Long-term hydraulic performance and replacement forecasting of UF-PVDF membranes in water treatment

Ultrafiltration (UF) has become increasingly prevalent in drinking water treatment applications; however, limited published information exists regarding changes in hydraulic performance over extended (>5 years) periods of full-scale operation. The present study assessed hydraulic performance at six full-scale facilities operating PVDF-based hollow-fiber membranes over 7–12 years. Resistance to permeate flow immediately after recovery cleaning was used as the metric of hydraulic performance, evaluated using data obtained from both harvested membrane fibers and historical operational data. Resistance generally increased with operational age, with site-specific factors such as source water and pretreatment strongly influencing the rates. Differences between harvested and historical resistance highlighted the potential for incomplete chemical cleaning at some facilities and underscored the value of combining both measures for a more complete assessment. Application of linear regression to historical resistance data provided an accurate forecast of membrane replacement, with predicted replacement ages ranging from 14 to 18 years. Results demonstrate that combining site-specific data with predictive modeling offers a practical framework for evidence-based membrane asset management. • Harvested and historical resistances increase with operational age • Insight regarding chemical cleaning efficiency can be obtained by considering both harvested and historical resistance • Increase in resistance is influenced by site-specific factors • Historical resistance can be used to forecast membrane replacement