Multiple Particle Retention Mechanisms during Filtration in Porous Media

Santos, A.; Barros, P. H. L.

doi:10.1021/es9034792

Cited by 23 publications

(6 citation statements)

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“…activated carbon, metal oxide) by different transport mechanisms and then adhered to the grain surfaces by various attachment mechanisms for their successful removal [79,80]. Filtration is thus a complex process involving physico-chemical mechanisms and essentially depending on four major various factors: (i) filtration rate, (ii) media grain size, (iii) affinity of contaminant to bed media, and (iv) contaminant concentration.…”

Section: Mechanism Of Contaminant Removal In Fe 0 Filtersmentioning

confidence: 99%

Metallic iron for safe drinking water worldwide

Noubactep¹

2010

Chemical Engineering Journal

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a b s t r a c tA new concept for household and large-scale safe drinking water production is presented. Raw water is successively filtered through a series of sand and iron filters. Sand filters mostly remove suspended particles (media filtration) and iron filters remove anions, cations, micro-pollutants, natural organic matter, and micro-organisms including pathogens (reactive filtration). Accordingly, treatment steps conventionally achieved with flocculation, sedimentation, rapid sand filtration, activated carbon filtration, and disinfection are achieved in the new concept in only two steps. To prevent bed clogging, Fe 0 is mixed with inert materials, yielding Fe 0 /sand filters. Efficient water treatment in Fe 0 /sand filters has been extensively investigated during the past two decades. Two different contexts are particularly important in this regard: (i) underground permeable reactive barriers and (ii) household water filters. In these studies, the process of aqueous iron corrosion in a packed bed was proven very efficient for unspecific aqueous contaminant removal. Been based on a chemical process (iron corrosion), efficient water treatment in Fe 0 beds is necessarily coupled with a slow flow rate. Therefore, for large communities several filters should work in parallel to produce enough water for storage and distribution. It appears that water filtration through Fe 0 /sand filters is an efficient, affordable, a flexible technology for the whole world.

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Section: Mechanism Of Contaminant Removal In Fe 0 Filtersmentioning

confidence: 99%

Metallic iron for safe drinking water worldwide

Noubactep¹

2010

Chemical Engineering Journal

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“…During the bacterial transport process, retention of bacteria may take place due to straining and/or attachment to solid surfaces. The extent to which bacteria are retained by straining depends on the ratio of the bacteria to porous medium grain diameters, the shape and size irregularity and surface roughness of porous media, the rate of water flow, and bacterial concentration [ Bradford and Bettahar , ; Bradford et al ., ; Díaz et al ., ; Ding et al ., ; Santos and Barros , ; Stevik et al ., ; Tufenkji et al ., ]. The attachment of bacteria is affected by a number of factors, including the surface charges of both the porous media and the bacteria, the cell surface hydrophobicity (CSH), the composition of the cell surface (e.g., lipopolysaccharide, extracellular polymeric substances, outer membrane proteins, flagella, and fimbriae), physical and geochemical properties of the solid surfaces, and groundwater chemistry (e.g., ionic strength, pH, dissolved organic matter (DOM), etc.)…”

Section: Introductionmentioning

confidence: 99%

Effect of low‐concentration rhamnolipid biosurfactant on Pseudomonas aeruginosa transport in natural porous media

Liu

Zhong

Jiang

et al. 2017

Water Resources Research

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Enhanced transport of microbes in subsurface is a focus in bioaugmentation applications for remediation of groundwater. In this study, the effect of low‐concentration monorhamnolipid biosurfactant on transport of Pseudomonas aeruginosa ATCC 9027 in natural porous media (silica sand and a sandy soil) with or without hexadecane as the nonaqueous phase liquids (NAPLs) was studied with miscible‐displacement experiments using artificial groundwater as the background solution. Transport of two types of cells was investigated, glucose‐grown and hexadecane‐grown cells with lower and higher cell surface hydrophobicity (CSH), respectively. A clean‐bed colloid deposition model was used to calculate deposition rate coefficients (k) for quantitative assessment on the effect of the rhamnolipid on the transport. In the absence of NAPLs, significant cell retention was observed in the sand (81% and 82% for glucose‐grown and hexadecane‐grown cells, respectively). Addition of low‐concentration rhamnolipid enhanced cell transport, with 40 mg/L of rhamnolipid reducing retention to 50% and 60% for glucose‐grown and hexadecane‐grown cells, respectively. The k values for both glucose‐grown and hexadecane‐grown cells correlated linearly with rhamnolipid‐dependent CSH quantitatively measured using a bacterial‐adhesion‐to‐hydrocarbon method. Retention of cells by the soil was nearly complete (>99%). Forty milligrams per liter of rhamnolipid reduced the retention to 95%. The presence of NAPLs in the sand enhanced the retention of hexadecane‐grown cells with higher CSH. Transport of cells in the presence of NAPLs was enhanced by rhamnolipid at all concentrations tested, and the relative enhancement was greater than in the absence of NAPLs. This study shows the importance of hydrophobic interaction on bacterial transport in natural porous media and the potential of using low‐concentration rhamnolipid for facilitating cell transport in subsurface for bioaugmentation efforts.

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“…In a filtration process, the most effective particle capture mechanism depends on many parameters, such as flow velocity, particle concentration and fluid composition, particle and pore size distributions, and interaction energies (Santos and Barros, 2010). The interac-Investigating particle behavior in porous media requires selecting a model to describe the porous matrix.…”

Section: Introductionmentioning

confidence: 99%