CHAPTER 12 – Performance of packed-bed filters

This chapter illustrates the application of fundamental theories of particle deposition to the modeling of particulate removal in packed-bed filters. Filtration theories that describe the capture (or removal) of particles in packed-bed filters can be classified into two types—phenomenological (macroscopic) and fundamental (microscopic). The ultimate aim of filtration models is to predict removal of particles as a function of suspension characteristics, physical and chemical properties of the filter, and flow conditions. Important suspension characteristics are density, size, size distribution, and surface chemistry of the particles; and temperature, viscosity, and solution chemistry of the suspending medium. The parameters that describe the properties of packed-bed filters are bed depth, grain size, grain shape, grain surface chemistry, and porosity. Another important parameter in packed-bed filtration is the approach (superficial) velocity. The approach velocity is defined as the ratio of the volumetric flow rate to the filter cross-section area.