污水脱氮过程中同步厌氧甲烷氧化和氨氧化的实现及控制策略

Nitrite-dependent anaerobic oxidation of methane (N-DAMO) and ammonium (anammox) are two recently discovered processes in the nitrogen cycle, mediated by N-DAMO bacteria and anammox bacteria, respectively. The coupling of N-DAMO and Anammox can not only reduce energy consumption and carbon sources, but also mitigate CH4 and N2O emissions. Therefore, the combined process of anammox and N-DAMO is very significant for implementation in wastewater treatment systems that contain both substantial amounts of methane and ammonium. Due to their relatively slower growth rates, it is difficult to enrich an anammox and N-DAMO coculture and no relevant reports are available in literature.. Apparently, even though the bacteria that perform these processes compete for the same electron acceptor (nitrite) they are able to coexist in nature. The objectives of this project is to achieve the comibination of N-DAMO and Anammox processes and inverstigate the feasibility of an anammox and n-damo coculture by adjusting operating conditions and control parameters in one reactor. It is expected to develop a cost-effective and environment-friendly alternative to conventional nitrogen removal systems.. To achieve this aim, we will examine the abundance, activity, community structure and the competition mechanism of N-DAMO and Anammox in a novel sequencing membrane reactor (SMBR) using a complementary array of methods, including isotope pairing technique, qPCR assays and 16S rRNA gene or function gene clone libraries and process control technique. The quick enrich approach of N-DAMO culture, Anammox culture and the feasibility of cocultures where N-DAMO and anammox processes will be highly investigated. The operational factors influencing the competition and cooperation relationship will be studied. Based on sludge population optimization, control strategies will be developed to achieve simultaneous nitrite-dependent anaerobic methane and anaerobic ammonium oxidation. Finally, the combination process will be used to remove ammonium, dissolved methane and nitrite simultaneously from anaerobic sludge digestion supernatants.

同步厌氧甲烷氧化(DAMO)和氨氧化(Anammox)的实现不仅能节约曝气能耗和碳源，更能降低温室气体CH4和N2O的排放，在处理含亚硝态氮和溶解性甲烷的污水中具有明显技术优势，目前未见基于N-DAMO+Anammox的联合工艺进行生物脱氮。. 本项目将通过调节污水生物脱氮过程中的运行条件和控制参数，利用N-DAMO菌和Anammox菌在生态分布和代谢机制上的竞争和协同关系实现它们间的种群优化，使两种微生物在同一反应器内生长和富集。并将借助分子生物学、同位素示踪和过程控制技术，在新型间歇式膜生物反应器(SMBR)中，揭示N-DAMO菌和Anammox菌丰度、活性、种群结构的演变规律，提出SMBR中N-DAMO和Anammox菌的单独富集和共生富集的培养方法，建立面向种群优化的同步厌氧甲烷氧化和氨氧化耦合工艺控制系统和方法，最终实现同步厌氧甲烷氧化和厌氧氨氧化耦合工艺处理污泥消化上清液。

同步厌氧甲烷氧化(DAMO)和氨氧化(Anammox)的实现不仅能节约曝气能耗和碳 源,更能降低温室气体 CH4 和 N2O 的排放，在处理含亚硝态氮和溶解性甲烷的污水中具有明显技术优势，目前未见基于DAMO+Anammox的联合工艺进行生物脱氮。限制该工艺发展的主要瓶颈在于该微生物世代时间，难以富集培养。本项目首先搭建了一种基于中空纤维膜生物膜反应器（membrane biofilm reactor, MBfR）富集反硝化型甲烷厌氧氧化菌的生物装置，解决了如何快速富集长世代时间微生物的技术难题。并采用PCR-DGGE，pmoA功能基因和16S rRNA基因等现代分子生物学手段，对小试和实际的污泥厌氧消化处理系统中，以及人工湿地系统中类似DAMO 的功能微生物进行了分子生物学检测。确定了同时采用人工湿地土壤以及厌氧消化污泥作为接种物进行了DAMO微生物的富集培养研究。采用单独富集到的Anammox和DAMO 微生物作为接种源，接种二者的混合物到严格厌氧的 MBfR 反应器中，并提供二者生长所需的 NH4+-N、NO3--N 和 CH4 等底物，共同培养 Anammox 菌和 DAMO 菌的混合富集物。通过长期富集研究，实现了同步厌氧甲烷氧化和厌氧氨氧化耦合工艺的稳定运行，总氮去除率高达90%以上，氮去除负荷稳定提高，最高可达0.8gN/m3/d。此外，利用构建的数学模型揭示了Anammox和DAMO微生物之间的竞争协同关系进行了模拟研究，NH4/NO2比维持在1.0-1.1左右，生物膜厚度控制在750-1000um左右，可实现95%以上的总氮去除率。此外，采用宏基因组对三种不同的污泥形态内的Anammox种群结构进行了深度解析。生物膜和颗粒污泥内的Anammox丰度较生物絮体的Anammox丰度较高，三种污泥形态内均为Candidatus Kuenenia 属的Anammox丰度最高，发现生物膜和颗粒污泥中参与Anammox反应的关键基因hdh和hzs丰度明显高于絮体污泥。综述，本研究以节能降耗为目的，具有操作管理简易、节省人力物力，降低城市污水的曝气能耗和温室气体排放的优点，并将为最终实现厌氧甲烷氧化工艺处理污泥污水奠定基础。