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Abstract

In this paper, the antimicrobial effect of inert flue gas on indicator microorganisms in ballast water was investigated based on a 265h test. The inert flue gas consists of nitrogen (N2) and carbon dioxide (CO2) the microorganisms include Chlorella and Escherichia coli. Within the scope of the test, the killing effect of the microbes treated by combining N2 and CO2 was higher than that of using only either N2 or CO2. When the dissolved oxygen concentration in the ballast water was 0.5 mg/L and the pH value was 6, the killing effect was the highest. At this time, the mortality rate of Chlorella sp. and E. coli reached 99.99%, and 99.98%, respectively. After the experiment, property of the ballast water treated by N2 and CO2 were analyzed. The dissolved organic carbon concentration was lower than the recommended minimum concentration of 5 mg/L. The concentration of particulate organic carbon was higher than the standard value of 0.3%.The experiment proposes a new method for ballast water treatment of large ocean-going vessels in the future.

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