UF membranes use for RO pretreatment. If MWCO of UF membrane is low for sure the UF membrane fouling would be sever. And if the MWCO is high the solutes would pass and then we have sever fouling in RO membrane. What is the best MWCO range for UF as the RO pretreatment?
Less than 0.1 micron Absolute in terms of filtration is the coarsest microfiltration membrane typically used for wastewater RO pretreatment.
1 micron which has much larger filtration cut offs than UF, by a factor of 10-100 is generally the maximum filtration size acceptable for brackish and seawater RO pretreatment, depending on the raw feed water composition. (microfiltration starts around .1 micron And UF is .1 and below to 0.01 and smaller I believe.)
I'm not sure what these diameters relate to in terms of MWCO's
Dear Jared,
Firstly thanks for your time and support. We want to use of a UF membrane for pretreatment that the largest diameter of the pores are 10 nm. I believe that the membrane is not good for this application. I am afraid that we have a sever fouling for our UF membrane after a short time. I think we have to use a membrane with bigger pore size ! What is your idea ?
don't you have any pretreatment before UF? normally filtration processes are goes step by step. First big particles, then smaller ones, then more smaller particles.. untill you get what you want. If you use a membrane directly, you will waste your money
Dear Ahmet,
First of all thanks for your reply. Yes, for sure we have some other pretreatment processes like coagulation, ....
But as you know, the biggest UF membrane's problem is fouling, even for small molecules.
fouling is something you can not prevent. You can just decrease fouling so you can increase membranes lifetime. Coagulation is not a proper pretreatment for UF. mostly sand filter, activated carbon, cartridge or bag filters are commonly used (I assume that you are allready using chemical dosage like antiscalant, biosit etc) . (If your water has high turbidity, you should use sand filter, for chemicals, you should use activated carbon and filter for prevent any leakage from these filters).
Coagulation has not enough performance for pretreatment of membranes.
as a alternative method, you can search for Bernoulli filter which is actually 100 micron or bigger filter with capability of cleaning itself (but it is recommended for high flow rates also not an exact solution)
here is a link for you to take a look at this filters properties:
http://www.bernoulli.se/products/single-basket-bernoulli-filter
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