Comparison of Water Purifying Technologies

Charcoal Filters

 These come in powdered or granulated form which allows water to flow around
rather than through the carbon.
 Referred to as taste and odor filters because of the limited contact time
the water has with the carbon.
 Can promote the growth of bacteria.

Ceramic Filters:

 Ceramic filters use a process whereby water is forced through the pores of
the ceramic filtration media, providing mechanical filtration only.
 This type of filter can reduce asbestos, cysts (if the pores are one micron
or smaller), and particulate matter.
 Ceramic filters cannot reduce VOCs, endocrine disrupters, trihalomethanes,
mercury or lead.

Distillation:

 Removes dissolved minerals and trace elements essential to good health.
 No independent ability to remove all chemicals - the chemicals can vaporize
and/or recondense into the distilled water.
 Daily chore to provide enough water for the entire family.
 Requires electricity at a cost of about $240.00 per year.

Reverse Osmosis:

 No independent ability to reduce most Volatile Organic Chemicals.
 Very low output - takes up to 24 hours to process 5 gallons of water.
 Must have holding tank to store the processed water.
 Wastes water - for every gallon processed, 3 to 9 gallons are wasted.
 Removes minerals and trace elements essential to good health.

Mixed Media:

 This type of filter is specially engineered for specific contaminant
reduction. For example, KDF filters reduce chlorine well; ATS filters reduce
lead well.
 These filters show a high performance against the specific contaminants,
but not against other contaminants.

Ion Exchange Treatment (Water Softeners):

 Ion Exchange uses the chemical ion exchange process to exchange anions or
cations on a "resin" bed for cations or anions of the contaminant that needs
to be reduced (usually heavy metals or minerals like lead or mercury).
 Water softeners are neither filters nor purifiers and are used only to
change the water hardness.
 Softeners put sodium into the water in exchange for magnesium or calcium
ions. It is recommended that water softeners be bypassed when installing a
water filter.
 Most softeners must be professionally installed.

Ultraviolet Treatment:

 Water passes through a chamber where it is exposed to Ultraviolet
radiation.
 Very turbid water can reduce the effectiveness of this type of treatment.
 This treatment is effective against many bacterial contaminants but is not
effective in reducing cryptosporidium.
 Other contaminants of health concern are not affected by ultraviolet
treatment.

Carafes/Pitchers:

 Limited in its ability to remove contaminants of health concern.
 Limited in its ability to microstrain the water.
 Most do not reduce microscopic cysts (Giardia Lambia or Cryptosporidium),
asbestos, THMs, Pesticides, VOCs, etc.
 Must replace filters about every 35 gallons.
 Although the initial cost is low, the ongoing cost of filters can be
expensive.  Each replacement filter costs $7.00 - $10.00 or between
$150.00 - $200.00 for 750 gallons compared to Multi-Pure's 750 gallon filter
for $49.95.
 Inconvenient to use.  First you draw the water from the tap, then pour the
water through the filter, refrigerate and wait.

Ozonation:

 Ozonation "super-oxygenates" the water which can kill bacteria with
adequate contact time.
 This process is often used at public water utilities and not in the home at
point-of-use or point-of-entry.
 This is a process that only addresses bacterial contamination.
 This type of treatment can create by-products in the treated water. Some of
the created by-products also allow for increased bacterial growth in the
pipes down the line which contributes to re-infection of the water.

Silver-Charcoal Filters (Bacteriostatic):

 Same as charcoal filters above; however, uses silver to inhibit the growth
of bacteria while water sits in filter.
 Silver ingested in certain doses can be poisonous to the human body;
therefore, it must be registered with the EPA as containing a poisonous
substance.
NOTE: August, 1989 Federal Trade Commission Report states, "Studies on the
effectiveness of Bacteriostatic filters have shown unpromising results as to
their ability to control bacterial growth."

Here's my choice after much research:

Multi-Pure Drinking Water Systems are designed and engineered to provide the
consumer the utmost in performance, safety, and convenience. The replaceable
triple-action filter has been formulated of materials approved by the U.S.
Food and Drug Administration to provide the highest quality drinking water
without removing the healthful, natural minerals. The filter media combines
mechanical filtration, electrokinetic adsorption, and physical adsorption to
provide the most efficient contaminant reduction possible.

Water enters the filter through a graded density pre-filter, a special blend
of materials which acquire a positive molecular charge in a moving stream of
water. Since most colloidal and bacterial contaminants exhibit a negative
charge in solution, the media fibers will electrokinetically adsorb charged
colloidal particles too small for removal by mechanical straining. The media
combines the technology of mechanical straining, for the removal and
retention of solid and semi-solid contaminants that can cause premature
clogging, and electrokinetic adsorption for the reduction of colloidal
contaminants down to sub micron range.

The water then passes through the highly compacted solid carbon block filter
media which is a blend of selected activated carbons and polyethylene. The
compacted solid carbon block filter media is designed to mechanically filter
particles down to  sub-micron size, including microscopic organisms, cysts,
asbestos, turbidity, and particulate matter. The components of the carbon
block are insoluble, and while themselves chemically inactive, some of the
material exert a catalytic effect, inducing molecular changes in many
chemicals contained within the water. It is through this chemical reaction
and physical adsorption that chlorine, certain pesticides, volatile organic
chemicals, trihalomethanes, dissolved lead and mercury are reduced.

The solid carbon block filters are exceptionally uniform and do not channel
or bypass as conventional granular activated carbon filters (GAC) are known
to do. Conventional GAC filters become incubators of bacteria, encouraging
growth; however, the densely compacted Multi-Pure filters eliminate this
problem because there is no room for growth in the tightly compacted carbon.

