BIOSCREEN–AT – Karanovic et al. (2007)

The model provides a three-dimensional solution for transport of dissolved contaminants, incorporating natural attenuation processes. As shown in Figure 1, the source is given as a patch specified-concentration boundary condition.

Figure 1: Conceptual Model

Newell et al. (1997)/ Karanovic et al. (2007) Provide the following expression for an exact analytical solution:

with:

$c_{o}$ = initial source concentration
$D_{x}^{'}$ = dispersion coefficient divided by retardation factor Dx/R
$D_{y}^{'}$ = dispersion coefficient divided by retardation factor Dy/R
$D_{z}^{'}$ = dispersion coefficient divided by retardation factor Dz/R
$\gamma$ = source decay coefficient
$\lambda_{eff}$ = effective first order decay coefficient

$W$ = source width

$H$ = source depth

The model is based on the following assumptions:

  1. Aquifer extends semi-infinite in x-direction, infinite in y-direction and extends from water table to relatively large depth.
  2. Groundwater flow is steady and one dimensional.
  3. The solute undergoes equilibrium sorption and first-order transformation reactions.
  4. The aquifer is homogeneous and Lmax is always found on the center line.

The CAST Project acquires the maximum plume length Lmax from this model, using Gauss-Legendre-Quadrature to obtain a solution. Figure 2 shows the concentration of the contaminant along x-direction.

Figure 2: Concentration along center line

Reference:

Marinko Karanovic, Christopher J. Neville, and Charles B. Andrews. BIOSCREEN-AT: BIOSCREEN with an Exact Analytical Solution. Vol. 45, No. 2 GROUND WATER March–April 2007 (pages 242–245).

S.S. Papadopulos & Associates, Inc. , https://www.sspa.com/software/bioscreen