Membrane fouling of ultrafiltration membranes by natural organic matter (NOM) has
become an important concern in advanced water treatment applications. Surface water,
after pre-filtration with a 0.45µm filter, was separated into colloidal and non-colloidal
NOM through dialysis with two types of dialysate (deionized water and a synthetic
surface water solution). Filtration experiments were conducted at constant flux (138.5
L/m<sup>2</sup>.hr) running 10 filtration cycles of 30 min, followed by immediate backwashing
with permeate water. Results of dialysis showed that circa 33-40% of the total dissolved organic carbon (DOC)
(~17mg/L) of pre-filtered surface water was colloidal NOM, in the size range 1.3nm-
0.45µm; and ca. 60-67% was non-colloidal NOM (<1.3nm). Colloidal NOM was
composed mainly of polysaccharides and humics. However, the inorganic colloidal
concentration was assumed to be below 0.5mg/L (total silica content measured by ICP).
The non-colloidal NOM comprised humics, building blocks, neutral amphiphilics and
low molecular weight acids. Results of ultrafiltration (UF) filtration tests of pre-filtered 0.45µm and
colloidal NOM revealed that colloidal NOM was responsible for the major increase in
transmembrane pressure (TMP) during ultrafiltration. LC-OCD analyses identified
polysaccharides as foulants that were backwashable. UF filtration test of non-colloidal
NOM with a DOC concentration of 5mg/L, also resulted in an increase in TMP over
time. Simulations of surface water fouling were made using the normalized noncolloidal
NOM (~11mg/L) and colloidal NOM (~6mg/L) fouling results, and the
simulated increase in TMP matched the surface water quite well. Includes 22 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 380 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 10 |
| Published : | 03/01/2007 |
