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In all fish, poultry and red meat processing
industries the problem of Salmonella and Listeria bacteria represents one of the biggest
challenges. Frequent use of water to rinse and remove dirt and debris from the product,
the work stations, floors, and walls is essential. Yet, most water supplies are
contaminated, or treated with chlorine. Large amounts of chlorine are needed to kill
bacteria in a short time available on the process conveyors. Unfortunately, chlorine also
reacts with the meat, forming highly toxic and carcinogen compounds called THMs or
Tri-Halomethanes. The color of the meat surface may also be degraded by chlorine,
potentially rendering a lesser quality product. This is especially concerning when the
rinse water stays in pockets inside the meat product.
Ozone comes closest to the ideal solution. Ozone has been used in this
application for almost a hundred years. For decades, chlorine seemed to be a cheaper
alternative. Only about two decades ago, massive research into the byproducts of chlorine
alerted the scientific world. It has been concluded that chlorine should ideally be
eliminated not only from drinking water purification systems, but also from any
application where organic materials are involved, and in the food processing industry in
particular. Previously set dosages of chlorine are no longer effective on some viruses and
parasites. For complete disinfection much higher dosages would have to be used, but such
levels are not allowable to contact the meat.
WHY USE OZONE:
•Ozone is a tri-atomic oxygen molecule which
loses one oxygen atom in the disinfection process to become a normal oxygen molecule.
Oxygen is not toxic and it does not form toxic substances. Any excess of ozone breaks down
into oxygen.
• Ozone is by far more effective than chlorine in killing all bacteria, fungi and
viruses, and it does this at a concentration 1/10 of that required by chlorine.
• Ozone has a short reaction time and requires a shorter contact time than
chemical disinfectants.
• Ozone is a strong Oxidant and will eliminate odors as well as the
micro-organisms causing the odors.
• Ozone can be generated onsite from air and electricity, as a result the need for
transporting and storing hazardous chemicals is eliminated.
• The correct ozone level can be maintained electronically; there is no need for
the manual preparation of washing solutions.
While in theory ozone has always appeared to be the perfect disinfectant, some practical
challenges have prevented the full use of ozone much earlier in this century. The process
requires that ozone gas be dissolved in the water first and any undissolved ozone gas
removed and disposed of. Likewise, the maintenance of the ozone level in the water supply
must be consistent all the time — no matter what the actual water demand is at any
given moment.
O3 Water Systems has a system to meet all of the above conditions — in developing
a fully automatic supply of Ozonated water for the meat processing industry. Each system
is customized to the specific flow and needs of each specific operation, and consists of
the following:
1. A FOOD GRADE STAINLESS STEEL TANK for ozone mixing, contact and off-gas. Mounted on
the tank are:
- Low and High water level sensors for automatic control of
water supply, and for the protection of the pumps.
- Two stainless steel pumps. One for the ozonation circuit,
and one for boosting the tank pressure to 3 atm (45 psi) as needed at the plant.
- Tank controller with solid state, zero crossing pump drivers
and water supply automatic control.
- Ozone off-gas system.
2. THE OZONE GENERATING SYSTEM comes with:
- Ozone generating modules to the full capacity required.
- Air dryer sized to the capacity required.
- Controller with the system power distribution, ozone level
controller, dry air sensor, ambient air sensor, the tank controller interlock, and more
— for fully automatic operation and the safety of the whole system. The controller
allows for the programming of the ozone level, so that the desired dissolved ozone
concentration will be maintained automatically — and independently of any momentary
water demand. A warning light will indicate lower than acceptable conditions. The system
can be wired to a central computer if desired.
3. PIPE DISTRIBUTION SYSTEM:
- The pipe distribution system includes manifolds for the ozonized water and allows
proper distribution throughout the whole plant. A feedback to the contact tank is
implemented to assure consistent levels of dissolved ozone in the distribution pipes when
the water demand changes during the day.
The following are examples of the practical results achieved in various system
installations:
CHICKEN PROCESSING
In chicken processing plants it is common to hold the eviscerated birds in a chilled
water bath for 1.5 hours. During this time the ozonation could be performed and the
carcasses would be sterilized.
SHIPSIDE FISH PRESERVATION
The above process is similar to the treatment of fresh fish in holding tanks on fishing
vessels. Prior to the introduction of ozone, chilled brine was used to maintain the
quality of the fish. This worked for up to about 5 days, after that time the fish was
unmarketable. Since ozone has been implemented in fish holds, the fish can be now be held
preserved as long as 21 days, and still be as good as if freshly caught. In reality, the
actual time fish is held is always much less than 21 days as the fish is delivered to a
processing plant or market. Three weeks has probably been the longest time tested. Once
the fish processors in Norway saw the difference in the quality of the fish delivered,
they demanded that all fish boats use ozone to maintain their catch.
In the fish processing plants which were previously contaminated with bacteria, all
sanitation problems have now been solved. There is no more need to buy costly chemicals,
nor to worry about losing business to an outbreak of Listeria or Salmonella. Over the
years, the use of ozone in this application proved to be superior to any other treatment.
WASTEWATER TREATMENT FOR PLANTS
Wastewater treatment with ozone eliminates any formation of toxic byproducts, and helps
to meet local requirements for water discharge quality. This process involves a
combination of settling, ozone assisted flotation, foam fractionation, flocculation and
bio-filtration is followed by a direct, end treatment with ozone. In some cases, where
long chain organic molecules are difficult to break, the ozone treatment may be assisted
with UV radiation and/or hydrogen peroxide. The resulting free hydroxyl radicals may speed
up the treatment up to 30 times, thus saving on space and energy. The systems may further
be combined with multimedia filters, rotating screens, carbon or cartridge filters, in
order to reach the required resulting water quality.
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