EFFECT OF GRAVITY AND PARTICLE SIZE DISTRIBUTION ON THE SUSPENDED PARTICLE TRANSPORT AND DEPOSITION IN A SATURATED POROUS MEDIUM

The role of particle size, particle size distribution (PSD), gravity and hydrodynamic effects in the transport and deposition of suspended particle (SP) through saturated quartz sand media have been systematically investigated. To achieve this objective, two experimental series were performed, including downward flow and upward flow; three populations with different particles size distributions were selected. The median diameters d(50) of these populations were 3.24, 10.59, and 20.73 mu m. In order to study the effect of polydispersivity, a fourth mixture population of particles (d(50) =12.54 mu m) obtained by mixing in equal proportion (volume) the populations 3.24, 10.59 and 20.73 vim was also used. The breakthrough curves were well described with the analytical solution of a corrected convection-dispersion model that takes into account dispersive flux on the deposition kinetics. The results show that the deposition kinetics and dispersion depend strongly on the particle size, their distributions and gravity. The rate of particle deposition increases with particle size. The longitudinal dispersivity increases, respectively, with the increasing of the flow rate and the SP size distribution. The range of the particles' dispersivity in vertically downward flow is larger than that in vertically upward flow. This study highlights the complicated interdependence of the effects of flow rate, gravity, and PSD on particle transport and deposition.