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Water Filters
for Home, Marine, and
Aviation Water is
generally classified into two groups:
Surface Water and Ground Water. Surface
water is just what the name implies; it
is water found in a river, lake or other
surface impoundment. This water is
usually not very high in mineral content,
and many times is called "soft water"
even though it usually is not. Surface
water is exposed to many different
contaminants, such as animal wastes,
pesticides, insecticides, industrial
wastes, algae and many other organic
materials. Even surface water found in a
pristine mountain stream possibly
contains Giardia or Coliform Bacteria
from the feces of wild animals, and
should be boiled or disinfected by some
means prior to drinking.
Ground Water is that which is trapped beneath
the ground. Rain that soaks into the ground,
rivers that disappear beneath the earth,
melting snow are but a few of the sources that
recharge the supply of underground water.
Because of the many sources of recharge, ground
water may contain any or all of the
contaminants found in surface water as well as
the dissolved minerals it picks up during it's
long stay underground. Waters that contains
dissolved minerals, such as calcium and
magnesium above certain levels are considered
"hard water" Because water is considered a
"solvent", ie, over time it can break down the
ionic bonds that hold most ubstances together,
it tends to dissolve and 'gather up' small
amounts of whatever it comes in contact with.
For instance, in areas of the world where rock
such as limestone, gypsum, fluorspar,
magnetite, pyrite and magnesite are common,
well water is usually very high in calcium
content, and therefore considered "hard".
Due to the different characteristics of these
two types of water, it is important that you
know the source of your water -- Surface or
Ground. Of the 326 million cubic miles of water
on earth, only about 3% of it is fresh water;
and 3/4 of that is frozen. Only 1/2 of 1% of
all water is underground; about 1/50th of 1% of
all water is found in lakes and streams. The
average human is about 70% water. You can only
survive 5 or less days without water.
Hard
Water
What is hard
water?
Hard water is the most common problem found in
the average home. Hard water is water that
contains dissolved hardness
minerals above 1 GPG.
What are
hardness minerals?
Calcium, manganese and magnesium are the most
common.
How do you
Measure Hardness?
Parts per million or grains per gallon are the
most common. One part per million (PPM) is just
what it says: out of one million units, one
unit. Grains, or grains per gallon (GPG) is a
weight measurement taken from the Egyptians;
one dry grain of wheat, or about 1/7000 of a
pound. It takes 17.1 PPM to equal 1
GPG.
Why Should Hard Water Concern
Me? For many uses,
it would not matter. For instance, to put
out fires, water your lawn, wash the mud
off the streets or float your boat, water
would have to be pretty hard to cause a
problem. But for bathing, washing dishes
and clothes, shaving, washing your car
and many other uses of water, hard water
is not as efficient or convenient as
"soft water."
For
instance: you use only
1/2 as much soap cleaning with soft
water. because hard water and soap
combine to form "soap scum" that can't be
rinsed off, forming a 'bathtub ring' on
all surfaces and drys leaving unsightly
spots on your dishes. when hard water is
heated, the hardness minerals are
re-crystallized to form hardness scale.
This scale can plug your pipes and hot
water heater, causing premature failure,
necessitating costly replacement. the
soap scum remains on your skin even after
rinsing, clogging the pores of your skin
and coating every hair on your body. This
crud can serve as a home for bacteria,
causing diaper rash, minor skin
irritation and skin that continually
itches. For many industrial uses, the
hardness minerals interfere with the
process, causing inferior product.
Who Will Test
My Water for
Hardness?
If you are connected to a municipal supply,
call the water Superintendent, or City Hall.
They can either provide the answer, or direct
you to the proper individual. Remember the
conversion factor: it takes 17.1 PPM to equal 1
GPG. In other words, if your water has 171 PPM
calcium in it, divide 171 by 17.1 to get the
answer in grains. This example would be 10
grains, or GPG. If you are on a private supply,
you could contact your county extension agent:
collect a sample in an approved container and
send to the city or state health department for
testing: find a testing lab (try the yellow
pages): call a water conditioning company. By
the way, if you are on a private well, YOU, AND
YOU ALONE are responsible for the safety of the
water you and your family drink. You should
test your supply for bacteria at least once per
year and other contaminants at least every
three years -- more under certain
conditions.
