Inside / Out
or Outside / In ?
Inside/Out filtration was originally
developed for fluids concentration (when the valuable stream
is the concentrate). The Outside / In filtration has many advantages for water treatment :
• Higher membrane area in a smaller volume
• Simpler process thanks to dead end filtration mode
• Less pipping in the system
• No risk of fiber plugging
• Easier backwashing with air and less water
Ultra or Micro Filtration
?
• Investment and operating costs are the same
for both, and both allow to work at the same flux
• depending to the test procedure UF will remove 4 log and more viruses while MF will remove 1 to 4.
• The SDI removal is better with UF than MF
That is why UF is more
and more selected instead of MF.
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The
membrane filtration technologies reminder
•
Low pressure
Microfiltration (0.1
µm to 1 µm)
Clarification, disinfection
Ultrafiltration (0.005 µm to 0.1 µm )
Clarification, virus disinfection,
NF or RO pretreatment
• High pressure
Nanofiltration
(< 0.005 µ)
Organic molecules and large ions retention
: COD removal, color removal, partial desalination, softening,
desulfatation,..
Reverse Osmosis
Water is passing by diffusion through a dense membrane while
ions and small organic species are rejected : desalination,
demineralization.
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Ultrafiltration
