| Ship ballast water ensures the ship navigation safety guarantee, but its discharge sometime causes the introduction of invasive marine species into a new environment. It has been recognized as one of the four greatest threaten to marine pollution resources by the Global Environment Fund (GEF). Due to ecological significant international safety demand, this thesis was analyzed the preventing and to control the spreading marine invasive species into the marine environment and its protection. A new ion exchange membrane electrolysis system and lab-on-a-chip system were established respectively focusing on the bottleneck existing problems in the aspects of ship ballast water treatment and detection.A new ion exchange membrane electrolysis system was designed and built for ballast water treatment in this paper and the electrolysis system effects on ballast water treatment system was studied to propose the research on further new description method for optimization process. On the other hand, a kind of lab-on-a-chip detection method and system based on chlorophyll fluorescence was proposed for the detection of ballast water.The following factors were focused on this thesis:1. Design and construction of the ion membrane electrolysis system and to determine the best working parameters of electrolysis system through the experiment.In the design of electrolysis system, high selectivity and low membrane resistance perfluorocarboxylic acid composite membranes were adopted in the system, which effectively improves the electrolysis efficiency. In the research, a mathematical model between current intensity and cell voltage for the ion exchange membrane electrolysis system were established and explored the law of current intensity’s effects on cell voltage, current efficiency, electrolysis performance, etc. In addition, the best working parameters such as voltage, current electrolysis were confirmed under the condition of maximum current efficiency and the lowest power consumption via electrolysis system effectiveness impact experiment. The ballast water treatment experiments were completed under the working parameters.2. Proposed a new method of optimizing ballast water treatment process and researched on the work performance of electrolysis system and then determined the optimal parameters of ballast water treatment through experiments.Platymonas subcordiformis, Dunaiella solina, Nitzschia closterium f.minutissima, Isochrysis galbana, Chlorella vulgaris, Karenia mikimotoi and Prorocentrum micans were tested for an inactivation research. Results showed the inactivation effect was directly influenced by the concentration and duration of anode electrolysis products. Under the condition of 5mg/L effective chlorine concentration and 24h duration, Platymonas subcordiformis, Dunaiella solina, Nitzschia closterium f.minutissima, Chlorella vulgaris and Karenia mikimotoi were completely dead. Isochrysis galbana was dead in duration of 48h. Furthermore, Prorocentrum micans turned out to be dead after 72h of working time. On the basis of proving the effectiveness of inactivation experiments, a new method of ballast water treatment process was introduced, that is, the optimized method adopted a multiple small dose injection of electrolysis products.It was explored that the effects of injection times of anode electrolysis products, time interval between two injections and dosage for one injection on the performance of ballast water disposal. Results demonstrate that:In the experiment, Injection Times=3, Effective Chlorine Concentration lmg/L (Effective Chlorine Concentration can reach 3mg/L in total) and Time Interval=5h, which turned out to be the best parameters. In addition to 11h. acting duration, all algae were killed and no more regeneration exists. Compared with the common experiments, Effective Chlorine Concentration can be lowered by about 40% and duration can be shortened by about 84.7% remarkably.3. By simulating the ocean environment factors, it was investigated that the ion exchange membrane electrolysis system was affected by the factors such as temperature, illumination, the concentration of algal cells, organic compounds in sea water, etc.Results indicated that the death rate increases when the temperature rises. However, it started to drop when the temperature reached at 30℃. Illumination was an impact on repair of post-treated algal cell. The inactivation effect standed out obviously till all the algal cells became dead while the effective chlorine concentration was only high. When the concentration of algal and organics content in the sea water was going up then the death rate of algal was decreased.4. Established a microalgae activity detecting method based on the technique of microfluidic chip and chlorophyll fluorescence by studying the relationship between chlorophyll fluorescence intensity and life state of algal cells.Results showed that the lab-on-a-chip detecting system based on chlorophyll fluorescence is able to detect not only single living algal cell, but also obtains quantitative evaluation about the activity of algal cell. Moreover, it was proved that Chlorella vulgaris with the diameter of 3 μm was detected by the system through limit detection experiment. Finally, the system was able to detect the activity detection of algal cells without marking only on a piece of lab-on-a-chip. The system has the advantages of low cost, small size, rapid detection, simple operation, etc. which presents great potential aiming for the online detection of ballast water. |
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