My Water is
Hard; Now What?
If your water tests over 3 GPG hard, you should
mechanically soften it. Softening water that is
less than 3 GPG, while it makes your shaving
and bathing more comfortable, is considered a
luxury due to the fact that the cost is more
than your savings. Over 3 GPG, you will save
enough to pay for the cost and maintenance of a
water conditioner.
As of this writing, the most economical way for
you to soften your household water is with an
ion exchange water softener. This unit uses
sodium chloride (salt) to recharge man made
plastic like beads that exchange hardness
minerals for sodium. As the hard water passes
through and around the plastic like beads, the
hardness minerals (ions) attach themselves to
the bead, dislodging the sodium ions. This
process is called "ion exchange". When the
plastic bead, called Resin, has no sodium ions
left, it is exhausted, and can soften no more
water. The resin is recharged by flushing with
salt water. The sodium ions force the hardness
ions off the resin beads; then the excess
sodium is rinsed away, and the resin is ready
to start the process all over again. This cycle
can be repeated many, many time before the
resin loses it's ability to react to these
forces.
Which Water
Conditioning Company should I
call?
As in any purchase, talk to your friends and
neighbors -- who do they use? Are they happy
with them? Check with the Better Business
Bureau for complaints. The BBB can't prevent
shady business, but they can and do keep a file
of complaints filed by people who have had
dealings with them.
Ask at least two to come to your home to look
at your plumbing and then give you a quote on
their equipment. Have them explain all the
features of the unit, as well as the
warranty.
What Should I
look for in a Water
Conditioner?
Make sure the unit has enough resin to treat
all the water you and your family will use. As
of this writing, the average usage per day, per
person (including children), for inside the
house is 87 gallons. You should also be shown
two or three ways to initiate recharging the
unit.
The oldest way is by a timeclock, ie, your
water usage is calculated and the frequency of
recharging programmed into the timer. On the
appointed day, at the appointed hour, the unit
recharges. If all went as calculated, ok. If
you were gone -- too bad -- you just wasted
salt and water. If you had extra company -- too
bad -- you ran out of soft water. You must pick
a unit that will treat one days supply of water
and still have about 40% of the resin in the
recharged state. This will provide you with the
most efficiency for salt and regeneration
water.
A second way to initiate recharge is by
electronic sensing. By electronically checking
the resin, these units can determine when the
resin needs to be recharged -- this is a great
help when your water hardness changes, when you
have extra company or when you are gone for a
few days. These 'sensor' units can save you up
to 42% of your salt and recharge water as well
as keep you in soft water when you have extra
guests.
A third way to initiate recharge is by using a
meter. These units have a meter installed in
the water line and simply measure how many
gallons of water you actually used. The unit is
set according to your water hardness, and will
recharge when the gallons used approach
exhaustion of the resin bed, saving you a high
percentage of your recharge salt and water.
Many variations of these methods are on the
market. Some use computers to calculate in
advance, when to recharge the unit; some have
two resin beds (tanks), and switch back and
forth between the two, keeping you in soft
water all the time, at the highest efficiency.
These systems are most effective in
high-hardness waters, ie, over 10-12 GPG, and
over 4 people in the family. Low hardness water
and smaller families do not require the extra
expense of these options.
I Have a Water Conditioner, Now my Water Feels
"Slimy"
When the hardness minerals are removed, soap no
longer forms a soap curd, or "bathtub ring" on
your skin, plugging your pores, clinging to
every strand of hair. You are now truly clean.
That slick, slimy feeling you feel is your
natural body oils -- without the soap scum. The
old saying that you get "squeaky clean" is a
myth; that feeling was caused by the soap scum
on your skin. By the way, that soap scum
provided an excellent place for bacteria to
hide and grow, causing numerous minor skin
ailments.
My Water
Stinks! What can I
Do? First, you must
learn a little about your nose: Once you
smell some things, your sense of smell is
dulled for a short while, and you can't
make accurate judgments of smell. For
instance, if I blindfold you, let you
smell gasoline, hand you a piece of onion
to eat and tell you it is an apple, you
can't tell it's not because your nose
isn't working properly!! (Your sense of
taste isn't working either -- smell and
taste are closely related and affect each
other!)
