Membrane autopsy

Membrane autopsy and subsequent tests are generally the last resort in determining a definitive cause for membrane failure. This is because these tests are all destructive to the membrane module and membrane itself. The tests are used to determine the morphology of material on the membrane, the types of chemicals present, the amount of a specific species found on the membrane, and the nature of the materials that oxidized the membrane.7 

Modules should be prepared for autopsy following the vendor s instructions. Typically, preparation involves bagging each module individually in plastic and boxing it into the original shipping container, if available. Modules should be sent via express mail within 2 days of removing them from service. Membranes should not be cleaned prior to autopsy. 

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It may be possible to do a membrane autopsy to identify the foulant(s) and fouling mechanism. For microporous membranes the blocking law analysis [1], which uses permeate volume (V) vs. time (t) data, can supplement the observations. The generalized relationship at constant pressure and in dead-end filtration mode gives,... 

Fazel, M. and Darton, E.D., "Statistical Review of 150 Membrane Autopsies," presented at the 62nd Annual International Water Conference, Pittsburgh, Pa, October 21 -25, 2001. 

High doses of iron salts by mouth can cause severe gastrointestinal irritation and even necrosis of the mucous membrane. Autopsy shows severe damage to brain and liver. Iron poisoning is particularly dangerous in children. Sustained-release forms are safer in homes where heedless parents live with small children. Ferrous sulphate is the most toxic. 

Membrane autopsy of desalination RO membranes that had been in service for 2.5 yr in Saudi Arabia revealed bacterial deposits that are slimy and very adherent (64). This is primarily due to accumulation of extracellular polysaccharides excreted by microorganisms, thus resulting in biofilm formation (54). Bacteria embedded in a biofilm are found to be more resistant to biocides than freely suspended ones (65). 

L. Y. Dudley, Membrane autopsies for reversing fouling in reverse osmosis. Membrane Technology 95, 9-12 (1998). 

The 2D monitoring of membrane bioreactors at multiple locations, including the feed stream inlet, the membrane bioreactor itself at various positions, the permeate stream and membrane inspection during membrane autopsy... 

Pontie., M., Rapenne, S., Thekkedath, A., Duchesne, J., Jacquemet, V., Leparc, J., and Suty, H. (2005). Tools for membrane autopsies and antifouling strategies in seawater feeds A review. Desalination 181, 79. 

Xu, P., C. Bellona, and J. E. Drewes. 2010. Fouling of nanofiltration and reverse osmosis membranes during municipal wastewater reclamation Membrane autopsy results from pilot-scale investigations. J. Memb. Sci. 353 111-121. 

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