焦化纳滤浓水的生物脱氮及其微生物菌群结构分析

Biological denitrifying processes and microbial communities analysis in a sequencing batch reactor treating NF concentrate from coking wastewater

针对焦化纳滤浓水中高总氮的问题,采用序批式反应器(SBR)对纳滤浓水进行了生物脱氮实验,并对其反硝化脱氮效果和反应器中微生物菌群特征开展了研究。结果表明,在SBR系统稳定运行期间,总氮和硝态氮的平均去除率分别为58.2%和93.8%,出水中硝态氮平均浓度为2.0 mg·L-1。微生物菌群结构分析表明:变形菌门和拟杆菌门为纳滤浓水反硝化过程中的核心菌门,相对丰度之和为90.0%~96.0%;反硝化功能基因定量检测表明,在纳滤浓水反硝化过程中,亚硝酸盐还原酶nirS的拷贝数高于亚硝酸盐还原酶nirK约1~2个数量级,这说明nirS在亚硝酸转化为一氧化氮过程中起到了重要作用。SBR工艺处理焦化纳滤浓水具有良好的效果,为解决高盐水生物脱氮提供了新的途径。

Aiming at the problem of the high total nitrogen(TN)in NF concentrate from coking wastewater,a biological denitrifying process with a sequencing batch reactor(SBR)was employed to treat this concentrate.The denitrification effect and microbial communities characteristics were determined.The results showed that during stable operation of SBR,the average removal efficiencies of TN and nitrate were 58.2%and 93.8%,respectively,and the average effluent nitrate was 2.0 mg·L-1.The most abundant bacterial phyla in the SBR were Proteobacteria and Bacteroidetes,the sum of their relative abundances accounted for 90.0%~96.0%.It shows that Proteobacteria and Bacteroidetes are the important contributors for both nitrate removal and COD degradation in NF concentrate from coking wastewater.Quantitative real-time PCR was used to assess the absolute abundance of microbial genera,the quantity of nitrite reductase for nirS was higher than that of nirK by 1~2 orders of magnitude,indicating that the denitrifying bacterial genera containing nirS may be more responsible for the reduction of nitrite to nitrate.This study provides new insights to the understanding of microbial community dynamics and structures during the denitrifying processes of NF concentrate.