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Ozone
Advantages
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Ozone
Disadvantages
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Inlet water treatment
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When combined with inlet filtration to <40mm
can give a guarantee of 100% sterilisation.
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Control and monitoring system to ensure full
sterilisation is expensive.
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Can oxidise some pesticides and herbicides which
may be of help in reducing losses through diseases such as Taura
Syndrome in shrimps.
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Treatment of seawater (and some freshwaters
containing contaminants) can result in the formation of potentially
toxic compounds.
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Ability to sterilise in turbid conditions where the
use of UV would not be suitable.
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Ozone removal system required, especially if water
is used for flow through system rather than recirculation.
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Systems operating indoors must house ozone gas
alarms to ensure safe working levels for workers. Off-gassing of
ozone into the air can occur if the control system does not operate
correctly. Exposure of humans to ozone gas can result in very
serious, long term health problems. |
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Use of oxygen as the supply gas for the generator
can result in supersaturated oxygen concentrations.
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Recirculation Systems
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Breaks down complex molecules that biological
filters are unable to cope with, into smaller molecules that they
can handle. Without ozone, these complex molecules are responsible
for the water colouration and some of the taints found in
recirculated water, which can make marketing the fish difficult.
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Improper control of the ozone system can lead to
fluctuating concentrations and damage to the fish.
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Oxidises nitrite to nitrate
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Failure of the ozone system can lead to an increase
in the concentration of nitrite (and ammonia in seawater) in the
systems. This is because the population of bacteria in the
biological filters have grown to handle the level of nitrite in the
water when the ozone system is operating. When the ozone is no
longer taking the nitrite out of the water, it can take the
bacterial colony up to 24hours to multiply so that they can cope
with the additional loading. This results in a spike
in the nitrite concentrations which can kill the fish.
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Oxidises ammonia to nitrate in seawater (and
freshwater > pH9)
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Recirculation systems operating indoors must house
ozone gas alarms to ensure safe working levels for workers.
Off-gassing of ozone into the air can occur if the control system
does not operate correctly. Exposure of humans to ozone gas can
result in very serious, long term health problems.
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Improves efficiency of foam fractionation
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Use of oxygen as the supply gas of the generator
can result in supersaturated oxygen concentrations which may be
undesirable.
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Can provide full or partial sterilisation
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Capitally and operationally expensive
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