Reactive dispersive contaminant transport in coastal aquifers: Numerical simulation of a reactive Henry problem

Handle URI:
http://hdl.handle.net/10754/599454
Title:
Reactive dispersive contaminant transport in coastal aquifers: Numerical simulation of a reactive Henry problem
Authors:
Nick, H.M.; Raoof, A.; Centler, F.; Thullner, M.; Regnier, P.
Abstract:
The reactive mixing between seawater and terrestrial water in coastal aquifers influences the water quality of submarine groundwater discharge. While these waters come into contact at the seawater groundwater interface by density driven flow, their chemical components dilute and react through dispersion. A larger interface and wider mixing zone may provide favorable conditions for the natural attenuation of contaminant plumes. It has been claimed that the extent of this mixing is controlled by both, porous media properties and flow conditions. In this study, the interplay between dispersion and reactive processes in coastal aquifers is investigated by means of numerical experiments. Particularly, the impact of dispersion coefficients, the velocity field induced by density driven flow and chemical component reactivities on reactive transport in such aquifers is studied. To do this, a hybrid finite-element finite-volume method and a reactive simulator are coupled, and model accuracy and applicability are assessed. A simple redox reaction is considered to describe the degradation of a contaminant which requires mixing of the contaminated groundwater and the seawater containing the terminal electron acceptor. The resulting degradation is observed for different scenarios considering different magnitudes of dispersion and chemical reactivity. Three reactive transport regimes are found: reaction controlled, reaction-dispersion controlled and dispersion controlled. Computational results suggest that the chemical components' reactivity as well as dispersion coefficients play a significant role on controlling reactive mixing zones and extent of contaminant removal in coastal aquifers. Further, our results confirm that the dilution index is a better alternative to the second central spatial moment of a plume to describe the mixing of reactive solutes in coastal aquifers. © 2012 Elsevier B.V.
Citation:
Nick HM, Raoof A, Centler F, Thullner M, Regnier P (2013) Reactive dispersive contaminant transport in coastal aquifers: Numerical simulation of a reactive Henry problem. Journal of Contaminant Hydrology 145: 90–104. Available: http://dx.doi.org/10.1016/j.jconhyd.2012.12.005.
Publisher:
Elsevier BV
Journal:
Journal of Contaminant Hydrology
Issue Date:
Feb-2013
DOI:
10.1016/j.jconhyd.2012.12.005
PubMed ID:
23334209
Type:
Article
ISSN:
0169-7722
Sponsors:
This work was generously supported by the King Abdullah University of Science and Technology (KAUST), as part of the SOWACOR project, by the Government of the Brussels-Capital Region (Brains Back to Brussels award to P. Regnier), and by the Helmholtz Association via grant VH-NG-338 (GReaTMoDE).
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Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorNick, H.M.en
dc.contributor.authorRaoof, A.en
dc.contributor.authorCentler, F.en
dc.contributor.authorThullner, M.en
dc.contributor.authorRegnier, P.en
dc.date.accessioned2016-02-28T05:51:26Zen
dc.date.available2016-02-28T05:51:26Zen
dc.date.issued2013-02en
dc.identifier.citationNick HM, Raoof A, Centler F, Thullner M, Regnier P (2013) Reactive dispersive contaminant transport in coastal aquifers: Numerical simulation of a reactive Henry problem. Journal of Contaminant Hydrology 145: 90–104. Available: http://dx.doi.org/10.1016/j.jconhyd.2012.12.005.en
dc.identifier.issn0169-7722en
dc.identifier.pmid23334209en
dc.identifier.doi10.1016/j.jconhyd.2012.12.005en
dc.identifier.urihttp://hdl.handle.net/10754/599454en
dc.description.abstractThe reactive mixing between seawater and terrestrial water in coastal aquifers influences the water quality of submarine groundwater discharge. While these waters come into contact at the seawater groundwater interface by density driven flow, their chemical components dilute and react through dispersion. A larger interface and wider mixing zone may provide favorable conditions for the natural attenuation of contaminant plumes. It has been claimed that the extent of this mixing is controlled by both, porous media properties and flow conditions. In this study, the interplay between dispersion and reactive processes in coastal aquifers is investigated by means of numerical experiments. Particularly, the impact of dispersion coefficients, the velocity field induced by density driven flow and chemical component reactivities on reactive transport in such aquifers is studied. To do this, a hybrid finite-element finite-volume method and a reactive simulator are coupled, and model accuracy and applicability are assessed. A simple redox reaction is considered to describe the degradation of a contaminant which requires mixing of the contaminated groundwater and the seawater containing the terminal electron acceptor. The resulting degradation is observed for different scenarios considering different magnitudes of dispersion and chemical reactivity. Three reactive transport regimes are found: reaction controlled, reaction-dispersion controlled and dispersion controlled. Computational results suggest that the chemical components' reactivity as well as dispersion coefficients play a significant role on controlling reactive mixing zones and extent of contaminant removal in coastal aquifers. Further, our results confirm that the dilution index is a better alternative to the second central spatial moment of a plume to describe the mixing of reactive solutes in coastal aquifers. © 2012 Elsevier B.V.en
dc.description.sponsorshipThis work was generously supported by the King Abdullah University of Science and Technology (KAUST), as part of the SOWACOR project, by the Government of the Brussels-Capital Region (Brains Back to Brussels award to P. Regnier), and by the Helmholtz Association via grant VH-NG-338 (GReaTMoDE).en
dc.publisherElsevier BVen
dc.subjectDensity driven flowen
dc.subjectDilution indexen
dc.subjectDispersionen
dc.subjectKeywordsen
dc.subjectNode-centered finite-volume-finite-element methoden
dc.subjectReactive transporten
dc.subjectSubmarine groundwater dischargeen
dc.titleReactive dispersive contaminant transport in coastal aquifers: Numerical simulation of a reactive Henry problemen
dc.typeArticleen
dc.identifier.journalJournal of Contaminant Hydrologyen
dc.contributor.institutionUtrecht University, Utrecht, Netherlandsen
dc.contributor.institutionHelmholtz Zentrum f?r Umweltforschung, Leipzig, Germanyen
dc.contributor.institutionUniversité libre de Bruxelles (ULB), Brussels, Belgiumen

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