Evaluation of ultrafiltration process fouling using a novel transmembrane pressure (TMP) balance approach

• Limitations with current UF fouling characterization techniques are discussed.
• A new fouling assessment approach, termed the TMP balance, is developed.
• The TMP balance quantifies membrane fouling and deterioration related pressure loss.
• TMP balance values enable direct membrane fouling comparisons at different fluxes.
• A method for presenting process data to improve data interpretation is presented.

The successful operation of ultrafiltration (UF) membrane processes is dependent on the ability to assess and manage membrane fouling, because membrane fouling reduces process efficiency and results in increased operation and maintenance costs. An evaluation of current fouling characterization methods identified limitations with the use of specific flux and transmembrane pressure (TMP) for interpreting fouling trends. This paper proposes that fouling characterization may be improved by distinguishing between the membrane and associated foulants. A new TMP balance approach has thus been developed that quantifies the pressure loss associated with foulants as well as membrane deterioration and facilitates the direct comparison of membrane fouling at different flux values. A method for presenting TMP balance data relative to filtration, backwash, CEB, and CIP events is also discussed that enables the TMP balance to differentiate between physically and chemically unresolved membrane fouling. The TMP balance approach is demonstrated using over 7000 h of runtime data from an UF pilot filtering conventionally pretreated surface water.