Clogging of Nonuniform Filter Media

Abstract

The relationship of the increase in pressure drop owing to the retention of solids during deep filtration is studied using a capillaric model with nonunifcrm pores. The change in filter medium properties is examined using two limiting rates of solid deposition within the pore structure. The nonuniformity in the pore size distribution and the variations in the rate of particle deposition are found to be significant factors. The Kozeny constant, previously assumed to be unchanged during clogging, is found to depend upon certain moments of the evolving pore size distribution function and, therefore, to vary with retention.

Combining physical-based models and satellite images for the spatio-temporal assessment of soil infiltration capacity

“…To complicate matters even further, natural ''pore clogging'' also depends on some initial properties of the soil (e.g. Guin 1972). In typical situations, the impossibility of complete characterization of geological heterogeneities make these variables random parameters for modelling purposes (Tartakovsky and Winter 2008).…”

“…For instance, the soil can be conceptualized as a natural filter in which suspended particles circulate in the soil while percolating; they are attracted and collapse into the pore spaces. At some macroscopic scale, this effect is called ''physical clogging'' and has been modeled using ''depth filter'' theories (see Zamani and Maini 2009;Pedretti et al under review;Guin 1972 for details). A significant point is that the capacity of the soil to retain the particles (i.e.…”

“…Baveye et al 1998) that cannot be easily measured, or that cannot be easily upscaled to the field pond scale and (ii) the rate at which clogging mechanisms jointly develop depends on a variety of site-specific conditions and factors, such as textural heterogeneities of the soil (e.g. pore or grain size distributions-PSD/GSD) (Zamani and Maini 2009;Tien and Payatakes 1979;Guin 1972), soil density heterogeneities (Clement et al 1996), chemical heterogeneity (Greskowiak et al 2005), and fluctuations of the water temperature (Civan 2007(Civan , 2010.…”

“…Kozeny 1927;Carman 1938;Hazen 1882) and non-uniformly (e.g. Guin 1972) distributed is essential to correctly estimate the development of clogging. Indeed, the use of uniform formulations implicitly include average macrocharacteristic features of PSD and GSD, such as the total soil porosity / or some characteristic grain size d g , from which the seepage velocity is calculated.…”

“…On the other hand, physical mechanisms act differently. According to the filter theory (see Zamani and Maini 2009;Pedretti et al under review;Guin 1972 for details) the clogging rates are inversely proportional with d g but this relationship depends strongly on other factors such as the suspended solid size (d s ) and I c (t = 0). Guin (1972) adopted a macroscopic Kozeny-like model where the porous medium is decomposed into a bundle of channels with different hydraulic radii R (ratio between porosity and the specific surface area of the soil, S a ).…”