以玉米芯为缓释碳源的反硝化滤池深度脱氮效能研究

发布时间：2018-09-19 19:54

【摘要】：城镇污水二级处理出水由于TN达不到一级A标准,常常需要进行深度处理,但水中的碳源不足,难以进行反硝化作用,因此需要外加碳源。固体碳源在充当碳源的同时还可以作为生物载体,因此常被用作外加碳源。在众多的固体缓释碳源中,从反硝化效果和成本方面看,玉米芯更适合作为缓释碳源。而且在我国玉米芯的处理方式大多是焚烧,玉米芯作为碳源可以使其得到资源化。但是由于玉米芯的成分中含有不容易被利用的成分,因此需要对玉米芯进行处理。本文以反硝化滤池为主体反应器,分别考察以玉米芯和碱处理玉米芯为缓释碳源并外加白腐菌时的脱氮效能情况。本文设置了碱处理玉米芯为碳源的反硝化滤池(碱反应器)、玉米芯为碳源并外加白腐菌的反硝化滤池(玉+菌反应器)和碱处理玉米芯作为碳源并外加白腐菌的反硝化滤池(碱+菌反应器),分析了其最佳HRT、运行效能和有效运行周期。通过比较认为玉+菌反应器的效果最好。以TN是否达标为标准,玉+菌反应器在HRT=70 min的条件下,能有效运行111 d,TN和NO_3~--N的去除率最高可分别达到92%和98%。为了验证结果的准确性,应用高通量测序技术分析三组反硝化滤池内微生物群落结构。从真菌层面分析,碱反应器的微生物多样性最大;从细菌层面分析,碱+菌反应器的微生物多样性最大。在玉+菌反应器和碱+菌反应器中都发现了白腐菌,并且碱+菌反应器中白腐菌含量较高达到了18.30%;在三个反硝化滤池中都发现了常见的具有反硝化功能的菌属,并且在玉+菌反硝化滤池中的反硝化菌群丰度最高为13.32%,这也与其反硝化效果最好相对应。因此采用玉米芯为碳源并外加白腐菌反应器进行后续的玉米芯更换实验。对已经失效的玉米芯进行更换,更换比例分别为1/2、1/3、1/4和1/5。以TN是否达标为标准,发现更换1/4的玉米芯可以运行31 d,NO_3~--N去除率可以达到70%以上;应用环境扫描电镜发现更换1/4的玉米芯表面的生物膜最厚。综合出水COD、TN去除率和NO_3~--N去除率的情况,认为HRT=70 min时玉米芯为碳源并外加白腐菌反硝化滤池更换1/4玉米芯为最佳填料更换比。
[Abstract]:Due to the fact that the secondary effluent of municipal sewage can not reach the first A standard, advanced treatment is often needed, but the carbon source in the water is insufficient and it is difficult to carry out denitrification, so it is necessary to add carbon source. Solid carbon sources are often used as external carbon sources because they can act as biological carriers as well as carbon sources. Corn cob is more suitable as a slow release carbon source in terms of denitrification effect and cost among many solid sustained-release carbon sources. The corncob is mostly incinerated in China, and the corncob can be used as carbon source. However, corncobs need to be treated because they contain ingredients that are not easy to use. The denitrification efficiency of corncob and alkali-treated corncob was studied by using denitrification filter as the main reactor. In this paper, a denitrifying filter (alkali reactor) with alkali treated corncob as carbon source, corncob as carbon source and white rot fungus applied in denitrification filter (Jade fungus reactor) and alkali-treated corncob as carbon source and added white rot fungus were set up. Denitrification filter (alkali-bacteria reactor) was used to analyze the optimal HRT, operation efficiency and effective operation period. By comparison, it is considered that the effect of Jade bacteria reactor is the best. Under the condition of HRT=70 min, the removal rate of TN and NO_3~--N can reach 92% and 98%, respectively, when the TN is up to standard or not, and the removal rate of TN and NO_3~--N can be up to 92% and 98% respectively under the condition of HRT=70 min. In order to verify the accuracy of the results, the microbial community structure in three groups of denitrification filters was analyzed by high throughput sequencing technique. The microbial diversity of alkali-reactor was the largest in terms of fungi level, and that of alkali-bacteria reactor was the largest in bacteriological level. White rot fungi were found in both jade and alkali bioreactor, and the content of white rot fungi reached 18.30 in alkali bacteria reactor, and common bacteria with denitrification function were found in three denitrification filters. The highest abundance of denitrifying bacteria in the denitrification filter was 13.3232, which was the best corresponding to the denitrification effect. Therefore, corncob was used as carbon source and white rot fungus reactor was used to carry out the subsequent corncob replacement experiment. The corncob was replaced by 1 / 2 / 1 / 3 / 3 / 4 and 1 / 5 / 5 of the corncob. According to the standard of TN, it is found that the removal rate of N can reach more than 70% by replacing 1 / 4 corncob for 31 days, and the biofilm on the surface of 1 / 4 corncob is the thickest by using environmental scanning electron microscope. Considering the COD,TN removal rate and NO_3~--N removal rate of the effluent, it is considered that the best packing replacement ratio is that the corncob is a carbon source and the white rot fungus denitrification filter is used to replace 1 / 4 corncob at HRT=70 min.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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