Re: Ozone & chlorine as sanitizers

From: gregory.scher@us.army.mil
Date: Wed Jan 11 2006 - 12:15:56 PST

  • Next message: Aquatfs@aol.com: "Re: Ozone & chlorine as sanitizers"

    Is anyone studying the effect of ozone oxidizing naturally occurring
    bromide into bromine? Is there residual bromine in the fish?
    >
    Greg Scher
    CW2, US Army Veterinary Corp

    ----- Original Message -----
    From: Aquatfs@aol.com
    Date: Wednesday, January 11, 2006 10:05 am
    Subject: Re: Ozone & chlorine as sanitizers

    > I would like to clarify several issues concerning the use of ozone
    > as a
    > sanitizer. Ozone generators are rated to produce an amount of
    > ozone gas per hour
    > or per day. This gas must then be efficiently mixed with water in
    > order to
    > produce ozonated water. Using a coarse sparging stone for example
    > will probably
    > result in most of the ozone bubbling through the water and then
    > outgassing
    > before being of any use. The potential for ozone in water to kill
    > bacteria has
    > the same constraints as chlorine. There is a difference between
    > free chlorine
    > (chlorine that has not reacted with organic matter and is
    > effective at
    > killing bacteria) and total chlorine which includes free and
    > bound chlorine (the
    > latter being chlorine that has reacted with organic matter and is
    > not
    > effective at killing bacteria).
    >
    > There must be sufficient ozone or chlorine to overcome the organic
    > demand
    > and still have a residual. Obviously this is a function of how
    > much sanitizer is
    > being added and the demand that is imposed by the amount of
    > organic material
    > in the water. If someone states that they are adding 3-5 ppm of
    > ozone, the
    > first question is whether this is calculated as the amount of
    > ozone being
    > produced by the generator divided by the amount of water. Was the
    > assumption that
    > 100% of the gas would be dissolved in the water as this is never
    > the case.
    > There are test methods and instruments for measuring the net
    > residual in
    > ozonated water although there are some difficulties in getting
    > good measurements
    > especially at lower concentrations.
    >
    > The next problem involves the organic load in the contacting
    > vessel for
    > ozonated water and the product. Ozone will react quickly with
    > organic matter
    > before it kills bacteria. If the amount of ozone available is less
    > than or equal
    > to the amount that will react with the organic load, then little
    > or no
    > sanitizing effect is possible. And finally, contact time is a
    > consideration for any
    > sanitizer.
    >
    > Alan Ismond, P.Eng.
    > Aqua-Terra Consultants
    >



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