Finally, the water passes through a pharmaceutical grade post-filter which
provides integral strength to the carbon block section and prevents material
degradation of the filter. The threaded polypropylene end caps seal the
carbon block and assure the integrity of the seal between the filter and the
housing.

The unique formulation of Multi-Pure solid carbon block filters provide for
the reduction of substances that cause water to taste or smell bad as well
as reduce a wide range of contaminants of health concern, including lead,
mercury, trihalomethanes, cysts, turbidity, asbestos, certain pesticides and
volatile organic compounds.

And the specs:

- Health Effects -

Substance/ Chemical  PERCENT REDUCTION**
ALACHLOR* >98%
ASBESTOS >99%
ATRAZINE* >97%
BENZENE* >99%
BROMODICHLOROMETHANE (TTHM) >99.7%
BROMOFORM (TTHM) >99.7%
CARBOFURAN (Furadan)* >99%
CARBON TETRACHLORIDE* 98%
CHLORDANE >99.8%
CHLOROBENZENE (Monochlorobenzene) * 99%
CHLOROPICRIN >99%
CHLOROFORM (TTHM) 99.8%
CRYPTOSPORIDIUM (Cysts) >99.9%
CYSTS (Giardia; Cryptosporidium; Entamoeba; Toxoplasma) 99.9%
2, 4-D* 98%
DBCP (Dibromochloropropane)* >99%
1,1-DCA (1,1 - Dicholoroethane) >99.1%
1,2-DCA (1,2 - Dichloroethane)* 95%
1,1-DCE (1,1 - Dichloroethylene)* > 99%
DIBROMOCHLOROMETHANE (TTHM) > 99.7%
DIBROMOCHLORPROPANE (DBCP)* >99%
1,2-DICHLOROBENZENE (o-Dichlorobenzene)* > 99%
o-DICHLOROBENZENE (1,2-Dichlorobenzene)* > 99%
p-DICHLOROBENZENE (para - Dichlorobenzene)* > 98%
para-DICHLOROBENZENE (p - Dichlorobenzene)* > 98%
1,1-DICHLOROETHANE (1,1 - DCA) > 99.1%
1,2-DICHLOROETHANE (1,2 - DCA)* 95%
trans-1,2- DICHLOROETHYLENE* > 99%
1,1-DICHLOROETHYLENE (1,1 - DCE)* > 99%
cis-1,2-DICHLOROETHYLENE* > 99%
1,2-DICHLOROPROPANE (Propylene Dichloride)* > 99%
cis-1,3- DICHLOROPROPYLENE* > 99%
DINOSEB* 99%
EDB (Ethylene dibromide) * >99%
Endrin* 99%

ENTAMOEBA (CYSTS) 99.9%
ETHYLBENZENE* > 99%
ETHYLENE DIBROMIDE (EDB)* >99%
FURADAN (Carbofuran)* >99%
GIARDIA LAMBLIA (Cysts; Protozoan) > 99.9%
HALOACETONITRILES (HAN):
BROMOCHLORACETONITRILE
 98%
DIBROMOACETONITRILE
 98%
DICHLOROACETONITRILE
 98%
TRICHLOROACETONITRILE
 98%
HALOKETONES (HK):
1,1-DICHLORO-2-PROPANONE
 99%
1,1,1-TRICHLORO-2-PROPANONE
 96%
HEPTACHLOR* > 99%
HEPTACHLOR EPOXIDE * 98%
HEXACHLOROBUTADIENE (Perchlorobutadiene)* > 98%
HEXACHLOROCYCLOPENTADIENE* >99%
LEAD (ph 6.5) >98.3%
LEAD (ph 8.5) >98%
LINDANE* > 99%
MERCURY (pH 6.5) >91.4%
MERCURY (pH 8.5) >99.3%
METHOXYCHLOR * >99%
METHYLBENZENE (Toluene)* >99%
MONOCHLOROBENZENE (Chlorobenzene*) >99%
MTBE > 96.6%
PCBs >99%
PCE (Tetrachloroethylene)* > 99%
PENTACHLOROPHENOL* > 99%
PERCHLOROBUTADIENE (Hexachlorobutadiene)* > 98%
PHENYLETHANE (Ethylbenzene)* > 99%
PROPYLENE DICHLORIDE (1,2 -Dichloropropane)* > 99%
SIMAZINE* >97%
Silvex (2,4,5-TP) * 99%
STYRENE (Vinylbenzene)* > 99%
1,1,1-TCA (1,1,1 - Trichloroethane)* 95%
TCE (Trichloroethylene)* > 99%
1,1,2,2- TETRACHLOROETHANE* > 99%
TETRACHLOROETHYLENE* > 99%
TOLUENE (Methylbenzene)* > 99%
TOXAPHENE > 99.9%
TOXOPLASMA (CYSTS) 99.9%
2,4,5-TP (Silvex)* 99%
1,2,4-TRICHLOROBENZENE (Unsym-Trichlorobenzene)* > 99%
1,1,1-TRICHLOROETHANE (1,1,1 - TCA)* 95%
1,1,2-TRICHLOROETHANE*
TRICHLOROETHYLENE (TCE)* > 99%
TRIHALOMETHANES (TTHM) > 99.7%
(Chloroform; Bromoform;

Bromodichloromethane; Dibromochloromethane)
 > 99.8%
TURBIDITY 99.7%
UNSYM-TRICHLOROBENZENE > 99%

NSF Standard No. 42 - Aesthetic Effects

Taste, Odors, and Chlorine > 97.5% (maximum per standard)
Chloramines >96.9%

Particulate Matter Down To 0.5 Micrometer (Class I)

Siobhan