基于“铁-EPS-信号分子”交互机制解析黄铁矿-硫磺填料曝气生物滤池同时脱氮除磷机理

Based on sulfur autotrophic denitrification and precipitated phosphorus by pyrite, the biological aerated filter using pyrite-sulfur (FeS2-S) as fillers is developed to simultaneously remove ammonia, nitrate and phosphorus in secondary settler effluent with low temperature and limited organics. The preliminary study found that the interaction among the iron ions, extracellular polymeric substances (EPS) and signaling molecule was important to explore the nutrient removal mechanism and its application. Therefore, the main research contents are as follows: (1) the operation strategy of efficient nutrients removal in the biological aerated filter with FeS2-S as fillers is established. By the studies of kinetics, and the key control factors of pollutants removal is obtained during the biodegradation process in biofilm. (2) the effect of iron electronic shuttle on electron transfer is investigated during the nitrification-sulfur autotrophic denitrification process. (3) via assessing the characteristic of EPS and signaling molecules in iron electronic shuttle process, the regulatory feedback network among iron electronic shuttle-bacterial secretions-processing properties is built. (4) Depend on the metagenome sequencing technology, the correlation among bacterial community, characteristic of “Fe-EPS-signaling molecules” and nutrients removal performance is analyzed. On the other hand, microbial metabolic pathway is also studied. The research will be beneficial to deeply understand nutrients simultaneous removal mechanisms in terms of interaction among “Fe-EPS-signaling molecules” , and provide the theoretical guidance and technical support for improving water environment.

基于硫自养反硝化、黄铁矿絮凝除磷并耦合好氧硝化，构建黄铁矿-硫磺(FeS2-S)填料曝气生物滤池新工艺以解决低温及有机物受限时生物脱氮除磷效率低的问题。预研究发现铁离子、胞外分泌物(EPS)及信号分子间的交互机制是深入解析氮磷去除机理并将新工艺应用的关键问题。故开展:(1)建立FeS2-S填料曝气生物滤池高效脱氮除磷运行策略，通过动力学解析污染物降解过程的关键控制因素;(2)明晰铁的电子穿梭特性对硝化-硫自养反硝化电子传递的影响机制;(3)探讨铁电子穿梭介导的菌群分泌物(EPS和信号分子)特征与FeS2-S填料脱氮除磷性能间的内在关联，建立电子穿梭效应-菌群分泌物信息-工艺性能间的调控反馈网络;(4)明晰菌群结构与铁、EPS、信号分子及脱氮除磷性能间的相关性，构建硝化-硫自养反硝化菌群代谢网络。研究为深入理解“铁-EPS-信号分子”交互机制下脱氮除磷机理、改善水环境提供理论支持和技术参考。

二沉尾水过量排放是造成自然水体富营养化的主要原因之一，严重的危害到社会经济的发展和人类的健康。因此，国家制定了更为严格的地表水排放标准来控制水体富营养化的发生（TN<2 mg/L，TP<0.2 mg/L，GB3838-2002）。为了高效地去除二沉尾水中的氮、磷污染物，本课题采用硫自养工艺结合曝气生物滤池系统，通过填料性质的优化、填装方式的改进、DO浓度和HRT的调控逐步实现NH4+-N、NO3--N和PO43--P同时高效的去除，并通过Fe2+的介导、EPS的分泌和种间交流过程深入探讨硫自养反硝化过程的影响机理。硫磺和黄铁矿结合作为复合填料的曝气生物滤池在DO=1.2-1.5 mg/L和HRT=8-12 h的条件下实现了同时硝化自养反硝化和除磷过程，相应的TN和PO43--P出水浓度分低于2 mg/L和0.2 mg/L。硫自养反硝化过程的反应级数（一级）明显高于黄铁矿自养反硝化过程（零级），表明硫磺的供电子能力明显高于黄铁矿。而硫磺和煅烧后黄铁矿混合填装的曝气生物滤池TN去除过程符合一级动力学模型，其供电子能力也被进一步提高。反应过程中Fe2+、EPS和信号分子产生与氮、磷的去除性能密切相关。同时，Fe2+、EPS和信号分子通过介导电子传递系统、生物膜的特性和种间交流过程同样是影响污染物去除性能的关键。Fe2+提高反应过程的ETSA并降低EIS，加速电子传递速率并提高脱氮效率。同时，Fe2+还可以刺激细菌分泌更多的EPS和信号分子。而EPS的产生不仅有助于生物膜的形成与结构的稳定，还可以加速电子传递效率，提高污染物的去除性能。信号分子的产生则有助于增强AHL-QS过程，调控细菌的密度从而间接的影响污染物的去除。因此，Fe2+的介导、EPS的产生和种间交流过程相互影响，相互促进，是硫自养反硝化过程的重要调控机制。