RO (Reverse Osmosis) membranes should be cleaned periodically to maintain their efficiency and prolong their lifespan. The frequency of cleaning will depend on various factors, including water quality, feedwater source, operating conditions, and system design. RO membranes should be cleaned when certain indicators suggest a decline in performance. 

Here are some common signs that indicate the need for cleaning:

Decreased permeate flow: If you notice a 10-15% decrease in the amount of purified (permeate) water produced by the RO system compared to its initial performance, it is a sign of fouling or scaling on the membranes.

Increased pressure drop: A 10-15% increase in the pressure required to maintain the desired flow rate indicates that the membranes are experiencing reduced permeability due to fouling or scaling. Cleaning will help to restore the pressure drop level.

Decline in salt rejection: If the quality of the purified water deteriorates, as indicated by an increase in the concentration of dissolved salts or contaminants, it suggests that the membranes are becoming less effective. Cleaning can help restore the salt rejection capacity.

Your RO system will probably show this as EC (Electrical Conductivity) in uS/sm, or microsiemens per centimetre, and a regular log should be kept of the EC and operating pressures.

Maintenance:

Some RO systems have a predetermined maintenance schedule that recommends cleaning at regular intervals. 

Avoid running your RO machine to the point that the membranes cannot be recovered. Some operators will close off the concentrate valve to maintain the water production. This is bad practice as the membranes need crossflow during operation to remain clean and avoid fouling, and closing the concentrate valve will result in quicker fouling.

If a membrane is too badly fouled, it may not be possible to recover by cleaning.

Cleaning is much cheaper than replacing!

Cleaning should be performed using highly specialised cleaning solutions, and procedures specified by the membrane manufacturer or recommended by water treatment professionals.

Improper cleaning techniques or the use of harsh chemicals can damage the membranes and compromise their performance. Regular maintenance and cleaning can help ensure the long-term efficiency and lifespan of RO membranes.

Contact us for information on RO membrane cleaning.