RO Membrane Cleaning Best Practices

Q: We are cleaning heavy scale compounds of Ca, Mg, carbonates, phosphates and organic matter from reverse osmosis (RO) membranes. Can you tell us some cleaning best practices and recommend a detergent?

A. Typical fouling of RO membranes is handled by an acidic detergent, as the foulants are inorganic in nature. If the organic matter on the RO membrane is significant, a two-step process, cleaning by re-circulation or soaking (re-circulation will likely be more effective) could be needed.

Thorough rinsing where TOC or conductivity of the rinse is monitored ensures both detergent and residue/membrane foulant is removed.  If these are tangential flow membranes, NWP can be monitored instead, or in addition.

If the organic matter is biologic in nature, we would recommend Tergazyme® Enzyme-Active Powdered Detergent which is both a powerful emulsifier along with protein enzymes. If the organic residue is more of an oily nature, we would recommend Alconox® Powdered Precision Cleaner which is an essentially identical emulsifier without the enzymes.

The second step would be use of Citranox® Liquid Acid Cleaner and Detergent, which is an acidic detergent for removal of inorganic compounds including scale.

You may also look to use the Citranox cleaner alone as it will have the capacity to remove some organic residue.  However, typical best practice would be alkaline, followed by acidic cleaning.

We are happy to discuss further at any time!

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