FISH FARMING
Ozone use can keep water cleaner and fish healthier. Healthier fish take on
feed faster and grow faster. Use of ozone in these applications has shown
great payback on investment.
Implementing ozone correctly is imperative as too much can damage the gills
of the fish, however, too little if other systems are designed around ozone, can
cause water quality issues. While the level of ozone and control is critical, the
actual implementation is not too difficult in most applications. Most facilities
already have some devices in place for overall water treatment and filtration,
along with devices to increase oxygen levels in the water. Ozone can typically
be added to air, or oxygen feeds that are already in place.
Control of ozone can be done with simple ORP monitors that may already be
on-site. By using the output signal of the ORP sensor into the ozone
generators ozone levels in water can be controlled within fairly tight
tolerances.
OZONE FOR FISH FARMING & AQUACULTURE CAN BE USED FOR THE FOLLOWING
PURPOSES:
Fine and colloidal solids consist of particles 1-30 microns and 0.001-1
microns, respectively. The small size of the particles enables the solids to
remain in suspension and avoid most mechanical separation methods. In
addition, the accumulation of fine and colloidal solids can impair bio-filter
nitrification efficiencies and stress fish stocks. By causing the solids to clump
together, ozone facilitates their removal by foam-fractionation, filtration, and
sedimentation.
REMOVAL OF DISSOLVED ORGANIC COMPOUNDS
Dissolved organic compounds (DOC’s) gives the water a characteristic tea-
colored stain. Furthermore, DOC is non-biodegradable and accumulates
based on feed input, water exchange rate, and solids removal rate.
A high level of DOC can stress fish and reduce the nitrification efficiency of a
biofilter. As a result of oxidation, dissolved organic matter is converted into
products that are more readily nitrified.
REMOVAL OF NITRITE
Nitrite can accumulate as production intensifies and organic loadings on the
bio-filter increase. Bacteria that process ammonia into nitrite operate more
efficiently under high organic loadings than bacteria that process nitrite to
nitrate. High levels of nitrite can be toxic to fish. Data available indicate that
nitrite levels as low as 2.8 parts per million (ppm) can reduce the growth of
fingerlings by 5%. By oxidizing nitrite directly to nitrate and reducing organic
loading, ozone improves bio-filtration and nitrification.
DISINFECTION
Facilities need to reduce pathogen loads introduced via the source water,
effluent waters must also be disinfected before being released into the
environment. Ozone can effectively inactivate a wide range of bacterial, viral,
fungal, and protozoan fish pathogens. The effectiveness of ozone treatment depends on ozone concentration, length of ozone exposure (contact time),
pathogen loads, and levels of organic matter. Virtually eliminated fish mortality
and disease saving thousands of dollars for fish farms. Increased fish weight
gain in the same time (about 40% in our client experience) increasing fish
farm profits. Also, eliminated the bad taste in fish. For example, there is a
stigma attached to the Tilapia taste, the fish farm that uses ozone, renamed
Tilapia into Northern Perch to be fair to the taste improvement and marketing
it very successfully.
OZONATED ICE
After fish are harvested they are typically stored on ice. Another great use of
ozone is ozonated ice. By dissolving ozone into water and quickly freezing this
water, ozone is essentially trapped within the ice.
Ozone is an excellent antimicrobial agent, and is commonly used to extend
shelf life of many food products. By locking ozone into the ice, and placing fish
on this ice, the benefit of ozone is slowly released to extend the shelf life, and
improve the quality of your fish while storing and shipping to your end user.
Should you have questions on implementing ozone in your aquaculture or fish
farming application, give us a call, or e-mail. We would be glad to share our
previous experience with you.
