AWWA WQTC65963

The primary goal of this AwwaRF funded research was to contrast natural organic matter (NOM)-relatedfouling potential for different types of waters (allochthonous versus autochthonous), anddevelop a predictive tool(s), either a surrogate parameter(s) or a fouling index, to estimatefouling potential. Interactions between water quality, pretreatment chemicals, membranematerials, and membrane configurations were tested at pilot-scale under various operatingconditions. 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 theWhite River WTP (predominantly autochthonous NOM), IN using US Filter's CMF-L pilotunit, utilizing raw, coagulated and clarified waters as feed. The pilot testing program wasdesigned to distinguish between three types of NOM-based fouling: hydraulicallyreversible fouling, chemically reversible fouling, and irreversible fouling. Membranefiltration cycle was evaluated through quantification of membrane flux decline rates. Atboth locations, increased flux and recovery caused comparable loss of flux; however, thebenefit was temporary; long term fouling rate was comparable to baseline conditions. Ofthe different chemical wash regimes evaluated, the most significant reduction in foulingwas observed using chlorine (sodium hypochlorite), followed by caustic (in combinationwith acid). The fouling results from these pilot studies with waters of varying quality werecorrelated to HPSEC, EEM data, compared and contrasted. The resultant data were thenrepresented in terms of the unified membrane fouling index (UMFI) concept. The conceptof UMFI was developed as a key analytical tool for this project to quantify the fouling rateencountered 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-scaletesting. Various statistical tools were used to probe linkages between fouling (UMFI) andNOM characteristics and/or membrane properties and/or operating conditions. It wasfound that allochthonous NOM had the lowest fouling potential as compared toautochthonous NOM. Includes 9 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2007

Number of Pages:

22

File Size:

1 file , 570 KB