AWWA MTC53660

Studies were conducted to develop correlation between nanofiltration (NF) membrane fouling, feedwater quality, and membrane characteristics. The water quality of the three seasonal NF feed samples wascharacterized by UV, DOC, HPLC-UVA-DOC, XAD, IC and ICP. Surface charge, molecule weight cut-off(MWCO), and functional groups of the NF 200 membrane surface were determined. The extent offouling was significantly dependent on water quality, membrane properties, and operational conditions.Higher flux decline was observed at high DOC, high divalent cations, high alkalinity and low temperature.Temperature strongly affected the specific flux and natural organic matter (NOM) rejection. Inorganic saltprecipitation was proven by FTIR and scanning electron microscopy (SEM). Scaling was observed at both high and low temperatures. Athigh temperature, homogeneous crystallization of CaCO3(s) occurred due to the decrease in solubility thatled to less flux decline. At low temperature, in spite of the increased solubility, heterogeneouscrystallization with NOM absorption was observed. This is due to an increase in pH and formation ofnucleus components induced by a temperature decrease. Heterogeneous crystallization caused moresignificant flux decline than homogeneous crystallization. Includes 14 references, tables, figures.