Ozone and Aquaculture

Ozone is increasingly used in aquaculture due to its numerous advantages over traditional water treatment methods. Supplementing or replacing an existing system, ozone implementation has the potential to boost the competitive advantage of your aquaculture application.

Ozone Advantages

• Reduced Water Usage
• Faster Growth Rates
• Reduction of Waterborne Diseases
• Higher Standard of Environmental Control
• Supplements other Treatment Processes

Why Ozone Use is Growing in Aquaculture

• It effectively removes organics, pesticides, discoloration, and nitrates.
• Typically unconsumed ozone reverts back to oxygen, leaving no harmful residuals behind.
• Ozone oxidizes long chain molecules, which are unaffected by biofiltration.
• Ozone involves far lower risk of accidental pollution in comparison to other water treatment methods.
• O₃ improves the effectiveness of biological and particulate filtration.

How does ozone work ?

1. The principle of ozone sterilization

Ozone (O3) is an allotrope of oxygen. It is a light blue gas with a special odor. Its molecular structure is triangular, with a bond angle of 116°, its density is 1.5 times that of oxygen, and its solubility in water is 10 times that of oxygen. Ozone is a strong oxidant, its redox potential in water is 2.07V, second only to fluorine (2.5V), its oxidation capacity is higher than that of chlorine (1.36V) and chlorine dioxide (1.5V), and it can destroy the decomposing bacteria. The cell wall quickly diffuses into the cell, oxidatively decomposes the glucose oxidase necessary for oxidizing glucose inside the bacteria, and can also directly interact with bacteria and viruses to destroy cells, RNA, and decompose DNA ( Polymers such as DNA, RNA, proteins, lipids, and polysaccharides destroy the metabolic and reproductive processes of bacteria. The killing of bacteria by ozone is caused by the disruption of the cell membrane. This process is called cell dissociation because the cytoplasm is comminuted in water and cells cannot be regenerated under dissipated conditions. It should be pointed out that, unlike hypochlorous acid disinfectants, the bactericidal ability of ozone is not affected by the change of pH value and ammonia, and its bactericidal capacity is 600-3000 times larger than that of chlorine. Its sterilization and disinfection effects occur almost instantaneously. When the ozone concentration is 0.3-2mg/L in water, bacteria can be killed within 0.5-1min.

1 Viruses Ozone has been shown to have a very strong killing effect on viruses. For example, at a concentration of 0.05-0.45 mg/L ozone, the Poloi virus loses its activity within 2 minutes.
2 The cysts were completely removed at a concentration of 0.3 mg/L ozone for 2.4 minutes.
3 Spores Due to the protection of the spore coat, it is 10-15 times more resistant to ozone than the growing bacteria.
4 Fungi Candida albicans and penicillium can be killed.
5 Parasites Schistosoma mansoni was killed after 3 min.


2 Ozone deodorizes water bodies

The substances that generate odorduring the sewage treatment process are mainly composed of carbon, nitrogen and sulfur.
Only a few odor-producing substances are inorganic compounds such as ammonia, phosphorus, and hydrogen sulfide; most of the odor-producing substances are organic compounds such as low-molecular fatty acids, amines, aldehydes, ketones, ethers, and the like. According to the analysis of the influent status of the wastewater treatment plant where I was located, 80% of the influent water is domestic sewage, ie, the content of organic matter is very high, and the content of inorganic compounds is relatively small.
Most of the odor-producing substances are organic compounds, such as low-molecular fatty acids, amines, aldehydes, ketones, ethers, etc. These substances all have active groups, are prone to chemical reactions, are particularly easily oxidized, and have strong ozone. Oxidation characteristics, oxidation of active groups, odor disappeared, so as to achieve the principle of deodorization.
In addition to the odor removal, ozone can also prevent the re-production of odors. This is because the gas generated by the ozone generator contains a lot of oxygen or air, and the odor-producing substances are easy to cause odor in the absence of oxygen, using ozone. Treatment, oxidation and deodorization at the same time, the formation of oxygen-rich environment, can prevent the re-production of odors. The improvement of the sewage treatment environment in the urban sewage treatment plant is still relatively large.


3 Decolorization of water by ozone

With the attention paid to the tap water source environment and the reuse of secondary treatment water for sewers, secondary treatment water destaining has received attention.
As for the color and taste caused by humus, the water color averages 10 degrees. Up to 20 degrees. Such chromas rely on general cohesion sedimentation and sand filtration processes that do not achieve adequate water quality standards, and may even exceed the worst-case criteria. After the ozone treatment, the color can be reduced to less than 1 degree. The reason for the coloring of tap water is that the content of iron and manganese is too much. If these metals are in the free state, the conventional method can be fully removed. If humus is present in the raw water, chromium salts are sometimes formed and it is very difficult to perform conventional treatment. Therefore, color removal is also an important factor in the introduction of ozone treatment.

The decolorization mechanism of ozone: With the vigorous development of molecular biology, microecology will extend the ecology to the molecular level. In fact, whether the protein or nucleic acid molecule is organic, they are all composed of carbon, hydrogen, oxygen, nitrogen and phosphorus or sulfur (C, N, O, N, P, or S). At the same time, the coat of virus is composed of many The protein subunit is composed of shell particles. Each shell particle is linked by non-covalent bonds and is tangled together symmetrically. The protein is composed of multiple chains and the nucleic acid is composed of linked nucleotide chains. Of these, OH, as a whole, is electrically neutral (R-OH), but if viewed from the inside of the group, part of it has more negative charges (such as oxygen atoms) because of this part of the group. (R-OH) has "additional" bonding electrons, so it is negatively charged: the other part has more positive charges (such as hydrogen atoms), and this part of the group lacks bonding electrons, so it is positively charged. If there is another similar group close to each other, positive and negative charges attract each other to generate a weak bond, which is called a hydrogen bond, such as between polypeptide groups or between nucleotide thiol groups and DNA or RNA molecules. The thiol groups in the pair are all likely to form hydrogen bonds. Although a single hydrogen bond is very weak, many hydrogen bonds together to form a tough cell wall in plant cells. Now look at ozone, it is a strong oxidant, high oxidation potential (2.07ev). Any element with high electronegativity can strongly attract electrons, oxidize each other, and restore oneself. Oxidation results in nucleic acid breakdown, protein disintegration, antigen denaturation, negative detection, and chroma fade.