Portable Water Filtration
PORTABLE WATER TREATMENT PRODUCTS - Options
in Application and Technology
The range of portable water treatment products has expanded significantly
over the last several years. Much of this expansion is due to the
increased variety of technologies and media available in the market.
These technologies have enabled manufactures to produce products
with greater reduction capabilities.
Although new technologies and media have enabled manufacturers to
improve product performance there has been little change in either
the types of products or the basic applications. Water bottles,
gravity feed/pour through devices and hand held pump/filter units
continue to be used to replace bottled water, during outdoor recreational
activities and travel and for emergency preparedness. In addition,
sometimes 'questionable' quality of bottled water and concerns about
chemicals leached from plastic containers has further increased
the demand for this type of product.
FOR MORE INFORMATION ABOUT PORTABLE WATER
Portable Water Devices
Portable Water Testing
What Portable Product Do I Choose?
WATER FILTRATION TECHNOLOGIES
There are multiple technologies and media currently
used in portable water treatment devices, some are common and some
are new. Each is used to address a specific contaminant or water
problem. In many cases several of these technologies are used in
conjunction with one another to create the end product.
Spun Polypropylene is used as a filter
to reduce sediment, dirt
and turbidity that may be present in the water source. It is
also useful as a pre-filter to protect a secondary stage of treatment
such as ceramic filters, porous molded plastic, carbon block and/or membrane.
Porous Plastic technology can be
applied in a variety of ways, contingent upon the finished products
micron rating; to
reduce sediment, as a spacer between media layers, or as a method
of mechanically reducing cysts and bacteria. (I've explained micron
rating in my article...we may have to mix and match a bit.)
Granular Activated Carbon is used
to improve taste and odor by reducing chlorine, industrial chemicals
and a multitude of organic contaminants. Additives to GAC may help
to reduce lead, some forms of heavy metals and additional contaminants.
GAC can also be used as Pre and Post Filtration for other technologies
and as a method for removing chlorine or iodine after disinfection.
Carbon Blocks perform the same function
as GAC. In addition, based upon micron rating, carbon blocks have
cyst and bacteria removal capabilities via mechanical filtration.
Ceramics will mechanically filter
waterborne pathogens such as cysts and bacteria. Their effectiveness
in a given application is dependent upon choosing the right
micron rating for the application. Various micron ratings are available.
KDF is generally used to compliment
other methods of treatment. It has a high capacity to remove chlorine
and selectivity for such contaminants as lead, arsenic, cadmium,
mercury, calcium carbonate and magnesium. In addition it is bacteriostatic.
Membranes are in use or are being
evaluated for use in portable devices. Their sub-micron pore sizes
enable them to eliminate cysts, bacteria and in some cases viruses.
Sediment pre-filtration is necessary to protect the small pores
Iodinated Resin has proven to be
an excellent method of eliminating bacteria and virus from raw water.
Though effective, these resins have specific operating parameters.
Use outside of these parameters will negatively impact the products
effectiveness. A post media is used in conjunction with iodinated
resin to eliminate the concern of iodine or iodide in the product
Ion Exchange Resins are used to remove
selected contaminants. Resins are manufactured with this selectivity
in mind. For example, a specific ion exchange resin is produced
to remove nitrates.
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Pour Through/Gravity Feed Units
These units vary widely in size. One of the smaller units is an
8 oz. inverted cup using carbon to improve taste and odor. This
unit has a 50 gallon capacity. An example of the larger unit would
be a terra cotta or stainless counter top unit using ceramics with
media capable of reducing a multitude of contaminants including
cysts, bacteria, lead, chlorine and other heavy metals. The most
versatile, durable and portable of these large units is the Outback.
This system breaks down for storage and travel. It uses filters
and chloro tabs to remove bacteria, cysts, virus, chlorine and organic
matter. The large units have a 2,500 gallon capacity and replaceable
components. Many of the higher end products have been tested to
ANSI/NSF Standard 53 by credible independent laboratories.
