Ultrafiltration is a separation process using membranes with pore sizes in the range of 0.1 to 0.001 micron. Typically, ultrafiltration will remove high molecular-weight substances, colloidal materials, and organic and inorganic polymeric molecules. Low molecular-weight organics and ions such as sodium, calcium, magnesium chloride, and sulfate are not removed.
Because only high-molecular weight species are removed, the osmotic pressure differential across the membrane surface is negligible. Low applied pressures are therefore sufficient to achieve high flux rates from an ultrafiltration membrane. Flux of a membrane is defined as the amount of permeate produced per unit area of membrane surface per unit time. Generally flux is expressed as gallons per square foot per day (GFD) or as cubic meters per square meters per day.
Ultrafiltration membranes can have extremely high fluxes but in most practical applications the flux varies between 50 and 200 GFD at an operating pressure of about 50 psig in contrast, reverse osmosis membranes only produce between 10 to 30 GFD at 200 to 400 psig.
Ultrafiltration, like reverse osmosis, is a cross-flow separation process. Here liquid stream to be treated (feed) flows tangentially along the membrane surface, thereby producing two streams. The stream of liquid that comes through the membrane is called permeate. The type and amount of species left in the permeate will depend on the characteristics of the membrane, the operating conditions, and the quality of feed. The other liquid stream is called concentrate and gets progressively concentrated in those species removed by the membrane. In cross-flow separation, therefore, the membrane itself does not act as a collector of ions, molecules, or colloids but merely as a barrier to these species.
Conventional filters such as media filters or cartridge filters, on the other hand, only remove suspended solids by trapping these in the pores of the filter-media. These filters therefore act as depositories of suspended solids and have to be cleaned or replaced frequently. Conventional filters are used upstream from the membrane system to remove relatively large suspended solids and to let the membrane do the job of removing fine particles and dissolved solids. In ultrafiltration, for many applications, no prefilters are used and ultrafiltration modules concentrate all of the suspended and emulsified materials.
Ultrafiltration will find an increasing application in the production of high purity water. The basic principles outlined here should help in the understanding and use of this technology.
Ultrafilter for home & light commercial application: the best outdoor solution…
The ultrafiltration system is a very powerful outdoor water filtration system that can remove not only particles and sediments but also bacteria and virus. This system is covered by a stainless steel housing with additional auto flush that can clean by itself. The technology of the filtration system is through the membrane technology which started more than 20 years ago with Reverse Osmosis. Reverse Osmosis is 0.0001 micron while the ultrafiltration system is 0.01 micron, therefore the ultra filter can perform its function without the need of pump.
This system also wash automatically by itself. The auto flush is run by a battery (9v Energizer). The size of the system is around 3ft and 10 cm diameter makes it presentable and practical to install it on the wall instead of taking much of the floor space just like the conventional bulky sand filter bullet Vessel. The water pressure will not be affected because of the 1400 over hollow fibers that operates in the stainless steel housing.
This system comes with 2 filtration system which the first would be the ultrafilter and then the
second,the transparent indicator filter. This indicator filter serves to show how clean the first filter perform. This is the first in Malaysia that have a quality indicator so that you will know how good and clean the water that comes out from the first ultrafiltration system.
This system is fully auto washed and run by normal Energizer batteries. This system is 1000 times cleaner than the sand filter and it can actually protect your water heater, washing machine, internal piping and faucet from rusty and reduce oxidation. This system however is not fully being utilized especially by most of the untrained installer. Most of the installer does not install this system the correct way and therefore cannot prolong the lifespan of the internal membrane cartridge. This is the reason why many peope has the perception that membrane filter does not last.
or more information about the ultrafilter solution for you home, office or commercial, please email to us on info@waterexpress.com.my or call us at 03-5621 7915
