Research reactive transport (RT)

Description

Reactive transport is the interaction between two types of processes that controls the fate of solutes in groundwater:

Transport processes, such as advection, dispersion and diffusion
Chemical reactions, such as acid-base reactions, redox reactions, complexation, biodegradation, adsorption, cation exchange and precipitation/dissolution of minerals. These two are the main processes when dealing with soil and groundwater contamination problems or studies on groundwater quality and water-rock interaction.

The main topics treated at the hydrogeology group are.

Development of general purpose and numerical efficient codes (Retraso and VisualRetraso).
The study of reactive transport processes by means of laboratory and field experiments and numerical modelling; This include the study of the oxidation of metal sulphides at mine tailings (project PAROXIS), the construction of geochemical barriers (Project PYRAMID), and performance assessment of waste disposal facilities (project RETROCK and "Tratamiento de los procesos de retención en la geosfera").

Keywords

Reactive transport, Hydrogeochemistry, Geochemistry, Modelling

Projects

Treatment of the retention processes in the geosphere
Passive remediation of acid mine drainage
Sulphie oxidation in-situ unsaturated zone.
Sea-water intrusion
Colloid Transport.
Mont Terri
Onkalo

MATHEMATICAL FORMULATION AND NUMERICAL SOLUTION

A key concept in reactive transport is the 'component', which can be defined as a linear combination of the chemical species. By defining components in a clever way, we can obtain transport equations that are less coupled and easier to solve numerically. We proposed various ways for doing so (Saaltink et al., 1998;Molins et al.,2004; De Simoni, et al. 2005, Saaltink et al., 2013). For some cases it permits us to obtain analytical solutions for even complex chemical system (see below).

TYPES OF APPLICATIONS THAT WE ARE DEVELOPING:

REACTIVE TRANSPORT AND MULTIPHASE FLOW

For reactive transport with various flowing phases, such liquid and gas as in unsaturated soils, one has to take into account the transport of species in the various phases and the chemical reactions involved (e.g., aqueous and gaseous CO2). Simulation becomes particularly difficult when an important part of the phase may react. In that case flow and reactive transport becomes coupled. An example is the injection of CO2 in deep carbonate aquifers where the CO2 can dissolve in water, dissolve calcite and increase porosity (see below).

REACTIVE TRANSPORT AND HIGH SALINITY

In very dry conditions, such as evaporation can cause high concentration and precipitation of soluble minerals (gypsum, silvite, halite, ..). The high concentrations can effect density of water. More important for soils it effects water and vapor transport by effecting the activity of water flow. In both cases flow and reactive transport becomes coupled. A particular case is when various hydrited minerals precipitate or dissolve (see below).

