Membrane replacement is decided by data, not by the calendar. The five indicators we look at in the field and what each of them means.
The service life of a reverse osmosis membrane varies with the operating conditions: the composition of the raw water, the quality of the pretreatment and how the system is run are all decisive. So instead of saying “replace it every so many years”, you have to look at the system’s own data.
Reading the same points at every periodic inspection makes the values comparable against their own history. The five indicators below come out of that comparison.
None of the indicators is sufficient on its own; they acquire meaning when read together.
If the indicators point to a replacement, the cause must be found before the membrane is changed. If the source of the capacity loss lies in the pretreatment, the new membrane will foul just as fast.
When suspended solids, hardness and chlorine reach the membrane directly, its life is cut short. Assessing the filtration and softening stages together determines how long the replacement lasts.
Membrane supply can take time. When the indicators give notice in advance, the supply and site plan can be arranged so production never stops. Done without a plan, the same job arrives together with the cost of a shutdown.
If hardness appears early at the softener outlet, the problem usually lies not in the resin itself but in the water reaching it and in the regeneration settings.
View →In cooling water it is usually unnecessary to filter the full flow. The points that decide between side-stream and full-stream filtration.
View →Membranes are delicate structures and the cause of fouling is not always the same. The fouling we see in the field falls into three main groups; the remedy changes with that distinction.
View →Read flow and conductivity together and they point to the source of the damage with surprising clarity. Three typical patterns and the problem each one indicates.
View →The cleaning decision looks not at the calendar but at three measurements: differential pressure, permeate conductivity and production flow. The threshold values, and what to do after a long shutdown.
View →Silica is one of the most dangerous minerals for a membrane and it occurs in water in two different forms. The precaution differs for each.
View →An antiscalant is chosen from an analysis, not from a catalogue. The two decisive parameters, and why the projection calculation must not be skipped.
View →The short answer: yes, and irreversibly. Membranes have a low tolerance to chlorine and the damage cannot be undone by cleaning.
View →Activated carbon and SMBS dosing are the two ways of neutralising free chlorine ahead of a membrane. When to prefer which.
View →Let us size the system together; we will survey the site in person if needed.
