1.Close all valves of SFP system:
2. Connect the outlet pipeline of the concentrated water with the blowdown tank.
3. Connect the inlet pipeline of the concentrated water with the pipeline of the cleaning system equipment.
4. The cleaning pipeline shall be ensured that there is no leakage or splashing phenomenon.
5. Add 400L water produced by UF or RO to the blowdown tank , then add citric acid solid of 8kg  to 400 L water and fully agitate them to make evenly mixed to finally form 2% citric acid solid solution.
6. Start the cleaning water pump, slowly open the outlet valve of the cleaning water pump, control the flow of each membrane component at 500~1000L/h to let the cleaning solution enter to the concentrated water side of each membrane component, and at last return to the blowdown tank . The circulating time is 30min.
7. Close the cleaning pump to make it static and sock for 60min.
8. Drain the blowdown tank and cleaning pump, and flush them with clean water.
9. Start the backflushing procedure.
10. Open the drainage valve of concentrated valve, open the inlet water valve of SFP device, to make the incoming water pass through SFP membrane component, until the electric conductivity difference (the value exceeded) between the incoming water and the concentrated water is within 20μS/cm, and return to the production operating status.