Effect of regenerated soil structure on unsaturated transport of Escherichia coli and bromide

Safadoust, A.; Mahboubi, A.A.; Mosaddeghi, Mohammad Reza; Gharabaghi, Bahram; Unc, Adrian; Voroney, Paul; Heydari, Ali Akbar

doi:10.1016/j.jhydrol.2012.02.003

Cited by 37 publications

(25 citation statements)

References 52 publications

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“…Model fits were good with R 2 values ranging from 0.97 to 0.99. The dispersivity value calculated by CXTFIT 2.1 was approximately 0.289 cm, which is typical for these types of experiments, and is consistent with the range of values (0.06 to 0.816 cm) reported by others [38][39][40][41][42][43]. Next, the hydraulics of the HYDRUS model domain was calibrated using the conservative tracer breakthrough curves (BTC).…”

Section: Resultssupporting

confidence: 83%

Transport of Pathogen Surrogates in Soil Treatment Units: Numerical Modeling

Morales

Atoyan

Amador

et al. 2014

Water

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Abstract:Segmented mesocosms (n = 3) packed with sand, sandy loam or clay loam soil were used to determine the effect of soil texture and depth on transport of two septic tank effluent (STE)-borne microbial pathogen surrogates-green fluorescent protein-labeled E. coli (GFPE) and MS-2 coliphage-in soil treatment units. HYDRUS 2D/3D software was used to model the transport of these microbes from the infiltrative surface. Mesocosms were spiked with GFPE and MS-2 coliphage at 10 5 cfu/mL STE and 10 5 -10 6 pfu/mL STE, respectively. In all soils, removal rates were >99.99% at 25 cm. The transport simulation compared (1) optimization; and (2) trial-and-error modeling approaches. Only slight differences between the transport parameters were observed between these approaches. Treating both the die-off rates and attachment/detachment rates as variables resulted in an overall better model fit, particularly for the tailing phase of the experiments. Independent of the fitting procedure, attachment rates computed by the model were higher in sandy and sandy loam soils than clay, which was attributed to unsaturated flow conditions at lower water content in the coarser-textured soils. Early breakthrough of the bacteria and virus indicated the presence of preferential flow in the system in the structured clay loam soil, resulting in faster movement of water and microbes through the soil relative to a conservative tracer (bromide).

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Section: Resultssupporting

confidence: 83%

Transport of Pathogen Surrogates in Soil Treatment Units: Numerical Modeling

Morales

Atoyan

Amador

et al. 2014

Water

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“…There were no significant differences in the performance of the soil in filtering E. coli between the drip irrigated system with canal water and furrow irrigated treatment with canal water. The soil filtering described here is for lateral flow of water, in some ways analogous to previous published research on soil filtering of bacteria under vertical flow of water in soil and water columns (Jamieson et al, 2002;Unc and Goss, 2004;Mankin et al, 2007;Semenov et al, 2009;Safacoust et al, 2011Safacoust et al, , 2012. Regardless of initial counts, concentrations were typically highest near the drip tape for SDI or water's edge of furrow irrigation, lower at the points halfway between the drip tape/furrow and onion bulbs, and lowest at spots adjacent to the onions.…”

Section: Soil Filtration Of E Colimentioning

confidence: 57%

“…The path followed by water determines the direction of transport of bacteria. A study to understand the fate and transport of E. coli in soil columns showed that both the soil texture and structure affected the transport properties of the soil including dispersivity and attachment and straining coefficients (Safacoust et al, 2012). Semenov et al (2009) found limited E. coli movement in the field beyond the application layer with surface application of E. coli.…”

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confidence: 99%

Drip vs. Furrow Irrigation in the Delivery of Escherichia coli to Onions

Shock¹,

Reitz²,

Roncarati³

et al. 2016

Appl. Eng. Agric.

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“…2004). Filtration in soil depends on porosity, water velocity, pore size distribution, pore homogeneity, adsorption, filtration, sedimentation, and bacterial activity in the soil (Safadoust et al, 2012;Mosaddeghi et al, 2009). …”

Section: Introductionmentioning

confidence: 99%