Feed Cycling in Dead End Filtration

Abstract

The dead end ultrafiltration of dispersions of active carbon in water was studied. High flux of the permeate and effective purification were goals of the studies. Cyclical flow of the feed (cycling) was found to be the best condition for good purification. During the purification of the membrane, an air/water dispersion was injected into the hollow fiber membrane (air sparging) to improve the cleaning effect. A Simplex optimization of significant parameters was carried out. The behavior of pressure drop and module entrance pressure permitted the classification of the values into two groups. A different build-up of the cake of these groups during the filtration is possible.

Influence of the hydrodynamic efforts on the efficiency of the regeneration of the granular filtering material in a water treatment plant

“…In fact, air has long been used to improve the efficiency of the washing phases of sand filters (Degrémont 2012). It can be seen that different air injection modes have been studied: with circulation of raw water (Laborie 1998;Mougenot 1999;Richter et al 1999) or with counter-current of permeate (Laborie 1998;Ouadi 2002). During each study, the effectiveness of the air-assisted backwashing procedure was evaluated by different criteria which can be classified into two groups: backwash water was collected either to assess the total amount of particles removed during backwashing, by carrying out a material balance between the filtration step and the backwashing step, or to evaluate the kinetics of particle elimination.…”