CIP Chemical Cleaning Technical Guidelines for Reverse Osmosis Systems
The main reason for chemical cleaning (chemical cleaning or IP, i.e., in-place cleaning) of reverse osmosis membrane systems is to restore the performance of the membrane, prolong the service life of the membrane, and ensure the efficient and stable operation of the system.Conventional physical cleaning (e.g., low-pressure washing, air scrubbing) can only remove loose contaminants from the membrane surface, while chemical cleaning can more thoroughly remove stubborn contaminants (e.g., scaling, biofilm, etc.) through the dissolution, dispersion, oxidation or sterilization of chemical reagents
Alternate forward/reverse flushing with RO permeate
Continue until effluent pH 6.5-7.5
Conductivity returns to baseline ±10%
IV. Post-Cleaning Evaluation
Performance recovery:
Permeate flow recovery ≥95%
Salt rejection improvement ≥3%
Membrane autopsy (if needed):
Contaminant weight: <50mg/cm²
SEM analysis of membrane pores
V. Targeted Solutions for Specific Fouling
Fouling Type
Symptoms
Recommended Solution
Organic Fouling
Rapid ΔP rise, stable conductivity
Alkaline cleaner (pH11-12) + 50℃ heating
Inorganic Scaling
Sudden flow drop, salt rejection decline
2% citric acid + NH3 (pH4) + 40℃ circulation
Biofouling
Odor, slimy deposits
Alternate 1% peracetic acid and 0.1% NaOH
Colloidal Fouling
SDI >5, gradual ΔP rise
0.025% SDBS + EDTA composite cleaning
VI. Safety Protocols
Chemical compatibility:
Avoid mixing oxidizers (e.g., NaClO) with acids
Flush alkaline residues before acid cleaning
Waste treatment:
Neutralize pH to 6-9
Precipitate EDTA with FeCl3 (1:1 molar ratio)
Membrane protection:
Set temperature alarm at 45℃
Limit Cl– concentration <1000ppm during acid cleaning
Expected Outcomes:
Flux recovery >90%
Extended membrane lifespan (12-18 months)
8-12% energy consumption reduction
Note: Use rotary nozzle systems (e.g., GE TurboClean™) to enhance shear force by 3× and cleaning efficiency by 40%+
Hi, I am the author of this article and I have been working in this field for more than 8 years. If you want to know about water treatment related knowledge and products, please feel free to ask me any questions.
SHANGHAI CM
