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:
If a voracious consumer of the
signal producing enzyme is
introduced into the environment it
can prevent the chemical reaction
that produces the code signal
characteristic of the malodor. It
will consume the enzyme leaving
none available for reaction with
the malodor. It may also cause a
secondary signal to be generated
thereby altering the overall odor
perception and recognition. These
compounds are generally
non-specific. They block all
perception. Ionones, some ketones
and aldehydes have been used for
this purpose.
: This can be
accomplished either by closing of
the receptor sites via mechanical
means such as masks, filters or
nostril plugs, or by chemically
blocking or damaging the sites.
While the former technique is
cumbersome, transitory and
uncomfortable it is preferable to
the latter which could be
dangerous. The result of harsh
chemicals such as formaldehyde can
be more than transitory.
Substances powerful enough to
cause a radical physiological
change can have severe
and harmful long range effects
upon the body.
: Perfumes and
fragrances function in this
manner. Products of this type do
little to alter either the basic
perception of the odor character
or the intensity of the malodor.
The intent of their use is to
cause so many signals to be sent
to the brain, most of which are
pleasant, that the impact of the
malodor is relatively weak in
relation to the overall impact.
This approach can be effective
with low levels of malodor.
Effectiveness is debatable with
high levels of malodor. Most
often both fragrance and malodor
are perceived, and the potential
for exacerbating a problem exists.
: If a
malodor can be made to react
chemically with an introduced
substance, it will become
something else and will smell
differently. This reaction is
primarily oxidation-reduction.
Oxidation involves a donation of
electrons by one molecule, and
reduction involves acceptance of
electrons by another. Both
oxidation and reduction occur
simultaneously and in equivalent
amounts during any reaction
involving either process.
Oxidizing
agents include chlorine,
(chlorine/caustic) sodium and
calcium hypochlorite, chlorine
dioxide, potassium permanganate
and hydrogen peroxide. All are
effective, but non-specific. Thus,
they react with non-malodorous
organics and nitrogen-based
compounds which increases the cost
of their use. As a group, these
products generally pose safety
problems -- toxicity, the
production of toxic by-products,
inherent corrosive and explosive
characteristics. Temperature and
pH influence the effectiveness of
most. Stabilized chlorine dioxide
is an exception. Unwanted reaction
with nitrogen-based compounds can
not occur, it is much safer to
handle and does not form
chlorinated by-products.
Metal
salts are also used for
deodorizing. They bind and
precipitate. Their effectiveness
is restricted to addressing
sulfides in solution. They do not
react with malodorous organics
such as amines and mercaptans.
Those most commonly in use are
ferrous and ferric chloride;
ferrous and ferric sulfate.
:
Defined as the mutual diminution
of two odors, counteraction or
neutralization is achieved by the
application of a second odorous
substance to the original malodor
so that the combination of odors
becomes inoffensive. The
simultaneous reaction at receptor
sites in the olfactory cleft
causes the generation of a signal
other than that characteristic of
the malodor. The combined signal
may either overpower the malodor
signal or cause the brain to
recognize a different pattern
which results in perception and
recognition of a pleasant odor or
no odor at all.
In
order to achieve practical success
with this approach, a balance must
be achieved between the relative
concentration of the malodor and
counteractant, and their
respective rates of reaction with
stoichiometric concentrations of
enzymes at receptor sites. This
technology represents a clear
advancement in odor control.
: Nuisance odors are
rarely single-dimensional. Rather,
they are a combination of
malodors. As such, any product
which is to be successfully used
against them must provide
multi-interventional capabilities.
The
chemistry of odor Countervailant™
products is specialized and
complex, and provides the most
advanced and broadly useful
technology currently available. It
incorporates the principles of
counteraction and neutralization
technology, but expands
considerably beyond it. Polymeric
adsorption is a facet of
Countervailant™
product technology. This involves
the building up of malodor
molecules via electrostatic
attractions and Van der Waals
forces to form macro-molecules.
The resulting macromolecules
become unrecognizable at receptor
sites, thus a signal code is not
produced.
The
process of esterification is also
incorporated. Esters are the
product of intermolecular
dehydration involving an alcohol
and an acid. Literally thousands
of esters can be formed because of
the extraordinarily large numbers
of acids and alcohols available
for reaction in waste substrates.
This reaction ability is
particularly useful in dealing
with food processing odors -- such
as fatty acid and butyric acid
odors. Signal codes for the
resulting esters are normally
recognized and described as odors
of natural herbs, fruit and nuts.
Essential oils are used sparingly
as well. They are of plant origin,
and principal constituents are
terpenes. In diluted form,
essential oils are only faintly
perceived, and are included
largely as olfactory guides for
application rates.
Odor
Countervailant™
products are effective for both
gaseous malodors via spray
atomization and malodorous liquids
via direct addition. They function
in a broad range of pH and
temperature. Very importantly,
they are safe to use for
operators, equipment and the
environment.
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