which would improve the design and ensure its viability over the long term. Their invention has generated industry interest, Simpson said. —K. S. B.
Advanced bioremediation model due this fall The Remediation Technology Development Forum expects to release a general-purpose transport computer model this fall. Called RT3D, the three-dimensional multispecies reactive transport model will be available as public-domain software for helping to model sites with remediation through the use of accelerated bioremediation, bioventing, and natural attenuation. The RT3D code was written by a team of engineers from the Pacific Northwest National Laboratory (PNNL) and Washington State University to address the need for robust kinetic models for bioremediation. The new program is "an updated modification" of the MT3D code created in 1988 by Chun Miao Zheng of the University of Alabama, according to Brian Hooker of PNNL. "We've come up with 3. robust r63.c~ tive version where not only can vou simulate degradation of fuel hydrocarbons with preprogrammed modules but also chlorinated ethenes and carbon tetrachloride in a number of different metabolic regimes " said Hooker "In addition we have a way people can take their own kinetics and input them directly into the model so they're not locked into our preproffi-ammed modules "Other codes purport to do reactive flow and transport," Hooker continued, "but they're much more limited in scope and more specific in terms of what contaminants they reflect and what type of microbial regimes. A lot of them are more specific for an aerobic aquifer, but with all these contaminants you're usually looking at multiple metabolic regimes. So you need to account for aerobic and denitrifying, iron-reducing, sulfate-reducing, and methanogenic con~ ditions all in the same aquifer." The model has been validated by researchers at PNNL by comparing its results with those recorded at actual natural attenuation and accelerated bioremediation sites. The code proved able to predict degradation that directly matched field results. "You can simulate 30 years in a day," Hooker said. —K. S. B.
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