1. Close all the valves of SFP system.
2. Connect the outlet pipe of concentrated water with the blowdown tank  and connect the inlet pipeline of concentrated water with the pipeline of cleaning system equipment .
3. The cleaning pipeline shall be ensured that there is no leakage or splashing phenomenon.
4. Add 400L water produced by UF or RO to the blowdown tank , then slowly and evenly dissolve 1.6kg NaOH(100%) and 1kg hydrogen peroxide ( % concentration) in 400L water and pay attention to mixing evenly.
5. 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 5min.
6. Close the cleaning pump to make it static and sock for 10min.
7. Drain the blowdown tank and cleaning pump, and flush them with clean water.
8. Start the backflushing procedure.
9. Open the drainage valve of concentrated valve.
10. 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 50μS/cm, and return to the production operating status.