In membrane filtration processes, the decline in treatment performance caused by membrane fouling remains an unresolved challenge. Several fouling indices, such as the Silt Density Index (SDI), Modified Fouling Index (MFI), Fouling Mechanism Index (FMI), and Fouling Degree Index (FDI), have been proposed, all of which can be evaluated from limited spot filtration data and quantify the decrease in filtration rate during constant-pressure filtration tests.
In this study, we propose a Pressure-based Fouling Index (PFI) as a fouling indicator for constant-rate filtration, derived from changes in filtration pressure. PFI evaluates membrane fouling from the variation in pressure over a defined period and is expressed as...