Abstract
Membrane fouling is one of the main factors that hinders the wide application of ultrafiltration (UF) processes. Limited research on the influence of temperature condition on reversible and irreversible natural organic matter (NOM) fouling has been conducted. Fouling and cleaning of a submerged polymeric UF with different NOM components were examined at 5 degrees C, 20 degrees C, and 35 degrees C. Fouling was evaluated using the modified fouling index-UF (MFI-UF) and unified membrane fouling index (UMFI) indices, analysis of cake layer properties, and specific flux recovery. Results showed that fouling increased by 15%-35% when water temperature decreased from 20 degrees C to 5 degrees C, whereas fouling decreased by 15%-25% when the temperature increased to 35 degrees C. The UMFF fouling order was consistent across all temperature conditions with the NOM mixture and bovine serum albumin (BSA) fouling more severely than the alginate and humic acid. The UMFI and MFI-UF exhibited the same fouling order and can be used in complement to each other. BSA was found to be more sensitive to temperature changes and irreversibly fouling more than humic acid and alginate. The ratio of irreversible to reversible fouling (UMFIhir/UMFIhr) increased by 15%-25% from 35 degrees C to 20 degrees C and by 30%-40% from 20 degrees C to 5 degrees C indicating the need for altered cleaning strategies at cold water conditions.