So, to correctly analyze your problem, you need
to become a detective. The best time to locate
the smell is after you have been away from home
for a few hours -- this allows your nose to
become sensitive to "that smell" again. With
your 'sensitized' nose, go to an outside spigot
-- one that the raw, untreated water flows
from. Turn it on, let it run a few minutes,
then smell it. If it smells -- we found it. If
not, we must look further. (Many, many smells
are not in the raw water at all, they are
introduced into the water inside the house.) Go
to a cold, treated water spigot inside the
house, turn it on and let it run a minute; then
smell. If this water smells, and the outside,
untreated water didn't -- you must have a
device (cartridge filter, water softener, etc.)
in the water line that needs to be cleaned and
sanitized.
If it is a cartridge, or 'string' filter,
replace the element and sanitize the housing.
If you have a water conditioner call the
Company where you bought the unit for advise on
how to sanitize the unit. If you rent the unit,
just call! You can sanitize the unit by pouring
Hydrogen Peroxide or Chlorine Bleach in the
brine well of the salt tank, and placing the
unit into regeneration. Check with the seller,
or, if they are no longer in business, any
Professional Water Conditioning Dealer for how
much to put in your particular unit.
If the cold, treated water inside didn't smell,
turn on the hot water and let it run a few
minutes -- does it smell? If it does, chances
are you have a sacrificial anode inside your
hot water heater that is "coming apart at the
seams" and throwing off a "rotten egg" odor.
This obnoxious smell will drive you right out
of your shower! The only solution is to remove
the anode from the heater, voiding your
warranty, or replace it with a new one made
with aluminum alloy. This anode is placed in a
(glass lined) hot water heater to seal up any
cracks in the glass lining and prevent
corrosion of the heater tank. You will find the
anode on the top of the heater; remove the tin
cover and insulation -- look for what looks
like a pipe plug -- about 3/4 inch in size with
a 1 1/16"fitting. Turn off the heat source and
the water; have someone hold the tank to
prevent it from turning, and unscrew the
"plug". You will find that the 'plug' has a 30
- 40 " long pipe (or what's left of one)
attached to it. Hopefully, most of the rod is
still attached -- just corroded. If so, replace
the plug with a real pipe plug and throw the
anode away. If part of the rod has corroded
off, and fallen into the heater, you may have
to try to fish it out. Either way, before you
plug the hole, pour about 2 pints of chlorine
bleach into the heater first. This will kill
the smell left in the heater. If, after a week
or so, the smell returns, you must fish out the
rod that is in the bottom of the tank. Good
Luck!
OK, It's my Raw
Water That Smells -- Now
What?
First, you must determine what is causing the
smell, and how strong it is.
Minor,
musty smell
If it is a minor, or low-level smell, you
MIGHT be able to solve it with a small,
point-of-use carbon filter. You can place
these types of filters on the water line
going to the cold water where you draw you
drinking water. Or, you might solve it with
a whole-house filter on your incoming water
line to filter all of the water inside your
home.
Because carbon
removes smells by ADsorbtion, ie, the
smell "sticks" or "adheres" to the carbon
particles, you must be careful not to
exceed the manufactures recommended flow
-- some filters even have a flow
restriction built in them. If you run
water through them too fast, you will not
remove the smells. Whenever you place a
carbon filter in your water line, you
must be sure to replace the element and
sanitize the housing on a regular basis.
Carbon filters remove organics from
water, and the bacteria found in water
like to eat organics -- the carbon filter
is a nice, dark place, just full of food
for them to grow and reproduce in.
Regular and routine replacement will help
prevent any buildup of bacteria in the
cartridge.
Strong,
rotten-egg
smell
Strong, rotten-egg odors in the raw water
is usually the result of the decomposition
of decaying underground organic deposits.
As water is drawn to the surface, hydrogen
sulfide gas can be released to the
atmosphere. In strong concentrations, this
gas is flammable and poisonous. It rapidly
tarnishes silver, turning it black. It is
toxic to aquarium fish in sufficient
quantities. As little as 0.5 ppm hydrogen
sulfide can be tasted in your drinking
water.
Strong,
musty smell
If you are unlucky enough to have this
problem, you should look for a company that
has local experience in dealing with this
problem. There are three basic ways to
solve this problem for
homeowners.
