Wednesday, August 18, 2010


Normally filtration is a unit operation intended to separate solutes from a non-homogeneous dispersion where solutes are held on the filter while the liquid part passes through. The end goal is either to recover the solids or clean up the liquid. Filter papers, metallic filters and filter cartridges are the main component of a filtration system. Filtration is combined with extraction used by the food industry to prepare solutions containing active principles/soluble solids from raw materials like coffee, tea, spices, etc and the solvating agent can be water or any organic solvent that can get maximum extraction. The membrane filtration, on the other hand is used largely to selectively recover solids of particular particle size range using membranes containing pores of appropriate diameter and developments in membrane materials have been dramatic during the last one decade.

"The use of membrane filtration offers a wide range of advantages for the consumer as well as for the producer. On the one hand, filtration technology offers an efficient way to gain superior quality and safety without destroying the fundamental sensory qualities of the product. It removes unwanted ingredients like microorganisms, dregs or sediments that have a negative impact on product quality, making the final product more attractive in texture and increasing its shelf life. On the other hand, it may reduce some production steps and increase yield, has a high degree of selectivity, improves control over the production process and has low energy costs. The development of filtration techniques and their distribution is not yet complete. There is continuing development of new applications based on the technique. New methods, in particular development of better and longer lasting membranes, offer new perspectives".

To day water purification using compact reverse osmosis (RO) membrane system is very common being used widely in many house holds in India and provide protection from dangerous bacteria and virus which other wise pollute the public water supply making it non-potable. RO units are becoming increasingly being used for a variety of applications and the ability of the technology to desalinate sea water is opening up new sources of potable water in many areas where fresh water availability is constrained. Nano filtration, micro filtration, ultra filtration all refer to basically same technology and they are becoming part and parcel of food and beverage industry operations.


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