Immobilized Microbial Purification Of Flue Gas Process Of Low Concentrations Of So <sub> 2 </ Sub>

The problem about air pollution caused by sulfur dioxide from coal burning is one of the focus issues concerned by all over the world. SO2 not only brings seriously air polluted but also causes acid rain for its water-solubility. China is the country where coral is the primary energy sources, the pollution problem caused by SO2 will become the important factor which limits the development of national economy and society if it is not strictly controlled. At present, the mostly physical or chemical method with high removal rate treating SO2 has a few disadvantages of high cost and second pollution, but Biological method has many advantages of low cost, few energy sources needed and little second pollution.Immobilized microorganism technique with high concentration, fast reaction rate, less loss of microorganism and easy control has become the focus researched. In present, the research on biological method treating SO2 is little in the world. The immobilized microorganisms technology treating SO2 flue gas has been discussed in this thesis. The project concludes the following:1. To study in the optimal domesticated condition on microorganism treating SO2.2. To study in preparation condition and degradation capability on immobilized microorganism cell.3. To research process treating sulfur dioxide by biochemical reaction system.4. To study mechanism of desulfurization by immobilized microorganism.Using induced domesticating method, the bacteria with strong SO32- " degradation capacity can be cultivated in the waste water. With high of degradation ratio and rapid of degradation rate, the optimal domesticating condition is: rate of oxygen supply 0.4L/min, aeration time 30mine, retention time 60min, quantity of nutrient 17.5ml/L microorganism.The experiment on performances of immobilized microorganism in different conditions showed that the optimal pH value and temperature range of SO32- degradation by immobilized microorganism were bigger than that of SO32- degradation by suspended microorganism. Immobilized microorganism had more resistence to poisonous substance such as heavy metal ion than that of suspended microorganism. In the same condition, biodegradation rate and enzymatic activity of immobilized microorganism are greater than that of suspended microorganism. When packed-red bioreactor had worked continuously 60 days, the strength change ofimmobilized cells was little, and activity of immobilized microorganism was not reduced.The SO2 removal experiment in packed-red bioreactor proved that the removal efficiency of system was above 98% in the absence of spay liquid, with the gas retention time 5s and concentrated of SO2 below 5g/m3. Additionally, the system saturated after continuous treating 3 hours, the biodegradation capacity of the system can be regenerated by washing and aerating. The whole research indicated the feasibility of immobilized microorganism technique degradation SOj.The experiment results not only show a new way for biological low concentration flue gas desulfurization, but also provide a potential application and study in waste gas treatment by biological technology.