Consequences of membrane aging on real or misleading evaluation of membrane cleaning by flux measurements

Skim milk ultrafiltration is worldwide used in dairy. Its management at industrial scale based on the permeate flux mastering, first bottleneck, and consequently nature of overall fouling which not yet fully understood with respect to membrane lifespan. The second bottleneck mastering control cleaning efficiency aiming full removal initial irreversible mainly made proteins. In this study, we have deliberately chemically aged several spiral wound elements by filtering NaOCl solution (400 ppm total free chlorine pH 8.0 50 °C) up a cumulative dose 2,800 ppm.d. critical/threshold limiting fluxes been proven increase ageing together decrease their related transmembrane pressure. This suggest that, scale, UF might be managed received during its service life. SEM Raman spectroscopy localise whereas ATR-FTIR was tool quantify proteins membrane. Membrane achieved non-oxidative alkaline detergent removing hereafter called “removable fouling” “residual remained on/in However, following treatment (achieved for disinfection purpose scale) also acts both as cleaner (polishing step part residual fouling) degradation agent toward Unambiguously induced significant intrinsic hydraulic resistance associated an fouling, either or residual, build skim UF. paper shows how can transiently compensate each other lead impression water recovery. phenomenon misinterpretation cleanliness specific case membranes. Indeed, close 400 ppm.d = 8.0, remain, strongly anchored in/on recovery after only 15% less than that pristine favours rapid build-up more next filtration steps. accuracy measurement, amplitude problem will underestimated, preventing from getting rid crucial accumulated layers leading accelerated degrading process. Relationships found between could scale.