バラスト水処理におけるナトリウムピリチオン及び二酸化塩素の適用に関する研究

抄録

Many techniques are being developed in the world wide to prevent marine organism's transportation with ballast waters of ships. This study was conducted to know the availability of sodium pyrithione (NaPT) and chlorine dioxide (ClO2) for ballast water treatment. The concentrations of 3 mg/1 and 9 mg/1 of NaPT and 3 mg/l of ClO2 were prepared with sea water which was taken from Tokyo bay. These were incubated at 20 ± 1 ℃ and dark for 7 days. After 4 hours of the incubation, the number of heterotrophic bacteria deceased from 2.9 x 105 CFU/ml to 70 CFU/ml in the sea water containing C102. But more than 2.9 x 105 CFU /ml of heterotrophic bacteria was detected in the all sea waters after 7 days of the incubation. The chlorophyll a in the sea water containing ClO2 was almost disappeared after one day of the incubation. At 7th day of this study, each 800 ml of the sea water was divided into two groups, and 1.2 mgs of ClO2s were added to one group of the sea waters (”ClO2 additional group” and ”CｌO2 non additional group”). These were incubated at 20 ± 11C and a 12 hours cycle of light and dark for 43 days. Besides, each 5 ml of the sea water was injected into 100 ml of f/2 mediums to confirm existence of survived phytoplankton after 4 hours of the incubation. The increasing of chlorophyll a in the f/2 mediums were observed in both groups of control (only sea water at beginning of this study) and 3 mg/1 of C102 on ”CｌO2 non additional group”. The result of 43 days incubation showed existence of survived phytoplankton in all sea waters, and the lowest cell density of phytoplankton in 3 mg/1 of CI02 on ”CｌO2 additional group”. From these results, although heterotrophic bacteria and phytoplankton were not extinguished by NaPT and ClO2 under this experimental condition, it seems that ClO2 is available for ballast water treatment.