Killing of Invasive Species of Ship’s Ballast Water in 20t/h System Using Hydroxyl Radicals

A pilot-scale experiment of 20t/h for the treatment of ship’s ballast water was done in this paper. With the method of strong ionization discharge of dielectric barrier, O2 in air and H2O at gas state are ionized and dissociated into large numbers of OH• radicals, and then dissolved into a part of ballast water to form dissolved OH• with the concentration of 24.3 mg/L. When the dissolved OH• concentration is 0.63 mg/L, the kill efficiencies of bacteria, mono-algae, protozoan reached 100% within 2.67 s. The contents of chl-a, chl-b, chl-c and carotenoid were decreased to 35–64% within 8.0 s and not be tested after 5 min. At the same time, the ballast water quality was greatly improved. Therefore, the treatment of ship’s ballast water using OH• radicals is a kind of advanced oxidation technology, which is considered as zero pollution, zero emission and zero residual in the process of the production, of OH• radicals and the treatment of ballast water.