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high salt rejection RO membrane

Unlocking Efficiency: Common Pollutants in Reverse Osmosis Membranes and Effective Removal Methods

Explore the world of composite membrane pollutants in reverse osmosis (RO) systems and discover proven cleaning methods to enhance membrane performance. This article focuses on pollutants affecting 4-inch, 6-inch, 8-inch, and 8.5-inch diameter RO membrane elements, providing insights into common contaminants and their efficient removal techniques.

Note 1: Underlining the importance of avoiding free chlorine contact with composite membranes, this note emphasizes laboratory-tested confirmation and the use of acid solutions for neutralization, ensuring complete reaction and preserving membrane performance.

Note 2: Recommending consultation with the company’s field service personnel for RO membrane cleaning during the warranty period, this note stresses the crucial role of professional guidance in maintaining optimal membrane functionality.

Note 3: Warning against the use of cationic surfactants, this note highlights the risk of irreversible membrane contamination, emphasizing the need for cautious cleaning solutions.

Common Pollutants and Removal Methods:

1. Calcium Carbonate Scale:

  • Detection and Early Removal: Lower feed water pH to 3.0-5.0 for 1-2 hours.
  • Long-Term Scale: Utilize RT-818A cleaning solution for circulation or overnight soaking.
  • pH Considerations: Caution against extreme pH values and recommend ammonia or acids for pH adjustment.

2. Calcium Sulfate Scale:

Optimal Removal: Use RT-818B cleaning agent for effective elimination.

3. Metal Oxide Scale:

Removal Method: Apply the same approach as for calcium carbonate scale.

4. Silica Scale:

Special Cleaning: Consult the company for detailed methods tailored to silica scale characteristics.

5. Organic Deposits:

  • Cleaning Agent: Deploy RT-818C cleaning agent for organic deposit removal.
  • Sterilization: Utilize approved sterilizing solutions to prevent reproduction.
  • Fungicide Use: Consult with the company for appropriate fungicide during extended shutdowns.

6. Cleaning Solution:

  • Recommended Cleaning Agents: Utilize RT-818 series RO membrane cleaning agents.
  • Importance of Analysis: Conduct a detailed chemical analysis of contaminants before cleaning.
  • Record Keeping: Document cleaning methods and effects for future reference and optimization.
  • Temperature and Duration: Perform all cleaning at or below 40 degrees Celsius for a maximum of 60 minutes.

During the cleaning process, circulate the cleaning solution on the high-pressure side of the membrane at a low pressure and a large flow rate. Special cleaning devices are recommended while the membrane element remains installed in the pressure vessel.


Effectively navigating common pollutants and their removal methods is integral to sustaining peak performance in reverse osmosis membranes. By adhering to proven techniques and industry recommendations, water treatment professionals can optimize RO systems, ensuring reliable and efficient water purification.

Xi’an CHIWATEC Water Treatment Technology provide the RO membrane to clients both inland and oversea with more than 10years experience. We manufacture our own brand Daltonen RO membrane and we are also the official distributor of Dupont, Toray, CSM, Nitto, LG and Vontron RO membrane. Whatever product you need, we cold meet your requirement.

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