Membrane Cleaning Faq

Membrane Cleaning Faq

Membrane Cleaning Faq
  1. Which Membrane Cleaner Should I Use?
  2. How much cleaning solution will I need to clean my membranes?
  3. What should the flow rate be for proper membrane cleaning?
  4. What is the proper sequence to follow when cleaning membranes?
  5. How often should I clean my membranes?
  6. Is is necessary to heat our RO cleaning solution?

  1. Which Membrane Cleaner Should I Use? 

    The membrane cleaner required will depend on the type of fouling the membrane has been exposed to. Visit the below page to troubleshoot:



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  2. How much cleaning solution will I need to clean my membranes? 

    Estimate of Cleaning Solution Volume:
    V = El × Vol × 5

      • El = Number of Elements

    • Vol = Volume of one element from Table Below


    Membrane Type Chemical Solution Volume, Gallons (Vol)
    4" x 40" 2.5
    4" Magnum 3.5
    6" x 40" 4.0
    8" x 40" 6.0
    8" Magnum 8.5


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  3. What should the flow rate be for proper membrane cleaning? 

    Estimate of Total Flow Required for Membrane Cleaning:
    HTF = NV × HF
    MTF = NV × MF

     

      • HTF = High Total Flow

      • MTF = Medium Total Flow

      • NV = Number of Vessels in Parallel

      • HF = High Flow from Flow Table (below)

      • MF = Medium Flow from Flow Table (below)





    Membrane Type Medium Flow (MF) High Flow (HF)
    4" x 40" 4 10
    4" Magnum 4 10
    6" x 40" 12 20
    8" x 40" 25 35
    8" Magnum 25 35



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  4. What is the proper sequence to follow when cleaning membranes? 

    Whether the system needs acid or alkaline cleaner will depend on the type of foulant suspected. We reommend acid cleaning be performed first, even when alkaline cleaning is desired. If system performance recovers with acid cleaning, then alkaline cleaning is not necessary.

    Membrane Cleaning Sequence:
    1. Alkaline Cleaning
    2. Flush
    3. Acid Cleaning
    4. Flush
    5. Sanitizing
    6. Flush



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  5. How often should I clean my membranes?

    In normal operation, the membrane in reverse osmosis membrane elements can become fouled by suspended solids, microorganisms and mineral scale. These deposits build up during operation and cause loss in water output or salt rejection, or both. Membrane elements should be cleaned whenever the normalized water output rate drops by 15% from its initial flow rate (the flow rate established during the first 24 to 48 hours of operation) or when salt content in in the product water rises noticeably.

    It should be noted that the water output rate will drop if feedwater temperature decreases (see Temperature Correction). This is normal and does not indicate membrane fouling. Click here to view RO membrane cleaning chemicals.



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  6. Is is necessary to heat our RO cleaning solution? 

    If your cleaning solution temperature is at least 20 deg C, then you do not need a heating element.
    Also, as you recycle the water there will be further rise in temperature, which should be kept below 50 deg C.



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