The objective of this study was to characterize and identify the nature of the organic foulants responsible for
flux declines of low and high pressure membranes.
Experiments with lab-scale or pilot scale units were conducted on both clarified surface waters during
periods of more intense microbial activity and on solutions of natural organic matter (NOM) (especially cell wall residues and
also humic-like substances). HPSEC and Pyrolysis GC/MS analyses were the two major analytical tools
used in this study. Several TOF SIMS and amino acids and aminosugars analyses were also performed.
This work confirmed that during intense microbial activity in the source water (spring, summer time),
conventionally treated water exert stronger membrane fouling. This study showed that the organic
foulant that remains after backwash and chemical cleaning was a mixture of several biopolymers
(proteins, polysaccharides, aminosugars and polyhydroxyaromatics). Aminosugars and polysaccharides
which originate from microbial activity (microbial cell wall residues and/or exopolymers from DOM
constituents and/or biofilm) appeared to be the major constituents of the fouling material. However,
results from experiments with NOM fractions have shown that aromaticity appears to be a secondary
parameter which influences PES membrane fouling.
The second part of this article is focused on the membrane foulant autopsy conducted on nanofiltration
membranes isolated before and after cleaning from the M¿¿ry sur Oise filtration train. Elemental
analysis, Pyrolysis GC/MS, FT-IR, 13C- NMR analyses were performed on both insoluble and soluble
phases of the deposit extracted from nanofiltration (NF) modules. Again, results confirmed the microbial origin of the
fouling material. Polysaccharides and aminosugars were found to be the major organic constituents of
the fouling material. In addition, the inorganic content (calcium, phosphorous and aluminum as major
constituents) was found to increase significantly from stage 1 to stage 3 of the filtration train. After
chemical cleaning a significant reduction of the inorganic content was noticed, however the organic
composition of the foulant remained unchanged. Includes 8 references, table, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 3.4 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 15 |
| Published : | 11/01/2005 |