Whole House
Filters Installation of
a whole house filter loaded with a media
that is specific for hydrogen sulfide
removal is successful many times. These
types of filters must be recharged with
chlorine or potassium permanganate. The
removal capacities of these types of
filters are usually fairly low, and must
be sized to contain enough media to
prevent premature exhaustion, and
subsequent passage of the smell to
service. It is also typical that the
amount of hydrogen sulfide can fluctuate
rapidly, causing great difficulty in
sizing the unit. In addition, potassium
permanganate is extremely "messy", and
will leave stains that are very difficult
to remove.
Feeders Feeder systems
consist of a small pump that injects
small amounts of chlorine (usually) into
the incoming water. The water must then
be held for a short period of time to
allow the hydrogen sulfide to precipitate
out of the water. This tank should be
designed in such a manner that the water
that enters it will mix thoroughly with
the water in the tank, to assure complete
reaction. The water then should pass
through a filter to remove both the
precipitated matter and the chlorine
remaining in the water. You should be
aware, however, that whenever you mix
chlorine with organic materials (remember
where hydrogen sulfide come from!), the
chances are very high that
trihalomethanes (possible cancer causing
carginigns) will be formed. Also, feeder
maintenance is high, you should be
prepared to "play" with the unit
frequently.
Aeration
Aeration consists of breaking the incoming
water into small droplets (spray) into the air,
drawing fresh air through that spray,
collecting the water into a storage tank,
repressurize the water, passing it through a
particulate filter to catch any particles that
might be carried out of the storage tank. The
air drawn though the spray must be vented
outside the house -- remember, it is toxic and
explosive. Although this system necessitates
another pump to repressurize your supply, you
are not adding any chemicals to your water,
which makes it attractive. This system is low
maintenance and no chemicals to purchase.
Initial cost may be higher, however, and space
requirements may be greater.
Water that
Stains I have Red
Stains in my Sinks and Other Fixtures --
Help!
Red stains are normally caused by iron in the
water. You must test to determine the amount
and the type of iron you have. Some types are:
oxidized, soluble, colloidal, bacteria or
organic-bound. All are a problem! It only takes
0.3 ppm to stain clothes, fixtures,
etc.
Oxidized
This type of iron is usually found in a
surface water supply. This is water that
contains red particles when first drawn
from the tap. The easiest way to remove
this type of iron is by a fine mechanical
filter. A cartridge type filter is usually
not a good solution, due to the rapid
plugging of the element. Another method or
removal is by feeding a chemical into the
water to cause the little particles of iron
to clump together, and then fall to the
bottom of a holding tank, where they can be
flushed
away.
Soluable Soluble
iron is called "clear water" iron.
After being drawn form the well and
contacting the air, the iron
oxidizes, or "rusts", forming reddish
brown particles in the water.
Depending on the amount of iron in
the water, you may solve this problem
with a water conditioner, or a
combination of softener and filter.
You may use an iron filter that
recharges with chlorine or potassium
permanganate, or feed chemicals to
oxidize the iron and then filter it
with a mechanical filter. You can
sometimes hide the effects of soluble
iron by adding chemicals that, in
effect, coat the iron in the water
and prevent it from reaching oxygen
and
oxidizing.
Colloidal
Colloidal iron is very small particles of
oxidized iron suspended in the water. They
are usually bound together with other
substances. They resist agglomeration, ie,
the combining together of like substances
forming larger, heavier, more filterable
ones, due to the static electrical charge
they carry. This iron looks more like a
color than particles when held up in a
clear glass, as they are so small.
Treatment is usually one of two: Feed
chlorine to oxidize the organic away from
the iron, thus allowing agglomeration to
occur, or, feeding polymers that attract
the static charge on the particles, forming
larger clumps of matter that is
filterable.
Bacterial
Iron bacteria are living organisms that
feed on the iron found in the water, pipes,
fittings, etc. They build slime all along
the water flow path. Occasionally, the
slimy growths break free, causing extremely
discolored water. If a large slug breaks
loose, it can pass through to the point of
use, plugging fixtures. These types of
bacteria are becoming more common
throughout the United States. If you
suspect bacteria iron, look for a reddish
or green slime buildup in your toilet flush
tank. To confirm your suspicions, gather a
sample of this slime and take it to your
local health department, or water
department for observation under the
microscope. This type of iron problem is
very hard to eliminate. You must kill the
bacteria, usually by chlorination. You must
use high amounts of chlorine throughout
your plumbing system to kill all organisms.
