Membrane Separation in Deadend Hollow Fiber Filters at Constant Transmembrane Pressure

Abstract

A mathematical model of cake formation in deadend outside-in hollow fiber filters accounting for nonuniform cake deposition throughout the filter is developed. The model is used to study two possible mechanisms of cake growth: conventional (convective) and adsorption-peptization. The system of equations describing the cake formation is numerically solved with the generalized Crank-Nicholson finite-difference scheme. Comparison of the numerical solutions with experimental data shows that the cake formation in deadend outside-in hollow fiber filters is governed by the adsorption-peptization mechanism.

Particle deposition in outside-in hollow fiber filters and its effect on their performance

“…2) [8]. Likewise, the theoretical model described well the data of an experiment in which the water was recovered from a slurry with activated sludge using a DOIHF module (Fig.…”

“…Likewise, the theoretical model described well the data of an experiment in which the water was recovered from a slurry with activated sludge using a DOIHF module (Fig. 3) [8]. This implies that the adsorption-peptization model can be used to carry out simulation studies for both DOIHF filters and HFM adsorbers.…”

“…Comparison of the numerical solutions to problem (1)-(3), (5)- (8) with data obtained at three different values of TMP in pilot experiments on stabilization and dewatering of industrial wastewater using a STERAPOR-S housingless microfiltration DOIHF module sumberged in a bioreactor showed that the adsorption-peptization mathematical model is in good agreement with experimental results (Fig. 2) [8].…”

“…[5,6,[8][9][10]: concentration polarization and particle dispersion are ignored (β ≥ V p [8]); cake deposition rate does not depend on the membrane geometry; decrease in permeate velocity is caused only by the growth of cake layer; liquid velocity w is the velocity averaged over the cross-section of all interfiber channels at z; effect of the filter casing walls is neglected; the entire HFM shell surface is perfectly retentive to suspended particles and can adsorb them, even after a layer of the particles is already formed; the liquid flow inside the filter/adsorber is laminar.…”

“…It was recently suggested to use an outside-in hollow fiber UF/MF filter with highly adsorptive membranes as a particlecollecting device [5][6][7][8]. This type of filter ( Fig.…”