硝化细菌的固态发酵及硝化菌剂的试验研究

发布时间：2018-03-31 22:14

本文选题：硝化细菌　切入点：氨氮　出处：《扬州大学》2017年硕士论文

【摘要】：氨氮是水体中的主要污染物,在污水脱氮过程中,氨氮在硝化细菌作用下被转化为硝态氮,后者进一步被反硝化细菌转化为气态氮。硝化过程是生物脱氮的限制性步骤,其核心是硝化细菌。由于硝化细菌具有严格自养、生长缓慢、对环境因子变化敏感等特性,使其在与异养菌的竞争中处于劣势,极易被系统淘汰,造成水体中硝化菌群十分贫乏。因此通过投加硝化细菌增加系统中硝化细菌的数量,加强硝化过程对提高污水脱氮效率具有十分重要的意义。本实验在模拟污水条件下定向驯化高活性硝化污泥的基础上,将高活性硝化污泥作为种子污泥,研究了硝化细菌固态发酵条件,及投加硝化菌剂对硝化系统启动及硝化活性的影响。结果表明:1.本研究硝化污泥采用模拟污水方式进行驯化,驯化初期进水氨氮浓度控制在100mg/L左右,经过15d驯化,氨氮去除率达到93.44%,之后进水氨氮浓度由100mg/L提高到150mg/L左右,经过9d驯化(第24d),出水氨氮去除率达到97.24%,驯化后期进水氨氮浓度提高到200mg/L左右,再经过10d(第34d)时,出水氨氮去除率达到90.15%,出水氨氮维持在20mg/L以下,系统中氨氮去除率维持在90%以上,整个硝化脱氮系统通过好氧方式进行驯化,共经历37d驯化完成。2.本实验中硝化细菌固态发酵基质采用椰壳和珍珠岩,并研究了椰壳与珍珠岩不同体积比条件下,固态发酵过程中氨氮去除率,发现椰壳与珍珠岩体积比为1:2时,氨氮去除率最高,为89.74%。固态发酵最佳含水量为55%左右,固态发酵硝化活性与初始氨氮浓度、DO、种子污泥接种量呈正相关。3.硝化系统启动初期,接种硝化菌剂可缩短硝化系统启动时间。本研究中,以氨氮去除率80%为准,和未接种硝化菌剂处理相比,接种硝化菌剂后,硝化系统启动所消耗的时间由未接种处理的18d缩短到14d。即和未接种处理相比,接种硝化菌剂后,硝化系统的启动时间缩短22.2%。4.在正常运行的硝化系统中投加硝化菌剂,可促进系统硝化活性。和未接种硝化菌剂的处理相比,接种硝化菌剂后,系统运行前4h,氨氮的去除率提高18%。
[Abstract]:Ammonia nitrogen is the main pollutant in water. In the process of denitrification, ammonia nitrogen is transformed into nitrate nitrogen under the action of nitrifying bacteria, the latter is further transformed into gaseous nitrogen by denitrifying bacteria. Nitrification is a restrictive step of biological denitrification. Nitrifying bacteria is the core of nitrifying bacteria. Because of its strict autotrophic, slow growth and sensitive to environmental factors, nitrifying bacteria are at a disadvantage in the competition with heterotrophic bacteria and are easily eliminated by the system. The nitrifying bacteria population in the water is very poor. So by adding nitrifying bacteria to increase the number of nitrifying bacteria in the system, The enhancement of nitrification process is very important to improve the nitrogen removal efficiency of wastewater. On the basis of directional acclimation of highly activated nitrifying sludge under simulated sewage condition, the highly activated nitrification sludge is used as seed sludge in this experiment. The effects of nitrifying bacteria on the start-up and nitrification activity of nitrifying system were studied. The results showed that the nitrifying sludge was domesticated by simulated wastewater. At the beginning of domestication, the concentration of ammonia nitrogen in influent was controlled at about 100mg/L. After 15 days of acclimation, the removal rate of ammonia nitrogen reached 93.44%, and then the concentration of ammonia nitrogen in influent increased from 100mg/L to 150mg/L. After 9 d acclimation (24 d), the ammonia nitrogen removal rate of effluent reached 97.24%. In the later stage of acclimation, the influent ammonia nitrogen concentration increased to about 200mg/L. After 10 days (34 d), the ammonia nitrogen removal rate of the effluent reached 90.15%, and the effluent ammonia nitrogen was maintained below 20mg/L. The removal rate of ammonia nitrogen in the system was above 90%. The nitrifying nitrogen removal system was acclimated by aerobic method and was domesticated for 37 days. In this experiment, coconut shell and perlite were used as the solid fermentation substrate of nitrifying bacteria. The ammonia nitrogen removal rate of coconut shell and perlite was studied under the condition of different volume ratio of coconut shell and perlite. When the volume ratio of coconut shell to perlite was 1:2, the removal rate of ammonia nitrogen was the highest (89.74%). The optimum water content of solid fermentation was about 55%. The nitrification activity of solid fermentation was positively correlated with the initial ammonia nitrogen concentration and the inoculation amount of seed sludge. 3. In the initial stage of nitrification system, nitrifying agent inoculated with nitrifying bacteria could shorten the start-up time of nitrification system. In this study, the removal rate of ammonia nitrogen was 80%. Compared with the treatment without nitrifying agent, the time consumed by nitrification system was shortened from 18 days without inoculation to 14 days after inoculation of nitrifying agent, that is, after inoculating nitrifying agent, the time of nitrifying system was reduced from 18 days to 14 days after inoculating nitrifying agent. The start-up time of nitrifying system was shortened by 22.2.4.The nitrifying activity of the system could be promoted by adding nitrifying bacteria in the normal running nitrification system. Compared with the treatment without nitrifying agent, the removal rate of ammonia-nitrogen increased by 18% after the nitrifying agent was inoculated 4 hours before the operation of the system.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703;X172

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