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Should increase in differential pressure be used as the sole indicator of membrane scaling/fouling?

Differential Pressure (∆P) alone should not be used as an indicator of membrane scaling/fouling. Increases in differential pressure (∆P) across a stage indicate that a foulant has growth thick enough to interfere with flow through the f...

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Are American Water Chemicals (AWC®) products PFAS free?

Yes. At AWC® all the ingredients used in the manufacturing of our chemicals are PFAS free because of the extra precautions we take in our manufacturing process. But first, what are PFAS and why are they bad? Per- and polyfluoroalkyl substa...

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Under which conditions can antiscalants cause RO membrane fouling?

Reverse Osmosis Antiscalants can cause membrane fouling in Reverse Osmosis systems under the following conditions: Fungal growth in the antiscalant –  some antiscalants contain impurities that can provide the necessary nutrients and ...

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Can I use citric acid to descale/clean a reverse osmosis (RO) Membrane?

Citric acid is an organic acid that is often used for removal of calcium carbonate scale and is often mistakenly believed to be effective at dissolving iron fouling.  It actually has only marginal impact on iron hydroxide deposits, and is ...

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When do we know if the cleaning of our Reverse Osmosis plant was successful?

Once the RO membrane system is placed back online after CIP, you can get a relatively good idea by comparing post-cleaning feed pressures and differential pressures for each stage to pre-cleaning values.  The most reliable method would be ...

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What is the best post-CIP flushing procedure in Reverse Osmosis systems? How do we know when flushing after a cleaning is done?

Always flush your membranes with RO permeate until the pH measured at the waste end is within a pH range of 5 – 9.  You can then proceed to flush with feed water until the pH of the water exiting the RO membrane system is similar to the ...

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Can we send the CIP solution to our deep injection well after cleaning our Reverse Osmosis membranes?

No, if a high pH RO cleaning solution is mixed with RO brine, it would result in severe scaling.  Always consult with your hydrogeologist before sending any solution to the deep injection well. See also: What is the procedure for cleaning ...

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Our RO plant doesn’t have a neutralization tank for our spent CIP solution. Can we just neutralize while circulating through the membrane system?

That is not recommended.  A high pH cleaning solution is designed to dissolve membrane foulants and scales that are soluble in basic conditions.  A low pH cleaning solution is designed to dissolve membrane foulants and scales that are sol...

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Can we send our CIP solution direct to the waste water treatment plant after cleaning our Reverse Osmosis System?

No, pH extremes can be very disruptive to bacteria and can upset the operation of the wastewater treatment plant.  The RO cleaning solution should always be neutralized prior to sending to a wastewater treatment plant.  The solution is us...

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Why does the RO permeate pH rise when the water passes through a degasifier? Does that higher pH really stabilize the RO permeate to help prevent corrosion in the distribution system?

Bicarbonate is in equilibrium with carbonic acid, and carbonic acid is in equilibrium with carbon dioxide. [1] $${HCO{_3}{^-} \Leftrightarrow CO{_3}{^2}{^-} + H^+}$$ [2] $${H_2CO_3 \Leftrightarrow HCO{_3}{^-} + H^+}$$ [3] $${CO{_2}{_(}{_...

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