【作者】 王雷；

【导师】 张秀霞；

【作者基本信息】 中国石油大学(华东) ， 环境科学与工程， 2014， 硕士

【摘要】 本文通过筛选高效脱氮菌,构建高效脱氮菌群;通过对制备的改性固定化微生物的载体材料的形貌及性能特征,选择合适的改性载体材料;采用聚乙烯醇-硼酸包埋法制备固定化微生物,通过响应面分析法优化固定化微生物脱氮性能参数,建立氨氮降解数学模型,确定最佳的工艺条件;在生物反应器中模拟固定化微生物脱氮过程,进一步分析固定化微生物脱氮性能,为固定化微生物用于污水处理提供理论依据。从污水处理厂二沉池活性污泥中筛选获得亚硝酸菌、硝酸菌和反硝化菌各一株,命名为YN-1、N-2、DN-2,其中YN-1菌株48h的氨氮去除率为50.47%,生理生化实验,确定YN-1为硝化杆菌科;N-2菌株48h的亚硝酸盐氮去除率为36.23%,生理生化实验,确定N-2为硝化杆菌科;DN-2,48h的硝酸盐氮去除率为83.25%,生理生化实验,确定DN-2为假单胞菌属。三种菌株体积比为1:1:1时,脱氮菌群的氨氮去除率最高。经过活性炭和麦秸粉末联合改性的固定化微生物,其弹性系数为163.3N/m,24h后的破碎率为0,膨胀系数为77.7%,重复3次实验后固定化微生物24h的降解率在80%以上,性能指数优于活性炭改性的固定化微生物和麦秸粉末改性的固定化微生物,同时在扫描电镜图中,固定化微生物内部孔隙发达,相互之间连通在一起,形成的空间网络交错杂糅,增强了固定化微生物的机械强度和对菌源的吸附能力。响应面优化实验得到的改性固定化微生物氨氮降解率的最佳实验条件为:温度为30℃、pH为7.8、转速为160r/min,此时的氨氮降解率最高为77.9%。通过各因素间对氨氮降解率的交互影响实验得到:温度与pH值对氨氮降解率的交互影响显著。将改性的固定化微生物投加到生物反应器中进行模拟实验,得到当在溶解氧浓度为4.2mg/L,C/N为6,进水pH为8.0左右,总氮去除率可达到60%,氨氮去除率接近90%。氮素在生物反应器中主要以氨氮、亚硝酸氮、硝酸氮三种形态存在,脱氮过程氨氮浓度总体下降,降到一定值后不再变化;亚硝酸盐氮浓度最低,一般波动幅度不大,在低温或缺氧状态会有少量的增加;硝酸盐氮浓度总体上升,且在反应器有一定的积累,出水浓度较高。更多还原

【Abstract】 In this paper, through selecting efficient denitrification bacteria to build efficient denitrification bacteria. By examining the morphology and performance characteristics of modified carrier material, selected a suitable modified carrier material. Using polyvinyl alcohol- boric acid prepared immobilized microorganisms and optimize the performance parameters of immobilized microbial denitrification via response surface analysis, build ammonia degradation mathematical models to determine the optimum process conditions. Simulating the process of denitrification in the bioreactor, further analysis of immobilized microbial denitrogenation performance, provide theory basis for immobilized microorganisms used in wastewater treatment.Screening nitrite bacteria, nitrate bacteria and denitrifying bacteria from the sewage treatment plant sludge of secondary sedimentation tank; named YN-1, N-2, DN-2. YN-1 of ammonia nitrogen removal was 50.47%. N-2 of nitrogen removal rate was 36.23%. DN-2 of nitrogen removal rate was 83.25%. When the volume ratio of three strains is 1:1:1, the removal rate of ammonia nitrogen were higher than others. After activated carbon and straw powder combined modification, the elastic coefficient of immobilized microorganisms is 163.3 N/m, and after 24 hours, the breaking rate is 0, expansion coefficient is 77.7%, the degradation rate is over 80% after repeated use of three times. Performance index is superior to other material’s immobilized microorganisms. Meanwhile in SEM graph, the phenomenon of agglomeration of immobilized microorganisms has disappeared; there are many holes inside modified immobilized microorganism, which communicated with each other, forming intricate spatial networks, to enhance the mechanical strength of immobilized microorganisms and adsorption capacity of the bacteria source. The response surface optimization experiments of modified immobilized microorganism calculated the best experimental conditions for ammonia nitrogen degradation rate were: temperature is 30 degree, pH is 7.8, rotate speed is 160r/min, and the maximum theoretical degradation rate of ammonia is 77.9%. The degradation rates of ammonia interaction among the factors affect the experiment is: the interaction effect of temperature and pH value is obvious. The modified immobilized microorganisms were added to the bioreactor to simulate experiments, the result was, when the dissolved oxygen concentration is 4.2 mg/L, C/N is 6, pH value is about 8.0, the total nitrogen removal rate can reach 60%, ammonia nitrogen removal rate is nearly 90%. Nitrogen in the bioreactor mainly exists in three forms: ammonia, nitrite nitrogen, nitrate nitrogen. In the denitrification process, ammonia nitrogen overall decline, when it was up to a certain value, it no longer changed. The concentration of nitrite nitrogen is lowest, generally less volatility; there will be a small increase in the low temperature or hypoxia state. The concentration of nitrate nitrogen rises in the overall, and has certain accumulation in reactor; the concentration is higher in effluent.更多还原