The RO membrane cleaning manual of 3TPH RO Plant

RO membrane Function:

Remove all harmful substances, make sure the treated water can meet the pure water standard.The most suitable temperature of RO membrane is 5℃~35℃, it is the best to control water temperature at 20℃-25℃.

Please pay attention to check the feed water and concentrated water pressure, controlling it in the setting range. After PP filter, before water entering, the lower limit of pressure gauge pointing at 0.3Mpa, the upper limit of high-pressure pump working pressure gauge pointing at 1.0Mpa.

Operation notes:

Often pay attention to the pressure differential of precision filter. The main reason for the sharp rise in pressure is precision filter clogging seriously. Instead, the cause of a sharp decline in dropout precision filter cartridge is damaged, as well as the fastening screws of precision filter element loose.

Chemical cleaning maintenance process

1) fter RO membrane running some time. Some contaminants intercepted by RO membrane.

The RO membrane should be chemical cleaning. Use permeated water mixed with the chemical powder in the chemical tank. Do it like this can remove all the organic and inorganic from the surface of RO membrane.Prolong RO membrane lifetime. Chemical cleaning standard:

a. The permeated water outflow reduce 10~15%.

b. The difference between feed water and the concentrated water is increased to 1.5 times of the initial value.

c. Products water quality reduce 10~15%.

2) Chemical cleaning frequency: It depend on the membrane polluted condition. Normal cleaning period 3~12 month.

If feed water is brackish water or treated waste water each 3-4 month make 1 time chemical cleaning,

If the feed water TDS less than 2000PPM suggestion 6 month make 1 time cleaning, each time 60~90 minutes.

3) RO chemical cleaning formula.

a) Liquid I: 2.0% (W) citric acid (C6H8O7) low PH 3-4. Remove inorganic scale (calcium carbonate scale, calcium sulfate, barium sulfate, strontium, etc.) and iron, manganese, copper, nickel, zinc, etc. Commercial available (C6H8O7) as powder solid.

b) Liquid II: 2.0 (W)% STPP (NaP₃O₁₀) and 0.8% (W) Na-EDTA mixture PH = 10. Remove natural organic contaminants. STPP and Na-EDTA commercial available powders are solid.

c) Liquid III: 0.1% NaOH and 0.03% (W) SDS / C₁₂H₂₅-OSO₃Na, high PH mixture (PH = 10) to remove natural organic contaminants, inorganic / organic hybrid colloids emblem biological contaminants and dirt ( fungoid, algae, mold, fungi) contamination. This liquid is to enhance chemical cleaning.

4) Cleaning agent for various pollutants

5) Chemical cleaning processes 

Note: Usually adopt High PH solution(③)cleaning oil and microbe pollution.Second stage to adopt low PH solution ①cleaning Inorganic scale or metal oxidation.

Example: 3T RO/Hr need below quantity:

3 piece *68L/piece=204 L soulution(Need)

Citric acid: 2.7KG with 200L water mixing. About Total 203 L solution.

Sodium tripolyphosphate: 2.7KG with 200L water mixing. Total 203 L solution.

We suggestion use more than 203 L solution. Like use 250L. Some parts solution on the pipes.

A. First soak then recirculate (Sodium tripolyphosphate )

After cleaning liquid is ready, start the chemical cleaning pump, The liquid enters from port A to port B of RO unit, when the chemical liquid outflow from port B, slowly close the chemical cleaning inlet valve, turn off the recirculation pump, in order to prevent the liquid out, turn off the outlet valve when soaked. Let the liquid stay for 30 minutes (soaking time depends on the degree of pollution ).

B. Flushing (use the permeated water flushing)

After soaking, open the outlet water valve and make it circulates for 30 minutes. Then use Clean water to flush until clean ( flush-time: 20 minutes). The machine replaced by emissions from circulation( at this time drainage water is forbidden to enter tank ).

C. Second soak then recirculate (Citric acid cleaning)

After cleaning liquid is ready, start the chemical cleaning pump, The liquid enters from port A to port B of RO unit, when the chemical liquid outflow from port B, slowly close the chemical cleaning inlet valve, turn off the recirculation pump, in order to prevent the liquid out, turn off the outlet valve when soaked. Let the liquid stay for 30 minutes (soaking time depends on the degree of pollution).

D. Flushing (use the permeated water flushing)

After soaking, open the outlet water valve and make it circulates for 30 minutes. Then use Clean water to flush until clean ( flush-time: 20 minutes). The machine replaced by emissions from circulation( at this time drainage water is forbidden to enter tank ).

E. After use cleaning, Please change the PP filter. Then start the machine.

More questions regarding the RO Plant, please feel free to contact us:

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