石灰石滤柱出水回流曝气生物滤池系统的处理效能及微生物群落多样性

Treatment efficiency and microbial community diversity in reflux biological aerated filter system of limestone filter column

摘要:

【背景】曝气生物滤池(Biological Aerated Filter，BAF)对有机物和氨氮的处理效果较好，但除磷效果不佳。【目的】提高BAF系统的除磷效能。【方法】在缺氧/好氧滤柱后设置了部分采用石灰石滤料的滤柱(未添加石灰石滤料的系统作为对照组)，对比分析了使用石灰石滤柱出水回流BAF系统的处理效能，通过最大或然法(Most Probable Number，MPN)和高通量测序技术考察了石灰石滤柱出水回流对好氧柱中硝化细菌的数量和微生物群落结构的影响。【结果】对比试验表明，有回流的BAF系统对化学需氧量、NH4+-N、总氮和总磷的去除率比无回流时分别提高了3.16%、41.21%、40.62%和18.93%；采用石灰石滤料的系统对化学需氧量、NH4+-N、总氮和总磷的去除率比对照组分别提高了1.75%、2.3%、2.2%和23.1%；由高通量测序结果可知，试验组的好氧柱中变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)、α-变形杆菌纲(Alphaproteobacteria)、β-变形菌纲(Betaproteobacteria)、γ-变形菌纲(Gammaproteobacteria)和黄单胞菌科(Xanthomonadaceae)的丰度比对照组分别提高了25.2%、4.8%、5.5%、7.4%、7.3%、12.0%和6.6%，属分类水平下两者不同物种数量为170种。【结论】石灰石滤柱出水回流能显著提高总氮和总磷的去除效果，回流液中的Ca2+具有化学除磷的作用，同时也能改善好氧柱内的菌群结构，强化生物除磷效果。

Abstract:

[Background] Biological aerated filter performs well on organic matter and ammonia nitrogen removal, whereas exhibits bad on phosphorus removal. [Objective] To improve the phosphorus removal efficiency of the BAF system. [Methods] The experimental group was an A/O filter, followed by a limestone-filling filter column. The control group was an identical one only without limestone filter. The treatment efficiency of reflux BAF system in experimental group and control group was compared and analyzed. Additionally, based on MPN method and high-throughput sequencing technology, the nitrifying bacteria quantity and microbial community structure in aerobic column were also investigated. [Results] Comparative tests showed that, compared with the BAF system without reflux, the removal efficiency of the reflux BAF system for COD, NH4+-N, TN, and TP increased by 3.16%, 41.21%, 40.62% and 18.93%, respectively. The removal efficiency of COD, NH4+-N, TN and TP in the experimental group increased by 1.75%, 2.3%, 2.2% and 23.1%, respectively. According to the results of high-throughput sequencing, the abundance of Proteobacteria, Actinobacteria, Firmicutes, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Xanthomonadaceae in the aerobic filter column of the experimental group increased by 25.2%, 4.8%, 5.5%, 7.4%, 7.3%, 12.0% and 6.6%, respectively, compared with the control group. Meanwhile, the amount of different species between the experimental group and the control group at the genus level was 170. [Conclusion] The removal efficiency of TN and TP could be significantly improved by the reflux of limestone filter column. Calcium ions could improve the removal efficiency of phosphorus by chemical precipitation, and enhance the effect of biological phosphorus removal by improving the structure of bacteria in aerobic column.