The primary goal of this AwwaRF funded research was to contrast natural organic matter (NOM)-related
fouling potential for different types of waters (allochthonous versus autochthonous), and
develop a predictive tool(s), either a surrogate parameter(s) or a fouling index, to estimate
fouling potential. Interactions between water quality, pretreatment chemicals, membrane
materials, and membrane configurations were tested at pilot-scale under various operating
conditions. Pilot studies were conducted at two locations: at the Tampa Water Treatment Plant (WTP), Florida
(predominantly allochthonous NOM) utilizing Zenon's immersed membranes; and, at the
White River WTP (predominantly autochthonous NOM), IN using US Filter's CMF-L pilot
unit, utilizing raw, coagulated and clarified waters as feed. The pilot testing program was
designed to distinguish between three types of NOM-based fouling: hydraulically
reversible fouling, chemically reversible fouling, and irreversible fouling. Membrane
filtration cycle was evaluated through quantification of membrane flux decline rates. At
both locations, increased flux and recovery caused comparable loss of flux; however, the
benefit was temporary; long term fouling rate was comparable to baseline conditions. Of
the different chemical wash regimes evaluated, the most significant reduction in fouling
was observed using chlorine (sodium hypochlorite), followed by caustic (in combination
with acid). The fouling results from these pilot studies with waters of varying quality were
correlated to HPSEC, EEM data, compared and contrasted. The resultant data were then
represented in terms of the unified membrane fouling index (UMFI) concept. The concept
of UMFI was developed as a key analytical tool for this project to quantify the fouling rate
encountered not only in constant pressure, as used with the bench-scale stirred cell tests,
but also in constant flux filtration as employed in the hollow fiber bench- and pilot-scale
testing. Various statistical tools were used to probe linkages between fouling (UMFI) and
NOM characteristics and/or membrane properties and/or operating conditions. It was
found that allochthonous NOM had the lowest fouling potential as compared to
autochthonous NOM. Includes 9 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 570 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 22 |
| Published : | 11/01/2007 |
