Miscible displacement of salinity fronts: Implications for colloid mobilization

Flury, Markus; Harsh, James B.; Mathison, Jon B.

doi:10.1029/2003wr002491

Cited by 3 publications

(2 citation statements)

References 19 publications

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“…This in turn causes more ions to diffuse from the intra‐aggregate water into the interaggregate water in response to the enhanced gradient in ionic strength. Decreasing ionic strength leads to an increasing release of particles from the aggregate surfaces and an associated higher particle concentration in the effluent (Grolimund et al, 1996; Flury et al, 2003). Observed dynamics of particle concentration and electrical conductivity of the effluent for the four experiments most abundant in drain outflow are given in Fig.…”

Section: Resultsmentioning

confidence: 99%

Effects of Manure Application and Plowing on Transport of Colloids and Phosphorus to Tile Drains

Schelde¹,

Jonge²,

Kjærgaard³

et al. 2006

Vadose Zone Journal

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Preferential flow and particle-facilitated transport may be largely responsible for observed leaching patterns of strongly sorbing contaminants such as phosphorus. A series of field experiments was performed to investigate the effects of slurry application and plowing on the subsurface transport of colloids and P. Two 25-m 2 plots at a structured sandy loam site were irrigated on six occasions during 1 yr. Effluent sampled in tile drains below the plots was analyzed for turbidity and fractions of dissolved (,0.24 mm) and particulate inorganic and organic P. The observed flow conditions indicated macropore flow. The particle concentration in the effluent was initially high, peaking before flow peak, and later gradually decreased with flow rate. The colloid leaching pattern was attributed to an initial depletion of high colloid concentrations in the pore water and an eventual diffusion-limited release of colloids from immobile intra-aggregate water to mobile water. Seasonal variability and management practices caused significant variations in the leaching of P forms. After slurry application dissolved P dominated P loss to the drains. At the events in autumn and winter, particle-facilitated transport of P came to dominate over dissolved P transport, reaching a maximum of 80% of P loss. Results suggested that plowing increases the risk of particle-facilitated and dissolved P leaching in rainstorms shortly after the inversion of the soil. We observed an almost fourfold increase in the leaching of P per volume of leachate when comparing irrigation experiments before and after plowing. Amounts of P associated with particulate matter in drain water were constant within events, but varying between storms. For Danish structured clay soils, P density in leached particles was found to range between a maximum of 6 mg P g 21 for soils having recently been fertilized and an approximate minimum of 3 mg P g 21 for soils not recently fertilized.

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Section: Resultsmentioning

confidence: 99%

Effects of Manure Application and Plowing on Transport of Colloids and Phosphorus to Tile Drains

Schelde¹,

Jonge²,

Kjærgaard³

et al. 2006

Vadose Zone Journal

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“…Flury et al . [] reported that colloids can be mobilized when low ionic strength pore water displaces high ionic strength pore water. Bradford et al .…”

Section: Introductionmentioning

confidence: 99%

Retention and remobilization of colloids during steady-state and transient two-phase flow

et al. 2013

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[1] In this work, we study colloid transport through a porous medium under steady-state and transient two-phase flow conditions. The porous medium was a PDMS micromodel and the immiscible fluids were water and fluorinert-FC43. Given that the micromodel was hydrophobic, fluorinert was the wetting phase, and water was the nonwetting phase. We used hydrophilic fluorescent microspheres (dispersed in water) with mean diameter of 300 nm. We directly observed colloid movement and fluids distribution within pores of the micromodel using a confocal laser scanning microscope. We also obtained concentration breakthrough curves by measuring the fluorescence intensity in the outlet of the micromodel. The breakthrough curves showed that, under steady-state flow at different water saturations, more colloids were retained at lower saturations. Our visualization results suggested that the enhanced attachment was due to the retention of colloids onto fluorinertwater interfaces (FWIs) and fluorinert-water-solid contact lines (FWSCs). At the end of a steady-state two-phase flow experiment, we changed the micromodel saturation by injecting either water (drainage) or fluorinert (imbibition). We found remobilization of colloids during imbibition events, but no remobilization was observed during drainage. Visualization showed that colloids deposited on solid-water interfaces (SWIs) were dislodged by moving FWSCs during imbibition. We simulated breakthrough curves by modeling colloids interactions with SWIs and FWIs separately. Remobilization of colloids attached to SWI was modeled as a first-order kinetic process and the rate coefficient was assumed proportional to temporal rate of change of saturation. Colloids attachment to and detachment from FWIs were modeled as an equilibrium process. Generally, good agreements between experimental results and simulation were obtained. This is the first study of colloid transport in two-phase flow, where pore-scale visualization, breakthrough concentration measurement, and modeling of results are combined.

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Effect of water-dispersible colloids in manure on the transport of dissolved and colloidal phosphorus through soil column

Zang¹,

Tian²,

Liu³

et al. 2011

Afr. J. Agric. Res.

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Miscible displacement of salinity fronts: Implications for colloid mobilization

Cited by 3 publications

References 19 publications

Effects of Manure Application and Plowing on Transport of Colloids and Phosphorus to Tile Drains

Effects of Manure Application and Plowing on Transport of Colloids and Phosphorus to Tile Drains

Retention and remobilization of colloids during steady-state and transient two-phase flow

Effect of water-dispersible colloids in manure on the transport of dissolved and colloidal phosphorus through soil column

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