Modeling the influence of an artificial macropore in sandy columns on flow and solute transfer

Lamy, Edvina; Lassabatère, Laurent; Bechet, Béatrice; Andrieu, H.

doi:10.1016/j.jhydrol.2009.07.048

Cited by 49 publications

(42 citation statements)

References 42 publications

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“…An understanding of pollutant transfer focuses on how water infiltrates—similarly through all pores or preferentially through certain pores. Flow patterns may exert considerable impact on the transfer of nonreactive solutes (Lamy et al, 2009), and maybe even more so for the transfer of reactive solutes (Lassabatere et al, 2004, 2007). Further studies will focus on characterizing BOF slag hydrodispersive parameters (i.e., parameters related to solute transport via water), along with chemical reactions in water and the related pollutant release by BOF slag (Deneele et al, 2008; Legret et al, 2008; Chaurand et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

Hydrodynamic Characterization of Basic Oxygen Furnace Slag through an Adapted BEST Method

Yılmaz¹,

Lassabatère²,

Angulo-Jaramillo

et al. 2010

Vadose Zone Journal

107

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Newer urban soils, frequently composed of several types of anthropogenic materials, may contain basic oxygen furnace (BOF) slag, which is a steel industry byproduct and considered a potential alternative material for road construction. An understanding of the flow and solute transfer processes through urban soils thus requires hydraulic characterization of these materials. The BEST (Beerkan Estimation of Soil Transfer Parameters) algorithm serves to estimate the full set of unsaturated soil properties by means of conducting an inverse analysis of Beerkan water infiltration data. This study aimed at characterizing unsaturated hydraulic properties of the BOF slag and its evolution during a 1‐yr period through water infiltration experiments and use of an adapted BEST method for inverse analysis. Results indicate the evolution with time of BOF slag hydraulic parameters due to their physicochemical changes when exposed to rainfall events. Moreover, the findings of this study highlight the initial spatial variability of hydrodynamic characteristics, which after a certain period shifts to mostly homogeneous behavior. This study has contributed to the hydrodynamic characterization of BOF slag by providing hydraulic conductivity and water retention curves, as required for modeling water and thus solute transfer processes vs. time, which is relevant to BOF slag reuse and environmental considerations.

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Section: Discussionmentioning

confidence: 99%

Hydrodynamic Characterization of Basic Oxygen Furnace Slag through an Adapted BEST Method

Yılmaz¹,

Lassabatère²,

Angulo-Jaramillo

et al. 2010

Vadose Zone Journal

107

View full text Add to dashboard Cite

show abstract

“…However, hydraulic performance may not be the sole criterion to be investigated, and considerable care must also be taken regarding the transfer of pollutants carried by infiltrating water (Mikkelsen et al, 1994;Legret and Pagotto, 1999). In addition, the modification of flow may exert considerable impact on the transfer of both nonreactive solutes (Lamy et al, 2009) and reactive solutes (Lassabatere et al, 2004;Lassabatere et al, 2007). Regarding pollutant transfers, decreasing flow velocities may be useful for their retention.…”

Section: Discussionmentioning

confidence: 99%

Effect of the settlement of sediments on water infiltration in two urban infiltration basins

Lassabatère¹,

Angulo-Jaramillo

Goutaland³

et al. 2010

Geoderma

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“…For the solute transport simulation, we assumed that solute transport is governed by the advection–dispersion equation:

\begin{matrix} \frac{\partial θ C_{w}}{\partial t} = \nabla \cdot [θ u C_{w} + θ D {\nabla C}_{w}] \end{matrix}

where C w is solute concentration in the water phase [M L −3 ], u is the pore water velocity vector [L T −1 ], and D is the local‐scale dispersion coefficient tensor (L 2 T −1 ), usually defined as

