Reverse osmosis integrity monitoring

Evaluation of methods for reverse osmosis membrane integrity monitoring for wastewater reuse

“…Later, the O-ring on the high pressure end (feed inlet) of the second pass pressure vessel was artificially damaged (Fig. 1, the star indicates the location of damaged O-ring) to simulate a typical failure of RO systems [9]. Five levels of damage were introduced to the O-ring (stretched, cut off, two notches, three notches and four notches).…”

“…TOC, turbidity and electrical conductivity (EC) are indirect methods based on constituents naturally present in the feed stream. But their sensitivity has been questioned due to the high purity of the RO permeate [9,10]. Recently, fluorescence excitation-emission matrix (EEM) spectroscopy was proposed for RO membrane integrity monitoring by analyzing the dissolved organic matter (DOM) in RO feed and permeate [11].…”

Pulsed marker method for real-time detection of reverse osmosis membrane integrity loss

“…Moreover, since quantifying the accuracy of the above parameters depends on the target species concentration in the feed water, variability in membrane integrity metrics can often be the result of variations in RO feed water quality and permeate flux and not necessarily related to the occurrence of a membrane breach [13,15,19,20]. In contrast with the above, direct physical tests such as pressure decay [12,21] or vacuum tests [12][13][14]21], have proven to be sensitive for detecting membrane breaches. However, these types of MIM require system shutdown, lead to membrane dewatering and can potentially result in membrane damage due to pressurization on the RO permeate side [19,22].…”

“…Indirect MIM methods, which rely on feed and permeate water quality parameters (e.g., particle counting [13][14][15][16], turbidity [12], conductivity [4,10,12,14], TOC [12,14,15], and sulfate monitoring [12]), have been utilized to monitor integrity of low pressure membrane (LPM) processes (e.g., microfiltration (MF) and ultrafiltration (UF)). Indirect MIM approaches, such as particle counting and turbidity monitoring, have successfully verified high LRV (up to 4 for MF and 5 for UF) in LPM processes [17,18], thus contributing to their regulatory acceptance with respect to virus removal.…”

“…As a consequence of membrane breaches (even as small as 20-30 nm in diameter), harmful pathogens can pass across the membrane to the product permeate stream and pose a potential health threat, which is of particular concern in potable water production [3,[10][11][12].…”