## Abstract

Discrepancies between classical model (CM) predictions and experimental data for deep bed filtration (DBF) have been reported by various authors. In order to understand these discrepancies, an analytic continuum model for DBF is proposed. In this model, a filter coefficient is attributed to each distinct retention mechanism (straining, diffusion, gravity interception, etc.). It was shown that these coefficients generally cannot be merged into an effective filter coefficient, as considered in the CM. Furthermore, the derived analytic solutions for the proposed model (PM) were applied for fitting experimental data, and a very good agreement between experimental data and PM predictions were obtained. Comparison of the obtained results with empirical correlations allowed identifying the dominant retention mechanisms. In addition, it was shown that the larger the ratio of particle to pore sizes, the more intensive the straining mechanism and the larger the discrepancies between experimental data and CM predictions. Finally, the CM and PM were compared via statistical analysis. The obtained \(p\) values allow concluding that the PM should be preferred especially when straining plays an important role.

This is a preview of subscription content, log in to check access.

## References

Alvarez, A.C.: Inverse problems for deep bed filtration in porous media. Ph.D. thesis, IMPA, Rio de Janeiro (2004)

Bradford, S.A., Abriola, L.M.: Dissolution of residual tetrachloroethylene in fractional wettability porous media: incorporation of interfacial area estimates. Water Resour. Res.

**37**, 1183–1195 (2001)Bradford, S.A., Bettahar, M.: Concentration dependent transport of colloids in saturated porous media. J. Contam. Hydrol.

**82**, 99–117 (2006)Bradford, S.A., Yates, S.R., Bettahar, M., Simunek, J.: Physical factors affecting the transport and fate of colloids in saturated porous media. Water Resour. Res.

**38**(12), 1327 (2002)Bradford, S.A., Simunek, J., Bettahar, M., van Genuchten, M.Th., Yates, S.R.: Modeling colloid attachment, straining and exclusion in saturated porous media. Environ. Sci. Technol.

**37**, 2242–2250 (2003)Bradford, S.A., Bettahar, M., Simunek, J., van Genuchten, M.Th.: Straining and attachment of colloids in physically heterogeneous porous media. Vadose Zone J.

**3**, 384–394 (2004)Draper, N.R., Smith, H.: Applied Regression Analysis, 3rd edn. Wiley, New York (1967)

Elimelech, M., Gregory, J., Jia, X., Willians, R.A.: Particle Deposition & Aggregation. Butterworth Heinemann, Portsmouth (1995)

Herzig, J.P., Leclerc, D.M., Le Goff, P.: Flow of suspension through porous media—application to deep bed filtration. Ind. Eng. Chem.

**62**(5), 8–35 (1970)Israelachvili, J.: Intermolecular & Surface Forces. 2nd edn. Elsevier, New York; Academic Press, London (2007)

Ives, K.J., Pienvichitr, V.: Kinetics of the filtration of dilute suspensions. Chem. Eng. Sci.

**20**, 965 (1965)Iwasaki, T.: Some notes on sand filtration. J. Am. Water Works Assoc.

**29**, 1591–1602 (1937)Maroudas, A.: Clarification of suspensions: a study of particle deposition in granular filter media. Ph.D. thesis, University of London, London (1961)

Maroudas, A.: Particle deposition in granular filter media, Pt II. Filtr. Scpar.

**8**(2), 115–121 (1966)Maroudas, A., Eisenklam, P.: Clarification of suspensions: a study of article deposition in granular media. Pt II. A theory of clarification. Chem. Eng. Sci.

**20**, 875–888 (1965)Redman, J.A., Grant, S.B., Olson, T.M., Estes, M.K.: Pathogen filtration, heterogeneity, and the potable reuse of wastewater. Environ. Sci. Technol.

**35**, 1798–1805 (2001)Santos, A., Barros, P.: Multiple particle retention mechanisms during filtration in porous media. Environ. Sci. Technol.

**44**, 2515–2521 (2010)Santos, A., Bedrikovetsky, P.: A stochastic model for particulate suspension flow in porous media. Transp. Porous Med.

**62**, 23–53 (2006)Santos, A., Bedrikovetsky, P., Fontoura, S.: Analytical micro model for size exclusion: pore blocking and permeability reduction. J. Membr. Sci.

**308**, 115–127 (2008)Sharma, M.M., Yortsos, Y.C.: Transport of particulate suspensions in porous media: model formulation. AIChE J.

