Aquaculture, also referred to as aquafarming, is the production of aquatic organisms under controlled circumstances. Similar to agriculture but instead cultivating fish for human consumption instead of crops and livestock. Aquaculture can meet the needs of providing mankind with animal protein with the least amount of impact on Earth's resources. The three types of aquaculture environments include freshwater, brackish water, and marine.
Ozone in Aquaculture
Ozone is a powerful oxidant that is needed as a component of an aquaculture system. Ozone generators are utilized in the aquaculture industry. Ozone and ozone-produced oxidants used in aquaculture systems provide benefits of healthy stock in an ideal environment.
Ozone for Disinfection
Due to the high rate of oxidation, ozone is a useful disinfectant. Ozone is highly effective due to its high oxidation potential. High stocking densities, fish stress, and the nutrient loads of a recirculating aquaculture system can become a breeding ground for pathogenic fish bacteria. Ozone has the ability to kill different types of pathogens including bacterial, viral, and fungal.
The effectiveness of ozone treatment for disinfection is dependent on the concentrations of ozone, ozone exposure time, and the levels of organic compound matter. Significant disinfection of aquaculture effluent water requires between 0.2-0.4 ppm residual ozone for up to five minutes after oxidation of organics. In pure water, residual concentrations of 0.01-0.1 ppm ozone for a minimal amount of time are highly effective in the reduction of bacteria. The three natural waters of aquaculture environments (seawater, brackish water, and freshwater) require residual concentrations of between 0.1-0.2 ppm ozone for periods of 1-5 minutes.
The short span of contact with ozone allows for quick disinfection of water, then decomposing back into oxygen without leaving toxic residue. Reduction in pathogen loads can be reached using moderate levels of ozone and can provide significant water quality improvements. Ozone can be applied into any incoming supply water to prevent the entry of pathogen loads in water brought into the facility. Disinfection of source water helps reduce the risk of disease outbreaks in the aquaculture system.
For providing the optimum rate of ozone as a disinfectant needs to be calculated on the total ozone demand comprised of dissolved organic compounds, colloidal solids, nitrate, and disinfection.
Removal of Nitrite
High levels of nitrite can be toxic to fish. As things such as fish discharge, decaying plants, and dirty filters begin to break down, they give off ammonia. Then a bacterium causes a breakdown of the ammonia into nitrite and finally, other bacteria feed on the nitrites resulting in nitrates (which are not nearly as toxic and provide additional food sourcing for plant growth.) The root of this is ammonia and the process for the transformation of ammonia into nitrates is nitrification. Reduction of nitrate levels is necessary for a healthy environment.
Nitrite can accumulate with increased production and as organic loading on the biofilter increase. Biofilter performance disruption can cause vast fluctuations in ammonia and nitrite levels. A few hours after feeding the fish, concentrations of ammonia and other waste products reach a maximum.
When levels of nitrite rise, it is then absorbed by the fish which prevents adequate oxygen flow in the bloodstream. Without the removal of nitrate, it can result in the suffocation of the fish due to a lack of oxygen. Although some types of fish have a higher tolerance, levels can contribute to overall fish health. The fish show the effects of change in colour, stunted growth, and fish diseases.
Ozonation of water, an oxidation reaction with ozone, is an effective method of removing ammonia from the water. Ozone has the capability of direct oxidation to nitrate by reducing the organic load which improves the biofilter performance. Nitrifying bacteria in biofilters removes dissolved ammonia and nitrite.
In order to apply ozone to aquaculture requires ozone generation, ozone transfer, contact time for reaction and disinfection, and ozone destruction to ensure that no residual ozone concentration seeps into other areas.
Reduction of Solids
Even with great waste removal processes, there can be a buildup over time of dissolved organic colloidal solids. Also, over time the biochemical oxygen demand increases which can cause a decrease in oxygen levels. The accumulation of these solids can impair biofilter nitrification efficiencies causing considerable risks to your fish. This can be controlled with the increased production of ozone.
Ozone causes the fine and solid colloidal solids to clump and have a removal by conventional filtration and sedimentation. Conventional treatment addresses the removal of filterable solids but not the removal of colloidal solids. Treatment of coarse solids can have expensive costs due to the fact that residual ozone must be increased to satisfy the additional ozone demand. However, a better solution to this problem would be to apply a larger water filter to get rid of coarse solids first.
Safe for Use
Ozone for treatment is safe and approved by the FDA and USDA for food substances. No record-keeping of ozone use is necessary to keep. This also reduces the need of using other more harmful chemicals of conventional treatment methods.
Due to being extremely toxic, any direct ozone exposure to humans constitutes a serious health hazard. Although low levels of residual ozone can be detected as a sharp, pungent odour, continued exposure can dull a person's senses.
When creating a generation of ozone in systems, it needs to consist of ozone-resistant materials that are nothing substandard. Using improper materials can result in erosion to your system and create costly leakages that can be dangerous.
Ozone applications continue expanding with increased knowledge of the positive effects of ozone. Application of ozone to aquaculture oxygenates reduces odour, and provides clarity of the water. It accelerates fish density and eliminates bacteria in water resulting in increased productivity.
Nebula Ozone utilizes technology to join ozone and water in producing an environment-friendly ozone system. With advanced ozone technology, Nebula can provide a cost-effective system that produces optimal ozone dosage that is safe for you, your customer, and the environment.
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