is sometimes called "activated oxygen". It contains three atoms of oxygen
rather than the two atoms we normally breathe. Ozone is the second most
powerful sterilant there is and it can be used to destroy bacteria, viruses,
and odors. Ozone is short-lived and readily decays back to normal oxygen.
It is a pungent gas created naturally in the earth?s upper atmosphere
by the action of ultraviolet sun light on oxygen molecules. Ozone can
be created for water treatment or other purposes by sending air through
a special chamber containing a high-voltage spark, which creates a blue
plasma corona. Ozone can also be produced by sending air through a chamber
radiated by intense ultraviolet light.
ozone does not receive widespread use in the United States as a primary
drinking water disinfectant this may change in the future because ozone
does have a number of advantages over chlorine and chloramines. Some have
reported that ozone can be up to 2500 times as powerful a disinfectant
as chlorine under certain conditions (Hamil and Clawson, Water Technology,
April 1997). Ozone is capable of destroying all cysts, fungus, viral agents
and bacteria instantly, whereas, chlorine is not effective in destroying
protozoa cysts and may take 30-60 minutes to destroy bacteria or other
agents. Ozone is much more capable of penetrating and destroying bio-films
in distribution systems and water wells than chlorine.
chlorine, ozone does not form halogenated organics like trihalomethane,
and in fact actually destroys them. Ozone does not generate byproducts
of oxygenation that contaminates a water source because ozone degrades
to regular oxygen leaving no harmful residual in water. And finally, ozone
is effective over a much wider pH and temperature range than chlorine,
making it more versatile. Once investment is made in ozone disinfection
there are other advantages over a chlorine system. There is no chlorine
or chemicals to purchase, no chemical storage or handling needed and no
labor requirements to mix chemicals. Therefore, ozone offers lower long-term
operating costs and fewer safety concerns to operations staff than chlorine.
addition to being used as a disinfectant, ozone is not normally used for
iron removal because ozone does not remove iron or manganese from water,
but it can facilitate their removal. Ozone will oxidize these metals from
dissolved forms to particulate (oxidized) forms. Once these metals are
oxidized, they can be more easily filtered. In some cases, these metals
can settle in a storage tank after ozonation.