Ozone Disinfection Safety And Efficiency Integration Technology Research In Marine Recirculating Aquaculture System

Disinfection proves to be an indispensable section in RAS （recirculatingaquaculture system）. As a disinfectant, ozone receives more and more attention inaquaculture industry. To estimate the use of ozone in RAS, this study includes ozone’seffect on water quality, on disinfection, attenuation of ozone and impact betweenozone and RAS. Main content and the conclusions are as follows:Water quality in RAS has a direct influence on the health of breeding biology.This experiment studied ozone’s effect on water quality such as ammonia nitrogen（TAN）, nitrate nitrogen （NO₂^--N） and COD_Mnetc. The experimental results show thatall of TAN, NO₂^--N and COD_Mnhave more or less reduced with the rise of ozonedosing. Among the three water quality index, NO₂^--N has the most obvious reductionat a low ozone concentration.Confirm the disinfection factor by change the ozone dosage and contact time.Experiment evidence that ozone is very efficient when it is used as disinfectant inRAS. To reach a high disinfect efficiency in RAS, the need of ozone dosage is verylow while the need of contact time is also very short.Different injection way of ozone returns different disinfect efficient. Batchinjection of ozone has a good effect on the total bacterial count control, limit itsgrowth. Moreover, the continuous injection of ozone can maintain a low bacterialcount. A reasonable selection of injection way can reduce production cost and ensurethe disinfect efficiency as well.To ensure the disinfect time and a safe concentration before ozone enter thefishpond. Through the experiment on the natural attenuation of ozone, fitting thepredicted results and founded the basic mathematical relationships among the residualozone concentration, the initial ozone concentration and the attenuation time. Resultof the experiment on the ozone attenuation efficiency in RAS show that biofilter is themain part to reduce the ozone concentration in RAS among foam separator, UVequipment and biofilter. Combine with the result of the natural attenuation, ozonereduce in foam separator mainly by natural attenuation. In recirculating aquaculture system, make sure each part functioning guaranteesthe fishes’ health. Biofilter is the key section of recirculating aquaculture system.Result of ozone’s effect on biofiter shows that the right use of ozone can enhance theefficiency of biofiter. At the same time, if the use of ozone is not in a right way, it canrestrain or even destroy the biofiter, so that the TAN in RAS appears accumulationand finally lead to the fish health problems.This study includes ozone’s effect on water quality, bacteria and biofilter, it canprovide reference to ozone’s optimize business usage. Besides, the study of ozone’sattenuation has guiding significance on how to avoid the harm to breeding biologycaused by residual ozone.