Reproducing the pressure–time signature of membrane filtration: The interplay between fouling, caking, and elasticity

• Published in: Journal of membrane science Vol. 577; pp. 235 - 248
• Main Authors: Herterich, J.G., Griffiths, I.M., Vella, D.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2019
• Subjects: Backflushing; Caking; Elasticity; Filtration; Fouling; Mathematical modelling; Caking; Elasticity; Mathematical modelling; Filtration; Fouling; Backflushing
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2018.12.073

We develop a mathematical model of direct-flow filtration operating at constant flux to understand the pressure–time signature. We combine the effects of fluid flow with those of membrane fouling and caking to explain the gradual increase in driving pressure that is often reported. We model the periodic backflushes used to clean such membranes and show that the elasticity of the membrane may explain the limited effectiveness of these backflushes. We also consider strategies for the operation of direct-flow filtration and show that tuning the flux and rate of backflushing, as well as the membrane material structure, may allow for improvements in membrane performance.
•Particles that foul membranes during filtration are not removed by backflushing.•Has been suggested that this is due to elastic deformation of membrane pores.•Develop a model of elastic deformation and its effects on filtration pressure.•Model reproduces qualitative properties of pressure-time trace.•Model is starting point for new filtration strategies that avoid fouling.