Transcript MODFLOW

Introduction to BIOPLUME III
BIOPLUME III
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Model engine written by Hanadi Rifai
GUI developed by ZEi/MicroEngineering, Inc.
Version 1.0 released September, 1997
New version due September, 2000
Available from the U.S. EPA at
http://www.epa.gov/ada/csmos.html
Differences from BIOPLUME II
• Graphical User Interface
• Models 6 components (Hydrocarbon, 5 electron
acceptors)
• Allows 3 kinds of reaction kinetics
– First order
– Monod
– Instantaneous
Biodegradation Solution
• Research indicates aerobic and anaerobic
biodegradation paths
• Electron acceptors available in the following
preferential order:
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Oxygen
Nitrate
Iron(III)
Sulfate
Carbon Dioxide
Sequential Reactions
• Nitrate only used when all oxygen depleted
• Iron(III) only used when all nitrate depleted
• Each subsequent electron acceptor is only
available when the previous one is depleted
Kinetic Methods
• Each reaction can be simulated via one of three
possible methods:
– First-order decay - Note: error in decay code
– Instantaneous reaction
– Monod kinetics
• Each reaction is limited to the available electron
acceptor supply
• Monod kinetics does not simulate microbial
growth
Error in Decay Code
• First-Order Decay designed to be used in two
modes
– Radioactive decay: HC decays, not limited by available
electron acceptors. This option works.
– Electron acceptor-limited decay: HC reduction and rate
coefficients tied to each electron acceptor in the decay
sequence.
• The Electron acceptor-limited decay option has
serious bugs.
• Do Not Use this option.
Applicability and Limitations
• Developed to simulate natural attenuation of
hydrocarbons using O2, NO3-, Fe3+, SO42-, and
CO2
• Can be used to answer following questions:
– How long will plume extend if no controls?
– How long will plume persist until NA?
– How long will plume extend/persist if
controls/remediation are applied?
Other Uses of BIOPLUME III
• Bioremediation with added electron acceptors
• Low flow rate Air Sparging
• Advection/Dispersion/Sorption with no
biodegradation
Notes on Usability
• BIOPLUME III (Version 1.0) has several bugs
– Contaminant concentrations at constant head cells
– Crashes – Save fairly often
– Occasional cosmetic naming problem
• Electron acceptors names get messed up
– Problem with first-order decay