation. The computational modeling can contribute to groundwater management and remediation planning of contaminated areas, making predictions for several scenarios of contamination without the cost of waiting or of putting them into practice. The aim this work is study mathematical models for the phenomena involved and develop numerical tools for the simulation that can assist in the prevention, control and remediation of groundwater pollution. In the computational experiments is simulated the multiple species transport. This problem is modeled for a system of nonlinear partial differential equations, coupled by the biodegradation and sorption reactions. Biodegradation is represented by the multiplicative Monod kinetic model. The sorption is described by the Freundlich isotherm and occur only with the contaminant. The solution of the PDE’s sistem is obtained in two steps. In the first resolves the contaminant and oxygen transport, the finite elements method and Crank-Nicolson scheme are respectively used in the spatial and time discretizations. The Newton method is used to treat the nonlinearity generated by the sorption equilibrium in the transport of the contaminant. The ordinary differential equations of the reactions is approximated by the fourth-order Runge- Kutta method. Numerical results presented in this work have shown good agreement with solutions introduced by others authors. In the simulations we observed the influence of the inclusion of non-linear reactions of biodegradation and sorption equilibrium and nonequilibrium happening simultaneously. So the study of interactions between the reactions should contribute to the modeling of contaminant transport in groundwater.