D = (α_{normalT} | boldu | + D_{m, eff}) I + (α_{normalL} - α_{normalT}) \frac{u {boldu}^{normalT}}{| u |}

where ‖ u ‖ = √( uu T ) is the Euclidean norm of the pore water velocity vector, α L and α T are the longitudinal and transverse dispersivities, respectively, D m,eff is the effective molecular diffusion coefficient, and I is the identity matrix. We set α L to the mean grain size and α T to 1/10 of α L , which are typical values reported for saturated unconsolidated homogenous porous media (e.g., (Greiner et al, 1997; Yoon et al, 2008; Lamy et al, 2009)). The diffusion coefficient D m of Gd‐DTPA 2− in water at 25°C was assumed to be 0.4 × 10 −9 m 2 s −1 (Osuga and Han, 2004) and was multiplied by the tortuosity factor evaluated as a function of water content using the relationship of Millington and Quirk (1961) to obtain D m,eff…”

Section: Methodsmentioning

confidence: 99%

Water Flow Monitored by Tracer Transport in Natural Porous Media Using Magnetic Resonance Imaging

Haber‐Pohlmeier

Bechtold

Stapf

et al. 2010

Vadose Zone Journal

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Magne c resonance imaging (MRI) was applied to the study of fl ow processes in model and natural soil cores. Flow veloci es in soils are mostly too slow to be monitored directly by MRI fl ow velocity imaging. Therefore, we used for the fi rst me diethylenetriaminepentaacetate in the form Gd-DTPA 2− as a tracer in spin echo mul slice imaging protocols with strong weigh ng of longitudinal relaxa on me T 1 for probing slow fl ow veloci es in soils. Apart from its chemical stability, the main advantage of Gd-DTPA 2− is the anionic net charge in neutral aqueous solu on. We showed that this property hinders adsorp on at soil mineral surfaces and therefore retarda on. We found that Gd-DTPA 2− is a very convenient conserva ve tracer for the inves ga on of fl ow processes in model and natural soil cores. With respect to the fl ow processes in the coaxial model soil column and the natural soil column, we observed totally diff erent fl ow pa erns. In the fi rst case, the tracer plume moved quite homogeneously in the inner highly conduc ve core only and the migra on into the outer fi ne material was very limited. A numerical forward simula on based on independently obtained parameters showed good agreement between experiment and simula on and thus proves the convenience of Gd-DTPA as a tracer in MRI for soil physical inves ga ons. The natural soil core, in contrast, showed a fl ow pa ern characterized by preferen al paths, avoiding dense regions and preferring loose structures. In the case of the simpler model column, the local fl ow veloci es were also calculated by applying a peak tracking algorithm.Abbrevia ons: DTPA, diethylenetriaminepentaacetate; MRI, magne c resonance imaging; NMR, nuclear magne c resonance; rf, radiofrequency; SEMS, spin-echo mul slice.Flow processes in soils control the water and nutrient supply in plants, contaminant transport, and the recharging of aquifers. Natural soils are heterogeneous media with locally varying grain size, pore size, and pore geometry. In addition, highly conductive structures like wormholes and decomposed roots are present. All these factors lead to so-called preferential pathways, along which water fl ows faster vertically than expected from the average fl ow velocity v av [(volume fl ow rate/area)/water content: v av = (Q/A)/θ = J w /θ] but from which water can also diff use laterally into neighboring small-pore-size regions. All these processes can strongly aff ect water redistribution in soils, its bioavailability for plants, and transport of contaminants Clothier et al., 2008). Classical investigations of such processes have been invasive and not temporally resolved. For example, soil cores are infi ltrated with dyes and aft erward sliced and photographed, so that only the static result of fl ow processes can be observed (Wehrhahn et al., 2007). Th e direct observation of such processes in situ is diffi cult due to the opaque nature of the systems. Th erefore, during the past two decades, tomographic methods have become popular for the investigation of soils and soil-r...

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Modeling the influence of an artificial macropore in sandy columns on flow and solute transfer

Cited by 49 publications

References 42 publications

Hydrodynamic Characterization of Basic Oxygen Furnace Slag through an Adapted BEST Method

Hydrodynamic Characterization of Basic Oxygen Furnace Slag through an Adapted BEST Method

Effect of the settlement of sediments on water infiltration in two urban infiltration basins

Water Flow Monitored by Tracer Transport in Natural Porous Media Using Magnetic Resonance Imaging

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