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64 3. DIAGNOSTICS OF MEMBRANE FOULING AND SCALING 3.4.13 Fujiwara Test
This test is applied to determine whether the RO membrane has been exposed to oxidizing halogen (i.e., sodium hypochlorite, bromamine, iodine). The Fujiwara test is applicable for membranes made of polyamide (PA) material such as most spiral-wound RO elements used for desalination at present.
This test is qualitative only (e.g., provides only positive or negative answer regarding exposure to oxidants) and does not quantify the magnitude of exposure. Fig. 3.23 illustrates typical discoloration of halogen-exposed membrane sample during the Fujiwara test.
References
AWWA, 2007. Manual of Water Supply Practices, M46, Reverse Osmosis and Nanofiltration, second ed. American Water Works Association.
Chesters, S., Pena, N., Gallego, S., Fazel, M., Armstrong, M., de Vigo, F., 2011. Results from 99 seawater RO membrane autopsies. In: Proceedings of IDA World Congress, Perth, Western Australia, September 4e9, 2011.
Voutchkov, N., 2014. Desalination Engineering e Operation and Maintenance. McGraw Hill Education, New York.
