Study On The Killing Of Microorganisms In Ballast Water With Hydroxyl Radical Produced By Strong Ionization Discharge

The introduction of invasive marine species into new environments has been identified as one of the Four Greatest Threats to the world's ocean and its main spread source is the ballast water. But MEPC and GloBallast think that there are not efficient shipboard treatment options till now. As part of the key NSFC Project "Studies of Method and Application of Gas Molecules Ionized with Strong Electric at High Pressure Field" (No.:60031001) and the prophase SSTC Project "Basal Studies of Killing Harmful Microorganism in Ocean by Free Radical of Strong Oxidation" (No.: 2002CCC00900), this dissertation, taking the world's status of treating the invasive marine species of ballast water into account, utilizes the strong ionization discharge to ionize and decompose O2 and HaO into high concentration hydroxyl and other active radcials on a molecular scale and then produces hydroxyl solution associated with efficient gas dissolving technique. Therefor, killing the microorganisms in the ballast water on the spot is realized when the hydroxyl solution is added to the main pipeline of ballast water, which provides a new ideal method to solve the invisave spread of marine species.In this dissertation, the experimental study on the sterilization of microorganism by hydroxyl radical is summarized and the main achievements are as follows, (1) Hydroxyl can kill microorganisms with great speed. Thus the microorganisms in the ballast water can be killed during the transportation of the ballast water. (2) Even at low concentration (0.6-0.7mg/L), the hydroxyl solution can kill monocell alga, protozoa, cyst and so on. (3) Hydroxyl can increase the lipid peroxidation for aobut two times, intensively destroy the amylose, protein, DNA and RNA in the microorganism cells, distinctly destruct the CAT, POD and SOD of antioxidant system and decompose the photosynthetic of the microalgae. (4) The residual hydroxyl can be decomposed into water and oxygen. (5) The body of the microorganism can be decomposed into carbon dioxide, water and inorgnic materials without residuals. (6) Hydroxyl can improve thequality of the ballast water. The concentration of nitrite and amonia salt drops about 197 times and 60 times respectively and the COT decreases from 0.54mg/L to a extend that can not be detected. The turbidity drops about 50% and the concentration of DO increased 77.2%. (7) The equipement of producing hydroxyl is of great benefit such as small size, secure operation and low cost.The experimental results show that hydroxyl solution produced by strong ionization discharge is an innovative, efficient and viable method without residuals.