The necessity of regular cleaning of reverse osmosis membranes-Hezhong Environment (Beijing) Co., Ltd. was established in 2003

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The necessity of regular cleaning of reverse osmosis membranes

Published Time:

2023-06-21

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During prolonged membrane separation, the water permeability of the 4040 reverse osmosis membrane decreases with increasing operating time. This phenomenon is due to membrane fouling. Therefore, it is necessary to regularly clean the membrane element system to remove contaminants from the surface or pores of the 4040 reverse osmosis membrane, thereby restoring water permeability and extending membrane life.

4040 Reverse Osmosis Membrane Cleaning Methods

Reverse osmosis membrane cleaning methods are divided into physical and chemical methods, both of which can effectively clean the membrane.

Physical methods: This method uses mechanical force to remove contaminants from the membrane surface. No chemical reactions occur during the entire cleaning process.

Chemical methods: This method uses certain chemicals to react with the filter cake on the membrane surface to achieve the purpose of cleaning the membrane. 4040 Reverse Osmosis Membrane Cleaning Physical Methods

1. Manual scrubbing method

This method is a relatively primitive but effective method. The basic procedure is to gently wipe the fouling on the surface of the disassembled flat membrane with a soft material (such as a sponge), rinsing with water as you wipe. This method can effectively remove a large amount of fouling from the membrane surface. However, it is ineffective against finer impurities deep within the membrane pores.

2. Isopressure hydraulic flushing method

This method can be used to clean ultrafiltration components of any configuration. The specific procedure is to close the product water valve and open the concentrate outlet valve, relying on the increased flow rate to flush the membrane surface. This is effective for removing large amounts of loose impurities from the membrane surface. The effectiveness of isopressure flushing is also related to the frequency of continuous flushing.

3. Backwashing method

Backwashing is a method of flushing from the back (porous support layer) to the front (dense layer) of the membrane. This is a highly effective cleaning method. After backwashing the membrane, followed by isopressure hydraulic flushing, the cleaning effect is very significant.

4. Hot water flushing method

Using heated water (30～40℃) to flush the membrane surface is effective for removing viscous and heat-soluble impurities (such as sugars).

5. Water-air mixed cleaning method

Purified compressed air and water are sent into the ultrafiltration device together. The water-air mixed fluid will produce a strong stirring effect on the membrane surface to remove stubborn impurities. The effect is also good.

4040 Reverse Osmosis Membrane Chemical Cleaning Methods

Principles for selecting chemicals when cleaning 4040 reverse osmosis membranes: First, they must not react chemically with the membrane or other component materials; second, they must not cause secondary pollution due to the use of chemicals. When using chemical cleaning methods, isopressure flushing and backwashing methods are often combined for more effective removal of contaminants from the membrane surface.

Oxidizing cleaning agents use 1%～3% H2O2, 500～1000 mg/L NaClO aqueous solutions for 4040 reverse osmosis membrane cleaning, removing fouling and killing bacteria. H2O2 is a commonly used disinfectant.

Enzyme detergents such as 0.5%～1.5% pepsin and trypsin are effective in removing protein, polysaccharides, and oily substances during 4040 reverse osmosis membrane cleaning.

The 4040 reverse osmosis membrane element is an important component of the water treatment system; therefore, regular cleaning of the 4040 reverse osmosis membrane is essential.