Particle fouling of a rotating membrane disk

Fouling of rotating disk membranes as function of operating conditions and Feed suspension characteristics was investigated in a series of laboratory experiments. A single-disk laboratory unit was operated over a range of dis k rotation speeds and permeation rates (as controlled by the global transme mbrane pressure drop) that were calculated to favor various conditions of p article transport and deposition. Permeate flux was found to be relatively insensitive to particle concentration in the feed stream. Thus, this membra ne configuration appears to be well suited to the treatment of suspensions at high concentrations. However, the interplay between appropriate operatin g conditions to maintain permeate Bur and the size of particles in the feed suspensions must be taken into account. Fouling was found to decrease with rotation rate and increase with transmembrane pressure (and therefore the initial permeate flux). Reductions in fouling observed at higher rotational speeds are attributed primarily to a high centrifugal force and radial com ponent of drag on particles near the membrane surface. However, a trade off exists between the generation of high shear rates and centrifugal accelera tions via high rotation rates and the radial distribution of the transmembr ane pressure drop across the membrane that may locally reduce or reverse th e Row of permeate across the membrane. (C) 1999 Published by Elsevier Scien ce Ltd. All rights reserved.