05 April 2017
Autopsy of the quarter
The membrane had the physical consistency we have observed after repeated high pH cleans using commodity caustic chemicals.
The methylene blue test for physical damage showed that this was the most damaged membrane Nuria had ever seen in over ten years. The methylene blue dye only passes through the membrane from the feed side if the polyamide layer is damaged.
Infrared spectroscopy indicated that all of the polyamide salt-rejecting layer had been stripped and only polysulfone could be detected.
The customer had to replace all the elements at the plant due to this extremely harsh clean. This is a great example of how doing things on the cheap can be an expensive mistake.
