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Improved Method for Estimating Reaction Rates During Push-Pull Tests |
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| Authors: | Charles J Paradis Emma R Dixon Lauren M Lui Adam P Arkin Jack C Parker Jonathan D Istok Edmund Perfect Larry D McKay Terry C Hazen |
| Institution: | 1. Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN
Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN;2. Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN;3. Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA;4. Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA Department of Bioengineering, University of California, Berkeley, CA;5. School of Civil and Construction Engineering, Oregon State University, Corvallis, OR;6. Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN;7. Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN |
| Abstract: | The breakthrough curve obtained from a single-well push-pull test can be adjusted to account for dilution of the injection fluid in the aquifer fluid. The dilution-adjusted breakthrough curve can be analyzed to estimate the reaction rate of a solute. The conventional dilution-adjusted method assumes that the ratios of the concentrations of the nonreactive and reactive solutes in the injection fluid vs. the aquifer fluid are equal. If this assumption is invalid, the conventional method will generate inaccurate breakthrough curves and may lead to erroneous conclusions regarding the reactivity of a solute. In this study, a new method that generates a dilution-adjusted breakthrough curve was theoretically developed to account for any possible combination of nonreactive and reactive solute concentrations in the injection and aquifer fluids. The newly developed method was applied to a field-based data set and was shown to generate more accurate dilution-adjusted breakthrough curves. The improved dilution-adjusted method presented here is simple, makes no assumptions regarding the concentrations of the nonreactive and reactive solutes in the injection and aquifer fluids, and easily allows for estimating reaction rates during push-pull tests. |
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