You may find it necessary to feed chlorine
continuously to prevent regrowth. A filter
alone will not solve this
problem.
Organic
bound
When iron combines with tannins and other
organics, complexes are formed that cannot
be removed by ion exchange or oxidizing
filters. This iron may be mistaken for
colloidal iron. Test for tannins; if they
are present, it is most likely combined
with the iron. Low level amounts of this
pest can be removed by use of a carbon
filter, which absorbs the complex. You must
replace the carbon bed when it becomes
saturated. Higher amounts require feeding
chlorine to oxidize the organics to break
apart from the iron and cause both to
precipitate into a filterable
particle.
I Have Blue or
Green Stains on my Fixtures --
Help!
You either have copper in your water supply, or
you have copper pipes and corrosive water. Test
for copper in your water. Test the pH, total
dissolved solids content and the oxygen content
of your water.
Copper
Copper can be removed by ion exchange, ie, a
water softener. The removal rate is about the
same as it is for iron.
Copper pipes
and corrosive water
If your pH is from 5 to 7, you may raise it by
passing the water through a sacrificial media.
By sacrificing calcium carbonate into the
water, the corrosively will be reduced. If the
pH is below 5, you will need to feed chemicals
into the water. If the corrosively is caused by
excess oxygen, the hot water will be much more
corrosive than the cold. Treatment is by
feeding polyphosphate or silicates to coat and
protect the plumbing, or to aeriate the water
to release the excess oxygen.
Improving your
Drinking Water
Filters; what can they do?
There are many types of filters available in
the market place today. I will try to group
them by the method they use to filter water.
Almost everyone has seen the ads for the filter
that fits on the end of your kitchen sink or
bathroom spigot. These filters usually use two
basic types of filtration: a filter 'pad'
catches the large (usually over 25 micron in
size) particles or 'chunks' , and a small
amount of carbon to adsorb organics and/or
chlorine. The main problem here is the flow
rates at which they are expected to work at.
The consumer expects to turn the tap on as
normal and draw "filtered" water. To remove
free chlorine, for instance, standard
engineering practices set the maximum flow rate
at 10 gallons per minute per square foot (144
square inches) of surface area of the carbon,
*if* you are using a standard 30" bed depth. To
remove chloramines or organics, the maximum
flow rate is set at 5 gallons per minute per
square foot of surface area. If your spigot
will provide a flow of 1.5 gallons per minute,
what size filter do you need hanging on the end
of that spigot to insure that the chlorine and
organics will not be swept past through the
filter, into your glass? If you purchase this
type of filter, make sure it has a way of
limiting the rate at which water passes through
it.
Next comes the cartridge type filter. Most
common are the 10 1/2 or 20 inch long filters.
This type filter will usually have a removable
housing, into which different types of
"elements" can be placed. A sediment filter
cartridge element can be manufactured to remove
certain size particles and larger. Most
elements for home use will indicate 30 or 50
micron and larger removal. More expensive
elements, usually for industrial use, may
indicate a particle size (in microns) and add
the words "Absolute" after it. No, it isn't
Vodka, it simply means that if it says 5 micron
absolute, it means it! Very few particles
larger than 5 microns will pass through the
filter. The regular filter may say 25 microns,
meaning that *most* of the particles 25 microns
and larger will be caught by the filter.
Remember, there filters actually get better, or
more effective, as they are used. The 'junk' in
the water collects on the surface of the filter
and becomes a part of the filter as well. As it
builds up, progressively smaller and smaller
particles are trapped, and the flow rate
through the filter slowly diminishes. This
slowing of the flow rate can be a source of
problems to water using appliances in your
home. If you use such a filter, regular
changing of the filter element is very
important. Elements for these filters can also
be carbon (block or granular, or powdered), can
be manufactured for use in hot water, can be
ceramic, pleated as well as many other
configurations. Some manufacturers are mixing a
small amount of silver into the carbon to help
prevent any bacteria growth in them. This has
yet to be a proven methodology. In fact, make
sure that such a filter doesn't give off more
silver than is allowed, if not rinsed
thoroughly prior to use, especially after a
prolonged period of non-use. Remember, all
filters, carbon especially, trap organics that
bacteria feed on, and as the water sits without
moving, they can multiply rapidly. Always
change the elements on a regular, frequent
basis.
