Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9681193 | Desalination | 2005 | 13 Pages |
Abstract
Permeate flux decline is a major item when considering pressure driven membrane filtration. The decline is a result of the deposition of (dispersed) feed materials as a layer on the membrane surface. This means loss of production of permeate or, when applying a higher compensating pressure, loss of energy. A number of characterization techniques such as SDI (Silt Density Index) and MFI (Modified Fouling Index) are available to study such effects by using a dead-end filtration set-up. A more recent technique, VFM (Vito Fouling Measurement), is described in [1], [2]. VFM is a pragmatic characterization method which presents dead end flux decline results as a graph or as a table formatted “multi value index”. To the author's opinion it is very difficult to sequeeze the complex permeate flux decline behaviour of a real feed into a one number “model” such as SDI or MFI without losing crucial information or even missing a crucial zone within the complete set of data. In this paper it is demonstrated that, even for a simple situation of a model dispersion of ceramic powders in water, it is improbable to achieve a correct mathematical description of the hydraulic conditions during cake formation on a membrane surface. Therefore, a universally applicable mathematical model which predicts in an accurate way the flux decline, for a real feed with a complex composition, seems impracticable. This argues in favour of the experimental approach, such as the VFM.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Filtration and Separation
Authors
E. Brauns, D. Teunckens, C. Dotremont, E. Van Hoof, W. Doyen, D. Vanhecke,