The
market for ceramic filtration systems is growing daily---in part due
to public concern about emergency water conditions which could be caused
by earthquakes, hurricanes, floods and so forth.
The
primary reason for the use of ceramic technologies is for bacteria removal.
A secondary reason includes the ability to remove various protozoa(cysts).
Therefore,
it is important to understand the various testing procedures used to
"verify" microbiological cleanliness of the water produced
by ceramic filtration systems.
In
this manner, one can identify whether or not a specific ceramic system
can provide safe drinking water according to accepted testing standards
established by the Environmental Protection Agency(EPA).
The
EPA has established a testing methodology(protocol) for water filters(purifiers)
which establishes minimum levels of performance for removal(reduction)
of the three classes of pathogenic(disease-causing) organisms: protozoa(cysts),
bacteria, and virus.
This
testing procedure, with associated required minimum performance levels,
is known as the "USEPA Guide Standard and Protocol for Testing
Microbiological Water Purifiers."
These
testing procedures, which are performed by independent(third party)
laboratories, must follow the "protocol" established by the
USEPA, which establishes the conditions for conducting the various tests
with the three classes of organisms. These conditions include such items
as # of gallons of test water, test water pH levels, etc.
The
"standard" establishes the minimum level of reduction performance
for each class of organism together with which particular representative
organism is to be used for testing in that class.
When
a microbiological water filter has demonstrated the ability to inactivate
or remove at least the minimum required level of the mandated(representative)
organism for a particular class, using the USEPA established testing
protocol, the manufacturer may then claim that their filter meets the
USEPA standard for that class.
When
a filter or equipment manufacturer meets the removal standard FOR
ALL THREE CLASSES
of organisms, it can claim the title of Microbiological Water "Purifier"
for that water treatment device.
For
example, water distillation systems destroy and remove all three classes
of organisms and thus can be called(marketed) as a "purifier".
Equipment such as carbon filters and reverse osmosis
systems do not meet these three standards and therefore cannot be called
"purifiers".
COMPLIANCE
WITH USEPA STANDARDS FOR CYST REMOVAL
Marathon
Ceramics, manufacturers of the ceramic elements for the Aqua
Rain gravity
filter system and both the Waterworks
II
and Miniworks hand pump filters
have fully met the USEPA requirements for cyst removal, not only when
they are new, but ALSO AT END OF LIFE.
No
other manufacturer has demonstrated compliance with USEPA Cyst removal
standards at end of life.
COMPLIANCE
WITH USEPA STANDARDS FOR BACTERIA REMOVAL
The
USEPA standard for bacteria is the removal of >99.9999%(6 log or
6 orders of magnitude) of Klebsiella terrigena with a NEW filter
element as tested in accordance with the USEPA methodology by a reputable,
third-party laboratory.
The
Aqua Rain gravity filter system is the only ceramic gravity filtration
system which has demonstrated full compliance with USEPA standards for
bacteria removal, not only at beginning of life(new filter element)
but also when abraded down to the minimum end-of-life wall thickness(as
measured by the caliper methods described below).
No
other gravity filter system manufactured anywhere in the world claims
to meet this USEPA standard. The Aqua Rain ceramic technology is American
Technology designed and tested to meet our own country's challenging
American Standards for water purification.
The
Aqua Rain gravity filtration system can be correctly summarized by stating
that it:
"Exceeds
EPA Purifier Standards for Bacteria and Protozoa(or cyst) Removal"
Theory
of Operation
In
ceramic filter systems(PUMP and DRIP/GRAVITY-type units described in
this section of the website) the exterior part of the ceramic element/candle
which the untreated water encounters first is composed of high density
ceramic materials. 
These
materials are compressed so tightly that bacteria and other micro-organisms
have extreme difficulty passing through this barrier.
Individual
manufacturers use various procedures for manufacturing their ceramic
elements, and as we have noted above, have resulted in varying degrees
of effectiveness in removing bacteria.
Most
bacteria have nominal sizes of 0.2 microns to several microns. One micron
is equivalent to 1/1000 of a millimeter. A millimeter is 1/1000 of a
meter. Hence, the designation "micron" which is 1/1,000,000
of a meter.
Viruses,
which can also cause various health problems, have dimensions far less
than 0.2 microns and must be dealt with separately as described below
in "Tips for Virus Removal" in the section on the WaterWorks
II hand filter.
Most
ceramic systems utilize some type of silver compound, impregnated in
various fashions into the ceramic element to reduce any bacterial accumulations
which might occur when bacteria "grow through" or accumulate
in the ceramic with time.
This
"grow through" process is known as "MITOSIS" and
is the name given for normal cell division. Although the nominal density
of the ceramic element(s) prevent individual bacteria from passing through
the ceramic material, when cells divide(and therefore multiply in number),
this "Mitosis" effect can occur.
This
"grow through" effect can be reduced by periodic cleaning
and/or sterilization of the ceramic element exterior surface. Manufacturers
provide "scrubbing" pads to periodically remove the exterior
layer of ceramic(containing bacteria).
If
this cleaning process is not conducted on a regular basis when the filter
system is in use(and exposed to bacteria in the untreated water), this
bacterial "grow through" takes place.
As
cells divide, this division is characterized by a reformation of the
chromatin of the cell nucleus into a threadlike form that condenses
into chromosomes, each of which separates longitudinally into two parts,
one part of each chromosome being retained in each of the two new "daughter"
cells.
When
conditions for cellular growth(cell division) are right(proper environmental
conditions such as temperature, pressure, etc) and sufficient nutrients
are also present, the "threadlike forms" noted above can penetrate
the ceramic structure of the elements and create bacterial cells on
the inside of the element which can then migrate into the product water
if periodic cleaning of the elements is not conducted as noted above.
The
basic ceramic materials in DRIP FILTERS and PUMP FILTERS are therefore
designed to remove and/or reduce BACTERIAL contaminants.
Some
manufacturers introduce ACTIVATED CARBON into the interior of the ceramic
element to remove potentially hazardous liquid and gaseous organic chemicals
such as chlorine, pesticides or industrial chemicals.
With
the proliferation of agricultural and industrial chemicals, the latest
emergency, backpacking and survival filters combine replaceable ceramic
and carbon elements.
Ceramic
filters which include carbon are more time efficient than using chemicals
or boiling water and more compact than the fuel needed for the boiling
process. They are rapidly becoming the preferred process for international
travelers(who also carry iodine tablets for pre-treating the water for
any virus problem).
Dual
purpose CERAMIC/CARBON elements are therefore powerful tools in combatting
bacteria and chemicals in industrialized areas of the world. They
also are preferred by those individuals who are preparing for domestic
or international emergencies in areas which may be susceptible to both
chemical and biological contamination.
Reference:
See Water Conditioning & Purification magazine, March 1998,
pp.66. for a good overview of ceramic technology and its applications.
