Pore-scale analysis on the effects of compound-specific dilution on transient transport and solute breakthrough

Massimo Rolle, Peter Kitanidis

    Research output: Contribution to conferenceConference abstract for conferenceResearchpeer-review

    94 Downloads (Pure)


    Compound-specific diffusivities significantly impact solute transport and mixing at different scales. Although diffusive processes occur at the small pore scale, their effects propagate and remain important at larger macroscopic scales [1]. In this pore-scale modeling study in saturated porous media we show that compound-specific effects are important not only at steady-state and for the lateral displacement of solutes with different diffusivities but also for transient transport and solute breakthrough [2]. We performed flow and transport simulations in two-dimensional pore-scale domains with different arrangement of the solid grains leading to distinct characteristics of flow
    variability and connectivity, representing mildly and highly heterogeneous porous media, respectively. The results obtained for a range of average velocities representative of groundwater flow (0.1–10 m/day), show significant effects of aqueous diffusion on solute breakthrough curves. However, the magnitude of such effects can be masked by the flux-averaging approach used to measure solute breakthrough and can hinder the correct interpretation of the true dilution of different solutes. We propose, as a metric of mixing, a transient flux-related dilution index that allows quantifying the evolution of solute dilution at a given position along the main flow direction. For the different solute
    transport scenarios we obtained dilution breakthrough curves that complement and add important information to traditional solute breakthrough curves. Such dilution breakthrough curves allow capturing the compound-specific mixing of the different solutes and provide useful insights on the interplay between advective and diffusive processes, mass transfer limitations, and incomplete mixing in the heterogeneous pore-scale domains. The quantification of dilution for conservative solutes is in good agreement with the outcomes of mixing-controlled reactive transport simulations, in which the mass and concentration breakthrough curves of the product of an instantaneous transformation of two initially segregated reactants were used as measures of reactive mixing.
    Original languageEnglish
    Publication date2015
    Number of pages1
    Publication statusPublished - 2015
    Event7th International Conference on Porous Media & Annual Meeting - Padova, Italy
    Duration: 18 May 201521 May 2015
    Conference number: 7


    Conference7th International Conference on Porous Media & Annual Meeting


    Dive into the research topics of 'Pore-scale analysis on the effects of compound-specific dilution on transient transport and solute breakthrough'. Together they form a unique fingerprint.

    Cite this