Virus Transport and Survival in Saturated and Unsaturated Flow through Soil Columns

Powelson, David K.; Simpson, James; Gerba, Charles P.

doi:10.2134/jeq1990.00472425001900030008x

Cited by 108 publications

(74 citation statements)

References 60 publications

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“…The presence of the AWI (air-water interface) under unsaturated conditions has been suggested by several researchers to be the dominant removal mechanism responsible for the increased removal of colloidal particles, including viruses, in unsaturated systems (Powelson and Mills, 1996;Jin et al, 2000). Powelson et al (1990) have shown MS2, in particular, to be strongly influenced by this and ultimately inactivated at the AWI. Hence, this mechanism may have played a significant early role in the MS2 inactivation between the infiltrative surface and the 0.35 m depth plane, particularly given the disparity in recorded concentrations between MS2 and the other two phages in this trial.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

The attenuation of microorganisms in on-site wastewater effluent discharged into highly permeable subsoils

O'Luanaigh

Gill

Misstear

et al. 2012

Journal of Contaminant Hydrology

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Please cite this article as: O'Luanaigh, N.D., Gill, L.W., Misstear, B.D.R., Johnston, P.M., The attenuation of microorganisms in on-site wastewater effluent discharged into highly permeable subsoils, Journal of Contaminant Hydrology (2012Hydrology ( ), doi: 10.1016Hydrology ( /j.jconhyd.2011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.The attenuation of microorganisms in on-site wastewater effluent discharged into highly permeable subsoils ABSTRACTAn extensive field study on percolation areas receiving both septic tank and secondary treated on-site effluents from single houses in Ireland was carried out to investigate the attenuation capacity of highly permeable subsoils with respect to E.coli bacteria and spiked bacteriophages (MS2, ΦX174 and PR772). The development of biomats across the percolation areas receiving the secondary effluent was restricted compared to the percolation area receiving septic tank effluent, promoting a much higher areal hydraulic loading which created significant differences in the potential microbiological loading to groundwater.Greatest E.coli removal in the subsoil occurred within the first 0.35 m of unsaturated subsoil for all effluent types. Analysis showed, however, that more evidence of faecal contamination occurred at depth in the subsoils receiving secondary treated effluents than that receiving A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 septic tank effluent, despite the lower bacterial influent load. All three bacteriophages were reduced to their minimum detection limit (< 10 PFU/mL) at a depth of 0.95 m below the percolation trenches receiving septic tank effluent, although isolated incidences of ΦX174 and PR772 were measured below one trench. However again, slightly higher breakthroughs of MS2 and PR772 contamination were detected at the same depth under the trenches receiving secondary treated effluent.

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Section: Accepted M Manuscriptmentioning

confidence: 99%

The attenuation of microorganisms in on-site wastewater effluent discharged into highly permeable subsoils

O'Luanaigh

Gill

Misstear

et al. 2012

Journal of Contaminant Hydrology

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“…MS-2 is a single-stranded RNA coliphage with a 25-nm diameter and an isoelectric point of 3.9 [13]. E. coli strain K12 was used as the host for the bacteriophage.…”

Section: Virus Tracermentioning

confidence: 99%

“…Three replicate vials were sacrificed periodically to enumerate the pathogen surrogates. Microorganisms were extracted with 20 mL of sterile PBS (for E. coli) [34] or sterile 1.5% beef extract, pH 8.7 (for MS-2) [13] added to each vial, after which the vials were placed on a reciprocal shaker for 10 min. GFP E. coli and MS-2 bacteriophage were enumerated as described above.…”

Section: Survival In Soil and Stementioning

confidence: 99%

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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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“…Several authors have investigated the generation and transport of colloids in the unsaturated zone (Kaplan et al 1996c, Kaplan et al 1993, Amrhein et al 1993, Powelson et al 1990). Based on their results, it is still not clear what mechanisms control the transport of colloids in the subsurface, especially under semiarid conditions.…”

Section: Colloid Mobility Under Unsaturated Conditionsmentioning

confidence: 99%

Colloid suspension stability and transport through unsaturated porous media

McGraw¹,

Kaplan²

1997

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Executive SummaryContaminant transport is traditionally modeled in a two-phase system: a mobile aqueous phase and an immobile solid phase. Over the last 15 years, there has been an increasing awareness of a third, mobile solid phase. This mobile solid phase, or mobile colloids, are organic or inorganic submicron-sized particles that move with groundwater flow. When colloids are present, the net effect on radionuclide transport is that radionuclides can move faster through the system. It is not known whether mobile colloids exist in the subsurface environment of the Hanford Site. Furthermore, it is not known if mobile colloids would likely exist in a plume emanating from a Low Level Waste (LLW) disposal site. No attempt was made in this study to ascertain whether colloids would form. Instead, experiments and calculations were conducted to evaluate the likelihood that colloids, if formed, would remain in suspension and move through saturated and unsaturated sediments.The objectives of this study were to evaluate three aspects of colloid-facilitated transport of radionuclides as they specifically relate to the LLW Performance Assessment. These objectives were: 1) determine if the chemical conditions likely to exist in the near and far field of the proposed disposal site are prone to induce flocculation (settling of colloids from suspension) or dispersion of naturally occurring Hanford colloids, 2) identify the important mechanisms likely involved in the removal of colloids from a Hanford sediment, and 3) determine if colloids can move through unsaturated porous media.Mobile colloid formation is commonly described as a three-step process: genesis, stabilization, and transport. Colloid genesis describes how the micron-sized particles are formed in groundwater. Stabilization describes how the colloids are brought into suspension, which is a function of the colloid and groundwater chemical composition and water flow (kinetic) forces. Transport describes how the suspended colloid move through the porous media or are retained by the porous media by physical forces (such as diffusion, straining, or gravitation settling) or physicochemical attraction of the colloid to the matrix.As the second step in mobile colloid formation indicates, colloids must remain in suspension, i.e., not flocculate, in order to be transported with groundwater flow. A series of batch experiments was conducted to identify the chemical conditions where dispersion and flocculation (settling out of suspension) of Hanford sediment colloids (

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Virus Transport and Survival in Saturated and Unsaturated Flow through Soil Columns

Cited by 108 publications

References 60 publications

The attenuation of microorganisms in on-site wastewater effluent discharged into highly permeable subsoils

The attenuation of microorganisms in on-site wastewater effluent discharged into highly permeable subsoils

Transport of Pathogen Surrogates in Soil Treatment Units: Numerical Modeling

Colloid suspension stability and transport through unsaturated porous media

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