Selective
Resins A relative
newcomer to the market, some small
filters now contain resins that only
remove specific things from the water,
such as Nitrates, Fluoride or Lead.
Technology is rapidly changing in this
area; If you have a need for such a
device, you should ask for supporting
test results from an independent testing
lab to verify that the unit will perform
as advertised. Many states now have
legislation that requires such data be
provided to you prior to purchase.
Deionization
Used mainly in labs, manufacturing processes,
or for serious aquarium owners, DI filters are
actually more complex than a filter. True
filters, unlike the selective resin and DI
units, work on a mechanical basis: they just
'catch' the particles that are too large to fit
through the spaces between the filter media.
(Well, I fibbed a little; but who wants to know
about the Van Der Waals or Coulomb forces?) DI
works by ion exchange, just like a water
softener. Just as a water softener exchanges
sodium for hardness minerals, a DI unit will
have two types of resin in it: Cation and
Anion. Basically, the Cation resin (like in a
water softener) removes the ions with a
positive charge, while the Anion resin removes
those ions with a negative charge. Instead of
using salt as a regenerant, acid and caustic
are used. Some small DI cartridges are sold as
"throw-aways", others can be returned for
regeneration and reuse. These small units can
treat only small amounts of raw, city water.
Usually, it is much more economical to pretreat
the water feeding a DI system with reverse
osmosis water.
Distillation
One of the oldest methods for cleaning water is
distillation. Simply put, you boil water, catch
the steam, and condense it back into water.
Theory is, the minerals stay behind in the
boiling chamber, and only *pure* water ends up
in your container. In the real world, most of
those things do happen; but if you do not
perform preventative maintenance on your still,
you can get very poor results. Distillation
will kill bacteria, viruses, cysts as well as
remove heavy metals, organics, radionuclides,
inorganics and particulates if properly
maintained. One thing you must watch out for is
VOC's (volatile organic chemicals). These
chemicals have a lower boiling point than water
(like benzene), and can vaporize and mix with
the steam, carrying over into the product
water. Some stills today have a volitle gas
vent -- a small hole at the top of the
condensing coil that allows the venting of such
substances. Many distillers have a carbon
filter to "polish" the product water before use
and to remove any VOC's that may carry over.
The energy used to treat a gallon of water is
usually about 3,000 watts, or about 25 cents
per gallon (average) in the US. This treatment
method requires that you 'plan ahead' and make
and store water for use, which makes it
somewhat less appealing. The more elaborate
units will make and store water automatically,
but raise the initial investment and
maintenance of the equipment.
Reverse
Osmosis
This is a process that is often described as
filtration, but it is far more complex than
that. We sometimes explain it as a filter
because it is much easier to visualize using
those terms. We should remember that osmosis is
how we feed each cell in our bodies: As our
blood is carried into the smallest of
capillaries in our bodies, nutrients actually
pass through the cell wall to sustain it's
life. Reverse osmosis is just the opposite: We
take water with "nutrients" (in this case,
junk) in it, and apply pressure to it against a
certain type of membrane, and, presto -- out
comes "clean" water. Lets review the basics: If
you take a jar of water and place a
semi-permeable membrane (like a cell wall? or a
piece of skin?) in it, dividing the jar into
two sections, then place water in both sides to
an equal level, nothing happens. But, if you
place salt (or other such substance) into one
side of the jar, you will notice that, after
awhile, the water level in the salty side
begins to rise higher as the unsalted side
lowers. This is osmotic pressure at work: The
two solutions will continue to try to reach the
same level of salt in each side by the unsalted
water passing through the membrane to dilute
the salty water. This will continue until the
"head" pressure of the salt water overcomes the
osmotic pressure created by the differences in
the two solutions. On the other hand,
researchers have discovered that if we take
that embrane and feed water with sufficient
pressure to overcome the osmotic pressure of
the two waters, we can 'manufacture' clean
water on the side of the membrane that has no
pressure. We sometimes say we "filter" the
water through the membrane. Depending on the
membrane design, and the material it made from,
the amount of TDS (total dissolved solids)
reduction will range from 80 to over 95 per
cent. Different minerals have different
rejection rates, for instance, the removal rate
for the membrane I am looking at now is 99.5%
for Barium and Radium 226/228; but only 85.9%
for Fluoride and 94.0% for Mercury. Removal
rates are very dependant on feedwater
pressures, and some membranes are not tolerant
to high or low pH. For home use, it is
important to make sure you get an RO *System*;
ie, a sediment prefilter, a carbon prefilter,
membrane, storage tank and post carbon filter.
