生物滞留设施硫协同处理城市降雨径流的脱氮代谢途径

Traditional biological retention facilities have a great challenge to enhance the nitrogen removal efficiency due to the lack of sufficient carbon source for heterotrophic denitrification. Moreover, heterotrophic denitrifying bacteria have a faster growth rate compared with the autotrophic bacteria, which contributes to the discharge of the biomass with effluent. To solve the problems, a new heterotrophic and sulfur-driven autotrophic denitrification process based on a biological retention facility is developed because the sulfur-driven autotrophic denitrification shows advantages of no carbon source limitation and sludge reduction. The research aims to reveal the mechanism of its denitrification process. The mechanisms of N removal pathway and pyrite decomposition is analyzed by a step-by-step verification method, exploring the denitrification existence, then prejudging the diversity of denitrification patterns, and finally verifying sulfur-based autotrophic denitrification. The elementary reaction process involved in the metabolic pathway is explored. Observation of the microbes and the pyrite erosion is used to predict the microbial growth rate and adhesion performance. The characteristics of the reaction environment and pyrite decomposition microenvironment is identified. A kinetic model of N removal in the biological retention facility combined with sulfur-driven autotrophic denitrification treating rainfall runoff is built and then calibrated. The research can provide a quantitative theoretical basis for the efficiency improvement and engineering application of the new technology.

针对传统生物滞留设施处理降雨径流时异养反硝化受碳源不足限制影响脱氮效能、异养反硝化菌相对自养菌繁殖量大且无排泥过程致使微生物随径流外排影响出水效果等问题，结合市政/工业废水的硫自养反硝化工艺体现出的无碳源限制和自养反硝化菌增殖缓慢的优势，研发一种硫铁矿基质生物滞留处理降雨径流的同步异养-硫协同自养反硝化新工艺并揭示其反硝化机理。采用初探反硝化阶段的存在、预判反硝化形式多样性、验证硫自养反硝化的逐级深入验证思路，揭示该工艺总氮代谢途径与硫铁矿分解机制，探明该代谢途径涉及的反应基元历程。采用微生物实验结果与参考微生物特性差异的对照分析，硫铁矿侵蚀分解微观路径及侵蚀微环境的镜检观测，微生物增殖速率与附着性能的定量测取等方法，探究反应发生的微生物环境特征与硫铁矿分解微环境。构建硫铁矿基质生物滞留设施处理径流的硫协同总氮代谢动力学模型并进行参数率定，为该新型工艺的效能提高和工程应用提供定量理论依据。

雨水生物滞留设施处理城市径流脱氮是落实“节能减排”、“水十条”等国家生态文明建设重大战略需求的具体举措。针对传统雨水生物滞留设施区别于污水处理厂缺乏机械调控手段致使反硝化脱氮有机碳源不足的问题，开展了生物滞留设施硫协同处理城市降雨径流的脱氮代谢途径系统研究。.研究阐明了硫铁矿基质被分解氧化后提供电子供体促进雨水脱氮反硝化、三价铁离子络合磷酸盐沉淀促进化学除磷的同步脱氮除磷代谢途径。取得了雨水径流污染物削减氨氮去除率98.1±0.1%，溶解性TN去除率64.1±2.5%，溶解性TP去除率79.0±5.1%，副产物总铁≤0.2 mg/L、硫酸盐≤50mg/L的高效性能，解决了径流脱氮分散处理有机碳源限制反硝化的技术瓶颈。揭示了硫铁矿基质雨水生物滞留设施多种自养和异养反硝化菌属相对丰度提高及其影响处理效能的微生物作用机制，发现了硫铁矿分解表层晶体消失及新出现FeOOH薄层的现象，为硫铁矿同步除磷及避免二次污染泄漏的机理提供了理论依据。构建了硫铁矿基质生物滞留设施处理降雨径流的硫协同总氮代谢动力学，发明了硫铁矿基质雨水生物滞留设施脱氮除磷新工艺并实现了成果转化与应用，明确了关键参数的影响，并对设施长期运行的老化情况进行了预测评估。.成果支撑“山地城市径流控制与利用”入选了2022年度水利部先进实用技术，发表学术论文6篇（含 Water Research 2 篇），申请发明专利2件（含已授权1件），培养博士后1名并支撑其获批国家自然科学基金青年项目（52200113），培养硕博研究生5名并支撑其获中国互联网＋重庆赛区金奖、1篇毕业论文获重庆市优秀硕士学位论文，支撑项目负责人入选了国家级高层次人才。成果已经和正在进行技术成果转化，已取得明显的科学价值和社会经济效益。