Diatomaceous Earth Precoat Filtration

Abstract

Filtration is the process by which particles are separated from a fluid by passing the fluid by passing the fluid through a permeable material (1). The filtrations discussed in this chapter concern the removal of suspended solids, including some semi-colloids, from liquids. Ideally the liquid goes through and solids remain, building a permeable cake on the screen. With large, incompressible particles, this ideal situation can be approached. In practice, however, finer solids often pass through with only larger solids remaining on the screen. If the latter are at all compressible, the liquid flow is reduced to an uneconomical level and the solids stick to the screen, making it very difficult to clean. These difficulties occur in almost all organic liquid and food product filtrations. Diatomaceous earth filter aids, properly used in a diatomaceous filtration system as outlined in this chapter, offer practical and economical solutions to these filtration operational difficulties.