Water Filtration via Membrane Technology
Purification or Filtration by Membrane technology is primarily used in commercial and industrial applications
There are 4 membrane processes that operate by applying
water pressure to a membrane; ie. Reverse Osmosis :
Microfiltration
(MF) is a process where water is forced under pressure
through a porous membrane. Membranes with a pore size of 0.45 Microns are
normally used.This size is relatively large compared with the other membrane
filtration processes. This process has not been generally applicable to
drinking water treatment because it either does not remove substances that
require removal from potable water, or the problem substances can be removed
more economically using other processes.
The primary use of MF is by industries to remove very fine
particles from process water, as in electronic manufacturing. Additionly MF is
often used as a pretreatment for other membrane processes. In particular, RO
membranes are susceptible to clogging or filter binding unless the water being
processed is already quite clean.
Ultrafiltration
(UF) is a process that uses a membrane with a pore size
generally below .1 microns. The smaller pore size is designed to remove
colloids and substances that have larger molecules, which are called
high-molecular-weight materials. UF membranes can be designed to pass material
that weigh less than or equal to a certain molecular weight. This weight is
called the molecular weight cutoff (MWC) of the membrane. Although UF does not
generally work well for removal of salt or dissolved solids, it can be used effectively
for removal or most organic chemicals.Again often used in combination with
Reverse Osmosis as a very effective pretreatment.
Nanofiltration
(NF) is a process using membranes that will reject even
smaller molecules than UF. The process has been used primarily for water
softening and reduction of total dissolved solids (TDS). NF operates with less
pressure that reverse osmosis and is still able to remove a significant
proportion of inorganic and organic molecules.
Reverse Osmosis
(RO) is a membrane process that has the highest rejection
capability of all the membrane processes. These RO membranes have very low MWC
pore size that can reject ions at very high rates, including chloride and
sodium. Water from this process is very pure due to the high reject rates. R.O
is used mainly in the water industry for desalinization of seawater because the
costs are equitable with other processes for this service
The RO also works effectively on most organic chemicals, and
radionuclides and microorganisms. Industrial water uses such as semiconductor
manufacturing is also an important RO process. Unlike domestic R.O units
industrial strength membranes are able to dump less than 30% of the flush water
to waste. This reject water is very concentrated, difficult to eradicate and in
the case of desalination it is often pumped deep offshore into drill holes.
Domestic R.O units are particularly inexpensive and do a
fantastic job of purifying drinking water for the home. They do, however,
require relatively clean pretreated water in order to protect the membranes.
Michael J runs a successful Water Filter distribution
company in South Africa and is particularly active in the Western Cape Coastal
area. Having acted as technical & sales trainer for larger water filtration
& wholesale suppliers he is qualified both in practical and theoretical
experience to advise on numerous water related conditions in South Africa and
abroad.
Look
For Synder At ECOAT 2012 And The International Cheese Technology Expo Next
Month!
Synder
Announces Consecutive Record-Breaking Quarters
Synder
Filtration Shows Strong Growth In 2012 And Purchases A New 53,000 Sq. Feet
Building.
Synder Doubles Production Capacity At Vacaville Manufacturing Center
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