新型复合厌氧颗粒污泥CW-MFC系统修复水体氮污染机理及其优化调控

Currently, the pollution trend of water environment has been effectively curbed in China, however, the nitrogen pollution of water body in some areas is an increasingly serious problem. The traditional nitrogen removal technology relies on the supplies of carbon source or/and electron donor, which have been considered as the technical bottleneck for high efficiency of nitrogen removal. Therefore, the nitrogen removal from polluted water body is becoming an increasingly important research topic. .It was generally accepted that the constructed wetland coupled with microbial fuel cell (CW-MFC) system had a better nitrogen removal ability through the biological nitrification-denitrification and chemical denitrification. However, the nitrogen removal process in CW-MFC was seriously inhibited by the low ammonification-nitrification efficiency. .In this study, the anaerobic granular sludge and deep-rooted wetland plants were used to design a novel CW-MFC system imbedded with anaerobic granular sludge (hereinafter referred to as “novel CW-MFC”) for nitrogen removal from water body. This system shows an advantage in high efficiency of ammonification-nitrification-chemical denitrification. .Through the nitrogen removal batch experiment on anaerobic granular sludge, deep root plant and the combination of them, we try to reveal the synergistic nitrogen removal effect between granular sludge and deep root plant. The mechanism of nitrogen removal was also evaluated by analyzing the characteristics of anaerobic granular sludge, plant physiology, nitrogen transformation and microbial community diversity in the process of nitrogen removal with high ammonia nitrogen or/and organic nitrogen wastewater by the novel CW-MFC. Finally, the key factors affecting the synergistic nitrogen removal of novel CW-MFC will be explored. This research will provide a technical reserve and scientific basis for the ecological restoration of polluted water body with nitrogen.

目前我国水环境污染总体趋势得到了有效遏制，但部分区域氮污染仍为水环境主要问题。传统脱氮技术存在依赖碳源或\和电子供体的技术瓶颈，因此高效修复氮污染水体成为一个重要的研究课题。人工湿地-微生物燃料电池（CW-MFC）耦合系统通过生物硝化-反硝化及化学反硝化具有更好的脱氮禀赋，但仍受限于氨化-硝化效率低的制约。本课题研究将厌氧颗粒污泥和深根性湿地植物联合应用于CW-MFC构建新型复合厌氧颗粒污泥CW-MFC（下简称“新型CW-MFC”），协同发挥高效氨化-硝化-化学反硝化等优势。通过新型CW-MFC对厌氧颗粒污泥、深根性植物及二者联合脱氮实验，揭示二者协同脱氮效应。通过新型CW-MFC对高氨氮或\和有机氮废水脱氮过程中厌氧颗粒污泥、植物生理、氮素形态转化及微生物群落多样性等特征分析，阐明协同脱氮机制。进一步探索影响新型CW-MFC协同脱氮关键因素，为水体氮污染生态修复提供技术储备和科学依据。

目前我国水环境污染总体趋势已得到有效遏制，但部分区域的氮污染问题仍不容忽视。人工湿地(CW)作为重要的水生态修复技术，传统湿地构建模式存在微生物量较低、电子受体不足、电子迁移途径不畅等劣势，导致其氨化、硝化和反硝化效率受限。为此，本研究采用厌氧颗粒污泥(AGS)、湿地植物+间歇曝气/Fe基填和微生物燃料电池(MFC)联合构建新型湿地系统以强化湿地氮转化效率为出发点，采用微生物电化学、高通量测序等方法对其脱氮机理展开探究。本项目的主要研究结果和关键数据归纳如下：（1）评估了AGS、湿地植物+间歇曝气/Fe基填料、MFC对新型湿地系统的氨化-硝化-反硝化脱氮的影响效应。结果表明，上述三种因素可协同促进湿地的氨化、硝化、反硝化效率，最高可达92%、80%、96%；（2）揭示了新型湿地系统高效氨化-硝化-反硝化脱氮机制。AGS区域形成以产甲烷菌Euryarchaeota和产酸菌Trichococcus为主的“共生”代谢体系提升其氨化效率，阳极区显著富集的产电细菌，如Trichococcus，Clostridium，Rhodobacter和Geobacter属，能够与Fe阳离子实现Feammox 过程强化其硝化效率，阳极区产电细菌丰度的提升可维持其稳定的生物电输出辅助增强其反硝化效率；（3）探索了新型湿地系统高效氨化-硝化-反硝化脱氮关键影响因素。研究影响脱氮关键影响因素如水力停留时间、氮形态(Org-N、NH3-N、NO3-N)、有机质浓度等，结果发现新型湿地系统能够耐受较高的有机物和有机氮负荷冲击。本项目研究结果证实新型湿地系统的有机物和有机氮负荷处理能力高达221 g-COD/(m2∙d)和38 g-N/(m2∙d)，较传统人工湿地提升了3~11倍，能够为高氨氮或\和有机氮水体的生物-（电）化学高效联合修复提供技术储备和科学依据。