In addition to separate styles of membranes, RO
membranes and systems range in their effectiveness
of precluding materials of varying sizes. There are
membranes that can prevent particles as small as
0.0001 microns to those that can trap particles as “large”
as 0.1 micron. For purposes of scale, a micron (abbre-
viation of “micrometer”) is one-millionth of a meter. A
typical human hair ranges from less than 50 microns
to just over 150 microns. Reverse osmosis membranes
are made from various materials like polyamide thin
film composites, or cellulosic types including cellulose
acetate, cellulose triacetate, or various blends of each.
Membranes are also designated by their recovery rate,
which means how much treated water they produce as
compared to the amount of untreated water introduced
to the system. This percentage is simply calculated by
dividing the volume of expelled, treated water by the
total volume of untreated water entering the system.
The efficiencies of these vary, but a household-sized
unit may only be in the 20-30 per cent effectiveness
range, with the balance of the water (called reject
water) being used to flush out the expunged solids
which then are diverted into the waste water stream.
“Water-borne bacteria that cause root rots and other fungal problems s m e l b o r p l a g n u f r e
can be eliminated or greatly reduced by using an RO system.”
Maintenance is yet another consideration and
distinction between types of RO systems and
membranes. Membranes are not permanent inserts. They
need to be replaced at least every five years depending
on use and sometimes as often as every one to two years.
The better the system in place to pre-screen sediments
and particles before entering the membrane, the longer
the useful life of the membrane.
After passing through a membrane of either sort,
water in an RO system then generally passes through
another filter containing carbon or charcoal to remove
any potential unwanted smells. It is then ready to be
consumed or is suitable for use in plant production.
WHY REVERSE OSMOSIS
IS USED IN HORTICULTURE
Plants are particularly susceptible to a wide range of
contaminants often found in some water sources. In some
cases those contaminants may negatively affect healthy
plant growth and in worse case scenarios, the plants can
absorb toxins that are then passed along to humans upon
consumption of the affected plants.
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Maximum Yield