**33**(13), 1636–1643 (1987)Tien, C., Ramarao, B.V.: Granular Filtration of Aerosols and Hydrosols. Butterworth Heinemann, Portsmouth (1995)

Tufenkji, N., Elimelech, M.: Deviation from classical colloid filtration theory in the presence of repulsive DLVO interactions. Langmuir

**20**, 10818–10828 (2004)Tufenkji, N., Miller, G.F., Harvey, R.W., Elimelech, M.: Transport of cryptosporidium oocysts in porous media: role of straining and physicochemical filtration. Environ. Sci. Technol.

**38**, 5932–5938 (2004)Yao, K., Habibian, M.T., O’Melia, C.R.: Water and wastewater filtration: concepts and applications. Environ. Sci. Technol.

**5**(11), 1105–1112 (1971)

## Acknowledgments

The authors gratefully acknowlege the financial support provided by Petrobras (T.C. 0050.0022723.06.4). J. A. Araújo acknowledges the PhD scholarship provided by ANP/PRH 14.

## Author information

## Appendix: Filter Coefficient for Straining

### Appendix: Filter Coefficient for Straining

In this section, we derive a filter coefficient function related to straining based on the following stochastic model for particle retention and pore blocking kinetics (Sharma and Yortsos 1987; Santos and Bedrikovetsky 2006; Santos et al. 2008), respectively:

where \(H\) and \(C\) represent pore radius (\(r_\mathrm{p})\) and particle radius (\(r_\mathrm{s})\) concentration distributions, respectively. In addition, \(U\) is the Darcy’s velocity, and \(\Delta \) is the distance between subsequent pore throats. In Eq. (11), \(\left( {\int _0^{r_\mathrm{s} } {r_\mathrm{p}^4 H \mathrm{d}r_\mathrm{p} } } \right) \left( {\int _0^\infty {r_\mathrm{p}^4 H \mathrm{d}r_\mathrm{p} } } \right)^{-1}\) represents the flow fraction through pores smaller than the particle size \(r_\mathrm{s}.\) Therefore, the above mentioned fraction represents the retention probability for particles with size \(r_\mathrm{s}.\)

Assuming that there are no suspended or deposited particles in the porous medium before the injection, we obtain the following initial and boundary conditions for the Eqs. (11) and (12):

where \(H_{0}\) is the initial pore concentration distribution, and \(C_{0}\) is the injected particle concentration distribution.

Let us consider transport of monosized particles:

through a porous media with \(N\) distinct pore sizes:

where \(h_{i }\) is the concentration of pores with radius \( r_{\mathrm{p}i },\) and \(\delta \) is the Dirac’s delta function (see Fig. 5). In this case, substituting Eqs. (14) and (15) into Eqs. (11) and (12) results in

where \(n\) defines the largest pore radius (\(r_{\mathrm{p}n})\) smaller than the particle radius (\(r_{\mathrm{s}}),\) see Fig. 5. In addition, \(c\) and \(\sigma \) represent the suspended and retained particle concentrations, respectively.

Comparing the traditional particle retention kinetics (second equation in system (1)) with the Eq. (16), we obtain

In addition, from Eq. (17), it follows that

The solution of Eq. (19) is given by

Moreover, the process of applying summation over all “\(i\)” in Eq. (20) and comparing the resulting equation with the Eq. (16) results in

Considering the initial conditions given by Eq. (13), the solution of Eq. (21) is given by

where

Substituting Eq. (20) into Eq. (22), it follows that \(h_{1}( \sigma \)). Therefore, Eq. (18) can be rewritten as

where

Because all \(h_{i}\) (with \(i \le n)\) are decreasing functions, from Eq. (24) it follows that \(\lambda \) is also a decreasing function of \(\sigma .\) In addition, DBF occurs only if retention probability tends to zero (Santos and Barros 2010). Therefore,

In this case, Eq. (24) tends to

Assuming that small pores can be represented by an unique pore radii, from Eqs. (27) and (22), it follows that

## Rights and permissions

## About this article

### Cite this article

Araújo, J.A., Santos, A. Analytic Model for DBF Under Multiple Particle Retention Mechanisms.
*Transp Porous Med* **97, **135–145 (2013). https://doi.org/10.1007/s11242-012-0112-z

Received:

Accepted:

Published:

Issue Date:

### Keywords

- Deep bed filtration
- Retention mechanisms
- Straining
- Attachment
- Analytic modeling