This pilot allows the study of the filtration in the mass. This method comprises circulating a fluid containing solid particles through a porous medium. The spaces between the particles must be well above the size of the particles in suspension. During their course, necessarily sinuous, the suspended particles hit those of the bed and cling gradually.
Bulk filtration is often used as a pre-treatment before the flocculation or coagulation steps. It eliminates most of the suspended particles (sediments, precipitates, coagulants, ...). The most commonly used filter materials are sand and anthracite.