污水处理好氧区总氮损失的氮素归趋及自养/异养脱氮菌群的协同机制

Biological nutrients removal is most commonly applied in wastewater treatment due to its economic and efficient characteristic. The phenomenon of total nitrogen loss generally occurred in the aerobic zone of wastewater treatment processes. Enhancing this phenomenon and developing cooperative action of autotrophic/heterotrophic denitrifying bacteria is an effective strategy to improve nitrogen removal efficiencies. Presently, the biochemical mechanism of this phenomenon has not been clearly explained, which is one difficult problem to solve in the field of biological nitrogen removal from wastewater. The key to achieve stable nitrogen removal in the aerobic zone is gain a clear insight into the fate of nitrogen and cooperation mechanism of autotrophic/heterotrophic denitrifying bacteria. ..In this study, the biochemical mechanism of total nitrogen loss in aerobic zone of real wastewater treatment processes and the dynamic response of metabolic activities of autotrophic/heterotrophic bacteria corresponding to environmental factors are revealed. The dynamics of nitrogen loss in the aerobic zone and the reaction routes of nitrogen are investigated using 15N stable isotope tracing techniques. Meanwhile, the cooperative action of autotrophic/heterotrophic bacteria and their contributions to nitrogen loss in the aerobic zone are analyzed using 13C-DNA-SIP. Real-time quantification PCR, high-throughput sequencing and ecological genomics are used to be the downstream technology of 13C-DNA for identification of autotrophic/heterotrophic bacteria. Through regulation and optimization of in-situ function of microorganisms, single-stage aerobic or oxygen-limited system combining establishment of innovative processes (novel autotrophic nitrogen removal) with the improvement of traditional process (heterotrophic denitrification) is developed to treat real wastewater with low ratios of carbon to nitrogen, aimed to achieve stable and efficient nitrogen removal.

污水生物处理普遍存在好氧区总氮损失现象，关于该现象的生物化学机制是目前国内外生物脱氮领域的一大难题。强化这一现象并构建自养/异养菌群协同脱氮体系是提高脱氮效率的有效途径。目前难以维持稳定高效的好氧区总氮去除的关键在于对该现象的氮素归趋和自养/异养脱氮菌群的协同机制不清楚。.本研究以揭示污水处理好氧区总氮损失的生物化学机制和自养/异养菌群代谢活性与环境条件的动态响应机制为目标。其特色和创新在于①采用15N同位素示踪技术解析好氧区总氮损失的动态变化及氮素转化途径；②采用13C-DNA-SIP分析特定条件下自养/异养菌群的协同作用及对总氮损失的贡献。以定量PCR、高通量测序和生态基因组学手段作为13C-DNA分析的下游技术进行微生物鉴别。通过微生物原位功能表达的过程优化与调控，建立将新型自养脱氮与传统异养反硝化脱氮相结合的单级好氧/限氧工艺用于低C/N比污水的处理，取得稳定高效的总氮去除。

污水生物处理普遍存在好氧区总氮损失现象，关于该现象的生物化学机制是目前国内外生物脱氮领域的一大难题。强化这一现象并构建自养/异养菌群协同脱氮体系是提高脱氮效率的有效途径。. 本研究以揭示污水处理好氧区总氮损失的生物化学机制和自养/异养菌群代谢活性与环境条件的动态响应机制为目标。采用15N同位素示踪技术解析好氧区总氮损失的动态变化及氮素转化途径；采用13C-DNA-SIP分析特定条件下自养/异养菌群的协同作用及对总氮损失的贡献。应用稳定性同位素示踪技术研究了短程硝化/ANAMMOX工艺（PN/A）中的氮素归趋，并解析了氮转化基因的数量生态学关系。15N-同位素示踪试验表明，ANAMMOX细菌的潜在活性达到3507.8 nmol/g-污泥/h，自养脱氮路径对总N2产量的贡献率为73.2%。计算生态学显示，在调查基因范围内，ANAMMOX细菌与Nitrospira细菌具有最小的生态位重叠值和最远的生态距离，表明两者在生态相似性上的较大差异。15N-DNA-SIP结果表明，Planctomycetacia纲与Anaerolineae纲和Proteobacteria纲具有密切的共生关系，体现出ANAMMOX细菌富集过程对周围环境细菌的依赖性生长，对自养型反应器快速启动具有指导意义。定量研究了连续流MUCT（Modified University of Cape Town）工艺中N2O的产生路径，原位水平解析了脱氮功能微生物群落结构。开发了主流“预曝气除COD-短程硝化-ANAMMOX”工艺处理实际生活污水，强化了好氧区TN损失效果，并在缺氧区富集了ANAMMOX生物膜。生物膜主导优势菌为Candidatus Brocadia，占生物膜细菌总数的12.75%。该工艺构型可有效实现常温连续流短程硝化的维持且富集ANAMMOX细菌，为增强好氧区TN损失和强化主流ANAMMOX工艺应用提供技术指导。