Some of these filters may be combined into one,
ie, the prefilter may be a particulate and
carbon both. A lot of comments have been made
concerning the *wasting* of water by an RO.
True, the old style units with the early type
membranes were more prone to becoming plugged,
or fouled by the "junk" they removed from the
water. To help keep this from happening, a
small amount of water was allowed to run across
the membrane to help carry away those
impurities to drain. Early designs only
recovered 1 gallon of good water for every 4-8
gallons used to keep the membrane clean. Even
worse, when your storage tank was full, water
still ran to the drain because the early
membranes were made of a material that the
little bugs in your water supply (no, not
pathogens, or dangerous to you in small
numbers) loved to eat! So to prevent that, we
just let the water run so they couldn't have
time to stop and eat. :>) Now membranes are
made to not only recover a much higher
percentage of the feedwater, but the bugs don't
eat them! Newer systems not only recover more,
they can have a shut off device that stops all
water flow when the storage tank is full.
Actual recovery rate is dependant on several
factors, including the TDS, and just what the
TDS is composed of, in your feedwater.
Temperature, pressure also have a big effect on
the amount of product water you can make in a
given period. Remember, all RO units are
normally rated using a feedwater temperature of
77 degrees F -- is your feed water temperature
that high?
What is the
best water for
Coffee? Well, that a
good question! After visiting with many
coffee people, I have gathered the
following as a basis for recommending the
"perfect water" for coffee.
1. All
oxidants removed. (Chlorine or other
such sanitizers".)
2. All organics removed. (You know, dead
fish, tadpoles, THM's, insecticides,
pesticides, etc)
3. TDS (total dissolved solids) from 60 to
100 ppm (parts per million)
4. Hardness of about 3-4 grains per gallon.
(51.3 to 68.4 ppm)
5. Low sodium water, ie, less than 10
mg/L.
6. pH depends on the Bean you are using,
plus the method of extraction.
7. Iron, Manganese and copper gone, or less
than 0.02 ppm.
What is the
best way to get this type of
water? There is no
single answer for this question, however,
if we assume you are getting your water
from a municipal supply, we *assume* the
Iron and Manganese problems are taken
care of by the city plant. (Some towns
may not solve these problems -- you be
the judge!) Copper *may* come from the
supply itself, or, if the water is
aggressive enough, it may actually be
picked off the copper plumbing in your
house as it sits overnight in the pipes.
(Lead can also be leached out of the
older "sweat" joints that may have used
solder that contained lead.) It is best
to "clear the pipes" the first thing in
the morning before using any water for
ingestion. Simply run enough water to
clear your pipes of the 'overnight'
standing water that *may* have picked up
the harmful metals from your pipes -- use
it to water your houseplants. If we use a
good, properly sized carbon filter, we
will substantially reduce the organics
and oxidants in the water, as well as
remove most of the particulates. However,
we still have TDS and Hardness to worry
about. If we soften the water, we do not
reduce the TDS, we simply *exchange* the
hardness minerals for Sodium -- which we
don't want for coffee! The best answer
(usually) is the reverse osmosis system.
This *system* usually has a particulate
and carbon filter (organics, oxidants and
particulates are reduced); and a membrane
(reduces the TDS by about 90% --
including hardness, sodium and others as
well); all linked together in one flow
path.
We can greatly improve the coffee by using any
one of the above mentioned methods, but if we
combine them, we get, for all practical
purposes, the *best* water for your coffee!
Rule of thumb: With an RO System, whatever
impurities were in the water are typically
reduced by 90% or more, leaving only water
behind, which is what we really wanted, anyway!
How much sodium does Ion-Exchange add to my
water?
