CIP Tips and Tricks
- Clean In Place (CIP) at the membrane manufactured recommended guidelines. Using Normalization formulas identify the appropriate time and conditions to schedule a CIP. Waiting too long can allow irreversible damage to the membranes. When should you clean:
- Normalized flow declines by 10%
- Normalized dP, increases by 15%
- Normalized salt passage increases by 5%
- While most water will have a primary foulant that requires either a high pH (biofouling, organics) or a low pH (mineral scale) CIP, both types of fouling typically occur and should be addressed.
- PWT Laboratory Services can assist in developing a cleaning protocol.
- It has been found that “normally” a high pH clean followed by a low pH clean is most effective. This does not always hold true and trialing different combinations and order of clean may be necessary to optimize the CIP procedure.
- Ensure there is enough time to complete the CIP. Cutting a CIP short on time may cause reduced production/performance.
- CIP is complete once no change in pH or color is noted.
- Use the recommended quantity of Specialized Cleaners. Shortcutting the recommended quantity can make the CIP ineffective.
- Note: One common mistake upon starting a CIP process is not displacing the water in the process piping and vessels. Ensure concentrate water is sent to drain before closing the CIP recirculation loop.
- RO permeate should be used to make up the CIP solution.
- Bringing CIP solution up in temperature 85°-105°F (29°-40°C) is helpful.
- High conductivity following a CIP may indicate the seals on the end adapter(s) have been displaced. This sometimes happens with the change in temperature and flow changes.
- Membranes should be allowed 24 hours to settle after a cleaning event before determining actual performance.
- High conductivity may also be a result of membrane damage that was masked by the scalant/foulant.
- Trimming with caustic or acid to adjust pH with the Specialty cleaners may be needed if extreme fouling has occurred.
- Identify the primary foulant to assist in selecting the appropriate cleaner. This can be done by evaluating scale potential, normalized pressure, flows, and conductivity. In some cases an autopsy by the PWT lab may be recommended to further identify foulants.
- If CIP does not bring the system back to near baseline parameters, a PWT cleaning study may be indicated. This allows a number of Specialty PWT products to be tested on a single membrane.
- High pH cleaners perform better with longer soaks, where low pH cleaners perform better with shorter soaks and more frequent recirculation event.
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