Chemical cleaning steps


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Preparation of cleaning solution

Prepare cleaning solution with reverse osmosis product water, accurately weigh the agent and mix evenly in the cleaning box. Check whether the pH value, temperature, and agent content of the cleaning solution meet the requirements.

Low pressure and low flow input of cleaning solution and circulation

Replace the raw water inside the component with the lowest possible cleaning solution pressure, which only needs to reach a pressure sufficient to compensate for the pressure loss from the inlet water to the concentrated water. The initial return water should be discharged to prevent the cleaning solution from being diluted. Allow the cleaning solution to circulate in the pipeline for 5-10 minutes. Observe the turbidity and pH value of the reflux liquid. If it becomes significantly turbid or the pH value changes by more than 0.5, timely supplement an appropriate amount of medication or prepare a new cleaning solution before proceeding with the above operations.


1. Cleaning pH and temperature limits

Module model

Maximum temperature 45 ℃

Maximum temperature 35 ℃

Maximum temperature 25 ℃





DNF100、DNF200、DNF300、DNF600 Series





2. follow

Stop the circulation of the cleaning pump to prevent the cleaning solution from flowing out of the pressure vessel. The cleaning solution inlet valve, cleaning solution concentrated water return valve, and cleaning solution produced water return valve can be closed. Depending on the contamination of the components, all membrane components should be immersed in cleaning solution for about 1 hour or longer (10-15 hours or overnight). During this period, the circulating pump can be intermittently turned on to maintain a constant cleaning solution temperature (25-30 ℃).


3. wash

First, rinse the system with product water for about 5 minutes, and then rinse the system with qualified pre-treatment water for 20-30 minutes. To prevent sedimentation, the minimum flushing temperature is 20 ℃, and the cleaning solution is completely flushed out without residue.


4. High flow water pump circulation

The flow cycle listed in the table below is 30-60 minutes. High flow rate can wash away pollutants that have been cleaned by the cleaning solution. If the pollution is severe, a flow rate higher than 50% specified in the table below can be used to improve the cleaning effect.


5. Recommended normal cleaning flow rate for membrane components

Membrane element diameter(in)

Flow rate of each pressure vesselgpd (m3 /h)






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