Identifying key controls on the behavior of an acidic-U(VI) plume in the Savannah River Site using reactive transport modeling

Bea, Sergio; Wainwright, Haruko M.; Spycher, Nicolas; Faybishenko, Boris; Hubbard, Susan S.; Denham, Miles

doi:10.1016/j.jconhyd.2013.04.005

Cited by 39 publications

(126 citation statements)

References 61 publications

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“…Applications have included, for example, geothermal systems [143][144][145], nuclear waste repositories [146][147][148][149], geologic carbon sequestration [150][151][152][153][154], and environmental remediation [155][156][157]. The development of TOUGHREACT has been ongoing since the late 1990s.…”

Section: Toughreactmentioning

confidence: 99%

Reactive transport codes for subsurface environmental simulation

et al. 2014

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A general description of the mathematical and numerical formulations used in modern numerical reactive transport codes relevant for subsurface environmental simulations is presented. The formulations are followed by short descriptions of commonly used and available subsurface simulators that consider continuum representations of flow, transport, and reactions in porous media. These formulations are applicable to most of the subsurface environmental benchmark problems included in this special issue. The list of codes described briefly here includes PHREEQC, HPx, PHT3D, OpenGeoSys (OGS), HYTEC, ORCHESTRA, TOUGHREACT, eSTOMP, HYDROGEOCHEM, CrunchFlow, MIN3P, and PFLOTRAN. The descriptions include a C. I. Steefel ( ) · B. Arora · S. Molins · N. Spycher

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Section: Toughreactmentioning

confidence: 99%

Reactive transport codes for subsurface environmental simulation

et al. 2014

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“…Results of reactive transport simulations using the NEM-GC model were compared with simulations using the electrostatic model previously developed by Dong et al (2012) and implemented by Bea et al (2013) to simulate reactive U transport at the SRS. The model of Dong et al (2012) considers three surface sites to represent the adsorption and exchange of U(VI) (and other ions, Table 2) onto kaolinite (>kOH, >k − ) and goethite (>FeOH); it is a diffuse layer model for kaolinite-goethite assemblages, using a CA approach (Davis and Kent 1990) that combines the U(VI) SCM of Sherman et al (2008) for goethite with that of Heidmann et al (2005) for kaolinite.…”

Section: Transport Simulations With An Electrostatic Scmmentioning

confidence: 99%

“…In their simulations, Bea et al (2013) augmented the model of Dong et al with (negligible) sorption onto quartz (>qz) using the data shown in Table 2. As in Bea et al (2013), the system modeled here also considers 21 aqueous U(VI) complexation reactions that are assumed to operate at chemical equilibrium (Table 2). Equilibrium constants for all reactions and other parameters for the SCM are provided in Table 2.…”

Section: Transport Simulations With An Electrostatic Scmmentioning

confidence: 99%

“…Based on these studies, quartz, kaolinite, and goethite constitute the main minerals at the site. Apart from schoepite, all of these minerals are considered to react under kinetic constraints, using the same kinetic rate laws and rate constants as in Bea et al (2013). Apart from schoepite, all of these minerals are considered to react under kinetic constraints, using the same kinetic rate laws and rate constants as in Bea et al (2013).…”

Section: Reactive Transport Modelmentioning

confidence: 99%

“…Base-case simulation using electrostatic SCM Table 2 S2 Transport simulation using NEM for H + sorption only Table 7 S3 Transport simulation using NEM for noncompetitive U(VI) sorption Tables 7 and 8 S4 Transport simulation using NEM for competitive H + and U(VI) sorption Tables 7 and 9 2012; Bea et al 2013), the results from the base-case simulation (Figures 2 and 3) show that early pH and U(VI) fronts are retarded by sorption and exchange processes onto kaolinite and goethite, and eventually reach a steady state as sorption/exchange sites equilibrate with the influent groundwater at lower pH and higher U(VI) concentration. After the basin closure, the acidic discharge stops and the plume constituents mix with uncontaminated groundwater.…”

Section: S1mentioning

confidence: 99%

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Comparison of Electrostatic and Non‐Electrostatic Models for U(VI) Sorption on Aquifer Sediments

Arora¹,

Davis

Spycher

et al. 2017

Groundwater

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A non-electrostatic generalized composite surface complexation model (SCM) was developed for U(VI) sorption on contaminated F-Area sediments from the U.S. Department of Energy Savannah River Site, South Carolina. The objective of this study was to test if a simpler, semi-empirical, non-electrostatic U(VI) sorption model (NEM) could achieve the same predictive performance as a SCM with electrostatic correction terms in describing U(VI) plume evolution and long-term mobility. One-dimensional reactive transport simulations considering key hydrodynamic processes, Al and Fe minerals, as well as H and U surface complexation, with and without electrostatic correction terms, were conducted. The NEM was first calibrated with laboratory batch H and U(VI) sorption data on F-Area sediments, and then the surface area of the NEM was adjusted to match field observations of dissolved U(VI). Modeling results indicate that the calibrated NEM was able to perform as well as the previously developed electrostatic model in predicting the long-term evolution of H and U(VI) at the site, given the variability of field-site data. The electrostatic and NEM models yield somewhat different results for the time period when basin discharge was active; however, it is not clear which modeling approach may be better to model this early time period because groundwater quality data during this period were not available. A key finding of this study is that the applicability of NEM (and thus robustness of its predictions) to the field system evolves with time and is strongly dependent on the pH range that was used to develop the model.

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Bayesian hierarchical approach and geophysical data sets for estimation of reactive facies over plume scales

Wainwright

Chen

Sassen

et al. 2014

Water Resources Research

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A stochastic model is developed to integrate multiscale geophysical and point data sets for characterizing coupled subsurface physiochemical properties over plume-relevant scales, which is desired for parameterizing reactive transport models. We utilize the concept of reactive facies, which is based on the hypothesis that subsurface units can be identified that have distinct reactive-transport-property distributions. To estimate and spatially distribute reactive facies and their associated properties over plumerelevant scales, we need to (1) document the physiochemical controls on plume behavior and the correspondence between geochemical, hydrogeological, and geophysical measurements; and (2) integrate multisource, multiscale data sets in a consistent manner. To tackle these cross-scale challenges, we develop a hierarchical Bayesian model to jointly invert various wellbore and geophysical data sets that have different resolutions and spatial coverage. We use Markov-chain Monte-Carlo sampling methods to draw many samples from the joint posterior distribution and subsequently estimate the marginal posterior distribution of reactive-facies field and their associated reactive transport properties. Synthetic studies demonstrate that our method can successfully integrate different types of data sets. We tested the framework using the data sets collected at the uranium-contaminated Savannah River Site F-Area, including wellbore lithology, cone penetrometer testing, and crosshole and surface seismic data. Results show that the method can estimate the spatial distribution of reactive facies and their associated reactive-transport properties along a 300 m plume centerline traverse with high resolution (1.2 m by 0.305 m).

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Identifying key controls on the behavior of an acidic-U(VI) plume in the Savannah River Site using reactive transport modeling

Cited by 39 publications

References 61 publications

Reactive transport codes for subsurface environmental simulation

Reactive transport codes for subsurface environmental simulation

Comparison of Electrostatic and Non‐Electrostatic Models for U(VI) Sorption on Aquifer Sediments

Bayesian hierarchical approach and geophysical data sets for estimation of reactive facies over plume scales

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