EFFECT OF MEMBRANE RESISTANCE ON FILTRATION CHARACTERISTICS FOR METHANOGENIC WASTE

To investigate the influence of membrane properties on filtration flux for methanogenic waste, filtration examinations employing tubular alumina membranes having controlled membrane resistances Rm, pore sizes and surface charges were carried out. The filtration flux for methanogenic waste through Rm-controlled membranes showed the same value except for the 0.01 μm pore membrane, which had the maximum Rm in the examination. It was also found that the limiting flux value was not affected by filtration pressure. These findings were explained by the gel layer model. Membrane pore size and surface charge affected filtration flux. It was assumed that membrane properties affected hydraulic resistance Rp, which was attributed to adsorption and plugging of particles to membrane, to induce the reduction of filtration flux. This influence was explained by the gel layer model. Taking into account the fact thatRp was formed in the starting period of filtration, permeability of the membrane was restricted not only by Rm but also by Rp. Therefore, it can be assumed that flux diminished form the limiting flux value when (Rm+Rp) became bigger than the filtration resistance RL, which was calculated by the limiting flux value. © 1990, The Society of Chemical Engineers, Japan. All rights reserved.