Biocurtain Design Using Reactive Transport Models |
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| Authors: | MS Phanikumar David W Hyndman Craig S Criddle |
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| Institution: | 1. Mantha S. Phanikumar is an assistant professor in the Departments of Civil and Environmental Engineering and Geological Sciences at Michigan State University, East Lansing. (A130 Engineering Research Complex;2. [517] 353–4366;3. fax [517] 353–8787;4. phani@msu.edu). He received a Ph.D. in mechanical engineering from the Indian Institute of Science, Bangalore, where he specialized in computational heat transfer and fluid dynamics. Before joining MSU, he was a scientist at the Center for Mathematical Modeling and Computer Simulation, National Aerospace Laboratories, India, where his research focus was surface water pollution in estuaries and the coastal ocean. His research interests include environmental and geophysical fluid dynamics, modeling biological/ecological systems, the fate and transport of contaminants, subsurface characterization, and ground water-surface water interaction.;5. David W. Hyndman is an associate professor in the Department of Geological Sciences (206 Natural Sciences Bldg., Michigan State University, East Lansing, MI 48824;6. [517] 353–4442;7. hyndman@msu.edu. He received M.S. and Ph.D. degrees in hydrogeology from Stanford University. He is an associate editor for Ground Water and Water Resources Research and was named the Henry Darcy Distinguished Lecturer by the National Ground Water Association for the year 2002. His research focuses on aquifer characterization methods using geophysical and hydrogeologic data, modeling the impacts of land use on water quality, the influence of seasonal recharge pulses on REDOX zonation, the design of bioremediation systems, and modeling microbial transport and contaminant biodegradation.;8. Craig S. Criddle is an associate professor in the Department of Civil and Environmental Engineering at Stanford University (M42 Terman Engineering Center, Stanford University, Standford, CA 94305;9. [650] 723–9032;10. ccriddle@stanford.edu). His work focuses on environmental biotechnology, and his research interests include biological processes for water quality control, the stability and invasibility of microbial communities, the fate of microorganisms in the environment, and the fate of persistent contaminants. He joined the Stanford faculty after nine years at Michigan State University, where he received the Withrow Distinguished Scholar Award and a faculty award from the 3M Company. He is currently a Leavell Family Faculty Scholar in the School of Engineering. |
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| Abstract: | Bioremediation is an attractive alternative to traditional remediation methods for a variety of ground water contaminants. However, widespread implementation of bioremediation is currently limited by the complexity of the dynamic chemical and biological processes that need to be understood and incorporated into the design approach. Reactive transport models provide a powerful tool to simulate these complex interactions and, thus, can be used to improve and guide the design of bioremediation systems. We present a remediation design approach for intermittently stimulated biodegradation using multicomponent reactive transport models, parameterized using a series of nondimensional Damkohler numbers. Designs were based on either (1) a target aqueous phase concentration at the exit of the treatment system, or (2) the total contaminant mass fraction removed from a region of interest. The equation set used to develop this design approach is specific to the case of intermittent electron donor addition to drive cometabolic transformations. We illustrate the design procedure for a biocurtain that removes carbon tetrachloride. Our results for this case indicate that intermittent injection is significantly more efficient than strategies based on continuous pumping. Example design parameters include the length of the biologically active zone (i.e., biocurtain), the effective rate of degradation in this zone, and the interval between electron donor injection cycles. The presented dimensionless parametric approach can be used to design bench-scale column studies and should be helpful for scale-up to field-scale remediation systems. |
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