| In the traditional way of treatment of wastewater, the cost of power consumption accounted for about 40% of the sewage treatment system operation cost.More than 60% of the power consumption of the sewage treatment system is run by aeration system. The study of aeration system is seeking a new approach of aeration movement to improve the efficiency of wastewater treatment and to reduce the cost of run.The study for continuous aeration process of oxygen transfer rate and the problem of large energy consumption combine with the actual situation of wastewater treatment and the analysis of factors affecting the oxygen transfer rate,puts forward the method of intermittent oxygen to improve the transfer rate of oxygen. The thesis is divided into seven chapters,each chapter is summarized as follows:In the first chapter, the background of wastewater treatment is introduced, analyze the present problems of the fine bubble aerator and puts forward the designing thoughts. Then fine intermittent aeration’s working principle and characteristics device are analyzed in detail.At the same time, the working principle of fine intermittent aeration and self-excited aeration device are simple overviewed.In chapter 2, analyzed the principle of aeration oxygenation theoretically, including classic oxygen mass transfer theory and analyzing flexible hole bubbles generated model,then analyze influence of the aeration diaphragm, orifice characteristic and the parameters on the bubbles generated. The intermittent aeration could reduce the size of the bubble, increase the gas-liquid contact area in theory, thus improve the oxygen transfer rate, and the intermittent aeration oxygen mass transfer model establishing to analyze its influencing factors.In chapter 3, the bubbles generated analysis of fine intermittent aeration is introduced in detail, including the comparison of the bore of the flexible and rigid bubbles and the rule of intermittent bubbles generated. Analyzed the influence of the aeration oxygenation between intermittent aeration and continuous aeration.In chapter 4, expound the implementation of the fine intermittent aeration experiment design process and scheme. Introduced the structure of PLC control aeration device and self-excited valve aeration device structure in detail. Then take a brief introduction to the experimental instruments and medicines, as well as the principle and method for the determination of the aeration performance.In chapter 5, the data of main analysis is summarized. Intermittent aeration can decrease the size of bubbles from the Image processing analysis to generate bubbles. Using aeration performance evaluation standard to process the experiment data intermittent aeration and continuous aeration respectively, comparing various performance indicators, to verify the fine aerator of intermittent aeration can increase the oxygen aeration performance efficiency,reducing energy consumption, be able to get the best intermittent aeration cycle at the same timeThrough four groups of different types of fine bubble aerator,it is found that intermittent aeration is generating bubble cluster under the experiment of intermittent and continuous aeration contrast. The results show that although the intermittent aeration at the time to reach oxygen saturation than continuous aeration mode increased by 10% or so, on the oxygen utilization ratio increase by more than 50%, and greatly improve the power efficiency.Therefore intermittent aeration mode greatly improved the oxygen utilization, saving energy and has better oxygenation effects. The study provides a new idea for aerobic activated sludge biological treatment system processes.The study shows that the fine intermittent aeration has a certain reference value, with better aeration oxygenation aeration effect in breakthrough conventional aeration mode which has the certain promotion and application value. |
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