Researchers

M. Saaltink (UPC)
P. Soler (CSIC)
F. Batlle (UPC)
J. Carrera (CSIC)
C. Ayora (CSIC)

Most relevant publications related to this line

Abarca, E., Carrera, J., Voss, C.I, Sánchez-Vila, X. Effect of aquifer bottom morphology on saltwater intrusion. 17th Salt Water Intrusion Meeting (SWIM), Delf, 2002.
Abarca, E., Carrera, J. and Sánchez-Vila, X. Heterogeneous Dispersive Henry Problem. Second International Conference on Saltwater Intrusion and Coastal Aquifers—Monitoring, Modeling, and Management. Mérida, México, March 30-April 2, 2003 (Submitted extended abstract).
Alcolea, A., Ayora, C., Bernet, O., Bolzicco, J., Carrera, J., Cortina, J.L., Coscera, G., de Pablo, J., Domènech, C., Galache, J., Gibert, O., Knudby, C., Mantecón, R., Manzano, M., Saaltink, M., Sigado, A., Barrera geoquímica, Boletin Geológico y Minero, 112, 229-255, 2001.
Ayora, C., C. Taberner, M.W. Saaltink and J. Carrera, The genesis of dedolomites: a discussion based on reactive transport modeling, Journal of Hydrology, 209, 346-365, 1998.
Ayora, C., Barettino, D., Domènech, C., Fernández, M., López-Pamo, E., Olivella, S., de Pablo, J., Saaltink, M.W., Meteorización de los lodos piríticos de Aznalcóllar, Boletin Geológico y Minero, 112, 137-262, 2001.
Bea S. A., Carrera J., Soler J. M., Ayora C., Saaltink M. (2004) Simulation of Remediation Alternatives for a 137Cs Contaminated Soil. Radiochimica Acta 92, 827-833.
Bea S. A., Soler J. M., Ayora C., Carrera J., Saaltink M. W. (2004) Modelización hidrogeoquímica de suelos contaminados. In: Enresa (2004) Vas Jornadas de Investigación y Desarrollo Tecnológico en Gestión de Residuos Radioactivos, Publicación Técnica 04/2004, Vol. I, 92-103.
Bea, S.A., J. Carrera, C. Ayora, F. Batlle, M. W. Saaltink (2009), CHEPROO: A Fortran 90 Object-Oriented module to solve chemical processes in Earth science models, Comput. Geosci., 35(6), 1098-1112, doi: 10.1016/j.cageo.2008.08.010
De Simoni, M., J. Carrera, X. Sanchez-Vila, A. Guadagnini (2005), A procedure for the solution of multi-component reactive transport problems, Water Resour. Res., 41, W11410, doi:10.1029/2005WR004056.
De Simoni, M., X. Sanchez-Vila, J. Carrera, M. W. Saaltink (2007), A mixing ratios-based formulation for multicomponent reactive transport, Water Resour. Res., 43, W07419, doi:10.1029/2006WR005256.
Gámez, D., J.A., Simó, E. Vázquez-Suñé, J.M. Salvany, J. Carrera, 2005. Variación de las tasas de sedimentación en el Complejo Detrítico Superior del Delta del Llobregat (Barcelona): su relación con causas eustáticas, climáticas y antrópicas. Pp. 175-178. Geogaceta, 38, 2005.
Gamazo, P., M.W. Saaltink, J. Carrera, L. Slooten, S.A. Bea, M. Gran (2013), Modeling the influence of MgSO4 invariant points on multiphase reactive transport process during saline soil evaporation, Physics and Chemistry of the Earth, 64, 57-64, doi: 10.1016/j.pce.2013.02.001
Iribar, V., J. Carrera, E. Custodio and A. Medina, (1997). Inverse modelling of sweater intrusion in the Llobregat delta deep aquifer. Journal of Hydrology, 198 (1-4), 226-247.
Molins, S., Carrera, J., Ayora, C., Saaltink, M.W. (2004), A formulation for decoupling components in reactive transport problems, Water Resources Research, 40(10), W10301, doi: 10.1029/2003WR002970
Saaltink, M.W., J. Carrera and C. Ayora, On the behavior of approaches to simulate reactive transport, Journal of Contaminant Hydrology, 48(3-4), 213-235, 2001.
Saaltink, M.W., C. Ayora and J. Carrera (1998), A mathematical formulation for reactive transport that eliminates mineral concentrations, Water Resources Research, 34(7), 1649-1656.Saaltink, M. W., J. Carrera, C. Ayora (2001) On the behavior of approaches to simulate reactive transport, J. Contam. Hydrol., 48, 213 - 235.
Saaltink, M.W., Batlle, F., Ayora, C., Carrera, J., Olivella, S. (2004), RETRASO, a code for modeling reactive transport in saturated and unsaturated porous media, Geologica Acta, 2(3), 235-251.
Saaltink, M.W., V. Vilarrasa, F. De Gaspari, O. Silva, J. Carrera, T.S. Rötting (2013), A Method for Incorporating Equilibrium Chemical Reactions into Multiphase Flow Models for CO2 Storage, accepted by Adv. Water Resour., doi: 10.1016/j.advwatres.2013.09.013..
Saaltink, M.W, Domènech, C., Ayora, C., Carrera, J., Modelling the oxidation of sulphides in un unsaturated soil, in: Mine Water Hydrogeology and Geochemistry, Younger, P.L., Robins, N.S. (eds.), Geological Society, London, Special Publications, 198, 187-205, 2002.
Sanz, E., Custodio, E., Carrera, J.,Ayora, C., Barón, A. González, C. Modeling coastal salty springs: first aproach in carbonate media (S’Almadrava, Mallorca, Spain). 17th Salt Water Intrusion Meeting (SWIM), Delf, 2002.
Sanz, E., Custodio, E. , Carrera, J., Ayora, C., Barón, A., González, C. Modeling coastal salty springs in carbonate media (S’Almadrava, Mallorca, Spain). Second International Conference on Saltwater Intrusion and Coastal Aquifers—Monitoring, Modeling, and Management. Mérida, México, March 30-April 2, 2003 (Submitted abstract).
Slooten, L.J., Hidalgo, J.J, Carrera, J.: Parameter estimation in density dependent groundwater flow and solute transport modeling. 17th Salt Water Intrusion Meeting (SWIM), Delf, 2002.
Soler J. M., Mäder U. K. (2005) Interaction between Hyperalkaline Fluids and Rocks Hosting Repositories for Radioactive Waste: Reactive Transport
Simulations. Nuclear Science and Engineering 151, 128-133.
Soler J. M., Ayora C., Carrera J. (2004) Procesos y modelos de retención y transporte en medios fracturados de baja permeabilidad (proyecto Retrock). In: Enresa (2004) Vas Jornadas de Investigación y Desarrollo Tecnológico en Gestión de Residuos Radioactivos, Publicación Técnica 07/2004, Vol. IV, 80-92.
Soler J. M. (2003) Reactive Transport Modeling of the Interaction Between a High-pH Plume and a Fractured Marl: The Case of Wellenberg. Applied Geochemistry 18, 1555-1571.
Van Loon L. R., Wersin P., Soler J. M., Eikenberg J., Gimmi Th., Hernán P., Dewonck S., Savoye S. (2004) In-Situ Diffusion of HTO, 22Na+, Cs+ and I- in Opalinus Clay at the Mont Terri Underground Rock Laboratory. Radiochimica Acta 92, 757-763.
Wersin P., Van Loon L. R., Soler J. M., Yllera A., Eikenberg J., Gimmi Th., Hernán P., Boisson J. Y. (2004) Long-Term Diffusion Experiment at Mont Terri: First Results from Field and Laboratory Data. Applied Clay Science 26, 123-135.

Software

RETRASO

The first code for reactive transport we developed is called Retraso (REactive TRAnsport of SOlutes). It has been coupled to CodeBright so that it can handle unsaturated flow together with heat transport. It uses 1D, 2D or 3D finite elements for the spatial discretiztion and DSA (Direct Substitution Approach) or Newton-Raphson for the solution of the non-linear reactive transport equations (Saaltink et al., 2004).

VISUAL RETRASO

CHEPROO

Cheproo is a tool for simulating complex hydrobiogeochemical processes. It uses object-oriented concepts, so that it can be easily linked to a conservative transport code. Both the DSA and SIA (Sequential Iteration Approach) have been implemented (Bea et al, 2009).

CREPROOST

A new code is under development. It also uses object-oriented concepts and will be coupled to Proost, a general purpose hydrological modeling tool.

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