硝酸盐异化还原菌（DNRA）协同厌氧氨氧化脱氮体系的构建与机理研究

Due to lower energy consumption, energy recovery, and carbon emission reduction, anaerobic ammonia oxidation (anammox) is considered to be the core technology of the future concept plant. However, effluent nitrate makes the TN removal quite low. Researchers found that dissimilatory nitrate reduction to ammonium (DNRA) coexisted with anammox in nature. This project will adopt DNRA to reduce anammox produced nitrate to improve nitrogen removal through the cooperation of anammox and DNRA. This study will evaluate cooperation system performance and microbial activity. The optimal strategy to build cooperation system and the method for the establishment of DNRA and anammox cooperation system will be screened. Through the 15N isotopic tracing technique and analysis of the stoichiometric relationship, the migrating and transforming course of nitrogen in DNRA and anammox cooperation system will be revealed. The nitrogen degradation pathway in the new-built system will be illustrated. The diversity and variation rules of microorganism communities will also be studied by molecular biological techniques such as qPCR and metagenomic sequencing in this research. Thus, the enhanced nitrogen removal mechanism in the DNRA and anammox cooperation system will be revealed from the enzymology and community level. Ultimately, the collaborative mechanism of DNRA and anammox will be clarified. This project aims to effectively solve the bottleneck problems in anammox process, such as effluent nitrate accumulation and the low total nitrogen removal rate. The results may help to improve the effluent water quality and promote the application and spread of anammox process.

由于具有降低能耗、能源回收、碳减排等特点，厌氧氨氧化被认为是未来概念厂的核心技术，然而伴生的硝氮使总氮去除率偏低。研究发现硝酸盐异化还原成铵菌(DNRA)与厌氧氨氧化菌在自然界中共存，本项目将通过DNRA菌转化厌氧氨氧化菌生成的硝氮，构建DNRA菌协同厌氧氨氧化脱氮体系；优化协同体系的系统性能和微生物活性，建立DNRA菌协同厌氧氨氧化的操作方法，筛选最适宜的协同体系构建策略；采用15N 同位素示踪、化学计量学等方法研究协同体系中氮的迁移转化，以明确协同体系氮降解途径；借助qPCR、宏基因组测序等分子生物学技术解析微生物群落多样性与演绎变化规律，从酶学和群落水平上揭示DNRA菌耦合厌氧氨氧化协同脱氮的机制，最终阐明DNRA菌协同厌氧氨氧化的作用机制。项目的实施可有效应对厌氧氨氧化工艺出水硝氮积累、总氮去除率较低的瓶颈科学问题，改善出水水质，促进厌氧氨氧化工艺应用推广。

针对厌氧氨氧化微生物富集困难、出水硝酸盐积累和总氮去除率较低等关键问题，项目解析了自然生境中异化硝酸盐还原为铵菌（DNRA）的丰度、活性、群落多样性以及关键影响因素，基于此成功建立了异养DNRA菌的富集培养策略，系统研究了厌氧氨氧化的过程强化，提出了通过协同DNRA和厌氧氨氧化及反硝化的全新污水脱氮思路。本研究的主要研究结论如下：.（1）高有机碳环境更适宜DNRA菌生存，人工湿地底泥更适宜作为富集富集DNRA菌接种物，不同生境的优势菌属不同。.（2）投加FeS、GO和接种灭活污泥都缩短了厌氧氨氧化反应器的启动时间，显著提高了氮去除率。FeS的投加并不会改变优势厌氧氨氧化属的优势地位。低浓度GO和接种灭活污泥提高了厌氧氨氧化菌Candidatus Brocadia属的相对丰度。特定电磁波辐照加快了厌氧氨氧化菌比生长速率，显著缩短厌氧氨氧化工艺的启动时间，提升反应器的脱氮性能。.（3）利用活性污泥作为DNRA培养的接种物，以乙酸钠为碳源，用无纺布膜生物反应器成功富集了DNRA菌，氨氮生成率为60.65%。反应器富集产物有反硝化菌，FeRB，SRB，SOB和发酵细菌五大功能类群。.（4）利用厌氧颗粒污泥为接种物，以丁二酸钠、葡萄糖和乙醇为碳源，在三个无纺布膜生物反应器中成功启动DNRA过程并保持稳定运行。COD/N比为7.7时，三个系统均达到了最高的NH4+-N转化效率。乙醇支持的DNRA系统具有最高的nrfA基因丰度和DNRA潜在速率。.（5）在nZVI与磁场的耦合作用下实现了协同短程反硝化、厌氧氨氧化和DNRA协同工艺（SPDAD），反应器的稳定性能得到提升，反硝化菌属Tauera以及DNRA功能菌Ignavibacterium在耦合反应器中得到明显富集，厌氧氨氧化菌的生长繁殖得到了促进。.（6）构建了部分硫自养反硝化-DNRA-厌氧氨氧化耦合工艺，氮硫比为1.08时，厌氧氨氧化的脱氮贡献率达到最高为68.3%，氮硫比为0.46时，DNRA反应速率为8.1 nmol N/h，具有17%的脱氮贡献率。