BIOSCREEN
Description:
BIOSCREEN is an easy-to-use screening model which simulates
remediation through natural attenuation (RNA) of dissolved
hydrocarbons at petroleum fuel release sites. The software
is programmed in MS Excel, based on the Domenico analytical
solute transport model, and will simulate advection, dispersion,
adsorption, and aerobic decay, as well as anaerobic reactions.
The two main uses BIOSCREEN is intended for are 1) As a screening
model to determine if RNA is feasible at a particular site,
and 2) As the primary RNA groundwater model at smaller sites.
Capabilities:
BIOSCREEN includes 3 different model types which encompass
its main uses:
• Solute transport without decay
• Solute transport with biodegradation modeled as a
first-order decay process
• Solute transport with biodegradation modeled as an
"instantaneous" biodegradation reaction
Limitations:
• BIOSCREEN assumes a uniform 1D flow field and homogeneous
conditions, so it is best applied to simple systems. The model
should not be applied where pumping systems create a complicated
flow field, or where vertical flow gradients affect contaminant
transport.
• As a screening tool, BIOSCREEN only approximates more
complicated processes that occur in the field. It is not a
good model selection where extremely detailed, accurate results
that closely match site conditions are required. In such cases
more comprehensive numerical models should be substituted.
Basic Inputs:
There are several different types of data which can be entered
into the cells on the main interface page:
• Hydrogeologic Data (seepage velocity, hydraulic conductivity,
gradient, porosity)
• Dispersion Data (Longitudinal, transverse, and vertical
dispersivity, estimated plume length)
• Adsorption Data (Retardation factor, soil bulk density,
fraction organic carbon)
• Biodegradation Data (first-order decay coefficient,
dissolved plume half-life; oxygen, methane, nitrate data)
• General Data (Model area length and width, simulation
time)
• Source Data (Plume source thickness in saturated zone,
source zone thickness and widtch, source zone concentration,
source half-life)
• Field Data for Comparison (any recorded field data
to compare to modeled data)
Basic Output:
The output will vary depending on whether the user runs the
model with "Centerline" or "Array" selected
• The "Centerline" output shows the average
concentratiopn at the top of the saturated zone along the
centerline of the plume
• The "Array" output shows the results on
a 3-D 10-point-long by 5-point-wide grid (these are defaults
and can be modified on the inputs screen). This output also
allows the user to calculate an approximate mass balance.
How to Run the Model:
1. Enter appropriate data into corresponding cells
2. Click outside of data cells before calculating
3. Select either "Centerline" or "Array"
depending on the type of output you want (see "Basic
Output" above), and run the simulation.
Developer: BIOSCREEN was developed for the Air Force Center for Environmental Excellence (AFCEE) Technology Transfer Division at Brooks Air Force Base by Groundwater Services, Inc., Houston, Texas.
Faculty Contact: Gavin Gong
Application: Hydrogeologic fate and transport of groundwater contaminants under Columbia University (CIEE E4252)
