How to use the new RO reverse osmosis membrane?

Author: Hongjie Water

1、 Key technical points for using a new RO reverse osmosis membrane:

1. First, clean the quartz sand and coconut shell activated carbon, and wash the newly installed quartz sand and coconut shell activated carbon for a long time.

2. Check for residual chlorine. If there is excess chlorine, solve the problem before proceeding to the next step of the RO reverse osmosis membrane.

3. After installing the new film, soak it in water for 1-2 hours. As it is a dry film, the soaked film is relatively moist to prevent damage to the film due to high pressure.

4. Then start the high-pressure pump, and the pressure should gradually increase, from 2 kilograms to 8-10 kilograms, to achieve better desalination efficiency for the new membrane.

5. Control residual chlorine below 0.003.

6. Before starting the high-pressure pump, open the concentrated water valve first. After the high-pressure pump is started, slowly adjust the concentrated water valve to control the recovery rate of a single membrane by about 15%.

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

8. Detect the pH value of the inlet water, which is above 6.5.

2、 How to determine if the reverse osmosis membrane needs to be cleaned?

Under normal circumstances, reverse osmosis membrane components can be used for about 2-3 years. If you want to extend the service life, you can clean the reverse osmosis membrane components, usually divided into physical flushing and chemical flushing. When physical flushing cannot restore the performance of the reverse osmosis membrane, chemical cleaning should be carried out. Under normal circumstances, reverse osmosis membrane components can be used for about 2-3 years. If you want to extend the service life, you can clean the reverse osmosis membrane components, usually divided into physical flushing and chemical flushing. When physical flushing cannot restore the performance of the reverse osmosis membrane, chemical cleaning should be carried out.

3、 Cleaning of reverse osmosis membranes

Based on experience, if the reverse osmosis device is cleaned every three months or more. If it is cleaned once every 1-3 months, it is necessary to improve the operating conditions and improve the pre-treatment effect.

Determine the cleaning situation:

(1) Standardized freshwater production has decreased by more than 10%.

(2) The standardized salt penetration rate has increased by more than 10%.

(3) In order to maintain normal fresh water flow, the pressure difference between feedwater and concentrated water has increased by more than 10% after temperature calibration.

(4) There are serious pollutants and scale deposits in the internal devices.

(5) Before long-term shutdown of the RO device.

(6) Routine maintenance of RO device.

Before determining whether to clean the reverse osmosis system, the following other reasons that may cause the above phenomenon should also be comprehensively considered:

(1) The operating pressure drops (pressure control device malfunctions and high-pressure pump malfunctions);

(2) The inlet water temperature decreases (due to heater failure or seasonal changes causing a decrease in water temperature);

(3) The salt content of the inlet water increases;

(4) Pre processing exceptions;

(5) Due to membrane damage, misalignment of the central tube of the series membrane components, and inadequate sealing of the pressure vessel O-ring, concentrated water seeps into fresh water.

4、 Replacement of reverse osmosis membrane

After a period of normal operation of reverse osmosis equipment, the reverse osmosis membrane components may be contaminated by suspended solids or insoluble salts that may exist in the feedwater, resulting in the following symptoms:

1. The weight of membrane components in reverse osmosis equipment has increased;

2. The removal rate of RO membrane significantly increases or decreases; 

3. Under standard pressure, the water production of reverse osmosis equipment significantly decreases;

4. In order to achieve standard water production, it is necessary to improve the operating pressure;

5. The pressure drop between the inlet and concentrated water of the reverse osmosis equipment increases;

6. Remove the membrane element from the pressure vessel and pour water onto the inlet side of the vertical membrane element. If water cannot flow through the membrane element and only overflows from the end face, it indicates that the inlet channel is blocked.

Whether it is necessary to replace the reverse osmosis membrane components depends on the actual situation.