There are several portable bottle units on the market. There is
a broad range of performance and price - the higher price not necessarily
indicative of higher levels of performance. Some bottles do their
job using a single filter. To achieve the same result others require
that the filtration component be changed once or even twice during
a single use. The most common performance claims are those of improved
taste and odor. This is achieved using a simple carbon filter that
fits inside the bottle. Other bottles are capable of bacteria and
cyst removal/reduction through the use of carbon blocks, porous
molded plastic or ceramics. Finally, in some cases the bottles can
reduce viruses through the use of membrane and/or iodinated resin.
There are several bottles that offer replaceable filters while others
have filters permanently affixed to the unit, a straw or to the
filter cap. One product actually opens from the bottom of the bottle,
allowing it to be used as a bottle and as a pour through/gravity
feed unit in conjunction with a larger container. Again, third party
testing is a critical consideration when evaluating these products.
Pumps and pump/filter combinations usually use a technology such
as Carbon blocks, ceramics, porous plastic elements or membranes
to effectively remove protozoan cysts and bacteria. It is generally
a good idea to incorporate some type of pre-filter to eliminate
particulate that are larger than the pore size that could cause
premature clogging of the filter. These products are used primarily
in the outdoor specialty markets. Because this application may entail
challenging a product with high levels of contaminants in 'worst
case conditions' the issue of performance testing becomes very important.
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Many of the available portable products can be used
in a multitude of applications. Within each product type are individual
products that are capable of producing potable water from non-potable
raw water sources, either by significantly reducing bacteria or
cysts or sediment etc. They can also be used in non-traditional
ways, both inside and outside the home and in emergency or survival
situations. A sports bottle can be used to replace bottled water
while at school, while traveling or during any recreational activity.
Some are designed specifically to filter water for babies while
others can double as gravity feed treatment/filtration devices to
fill larger water containers. Some have capacities of as little
as 25 gallons and some have capacities as high as 200 gallons. Some
remove only chlorine while some have proven effective against bacteria,
cysts and virus. Countertop gravity flow devices can replace bottled
water without the connection to the faucet. They can treat, filter
and cool the water and are easily emptied and moved. There are those
that have the same range of performance characteristics as sports
bottles. Although their applications differ due to their size their
capacity is higher than that of a sports bottle. Combination pump/filter
units are useful in both outdoor and emergency situation where the
user might need to capture water from streams, rivers, lakes, or
other suspect water sources.
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Though virtually all of the technologies used in portable
filtration devices are also used in larger (Counter top or Whole
House) systems the amounts of media used are significantly smaller,
hence the portable systems generally have a much lower performance
capacity. Many of the devices using mechanical filtration have capacities
similar to their larger counterparts. In the event that the product
is to be used as a water purifier and listed as such, the product
must pass the stringent performance evaluation required by the EPA.
For all of these reasons it is critical to ensure that portable
units have been sufficiently tested and evaluated by an independent
third-party laboratory and that the test results support any claims
made by the manufacturer and are available for general distribution
to the buyer.
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PRODUCT DO I CHOOSE?
Use the following process to weed out the good from
the not so good.
What contaminant do you want to remove? What are the problems in
water supply in question (chlorine, lead, cysts, bacteria)?
Identify media or technology:
What technology is necessary to improve aesthetics and/or remove
Which type of product (or combination of products) will produce
the water you need (bottle, gravity feed system, etc). Once this
is decided focus on products using this technology or media combination
and making claims to remove the contaminants you have identified.
Verify application given its operating parameters:
Make sure the product will work properly in the environment where
you will use it. For example, a water bottle using iodine to remove
bacteria will not be effective when used in freezing temperatures
by cross country or downhill skiers. It only 'works' within a certain
range of temperatures. Products may be rendered less effective by
a variety of conditions. These should be clearly stated in the operating
parameters furnished by the seller.
Verify the veracity of claims:
Ask the seller or the manufacturer to send you copies of third party
tests done by reputable labs showing the product can and has performed
in accordance with claims.
Evaluate ease of use:
Will product meet claims and be easy to use in the environment of
its intended use (outdoors, in an emergency situation, etc.)
Evaluate capacity in terms of need:
Will the product produce enough potable water to meet the your needs
in its intended application
Evaluate value versus price:
Don't assume that the higher price buys a 'better' product. Competing
products often use identical technology and differences in price
can be the result of fancy packaging or presentation.
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