MABR特殊生境下生物膜脱氮功能强化机理研究

It is difficult for the effective removal of nitrogen pollutants from the micro-polluted water in the coastal areas with high salinity and low contaminants concentration through conventional wastewater treatment technologies. Thus, the environmental problem needs to be solved urgently. Our present research revealed that MABR could perform excellent nitrogen removal and ammonia-oxidizing archaea (AOA) might play an important role for the treatment of saline wastewater. In the current study, an aerated-membrane biofilms reactor (MABR) will be introduced into the treatment of saline micro-polluted water via constructing microbial community with stratification in which AOA is the key nitrifier. The effect of low air-supplying pressure on the spatial distribution, population structure and function of microorganisms in biofilms mainly including AOA, AOB (ammonia-oxidizing bacteria), NOB (nitrite oxidizing bacteria) and denitrifiers will be investigated via microelectrode technology, high-throughput sequencing technology, FISH-CLSM as well as Real-time RT-PCR. This study aims to reveal the regulation mechanism for the shortcut nitrification and denitrification process via air-supplying pressure under the conditions with high salinity, low ammonia and low COD concentrations. It is expected to provide a new insight into the mechanisms of nitrogen removal in MABR in extreme environments, and a new approach into expanding the application range of MABR for saline micro-polluted water and wastewater treatment in the coastal areas.

沿海城镇含盐微污染水体因盐度高和污染物浓度低等特性导致氮污染物难以通过常规水处理技术达到理想的脱氮效果，是亟待解决的环境污染问题之一。研究发现膜曝气生物膜反应器（MABR）在高盐度环境下对含氮污水具有良好的脱氮功能，且氨氧化古菌起到了关键作用。本项目拟在前期工作基础上，以MABR为研究对象，构建以氨氧化古菌为主要硝化功能菌的生物膜脱氮菌群分层体系；通过微电极技术、高通量测序技术、FISH耦合CLSM技术和Real-time RT-PCR等研究低供氧压力对氨氧化古菌、氨氧化细菌、亚硝酸盐氧化菌以及反硝化菌在生物膜中空间分布、菌群结构和生理功能等生态关系的调控机制。初步揭示在高盐、低氨氮和低有机物（CODMn）浓度条件下，供氧压力强化MABR生物膜短程硝化反硝化的作用机理，为全面了解MABR在特殊生境中的脱氮机制提供新的思路，也为拓展MABR在沿海城镇含盐微污染水体修复领域的应用提供新的途径。

异向传质膜曝气生物膜反应器（MABR）在同时脱氮除碳方面具有显著的优势。前期研究多集中于MABR在生活污水处理方面的去除效果和工艺优化，但在特殊生境下的处理效能和运行机制尚不明确。我们设计出新型单级MABR和双级MABR反应器系统，将生物膜曝露于酚类有毒污染物、高盐度、低温、低供氧负荷、不同碳氮比和低过膜流速等生长不利环境，长期追踪反应器的脱氮除碳效能，发现MABR的脱氮性能容易收到高盐，低流速，低温和酚毒性等条件抑制,生物膜中的氨氧化古菌AOA的耐胁迫性高于氨氧化细菌AOB；采用16S rDNA高通量测序技术研究不同条件下稳态生物膜的群落结构组成，分布以及多样性，发现不同运营条件下的生物膜群落结构差异明显，但对碳去除影响不显著；通过宏基因组测序技术解析关键性降解基因的组成和分布，绘制污染物的代谢网络图谱，比对功能菌群的贡献度大小，发现群落中某些少数菌群在酚等污染物代谢方面的贡献度高于一些占据多数的菌群；结合冗余分析和皮尔逊相关性分析等数理统计方法探究工况参数对菌群结构和功能的影响大小，菌群对工况条件变化的响应规律，以及关键降解菌属和种群协作及竞争关系，发现我们可以通过改变工况参数对MABR生物膜菌群进行优化调控，进而强化反应器的脱氮除碳性能。该项目进一步阐明MABR在特殊生境下不同碳类污染物的生物降解和氮脱除机制，为MABR不同环境下的废水处理应用提供理论依据和技术支持。