溶解氧对单级自养脱氮系统功能菌数量的影响

Quantification of functional bacteria in one-step completely nitrogen removal process influenced by dissolved oxygen

摘要:

摘要：【目的】研究溶解氧（Dissolved oxygen, DO）对单级自养脱氮系统功能菌数量的影响，为系统运行操控提出理论指导。【方法】从不同DO水平下的单级自养脱氮反应器中，分别提取活性污泥及生物膜样品基因组DNA，通过特异引物扩增系统内亚硝化菌（Ammonia oxidizing bacteria, AOB）、硝化菌（Nitrite oxidizing bacteria, NOB）及厌氧氨氧化菌（Anaerobic ammonia oxidizing bacteria, ANAMMOX）基因序列，PCR产物经回收克隆测序后，证实扩增产物为AOB、NOB及ANAMMOX 16S rDNA 保守序列，以含该序列的重组质粒作为定量PCR标准品。用荧光定量PCR技术对单级自养脱氮系统中各类功能菌进行定量分析。【结果】高DO有利于亚硝化菌AOB及硝化菌NOB生存，同时，活性污泥中AOB、NOB数量多于生物膜。DO对厌氧氨氧化菌ANAMMOX数量影响明显，高DO浓度将对ANAMMOX数量产生直接抑制，低DO浓度水平时，由于系统内缺乏厌氧氨氧化反应的电子受体NO3-或NO2-，也将间接影响ANAMMOX数量。【结论】本试验研究条件下，DO为(曝气)2.0/(停曝) 0.4 mg/L时系统运行效能最佳，ANAMMOX数量最多，AOB、NOB及ANAMMOX在此时构成一个协同代谢的稳定状态。

Abstract:

Abstract: [Objective] To study the influence of dissolved oxygen (DO) on bacterial population in a one-step autotrophic nitrogen removal process and to improve the system operation. [Methods] Ammonia oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB) and anaerobic ammonium oxidizing bacteria (ANAMMOX) were amplified directly from the one-step completely autotrophic nitrogen removal reactor by using the specific PCR primers. The purified PCR products were cloned into T-vector and identified as the target fragments of AOB, NOB and ANAMMOX by sequencing. Recombined plasmid was used as standard molecule sample in Real-time PCR for quantification. [Results] High DO was beneficial to AOB and NOB. The population of both AOB and NOB were higher in activated sludge than biofilm samples. High DO had the directly influence on ANAMMOX population whereas low DO had the inhibitory effect of ANAMMOX activity if the system was lack of NO3- and NO2-. [Conclusion] DO of 2.0 (aeration)/ 0.4(non-aeration) mg/L was the best operation concentration. Meanwhile, ANAMMOX population reached the peak in this condition and AOB ，NOB as well as ANAMMOX composes of a steady co-metabolisms system.