Filter Membrane Blockage Prevention

Question

In a treatment package plant attached with a reverse osmosis machine, how can one resolve the issue of membrane filter blockage prematurely and how long does it take before a filter needs replacement?

MUHAMMAD ILYAS KHAN · Answer

Pl. install "HYDROFLOW" equipment upstream of RO. The Membrane shall not be blocked for Years. Its one time investment and equipment life is 10Years+. for details contact: milyaskhn@yahoo.com

Steve Oxtoby · Answer

I presume that you are meaning that the pre-treatment filters are blocking prematurely rather than the membranes becoming fouled. If that is the case it sounds like the raw water quality is rather worse than the system was designed for and that could be due to a lot of reasons such as others have mentioned silt, iron, biofouling etc.
What you need to do is to identify this and then put in additional treatment steps such as self washing filters and/or chemical treatment to reduce the load going onto the protection filters.

Jeff Crooks · Answer

We have a self cleaning filtration technology that works very well to remove TSS down to 20 um. This would be installed ahead of your membrane filter. We also have an environmentally friendly flocculent that works well to capture fines down to 3um.

Prem Baboo · Answer

Fouling remediation can be done through pre-treatment the feed to limit its fouling propensity, improving the antifouling properties of the membrane, membrane cleaning and backwash conditions and optimization of the operating conditions.Membranes are susceptible to fouling; therefore, pretreatment of the feed is required to control colloidal, organic, and biological fouling as well as scaling. The pre treatment scheme must be capable of controlling membrane fouling to such an extent that a practical cleaning frequency can be achieved. For low-pressure membranes, a number of pre-treatment methods are currently used.
Coagulation involves the addition of chemicals coagulants, such as: FeCl3 , FeSO4 , alum, polyaluminum chloride, etc.., to increase the size of suspended and colloidal particles in the feed prior to filtration. It was found that reversible fouling was reduced with coagulation pre-treatment, but the extent of irreversible fouling was unchanged. This can be attributed to the fact that large particles are formed from small particles, and hence, reversible fouling decreases with the use of coagulation. However, smaller particles, which are not coagulated, still remain in the feed and causes irreversible fouling. Factors affecting membrane fouling includes coagulant dosage, pH, nature of dissolved organic matters as well as Ca2+ content of the feed water.

Ronit Erlitzki · Answer

Hi Hakeem,
Membrane scaling and biofouling is a major operational concern, and adequate pre treatment is a necessary common practice. However one approach I know of that actually increases recovery and prevents scaling is Flow Reversal RO. Ronit@adedgetechnologies.com

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