Gravity Filtration with Accretion of Slurry at Constant Rate

Abstract

The separation of liquid from solid in many industrial effluents may be described by a physical theory developed originally to describe one-dimensional movement of water in a swelling soil. The theory makes use of measured hydraulic conductivity-liquid content, and liquid content-liquid potential relations. Both these functions have been found to be well defined, as required for their use in the theory.

The process of gravity filtration is explored in terms of this theory for vertical columns of effluent, to the top of which additional effluent is applied continuously at a constant rate, and from the bottom of which the liquid phase escapes through a membrane which prevents escape of the solid phase. The physics of the process is discussed, and illustrative calculations and experimental data are presented for one aspect of the process for which a quasianalytical solution is possible. The calculations are simplified using the flux-concentration relation of Philip.

The approach permits reliable calculation of the liquid-solid profile and the filtration rate for the process.