Numerical modeling of liquid-waste infiltration from storage facilities into surrounding groundwater and surface-water bodies

Resumo

This study focuses on the infiltration of saturated brine from liquid-waste storage facilities into the surrounding groundwater and surface-water bodies. The storage facilities are situated at the Verkhnekamsk Potassium and Magnesium Salt Deposit (Perm krai, Russian Federation); they store highly mineralized brine of potassium, sodium, and magnesium chlorides. An analytical solution of a one-dimensional equation of contaminant transport by a homogeneous steady-state groundwater flow is used to estimate the time it takes the contaminant to travel from the storage facilities to the nearest surface water body, as well as to evaluate the formation time of a stationary concentration profile, with contaminant adsorption in the porous matrix either neglected or taken into account. The contaminant concentration at the point of brine entry into the surface water body is calculated. The ANSYS Fluent software package is used for direct 3D simulation of brine infiltration into the surrounding medium. The simulation results revealed different stages of contaminant propagation in the porous medium. The contaminant was found to spread over a wide area with an almost uniform high brine concentration close to the saturation value. The contaminant reaches the nearest riverbed approximately 20 days after the start of infiltration. The estimates of the time required for the contaminant front to reach the surface water body obtained by three-dimensional simulation agree with the analytical estimates derived from a one-dimensional model. The proposed system of physical models adequately describes the hydrodynamic processes accompanying the operation of large storage facilities and can be used to predict contaminant-front propagation in the groundwater near storage facilities.