For every grain of hardness in your water, 7.5
mg of Sodium will be *added* to each quart of
water by the ion-exchange method. If you have
water that is 10 grains per gallon hard; you
will add 75.0 mg of Sodium per quart of water
softened by ion-exchange. To put that in
perspective, one 8-oz glass of milk contains
120 mg of Sodium, one slice of white bread
contains 114 mg of Sodium. You must also
remember that there is *probably* Sodium in the
raw water, too. If your city supply treats your
water by a "hardness reduction" treatment
plant, you can be sure that the Sodium level in
your water has increased as a result -- how
much? Call your plant operator and ask -- it is
information free to the public.
Water Testing
Information When Should I
test?Several factors
will influence when and how often you
test your water. Where do get your water
from? Has that source changed? Have you
done any plumbing changes lately? Is
there reason to believe that your water
is contaminated? Is there a sickness or
illness in your family affecting more
than one person and over a longer than
normal time period?
If you receive your water from a "Public
Supply", ie, a municipal supply, or a supply
that provides water to more than 25 persons for
60 days per year (some states are different --
check with YOUR local water department), you
can be fairly certain that the water supply is
checked on a regular basis. The frequency of
the testing is based on the number of people
served, and may vary from more than once per
week to once per month, or even less. Under
these conditions, test when you move into a new
residence to acquire a "base line" of
contaminant level, if any. Retest every three
years, unless you have reason to believe that
something has changed that could affect the
quality of your water.
If you have a private well, you are the only
person who is responsible for the water your
family drinks and bathes in. I recommend
testing by your local Health Department every
six months for Bacteria and Nitrate. These two
tests serve as indicators for other types of
contaminations -- that is not to say forget the
other tests; just that if you get a "bad" test
from them, you should also retest for the other
types of contaminants as well. Private wells
should be tested on a regular basis for
Pesticides, Herbicides, Metals, Organic and
Inorganic chemicals and volatiles. Currently,
no laws govern the frequency of such testing --
that is why I say YOU are the only person
responsible for your family's water. I
recommend an initial test (for a base line),
and then at least once per year. Remember, one
day after testing and finding "no
contaminants", your source could become
contaminated.
What Could I
Test For?
Coliform
bacteria are a group
of microorganisms that are normally
found in the intestinal tract of
humans and other warm blooded
animals, and in surface water. The
presence of these rganisms in
drinking water suggest contamination
from a surface or shallow subsurface
source such as cesspool leakage,
barnyard runoff or other source. The
presence of these bacteria indicate
that disease-causing (pathogenic)
organisms may enter the drinking
water supply in the same manner if
preventive action is not taken.
Drinking water should be free of
coliforms.
Cysts and viruses are
microbiological contaminants, usually
found in surface water supplies.
Giardia lamblia cysts can cause
giardiasis, a gastrointestinal
disease. Another "bug" getting a lot
of attention lately, is
cryptosporidium, single-cell parasite
measuring about 2 - 5 microns in
diameter. Many surface water supplies
contain this pest, which also comes
from the intestine of warm blooded
animals.
Nitrate
in drinking
water supplies may reduce the oxygen
carrying capacity of the blood
(cyanosis) if ingested in sufficient
amounts by infants under 6 months of
age. This could cause a disease
called "methemoglobinemia", or "blue
baby" syndrome. The EPA has
established a maximum contaminant
level (MCL) for nitrate at 10 mg/l
(ppm) measured as N. Unlike coliform
or other types of bacteria, boiling
the water will actually INCREASE the
amount of nitrate remaining in the
water, increasing the danger to
infants. If you have high nitrate
water, either treat it with an
approved treatment metholodgy or find
another source: Boiling will only
make it worse!
Lead
is now
known to leach from older sweat
joints in copper pipe. As the water
sits in the pipes, small amounts of
lead 'dissolve' into the water,
contaminating it. Lead is
particularly harmful to small
children as they more rapidly absorb
the toxic substance into their
systems. The EPA has estimated that
more than 40 million U.S. residents
use water that contains more than the
recommended levels.
National
Testing Laboratories, Inc. in Ypsilanti
has a five bottle testing kit, which is
supplied by many water quality
professionals across the nation. You
simply follow the directions in the kit
and return the sample to the lab. They
test your sample and then report to you.
Your test results will be a two page
report showing contaminant level, a cover
letter explaining the test results and
what you should do.
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