Circulation flushes dissolved foulants away from the membrane surface, and replenishes depleted cleaning chemical.  The higher the rate of circulation, the more energy the chemical molecules will have, and the faster the rate of cleaning.  Membrane cleaning at a high flowrate also creates turbulence and surface scouring to remove suspended solids and loose foulant. Don’t exceed differential pressure limits, If the feed channels are plugged with foulant, a high flow rate can cause the membrane elements to telescope, resulting in irreversible mechanical damage.  Start circulating at a lower flow rate while monitoring differential pressure (∆P).  As the feed channels get cleaner, the ∆P will decrease, and you can increase the flow rate accordingly.  Do always clean at 40 – 45 gpm per pressure vessel when cleaning 8” elements, but don’t ever allow differential pressure to exceed 10 psi per element.

See also:

Default ThumbnailWhat is the procedure for cleaning RO membranes? What CIP chemicals should be used? Default ThumbnailWhat does differential pressure or delta P (ΔP) mean when logging RO data? Default ThumbnailUnder which conditions can antiscalants cause RO membrane fouling? Default ThumbnailHow can I clean a membrane that has been clogged with suspended solids and sludge?