Lab scale에서 오존 버블을 이용한 선박평형수 처리장치의 생물 사멸효과

Abstract

Sea water in the areas is used for Ballast water used to balance of a vessel. The sea water for ballast water causes large problems which threaten ecosystem or marine environment not only the areas but also others. Therefore, IMO has enacted laws preventing discharges of toxicity water and regulating elimination of all organisms including virus in ballast water when the water is flowed in or out a vessel. Thus, a management treaty was signed, all vessels have to equip ballast water management system (BWMS). As the treaty is effective, maritime related industries have made a great effort to develop BWMS which is regarded as driving force of a nation’s economic prosperity in the world market. SUNBO Co., Ltd, DESEC Co., Ltd and KIMM have signed Technology commercialization agreement and cooperatively performed a project developing BWMS. In the Lab scale test for the Basic Approval, ozone which has the lowest toxicity and a 10m3 of water tank were used. Also, each 5m3 of tank for a treatment and control experiment was installed. Ozone generator system was consisted of an air compressor, an oxygen generator, and an ambient destructor, and a MFC controller, and the final concentration Ozone was 170 g/L. Indicator organisms for the experiment were Tetraselmis suecica and Artemia sp. To decide injection methods, first, two methods are compared: Side-stream is that sea water is pumped out, with a rate of 5.5L/min, of the treatment pipe which has 5m3/h flow, ozone is injected into the sea water, and then the mixed sea water with ozone flows in a treatment pipe: Main-stream methods is that ozone is directly injected into the treatment pipe. As a result of the comparison, the initial TRO concentration, 3.61mg/L as Br, by Main-stream methods was about 1mg/L as Br2 higher than that by Side-stream methods. The rate of elimination by Main-stream methods, also, was two percent higher than the rate by Side-stream methods. Therefore, Main-stream method was decided as the final injection method. Test on improvement of a nozzle was also conducted to maximize the functioning of injection by Main-stream method. Three types of nozzle were developed and compared by a test. The test had been done with the developed nozzles based on the findings that ozone should be ideally micro-sized bubble which can be effectively dissolved in sea water and fresh water and the outcomes with micro-sized bubbles can only meet the conditions for the Final Approval by IMO. Each nozzle was called LAB-1, 2, 3. The official test had been conducted with LAB-3 nozzle which had ideal value of TRO and in which ozone bubbles could work effectively. The initial value of TRO is 4.25 mg/L as Br2 in sea water and is 4.18mg/L as Br2 in blackish water. In terms of regulation D-2, which is regarded as the most important article, both results from sea water and blackish water test on elimination of organisms satisfied acceptance criteria by IMO. At the following test, the result from toxicity experiment was also satisfied with G8 and G9 criteria by IMO. From above tests, two assumptions were needed to meet IMO criteria: the initial value of TRO should be over 3.5 and decay process should have a slow decreasing tendency.