What conditions need to be met for chemical cleaning of membrane systems


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Suspended solids, colloids, organic matter, microorganisms, and salts precipitated after concentration in the influent will adhere to the membrane surface. After a period of operation, it will cause fouling and blockage of the membrane components, resulting in a decrease in system performance; The performance degradation of the membrane system is mainly manifested by a decrease in water production, a decrease in desalination rate (increased conductivity), an increase in pressure difference between influent and concentrated water, and a change of about 10% in the above indicators. Therefore, it is necessary to start the cleaning program in a timely manner. Only by cleaning can the initial performance be restored.




During normal operation, the membrane inside the reverse osmosis or nanofiltration element may be contaminated by inorganic salt scale, microorganisms, colloidal particles, and insoluble organic substances, resulting in a decrease or simultaneous deterioration of the standard production water flow rate and system desalination rate.

When the following situations occur, it is necessary to clean the membrane components:

1. Reduce standard water production by more than 10%;

2. The standard pressure difference between inlet water and concentrated water has increased by 15%;

3. After the standard salt penetration rate increases by more than 5% and meets the chemical cleaning conditions, chemical cleaning must be carried out in a timely manner. Generally, the initial performance can be basically restored after cleaning;

However, if not cleaned in a timely manner, it will cause deep pollution of the membrane system, resulting in minimal chemical cleaning effect and making it difficult to restore the system's good performance.

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