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- The Performance Says it All
by Paula Rice
| Summary:
It's clear not all carbon filters are alike in terms of contaminant
reduction performance. Rigorous product development, quality control
and experimentation have shown solid carbon block products to be
far more efficient at removing contaminants of aesthetic and health
concern. |
Drinking water pollution comes
from many sources. Surface water becomes contaminated from agricultural
runoff, community landfills, polluted runoff (the nation's leading cause
of water pollution), and hazardous waste produced as byproducts of manufacturing.
Groundwater is contaminated by leaks of pollutants such as gasoline and
MTBE from underground storage tanks and injection of hazardous waste into
deep wells (which is being phased out). The drinking water treatment industry
is experiencing significant growth due to consumer demand for products
that could protect them from these potentially harmful contaminants which
may be found in drinking water supplies as well as aesthetically improve
their water.
Highly Regarded
The effectiveness of any drinking water treatment device is measured by
the performance of its filter. A close review of drinking water treatment
unit certifications shows that solid carbon block filters are the most
effective for reducing a wide range of contaminants, including those that
may be found in groundwater. Certain drinking water treatment units (DWTU)
that use solid carbon block filters have been tested and certified to
reduce as many as 65 contaminants.
In the early 1970s, the solid carbon block filter technology was developed
for the purpose of treating contaminants for health reasons as well as
aesthetically improving water quality.
The technology combines mechanical filtration, chemical reaction and physical
adsorption into a single device to reduce a broad spectrum of harmful
contaminants.
Importance of Raw Materials
Activated carbon is the primary raw material used in solid carbon block
filters. Multi-Pure determines the characterization of activated carbons
to use for its filters. Carbons specified are especially effective in
reducing inorganics such as lead and mercury as well as organic compounds
- disinfection by-products (DBPs), volatile organic compounds (VOCs),
PCBs, MTBE, etc.
Many carbons are selected with a high surface area and high retentivity
characteristics. Years of research, development and manufacturing experience
have helped Multi-Pure develop specifications for carbon and other media
that give its compacted carbon block filters distinctive performance advantages
over other treatment alternatives. Quality assurance procedures are carefully
developed and maintained to assure that raw materials meet our high standards.
Technological Advantages
As evidenced by independent laboratory testing and certification of solid
carbon block filters, Multi-Pure has been successful in developing the
technology to produce filters that provide greater chemical adsorption
and mechanical filtration. Materials are formed into a carbon block, which
is densely compacted. Compression enhances the kinetics of the filter
and provides performance that cannot be achieved with extruded or granular
activated carbon (GAC) filters. Compacted solid carbon block filters have
a large surface area for chemical/physical adsorption to take place. With
a solid carbon block, the water contact time is longer and provides for
greater adsorption of many different chemicals, pesticides, herbicides
and certain heavy metals. A close review of product listings confirms
that Multi-Pure's Drinking Water Systems are among the few that have been
certified to reduce PCBs -a difficult contaminant to treat. Only a handful
of products have been tested and certified to reduce a wide range of contaminants
that are more difficult to treat.
In addition, the densely compacted carbon block mechanically filters particles
down to 0.5 micron, including Giardia and Cryptosporidium, asbestos, turbidity
and particulates. Our filter design incorporates an outer prefiltration
medium to remove large particles and prevent premature clogging of the
filter. Multi-Pure's solid carbon block filters are exceptionally uniform
and don't channel or allow bypass.
Filter
Capacity
Filter capacity varies depending on the density and size of the filter.
The characterization of activated carbons used by Multi-Pure determines
the capacity of the water filters. Capacity ratings apply to the chemical adsorption
capabilities of the carbon and specialized media. Carbons with a high
surface area allow for long life and high adsorption capacity. Capacity
ratings for Multi-Pure Drinking Water Systems range from 600 gallons to
1,200 gallons, depending on model.
Claims of capacity aren't applicable to contaminants reduced by mechanical
filtration because of broad variations in the quality and quantity of
physical matter in the drinking water. The solid carbon block filter is
engineered so that contaminants removed by mechanical filtration will
cause the flow rate to decrease and the water filters to clog, thus offering
protection to the consumer from Giardia, Cryptosporidium and other contaminants
with a specific physical size.
Applications
Solid carbon block filters are used in point-of-use drinking water treatment
devices designed for countertop, undersink and inline applications.
Conclusion
Solid carbon block filters effectively treat the age-old contaminants
of yesteryear, such as lead, TCE, chlorine, benzene and "new" contaminants
found in the nation's drinking water supplies today like MTBE, chloramines
and PCBs. They also likely will be proven capable of significantly reducing
contaminants that may be found in drinking water supplies in the future
such as antibiotics and other drugs. The effectiveness of solid carbon
block filters in treating a broad spectrum of contaminants of aesthetic
as well as health concern makes it the technology of choice by distributors
and more importantly, consumers throughout the country.
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Re-edited version of article published in Water Conditioning & Purification
Magazine
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