Ammonia is one of the most
commonly produced industrial chemicals in the United States. It is a naturally
occurring compound and it is not considered to be a contributor to ozone
depletion, greenhouse effect or global warming. It is a key intermediate in the
nitrogen cycle, a process by which nitrogen is converted into various chemicals
forms, and carried out through both a biological and physical processes.
Understanding the role of
ammonia in the nitrogen cycle is important.
There are four key processes
in the nitrogen cycle that result in the transformation of ammonia. These
processes are; Nitrogen Fixation, Ammonification, Nitrification, and
Denitrification. As part of this cycle, nitrogen gas and oxidized forms of
nitrogen are transformed and returned to the biological world.
The process begins with
Nitrogen Fixation, this is the process by which nitrogen gas, in our
atmosphere, is converted into organic nitrogen. This occurs naturally in free
living soil bacteria as well as other bacteria that forms symbioses with
legumes and other plant life.
Organic nitrogen then goes
through a process called Ammonification also known as nitrogen mineralization
and is the conversion of organic nitrogen into ammonia.
Next, is the biological
oxidation of ammonia nitrogen to nitrate, with nitrite serving as the
intermediate (NH4) - (NO2) - (NO3) this is referred to as Nitrification.
Finally, there is
denitrification a process whereby the nitrogen oxides (i.e., nitrate and
nitrite) are reduced under anaerobic conditions to (N2) and (N2O) which are
colorless odorless gasses that are safe to be released back into the atmosphere
The diagram below take from The
Ammonia Data Book gives a simplified visual of the Nitrogen Cycle.
Other common ways ammonia
is released into the atmosphere.
There are also several other
ways in which ammonia is released into the environment. Daily life cycle
occurrences play a vital role in the release of ammonia into our water, soil
and atmosphere as well.
Decaying matter, livestock
excreta, burning of coal wood and other natural products are contributors to
ammonia releases in the atmosphere and soil (more or less becoming part of the
Ammonia can also be released
into our water through effluent from sewage treatment plants, effluent from the
industrial process, and runoff from fertilized fields and over populated areas
The industrial refrigeration
industry has a very small effect on the overall environment in terms of
ammonia. We contribute less than 1% of ammonia into the atmosphere. Ammonia is
a natural part of our environment and imperative, not only to the nitrogen cycle,
but to many other biological processes as well. As a natural gas (and
refrigerant) in most cases it is hazardless.
For more information on the
effects of ammonia as a natural refrigerant check out The Ammonia Data Book or
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