厌氧环境下城市污水自有硫酸盐还原诱发氨氧化一步直接脱氮的建立、生化机理及活性强化研究

If sulfate reduction and ammonium oxidation（SRAO）can be established and applied to municipal wastewater treatment， ammonium can be directly transformed to nitrogen gas and removed under anaerobic condition, and the bottle-neck of the traditional biological nitrogen removal of the time will be broken. Although there are many researches on SRAO in special wastewater, the mechanism of the occurrence of SRAO, its functional microbes as well as its biological and chemical foundation concerned are not known very well yet. There are many fundamental questions to be solved, such as how to establish SRAO in municipal wastewater and control operation to cultivate more functional bacteria and high-performance biomass in the system. In this project，the process of SRAO establishment, the evolution of bacteria community structure, enrichment of SRAO functional bacteria and their profiles of activity, as well as transformations of substrate fed are to be investigated in several lab-scale anaerobic reactors treating synthesized wastewater and raw domestic sewage，under the environment of anaerobic digest, sulfate reduction，as well as with enrichment of substrate and specific substance to induce SRAO. The aims of the study are to find out the effects of environmental condition and operating parameters on the induction and establishment of SRAO, the essential connection between sulfate reduction and ammonium oxidation in the SRAO, biochemical pathway of the SRAO, he way and the fateful environment factors of cultivation and enrichment of functional SRAO bacteria, and activity augmentation, to supply some foundation to application of SRAO to nitrogen removal of municipal wastewater treatment in practice.

在城市污水中建立硫酸盐还原-氨氧化(SRAO)，就可在厌氧环境中实现污水中氨态氮的一步直接脱除，从而打破现有城市污水处理中生物脱氮这一“瓶颈”。尽管国内外研究报道了在一些特定废水中出现的SRAO，但对该现象发生的机制、功能性微生物、生物-化学机理等都还停留在推测层面。在城市污水条件下，如何能建立SRAO、控制怎样的条件可以培驯出高活性污泥等诸多基础性问题还有待解决。本课题拟采用多种模拟废水和实际生活污水，在不同反应器内，通过考察不同厌氧发酵和硫酸盐还原、基质强化等诱导条件下SRAO的建立过程、反应器内菌群演变、SRAO功能菌的富集、活性变化及物质的转变过程，探明不同环境要素和操作条件对SRAO的诱发及生物脱氮活性的影响，揭示硫酸盐还原与氨氧化的内在联系、SRAO脱氮的生物化学过程，提出功能菌优势增殖的关键环境条件及SRAO活性强化的措施，为城市污水SRAO脱氮技术的开发奠定基础。

为探明城市污水中硫酸盐还原厌氧氨氧化（SRAO）反应建立的条件，揭示SRAO脱氮的生化机理、掌握反应器运行条件对SRAO脱氮效能的影响规律，本课题分别采用有机和无机含铵及硫酸盐废水，在UASB和SBR中，接种不同污泥，对SRAO的建立和活性变化、环境因素的影响等进行了研究。结果表明，通过用硫酸盐逐步替代进水中的亚硝酸盐，培驯成功的高活性厌氧氨氧化污泥不能够被诱发/驯化为硫酸盐厌氧氨氧化污泥；对不同来源的混合接种污泥，一开始就直接供给氨态氮和硫酸盐的无机废水，铵与硫酸盐并不能被微生物同步去除，而在进水中有有机物存在下，反应器内形成了严格的厌氧条件，就出现水中铵和硫酸盐的同步去除，即SRAO现象。污水中硫酸盐还原厌氧氨的氧化是多种微生物共同的作用、由多个不同微生物的生物化学反应联合实现的，而不是单一微生物的代谢结果，也非单一生化反应，其中的硫酸盐还原、反硝化、硫自养反硝化和厌氧氨氧化是由多种不同微生物协同代谢、共同实现了同步脱氮除硫；一定程度上提高进水N/S比可以增加铵转化为亚硝态氮的过程，但不会大幅提高系统SRAO的脱氮量。参与SRAO的微生物包括SRB、反硝化菌和硫自养反硝化菌三类。SRB菌属有Desulfococcus、Desulfatiglans和Syntrophobacteraceae；反硝化菌属主要有Anaerolineaceae、Methyloversatilis、Longilinea、Simplicispira、Anaerolineaceae和Beta proteobacteria；硫自养反硝化菌属为Thiobacillus；此外还存在丰度较低的氨氧化菌属Nitrosomona。未检测到Anammox菌属。在以葡萄糖为碳源的高浓度UASB有机发酵系统中，形成了亚铁和铁离子的生物循环，并导致氨态氮的氧化和厌氧氨氧化脱氮，与发生的硫酸盐还原并无协同作用。本课题的研究结果丰富了人们对SRAO生物脱氮的认识。