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Format. Refer to Chapter 2 in Wiedemeyer. Read this chapter over paying particular attention to the highlights shown below.

Highlights.

Dissolved Plume Migration. The migration of ground water contaminants in the dissolved phase is a topic which involves the porous media mass transport processes of advection, dispersion sorption and reaction (i.e. biodegradation). Since these mass transport phenomena will be covered in detail in the INRA Core curse we will limit our coverage here to targeted reading assignments from appropriate text book sections. Our goal in this section is to cover the relevant background necessary to understand and use the BIOSCREEN Model. BIOSCREEN is an easy to use spread sheet model which simulates the migration of dissolved contaminant plumes down gradient from a source area. The mass transport processes of advection, dispersion , sorption and biodegradation are all considered in this model. The model will simulate biodegradation from both anaerobic and aerobic reactions. It was developed for the Air Force Center for Environmental Excellence (AFCEE) Technology Transfer Division at Brooks Air Force Base by Groundwater Services, Inc. Houston TX.

Please take some time here and look over the BIOSCREEN Users manual Version 1.3.

Background Reading. The mass transport processes of advection dispersion , sorption and biodegradation are covered in Wiedemeyer text book chapter 3 pages 118-150. The partial differential equation(s) describing these processes are presented along with various analytical solutions. If you are already familiar with the basic principals of porous media mass transport (from the INRA Core course or otherwise) then the material on pages 118-150 will be review. If this is your first exposure then it is important to read enough to gain a basic understanding of these individual mass transport processes. At this point you will be ready to examine the BIOSCREEN Model and proceed with the exercises and assignments which follow.

Background on Mass Transport (pages 118-150, Wiedemeyer, Chapter 3). Before starting this reading refer to page 367 (Wiedemeyer) to section 8.3 titled Governing Equations for Contaminant Fate and Transport. Examine Equations 8.1 –8.6. Note that the analytical solution for Equation 8.4 is the basis for the BIOCREEN model. Look at the definition of the variables and parameters in Equation 8.4. and note that the terms in the equation include the transport processes of advection, dispersion (three dimensional), sorption and biodegradation (first order).

Now proceed to read pages 118-150 with the goal realizing that this material provides detailed background for each term in Equation 8.4. Focus on gaining a conceptual understanding of each individual transport process (i.e. advection , dispersion, sorption, and biodegradation) as well as understanding how each term is modeled and, ultimately included in Equation 8.4.

BIOSCREEN Model. To further prepare to use the BIOSCREEN Model refer to page 380 in Wiedemeyer. Read the section on Three Dimensional Analytical Models. This section discusses the Domenico, 1987 solution to Equation 8.4 (note misprint in Wiedemeyer says Equation 8.5). Equation 8.4 is the three-dimensional partial differential equation describing transient solute (dissolved contaminant) transport with advection, dispersion, sorption and first-order biodegradation in saturated ground water flow. The analytical solutions for transient and steady state conditions are given by Equations 8.23 and 8.24. Continue reading page 382-385 to gain further insight into the features of BIOSCREEN. A good summary is given by Figure 8.4.

BIOSCREEN Example. Refer to pages 395-402 for a detailed example of applying the BIOSCREEN Model to a BTEX release at Keesler Air Force Base.

Assignment. Access BIOSCREEN and duplicate the Keesler example. Now complete problems I-15 and I-16.