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	Official RT3D Home Page Multi-Species Reactive Flow and Transport Simulation Software
What is RT3D? What's New in Version 2.5   RT3D Reaction Packages Application of RT3D User Interfaces for RT3D System Requirements       Acknowledgements History of RT3D Development RT3D-Related Publications       Downloadable Files    (Documentation, Executables, Source Code, Examples, Utilities) Version 1.0    1998-Nov-03 Version 2.5    2003-Feb-03    Watch for the RT3D-MNA beta release, Summer 2006!
Training Courses Bioremediation System Design Using Visual MODFLOW and RT3D Orlando, Florida, June 6, 2003 (in conjunction with the 7th In Situ and On-Site Bioremediation Symposium) Additional Resources		RT3D Contact Information /         Customized Solutions

RT3D is a Fortran 90-based software package for simulating three-dimensional, multi-species, reactive transport of chemical compounds in groundwater.  RT3D provides an easy-to-use and flexible framework that you can apply to your natural attenuation, accelerated bioremediation, or other reactive transport modeling scenarios.  Predefined modules are available for common kinetics, but you have the flexibility to add any reaction kinetics that you want for multiple aqueous and sorbed phase species.  Several graphical user interfaces to RT3D are available to simplify the process of defining a model and the required RT3D input information.  At the same time, the availability of the Fortran 90 source code provides flexibility for advanced users and users on a variety of computing platforms.

Example figures of post-processed data.

RT3D version 2.5 (RT3Dv2.5) has been updated (from version 1.0) in several aspects.  The base code has been updated to incorporate changes introduced into version 3.50 of the MT3DMS code (see Zheng and Wang [1999] for details on these changes, including a third-order total-variation-diminishing advection solver and an iterative generalized conjugate gradient solver).  The RT3Dv2.5 code now uses standard Fortran 90, which should allow seamless use across multiple platforms (e.g., the rxns.dll method of specifying user-defined reactions is no longer the default, although it is still available).  RT3Dv2.5 has new source/sink options of constant concentration and decaying sources, the latter of which is unique to RT3D.  Four new reaction solver options have been added, including Runge-Kutta solvers and solvers using an explicit Jacobian matrix for stiff problems.  Sorption parameters can now be specified on a cell-by-cell basis (in addition to the layer-by-layer basis).

RT3D comes with a set of pre-programmed general reaction packages including:

1. Tracer Transport
2. Two Species Instantaneous Reaction (BIOPLUME-II type reactions; e.g., Hydrocarbon & Oxygen)
3. Six Species, First-Order, Rate-Limited, BTEX Degradation using Sequential Electron Acceptors (e.g., O₂, NO₃^-, Fe²⁺, SO₄^2-, CO₂)
4. Rate-Limited Sorption
5. Double Monod Model
6. Sequential First-Order Decay (up to 4 species, e.g., PCE/TCE/DCE/VC)
7. Aerobic/Anaerobic Chlorinated Ethene Dechlorination

The reaction mechanisms for these packages are built-in to RT3D as a convenience to the user.   The key parameters (i.e., reaction rates) have default values based on data reported in the literature.  However, the user can adjust these parameters to better fit with data from a specific site.  See the RT3D Users Manual (PNNL-11720) for details of the reaction mechanisms and adjustable parameters for these pre-programmed modules.

A key feature of RT3D is the high degree of flexibility the user has in adding other reaction kinetics via the user-defined module.  For instance, coupled reactions for substrate use and subsequent dechlorination could be described for improved accelerated in situ bioremediation modeling (see example figures below).  Standard first-order representation of dechlorination for evaluation of natural attenuation could be improved to include non-sequential dechlorination pathways, inhibition terms (competitive or otherwise), and electron acceptor dependencies for the reactions.  One of the services that Battelle Northwest provides is customization of reaction modules.

Comparison of laboratory data and RT3D simulation results for a batch reaction.  Sediment, groundwater, lactate (500 mg/L), and PCE were combined in sealed microcosm tests.
A.  Measurements indicated complete removal of lactate in the first 12 days of incubation.  Propionate and acetate were produced and slowly degraded thereafter.	B.  Measurements showed PCE dechlorination with TCE and DCE intermediates.  RT3D simulation modeled dechlorination as a reaction coupled to lactate and propionate fermentation.

With a variety of pre-programmed reaction packages and the flexibility to insert user-specific kinetics, RT3D can simulate a multitude of scenarios.

As part of a natural attenuation evaluation, RT3D can be used to predict fate and transport of groundwater plumes.  A sensitivity analysis can be performed to evaluate the range of potential outcomes.  Such predictions may be used to define a long-term monitoring program that will feed back into future reactive transport simulations and model refinement.  The PPI Brooklawn site is an example where RT3D simulations were performed using kinetics derived from laboratory microcosm experiments with site sediments; the predictions indicated that natural attenuation would be an appropriate strategy for the PPI Brooklawn site and the resulting monitoring plan is now being implemented.

Active remediation can also be simulated, whether it be air sparging, chemical oxidation or accelerated bioremediation.  The key is understanding the reaction kinetics of the remediation process and applying that knowledge in a user-defined reaction module.  Reactive transport simulations could potentially be applied to scenarios involving contaminants such as heavy metals, explosives, petroleum hydrocarbons, and/or chlorinated solvents.  The Point Mugu IRP Site 24 is an example where RT3D was used to design an effective accelerated in situ bioremediation system.

RT3D may be run in a stand-alone configuration by creating input files in a text editor and running RT3D from a command prompt.  However, the following popular groundwater modeling packages provide graphical user interfaces for setting up a simulation model and post-processing data.

1. the U.S. Department of Defense Groundwater Modeling System (GMS) commercially distributed by EMS-i
        (Certain government users can contact the U.S. Army's Waterworks Experiment Station about GMS)
2. Visual Modflow from Schlumberger Water Services (formerly Waterloo Hydrogeologic, Inc.)
3. Groundwater Vistas by Environmental Simulations, Inc
4. Processing Modflow Pro by Excel Info Tech, Inc.

General
• Full download requires 8 MB of space on a hard drive (2.5 MB for zip file and 5.5 for the decompressed files).
• A version of MODFLOW with the LKMT package or a comparable flow model that can output a MODFLOW style head and flow (*.hff) file.  A modified version of MODFLOW-96 is included in the RT3D distribution.
• The more RAM, the better; memory requirements will depend on the size of the model (or vice versa)

For User-Compiled Option
• A Fortran 90 compiler.  Testing has been done with (Intel/Compaq/Ditital) Visual Fortran and a Fortran compiler on a DEC Alpha system.  The DLL option for the user-defined reaction module has been tested with Visual Fortan and Microsoft Fortran Powerstation v. 4.0.

For Pre-Compiled Binaries for Windows/Intel x86
• IBM Compatible PC, 486/66 or better (Pentium 200 recommended)
• Microsoft Windows 95 or newer

Direct general questions on RT3D use, functionality, documentation, etc. to Chris Johnson.  Complex questions, "wish list" requests, and RT3D project related inquires should be directed to Dr. Clement.  Contact Chris Johnson for discussion of how Battelle's Chlorinated Solvent Bioremediation Design Service may assist your project with customized reaction modules/RT3D, accelerated in situ remediation design, and/or natural attenuation evaluations.