Upscaling bimolecular reactive transport in highly heterogeneous porous media with the LAgrangian Transport Eulerian Reaction Spatial (LATERS) Markov model

Wright, Elise E.; Sund, N. L.; Richter, David H.; Porta, Giovanni; Bolster, Diogo

doi:10.1007/s00477-021-02006-z

Cited by 7 publications

(5 citation statements)

References 45 publications

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“…As mentioned in Section 5, RW methods do not simulate mixing or, worse, concentrations explicitly, which makes it hard to assess kinetic reactions and direct application of RW to RT. Some researchers seek to overcome this problem by getting around the need for concentrations and instead trying to find the probability of particles encountering each other to interact as a function of their distribution in space and time [268][269][270][271][272]. The probability of particle collisions, interactions, and transformations may be made to depend on the scale [273].…”

Section: Solution Methods and Toolsmentioning

confidence: 99%

Reactive Transport: A Review of Basic Concepts with Emphasis on Biochemical Processes

et al. 2022

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Reactive transport (RT) couples bio-geo-chemical reactions and transport. RT is important to understand numerous scientific questions and solve some engineering problems. RT is highly multidisciplinary, which hinders the development of a body of knowledge shared by RT modelers and developers. The goal of this paper is to review the basic conceptual issues shared by all RT problems, so as to facilitate advancement along the current frontier: biochemical reactions. To this end, we review the basic equations to indicate that chemical systems are controlled by the set of equilibrium reactions, which are easy to model, but whose rate is controlled by mixing. Since mixing is not properly represented by the standard advection-dispersion equation (ADE), we conclude that this equation is poor for RT. This leads us to review alternative transport formulations, and the methods to solve RT problems using both the ADE and alternative equations. Since equilibrium is easy, difficulties arise for kinetic reactions, which is especially true for biochemistry, where numerous challenges are open (how to represent microbial communities, impact of genomics, effect of biofilms on flow and transport, etc.). We conclude with the basic eleven conceptual issues that we consider fundamental for any conceptually sound RT effort.

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Section: Solution Methods and Toolsmentioning

confidence: 99%

Reactive Transport: A Review of Basic Concepts with Emphasis on Biochemical Processes

et al. 2022

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“…In case of discrete descriptions of the transport process, such as sequential particle tracking [11,35,45,53] and global random walk (GRW) simulations [38,39,40,41], concentrations are measured by counting particles in the sampling volume. The relation between the two spatial averaging procedures, by integrating continuous fields and by counting particles, is not trivial.…”

Section: Introductionmentioning

confidence: 99%

“…The alternative "counting particles" averaging approach requires a microscopic description given by trajectories of physical or computational particles. Assuming that the heterogeneity of the subsurface system can be modeled by random functions, a "microscopic" description corresponding to the local, Darcy scale of the transport process is given by trajectories of diffusion in random velocity fields [39] modeled numerically by particle tracking [53] or GRW algorithms [40]. A general method to obtain a macroscopic description at spatio-temporal scales that can be directly related to those of the measurements and hydrological observations is the coarse grained (CG) description of corpuscular systems through space-time (ST) averages [46].…”

Section: Introductionmentioning

confidence: 99%

“…Upscaling reactive transport in subsurface hydrological systems aims at obtaining models that can account for small scale processes in predicting the fate of contaminants at larger scales and in designing remediation strategies for contaminated sites. Solutions proposed so far, based on either Eulerian approaches [30] or on particle tracking transport models combined with Eulerian descriptions of the reactions [53] are essentially volume averaging methods. However, it has been argued that small-scale temporal fluctuations of reacting species concentrations, in conditions of locally varying effects of advection and diffusion, propagate from local to larger spatial scales and at least an implicit temporal averaging must also be included in upscaling reactive transport [7].…”

Section: Introductionmentioning

confidence: 99%

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Space-time upscaling of reactive transport in porous media

