Development of Water Disinfection Systems for Seed Production Facilities

Water supplies often provide an efficient means for the introduction and spread of infectious desease.Pathogen-free water sources are often essential for success in aquaculture.The surface waters commonly used in aquaculture come from coastal waters or rivers and may contain the fish pathogens.Such open water supplies should be used prior treatment to kill the fish pathogens.Disinfection of wastewater before discharging is better for the environment.Usually，the treatment systems make use of high efficiency sand filters to clarify the water before treatment with ultraviolet(UV)light or ozonation。Fish pathogens are divided into2groups based on their sensitivity to UV and TROs.Sensitive viruses include infectious hematopoietic necrosis virus(IHNV)，Oncorhynchus masou virus(OMV)，lymphocystis virus(LCDV)and Japanese flounder rhabdovirus(HIRRV)，and Gram-negative bacteria。These microorganisms are inactivated or killed by treatment with 10^4µW·sec/cm^2(UV Dose)or 0.1 mg/L(TROs)for 1…More min。Resistant viruses include infectious pancreatic necrosis virus(IPNV)，marine birnavirus，reovirus and fish nodavirus，Gram-positive bacteria，fungi and parasite which are inactivated with a dose of 106µW·sec/m^2or 0.5 mg/L(TROs)for 1min。Ozonated seawater containing TROs is toxic to fixh，thus it should be removed by charcoal before using.Bactericidal and virucidal effects of hypochlorite produced by Electrolysis of seawater(Salt Water)are examined。More than 99.99%cells of V.anguillarum and A.salmonicida were killed when the bacteria were exposed to 0.1 mg/L hypochlorite for 1min。Yellowtail ascites virus(YAV)and hirame rhabdovirus(HIRRV)were inactivated&gt；99099%after treatment with 0.58 mg/L hypochlorite for 1min。Using for wastewater，more than 99%of viable bacteria in waste-seawater was reduced treated with 0.5 mg/L of total residual chlorite for 1min。The bactericidal effects of electrolysis were almost same as that of ultraviolet irradiation(1.0×10^5µW·sec/cm^2)or ozonization(TROs 0.5 mg/L，1min)of seawater.This method is easy to treat large volume of water，so it suits to disinfection of wastewater.Less：Less

Water supplies often provide an efficient means for the introduction and spread of infectious desease. Pathogen-free water sources are often essential for success in aquaculture. The surface waters commonly used in aquaculture come from coastal waters or rivers and may contain the fish pathogens. Such open water supplies should be used prior treatment to kill the fish pathogens. Disinfection of wastewater before discharging is better for the environment.Usually, the treatment systems make use of high efficiency sand filters to clarify the water before treatment with ultraviolet(UV)light or ozonation. Fish pathogens are divided into 2 groups based on their sensitivity to UV and TROs. Sensitive viruses include infectious hematopoietic necrosis virus(IHNV), Oncorhynchus masou virus(OMV), lymphocystis virus(LCDV)and Japanese flounder rhabdovirus(HIRRV), and Gram-negative bacteria. These microorganisms are inactivated or killed by treatment with 10^4μW・sec/cm^2(UV dose)or 0.1mg/L(TROs)for 1 … More min. Resistant viruses include infectious pancreatic necrosis virus(IPNV), marine birnavirus, reovirus and fish nodavirus, Gram-positive bacteria, fungi and parasite which are inactivated with a dose of 106μ W・sec/m^2 or 0.5mg/L(TROs)for 1min. Ozonated seawater containing TROs is toxic to fixh, thus it should be removed by charcoal before using.Bactericidal and virucidal effects of hypochlorite produced by Electrolysis of seawater(salt water)are examined. More than 99.99% cells of V.anguillarum and A.salmonicida were killed when the bacteria were exposed to 0.1 mg/L hypochlorite for 1 min. Yellowtail ascites virus(YAV)and hirame rhabdovirus(HIRRV)were inactivated>99099% after treatment with 0.58 mg/L hypochlorite for 1 min. Using for wastewater, more than 99% of viable bacteria in waste-seawater was reduced treated with 0.5mg/L of total residual chlorite for 1min. The bactericidal effects of electrolysis were almost same as that of ultraviolet irradiation(1.0×10^5μW・sec/cm^2)or ozonization(TROs 0.5mg/L, 1min)of seawater. This method is easy to treat large volume of water, so it suits to disinfection of wastewater. Less