Studies On Treatment Ship's Ballast Water By Hydroxyl Radical And Determation Of Relevant Chemicals

Global Environment Facility(GEF) has identified that marine invasive alien species spread is one of the four major risk factors which threates global marine environmental safety. Ballast water discharge is the main way for the spread of invasive alien species.According to the great needs of management of marine invasive alien species spread and of protection the coastal ecological safety, and depending on Key Projects in the National Science & Technology Pillar Program During the Eleventh Five-Year Plan Period(No.2006BAC11B06) and Science & Technology Cooperation Program of China (No.2005DFA20800),·OH and other reactive oxygen particles were prepared by natural substances H2O and O2 through strong electric field ionization discharge atmospheric pressure. The treatment ship's ballast water by·OH was studied in this paper. The main studies are as follows.Principle and method of strong electric field discharge was introduced, and plasma chemical mechanism for the generation·OH from H2O and O2 through the discharge was explained. Integration method is employed to establish reaction kinetics for TRO decay in ballast water treated by·OH. The rate constant of TRO decay was obtained.And then confirming that the decay reaction in ballast water was first-order reaction approximately. The rate equation which predicts changing of TRO concentration in treated ballast water was derived. The quantitative detection method for·OH was established through measuring·OH scavenger salicylic acid (SA) by high performance liquid chromatography(HPLC). A test method for bromate, one of the relative chemicals in treated ballast water, was established using ion chromatograph equipping with electric conductance detector.According to the land-based test standard of International Maritime Organization(IMO) Guidelines for Approval of Ballast Water Management Systems(G8) entirely, the experiment of treatment ship's ballast water by·OH based on IMO guideline Procedure for Approval of Ballast Water Management Systems That Make Use of Active Substances(G9) had finished successfully. The results show that the concentration of alage was lower than 10 cell/mL, and no bacteria were detected after being treated for 6 s. The alage and bacteria did not revival during 24 h and 120 h, respectively. It complies with Regulation D-2 of International Convention for the Control and Management of Ships'Ballast Water and Sediments completely. The pollution level of treaed ballast water decreased. And the water quality was improved, which relieves the environmental pressure when the treated ballas water was dischanged. The results show that the concents for 18 kinds of reative chemicals, such as halogenated alkanes, haloacetic acids, halogenated acetonitrile, and bromate, and so on, were all lower than World Health Organization (WHO) criterion at 0 h,24 h,120 h, also.The technology for killing invasive alien aquatic organisms by·OH in the course of conveying ballast water in ships can provide technical support for breaking trading barriers and opening up the global shipping market and bring to great economic and social benefits.