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Filters
» Filter overview
» Do filters affect TDS?
» Filters, Membranes, DI.
Which process removes what from the water?
Filters
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| Filter overview | | I want to take a moment to discuss a very basic and important reverse osmosis topic.
Pre filters:
Sediment filters designed to remove dirt and particles from the water.
Carbon filters,designed to remove chemicals mixed with the water.
Carbon block filters sreve double duty removing both chemicals and sediments.
The optimal situation is to progressively remove the dirt/sediment.
Progressive filtration will distribute the dirt/ sediment load across the complete filter array.
In this manner the first filter protects the next filter and so on.
One possible arrangement of pre-filters is:
Stage one- a ten micron sediment filter
Stage two- a five micron coconut carbon block
Stage three-a one micron coconut carbon filter
This method of progressive filter placement will lower the pressure drop, increase filter life and improve the overall performance of any water treatment system.
The manufacturer of the FilmTec reverse osmosis membrane requires the removal of oxidants/chlorine and of particles/sediment larger than five (5) micron to comply with its three year warranty.
(www.filmtec.com)
We are in the filter replacement business and we could easily double or triple our filter sales by recommending a one micron sediment filter in stage one. | | Do filters affect TDS? | | Filters do not impact TDS. The total dissolved solids are just that dissolved as such they can not be filtered. The smallest micron rated of filter will not have a impact on TDS. In fact you can prove this to your self, test the incoming water, test the water after just the filters. Use any micron rating you want. Filters do not and can not remove dissolved solids. (TDS) dissolved solids can be removed from water by Reverse Osmosis, Distillation and DI
The role sediment filters play, is the removal of particulate matter or sediment. Material floating around or in water is not a part of the dissolved solids. (TDS)
When a substance is dissolved into water it is ionized or becomes an ion. That Ion can not be filtered. Membrane pores are hundreds of times smaller than the .5 micron filter you may using.
The term DI stands for deionization, removal of the TDS from water by cation and anion attraction to resins.
Distillation is the removal of water vapor from the dissolved solids.
Distillation and Deionization are more effect than Reverse Osmosis but nothing is more environmentally friendly or as inexpensive as RO.
Reverse osmosis is King when it comes to water purity, ease of production, cost, environmental impact and over all effectiveness. | | Filters, Membranes, DI.
Which process removes what from the water? | | Sediment filters filter out particulate matter only.
Carbon filters absorb chemicals, Carbin block filters, filter particulate matter (sediment as well).
Membranes: remove bacteria, virus, metals, salts (ions).
DI Cartridges: remove ions (heavy metals or salts) dissolved into the water.
The typical R.O. system is built in this fashion:
Sediment filter: to remove large sediment and particulate matter from the water. The sediment filter should have as large a micron rating as practical. We recommend ten micron.
The next stage is usually a carbon stage (GAC,PAC,or Carbon block) This stage is where chemicals start to be removed from the water. There are lots of different carbon filters. The best carbon filters are block type. We recommend a coconut carbon block that has been acid washed. Here I recommend a rating of five micron.
In a properly designed unit there will be a second carbon stage actually pre-filter number three. I recommend a one micron coconut carbon block filter. Why two carbon filters? Just ask any one about chloramines and ammonia leakage from a one carbon stage system. One carbon stage systems are basically obsolete.
The membrane stage this is where all of the real work is done. The membrane's pore is hundreds of times smaller than a one micron filter.
The Membrane is the first filter to impact the bacteria, virus, pathogens, endotoxins and the (TDS) total
dissolved solids. Sediment or carbon filters should not be relied upon to remove bacteria , virus or pathogens.
Your pre-filters, even if you use all one micron, have no impact on the TDS of the finished water.
The DI stage: The ions, dissolved metals, salts, that are missed by the membrane are captured by the DI stage.
A properly designed RODI provides sediment, bacteria, chemical, virus, and
dissolved metals free water. Just about as close to pure as you can get. Nothing provides more protection at any where near the cost or is as environmentally friendly. |
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