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In this research, membrane life-time is evaluated by means of accelerated ageingexperiments. In the performed experiments three main ageing factors are varied, namelymechanical stress (back-pulsing), chemicals exposure (cleaning with oxidativechemicals) and the membrane fouling status. A pressure-pulse-unit (PPU) was used tosimulate standard membrane operation in an accelerated way. The PPU can be used toback-pulse cleaning agents with a frequency of around twenty to thirty times per minutethrough a membrane module. During the back-pulses, the membranes are frequentlytested for integrity by means of permeability measurements, pressure decay test andbubble tests. The magnitude of a pressure pulse, the concentration of cleaning agent andthe fouling status of the membrane were varied. The outcomes of the experiments showthat the membrane fouling status is a major ageing factor. Clean membranes easilywithstand 300.000 back-pulses with 1000 ppm NaClO at 2.0 bars, respectively, 10 yearsof operation and 350.000 ppm.h sodium hypo chlorite exposure. The collected data willbe used in the further development of a mathematical membrane-life-time model thatpredicts the probability of membrane failure. Includes 17 references, table, figures.

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Edition: Vol. - No. Published: 03/01/2007 Number of Pages: 10File Size: 1 file , 340 KB