You are here: Home » News » Industry news » How to properly use a new RO reverse osmosis membrane?

How to properly use a new RO reverse osmosis membrane?

Views: 9     Author: Site Editor     Publish Time: 2022-03-29      Origin: Site

Technical points of using the new RO reverse osmosis membrane

1. Rinse the quartz sand and coconut shell activated carbon cleanly, and rinse the newly installed quartz sand and coconut shell activated carbon for a longer period of time.

2. detect whether there is residual chlorine, if there is residual chlorine exceeds the standard, solve the residual chlorine problem before the next step of RO reverse osmosis membrane.

3. After the new membrane is installed over water, soak the membrane for 1 to 2 hours, because it is a dry membrane, soak the membrane more wet, to prevent the pressure is too high to damage the membrane.

4. Then start the high pressure pump, the pressure should be increased slowly, from 2kg to 8-10kg, which will have better effect on the desalination rate of the new membrane.

5. Keep the residual chlorine below 0.003.

6. Open the concentrated water valve before starting the high-pressure pump, and slowly adjust the concentrated water valve after the high-pressure pump is turned on to control the single membrane recovery rate of about 15%.

7. The water produced in the first half hour must be drained because there is a protective liquid inside the membrane to avoid affecting the taste of the water.

8. Test the incoming water PH value, above 6.5.

How can I tell when a reverse osmosis membrane needs cleaning?

(1) The standardised fresh water yield has decreased by more than 10%.

(2) The standardised salt permeation rate has increased by more than 10%.

(3) The pressure differential between feed water and concentrated water has increased by more than 10% after temperature calibration to maintain normal fresh water flow.

(4) Serious contaminants and scaling material in the internal unit.

(5) Before the RO unit is taken out of service for an extended period of time.


Before judging whether to implement cleaning of the RO system, some other possible causes of the above phenomena should also be taken into account, as follows.

☆ A drop in operating pressure (failure of the pressure control device and abnormalities in the high pressure pump).

☆ Decrease in feed water temperature (heater failure, or seasonal changes causing a decrease in water temperature).

☆ an increase in the salt content of the incoming water

☆ Abnormal pretreatment.

☆ Damage to the membrane, misalignment of the central tube of the tandem membrane element, poor sealing of the pressure vessel O-ring, etc. resulting in the infiltration of concentrated water into fresh water.

How to clean reverse osmosis membranes?

How to clean reverse osmosis membranes

Different contaminants cause different levels of damage to the membrane and different cleaning solutions are used for different contaminants.

(1) Reverse Osmosis Cleaning System

It is generally composed of cleaning pump, chemical preparation tank, 5-20um security filter, heater, related pipeline valves and control instruments.

(2) Operation

Cleaning methods are static immersion and circulation cleaning. Static immersion with cleaning liquid soaking membrane, time depending on the degree of pollution, roughly 1-15h.

The general steps of circular cleaning are

1. Use the pump to send fresh water from the pharmaceutical preparation tank into the pressure vessel and discharge for a few minutes.

2. Prepare the cleaning solution in the pharmaceutical preparation tank with fresh water.

3. Use the cleaning solution to clean the pressure vessel in a cycle for 1h or up to a predetermined time.

4. After the cycle of cleaning is complete, the preparation tank is then washed clean with fresh water.

5. Rinse the above pressure vessel with fresh water.

6. After flushing, operate the reverse osmosis system with the fresh water discharge valve open until the fresh water is clean and free of foam or cleaning fluid, usually for 15-30 min.

Replacement of Reverse Osmosis Membranes

After a period of normal operation of the reverse osmosis equipment, the reverse osmosis membrane elements will be contaminated by suspended matter or insoluble salts that may be present in the feed water and the following symptoms will occur.

1 An increase in the weight of the membrane element of the RO plant.

2 a significant increase or decrease in the RO membrane removal rate.

3 a significant decrease in the water production of the RO plant at standard pressure.

4 the need to improve the operating pressure in order to achieve the standard water yield

5 the pressure drop between the incoming water and the concentrated water of the RO plant increases; 6 take the membrane element out of the pressure vessel and pour water on the incoming water side of the vertical membrane element, if the water cannot flow through the membrane element and only overflows from the end face, it indicates that the incoming water channel is blocked.


Whether the reverse osmosis membrane element needs to be replaced or not depends on the actual situation.