The chemical cleaning procedure for biological contamination of reverse osmosis element membrane is shown below. The details are determined according to the on-site operation situation and cleaning requirements.

1. Rinse the membrane element. Rinse with RO reverse osmosis or ion exchange for a few minutes.
2. Configure cleaning agent. Make sure that the cleaning agent is completely melted.
3. Loop. The water in reverse osmosis element membrane is replaced with a low flow rate, and part of the cleaning liquid is discharged and then circulated. When the environmental pollution is serious, if a large flow rate is selected, the problem of excessive pressure difference may be caused, and reverse osmosis element membrane may be damaged.
At this time, it is more reliable to choose the following methods for actual operation:
(1) The cyclic operation is carried out gradually for 5 minutes, and the cycle is carried out at 1/3 of the set flow;
(2) Circulate for 5-10 minutes, and circulate at 2/3 of the set flow;

(3) Circulate according to the flow rate after 10 minutes.

4. The cycle time should be determined according to the details. Generally one hour is the standard. During this period, check whether the pH value changes anytime and anywhere. The working pressure should be kept as low as possible, and water should not be produced as much as possible. At the same time, check whether the pressure difference has changed.
5. Soaking and recycling. Slowly close the gate valve of channel 1 of the reverse osmosis membrane. When the circulation volume is close to zero, close the circulation pump. In order to better prevent the liquid from being discharged from the high-pressure container, the relevant gate valve can be closed when soaking. The soaking time depends on the level of environmental pollution. Generally in the range of 1-12 hours. After soaking, open the relevant gate valve to circulate.

6. Rinse. The chemical solution in reverse osmosis ro membrane is washed with water filtered by reverse osmosis element membrane or ion exchange water. At this time, the circulation condition is converted to the discharge condition. The membrane system is flushed with tap water, and the flushing time is about 20-60 minutes, which can accurately measure the pH value and conductivity of the sewage and determine whether the flushing is performed. The pH value and conductivity value are similar to the value of injected water, and the flushing can be terminated without change.

7. Test run. It will start the system normally and drain the first batch of produced water until the water quality is specified. The repair time is likely to take several hours to several days to obtain a stable ro water filter membrane water production. It takes a certain amount of time to restore water quality, especially after cleaning with alkaline solution (high pH).