Suciu¹,

Radu²

2021

Preprint

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Reactive transport in saturated/unsaturated porous media is numerically upscaled to the spacetime scale of a hypothetical measurement through coarse grained space-time (CGST) averages. The one-dimensional reactive transport is modeled at the fine-grained Darcy scale by the actual number of molecules involved in reactions which undergo advective and diffusive movements described by global random walk (GRW) simulations. The CGST averages verify identities similar to a local scale balance equation which allow us to derive expressions for the flow velocity and the intrinsic diffusion coefficient in terms of averaged microscopic quantities. The latter are further used to verify the CGST-GRW numerical approach. The upscaling approach is applied to biodegradation processes in saturated aquifers and variably saturated soils and the CGST averages are compared to classical volume averages. One finds that if the process is characterized by slow variations in time, as in homogeneous systems or in case of observations of reactive transport in heterogeneous aquifers made at large times or far away from the contaminant source, the differences between the two averages are negligible. Instead, the differences are significant if the averages are computed close to the source at early times, in case of aquifer simulations, and can be extremely large in simulations of biodegradation in soils. In the latter case, the volume average is totally inappropriate as model for experimental measurements, leading for instance to overestimations by 100% of the CGST average.

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“…The complexity of multicomponent biodegradation in steady-state saturated zone transport is already quite large, as current complexity reducing approaches are mostly accurate for specific conditions that assume reactants are well-mixed to some extent. For example, quasi-steady-state chemical conditions (Schäfer et al, 2020), reaction rates dependent on averaged concentrations (Massoudieh & Dentz, 2020), predominantly rate-limited conditions (Wright et al, 2021), (near-)instantaneous kinetics (Loschko et al, 2019), or large time asymptotic behavior (Wright et al, 2017). Unsaturated zone solute leaching occurs on a much shorter length and time scale than saturated zone transport.…”

Section: Discussionmentioning

confidence: 99%

Managed aquifer recharge with marginal water for irrigation and contaminant attenuation

Tang¹

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Managed aquifer recharge with marginal water allows for contaminants of emerging concern (CECs) to be attenuated in-situ, and for water to be more efficiently used. In phreatic aquifers underlying agricultural fields, this also increases water availability for crops. Existing drainage systems may be adapted for both injection (subirrigation) and extraction (drainage). We address subirrigation with treated domestic wastewater by considering numerical simulations and an experimental field site implemented as a proofof-concept. The transport, adsorption, and biodegradation of tracers, and relatively mobile and persistent CECs (using carbamazepine as an example), are analyzed. For this scenario, almost all non-biodegraded solutes irrigated into the soil are advected laterally towards surface water channels by regional groundwater flow. During the crop season, tracers may rise to the root zone, but only directly above irrigation drains. Accordingly, although up to 10% of tracers irrigated over four years are passively taken up by crops, this is concentrated in the plants situated directly above irrigation drains. No significant spreading of carbamazepine to the root zone occurs, and <1% of the total irrigated amount is taken up by crops after four years. Due to the annual precipitation surplus, solutes that are not very mobile are unlikely to enter the root zone even after decades of irrigation, because the length of the short-term precipitation shortage (crop season) is insufficient for them to rise to the root zone. Furthermore, carbamazepine biodegrades almost completely before being advected any significant distance from the drains. As carbamazepine is a relatively mobile and persistent CEC, the risks of crop, soil and surface water contamination by most other CECs is even smaller. The fraction of the irrigated CEC mass that seeps into surface water channels from the phreatic aquifer decreases exponentially with the distance between the agricultural plot and the channel, and increases exponentially with the agricultural plot width. Thus, the studied subsurface wastewater irrigation system reduces the environmental impacts of marginal water discharge and agricultural water use, with minimal risk of crop and environmental contamination.

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Upscaling bimolecular reactive transport in highly heterogeneous porous media with the LAgrangian Transport Eulerian Reaction Spatial (LATERS) Markov model

Cited by 7 publications

References 45 publications

Reactive Transport: A Review of Basic Concepts with Emphasis on Biochemical Processes

Reactive Transport: A Review of Basic Concepts with Emphasis on Biochemical Processes

Space-time upscaling of reactive transport in porous media

Managed aquifer recharge with marginal water for irrigation and contaminant attenuation

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