Treatment characteristics of marine microalgae hydroxyl radicals in ship''s ballast water
船舶压载水中海洋微生物的羟基自由基致死特性研究

Currently, there is no effective method to treat the introduced algaes and bacteria in the ship's ballast water. To solve this problem, the method of advanced oxidation technology producing high-concentration hydroxyl radical solution was used to treat marine microorganisms. With strong ionization discharge, O2 in air and H2O in seawater could be ionized and dissociated into a number of activate particles such as hydroxyl radicals (·OH), which can dissolve into seawater (a part of ballast water) to form the high concentration ·OH solution. With the high reaction rate and broad-spectrum lethal characteristic,·OH radicals could kill the introduced microorganisms through dissociative radical reactions in the course of both discharging and inputting the ballast water, without the pollution by medicament. In this study, Isochrysis zhanjiangensis, Chaetoceros muelleri and Escherichia coli in ballast water were killed by ·OH radicals. Results indicated that the threshold lethal concentration of ·OH radicals for microorganisms in ballast water was 0.6 mg·L-1. A-chlorophyll was damaged by ·OH radicals during the treatment, which resulted in the death of algaes.