一株异养硝化细菌YL的筛选及其脱氮特性研究

发布时间：2019-05-19 23:01

【摘要】：近年来,由于含氮废水的大量排放,造成水环境污染日益严重和复杂。生物脱氮是目前废水脱氮中最经济有效的方法之一,而传统的生物脱氮工艺即自养硝化 厌氧反硝化工艺,存在工艺流程长、脱氮效率低的问题。近年越来越多异养硝化菌被发现,这类细菌生长快、活性高、增殖底物广泛、大多能同时进行异养硝化和好氧反硝化作用,因此异养硝化生物脱氮成为废水脱氮领域的研究热点之一。本研究从驯化成熟且具有高效同步硝化反硝化作用的SBR反应器中筛得一株高效异养硝化菌YL,并通过单因子试验和正交试验对其异养硝化和好氧反硝化特性进行了研究。此外,考察了菌株YL应用于模拟废水的处理效果,为今后的实际应用提供理论依据。主要试验和研究结果如下:(1)筛得一株异养硝化菌,命名为YL。经形态学观察、生理生化试验和分子生物学鉴定,为铜绿假单胞菌(Pseudomonas aeruginosa)。(2)菌株YL进行异养硝化作用的最适条件为:碳源为琥珀酸钠、C/N为10、pH为7.0、温度为30℃、转速为160~200 r/min。且菌株YL具有很强的高氨氮浓度耐受力。菌株YL能够以羟胺作为氮源进行生长和代谢,反应中间产物为亚硝氮和硝氮,48 h后羟胺去除率为94.8%,总氮去除率为90.4%。(3)菌株YL能够转化起始浓度为200 mg/L的亚硝氮和硝氮。转化亚硝氮过程的中间产物为氨氮和硝氮,48 h后亚硝氮和总氮去除率分别为92.7%和91.9%;转化硝氮过程有中间产物亚硝氮的积累,48 h后硝氮和总氮去除率分别为93.6%和63.4%。影响菌株YL好氧反硝化性能最主要的因素是C/N,在优化条件(C/N=10,T=30℃,r=200 r/min,pH=7.0)下,硝氮去除率为94.6%,总氮去除率76.3%。(4)在碳源为琥珀酸钠、C/N为10、pH为7.0、温度30℃及转速160 r/min条件下,相比于其它氮源,以氨氮为增殖底物时菌株YL的增殖速率最大,最大比生长速率为0.19 h-1,氨氧化速率为5.05 mg/g/h,TOC转化速率为45.95 mg/g/h,氨氮和TOC去除率分别为100%和90.8%,且反应过程无亚硝氮和硝氮的积累。(5)采用纯菌YL为种源形成的活性污泥处理模拟废水,反应器运行的8~20 d期间,菌株YL的数量约占细菌总数的43%以上,系统相对稳定,TOC去除率保持在85%左右,氨氮去除率高达96%~100%,总氮去除率始终在90%左右。系统的脱氮除碳效果显著优于菌株筛选所用的SBR中的硝化污泥(P=0.005、0.0020.05)。说明在该系统中菌株YL具有很强的竞争优势,能够稳定地存活于系统中,有助于维持系统长期高效脱氮运行。
[Abstract]:In recent years, due to the discharge of a large number of nitrogen-containing wastewater, the pollution of water environment is becoming more and more serious and complex. Biological denitrification is one of the most economical and effective methods in wastewater denitrification at present, while the traditional biological denitrification process, autotrophic nitrification / anaerobic denitrification process, has the problems of long process flow and low denitrification efficiency. In recent years, more and more heterotrophic nitrifying bacteria have been found. These bacteria grow fast, have high activity and proliferate a wide range of substrate, and most of them can carry out heterotrophic nitrification and aerobic denitrification at the same time. Therefore, heterotrophic nitrification biological denitrification has become one of the research hotspots in the field of wastewater denitrification. In this study, a strain of highly efficient heterotrophic nitrifying bacteria YL, was screened from a SBR reactor with mature domestication and high efficiency simultaneous nitrification and denitrification, and its heterotrophic nitrification and aerobic denitrification characteristics were studied by single factor test and orthogonal test. In addition, the effect of strain YL on the treatment of simulated wastewater was investigated, which provided a theoretical basis for its practical application in the future. The main results are as follows: (1) A strain of heterotrophic nitrifying bacteria named YL. was screened. The optimum conditions for heterotrophic nitrification of Pseudomonas aeruginosa (Pseudomonas aeruginosa). (2) strain YL were as follows: carbon source was sodium succinate, C 鈮，

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