铁碳微电解强化厌氧氨氧化脱氮的过程效应与实现机制研究

Introduction of electrochemical reaction in the anaerobic ammonium oxidation system would be an effective way to enhance the low metabolic rate of anaerobic ammonium oxidation (anammox) bacteria at low temperature. According to the previous studies about the positive effect of electricity/electric field or ferrous ions on the anammox, the project proposed a new high-rate nitrogen removal technology by coupling the anammox and the iron-carbon microelectrolysis. That is, ferrous iron coupling micro-electric-field, which continuously generated by the iron-carbon microelectrolysis reaction, will have synergistic-enhanced effect on the anammox process. For this purpose, the operating conditions of the iron-carbon microelectrolysis and anammox coupling system for enhanced nitrogen removal will be determined through the quantitative control of the micro-electrolytic reaction rate. Comparative research systems are constructed and operated. Based on the optimized nitrogen removal performance, the functional stability and the microorganism spatial-temporal evolution in each system, the long-term role of ferrous iron coupling micro-electric-field on the anammox process will be clarified. Through analyzing the physical, chemical and microbial characteristics of the micro-interface between the iron-carbon filler surface and attached biofilm, and building the key substance conversion model, the mechanism of the interaction among the electricity/electric field, ferrous iron and anammox bacteria will be clarified at the micro level. The research aims to develop efficient anammox technology and provide new ideas for promoting the anammox practical application.

在厌氧氨氧化微生物脱氮系统中引入电化学反应将是改善厌氧氨氧化菌生长代谢缓慢的一种有效途径。基于以往电流/电场、亚铁离子等单因子强化厌氧氨氧化技术研究，本项目提出铁碳微电解耦合厌氧氨氧化脱氮新技术，即利用铁碳微电解持续产生的亚铁离子和微电场，实现双因子协同强化的高效厌氧氨氧化反应。为此，研究（1）通过优化环境因子及系统运行条件，调控铁碳微电解反应速率，确定实现铁碳微电解厌氧氨氧化耦合脱氮的控制条件；（2）设定参照系统，通过调整进水基质比例和关键运行参数，对比研究不同系统脱氮效能、功能稳定性以及微生物种群时空演变规律，揭示亚铁离子和微电场长期协同强化厌氧氨氧化的过程效应；（3）聚焦铁碳填料表层与附着生物膜微界面上的物理、化学、分子生物学特征，构建关键物质转化过程模型，阐明微电场、亚铁离子协同强化厌氧氨氧化菌的作用机制。研究旨在发展高效厌氧氨氧化技术，为推进厌氧氨氧化的实践应用提供新思路。

与传统硝化反硝化脱氮技术相比，基于亚硝化-厌氧氨氧化的自养生物脱氮过程是一种极具可持续发展潜力的新型污水生物处理技术。然而，厌氧氨氧化菌一般生长速率缓慢且对环境变化敏感，促进厌氧氨氧化菌生长代谢，强化厌氧氨氧化系统脱氮效能，成为厌氧氨氧化研究领域的重要方向之一。首先，考察了基于废铁屑再利用的污水厌氧氨氧化强化脱氮技术可行性，结果表明与传统厌氧氨氧化系统相比，废铁屑耦合厌氧氨氧化系统TN去除效能可以提升15~35%，污泥比厌氧氨氧化活性提升12-30%；高通量测序及定量PCR结果证实，废铁屑的投加强化了厌氧氨氧化菌（ 以Ca. Kuenenia stuttgartiensis为主导）的生长富集。同时，考察了影响废铁屑耦合厌氧氨氧化系统强化脱氮的关键因素，如废铁屑投加量、NaHCO3、温度等，结果表明低温条件下，废铁屑耦合厌氧氨氧化系统具有更高的脱氮能力，废铁屑耦合厌氧氨氧化系统可以有效应对无机碳源不足产生的不利影响并提升系统的脱氮效能，在进水无机碳源不足（IC/TN=0.04）的条件下，废铁屑与厌氧氨氧化直接耦合系统比间接耦合系统具有更高的脱氮效能、污泥比活性以及NO3--N还原能力。此外，考察了限氨与限亚硝酸盐两种模式下厌氧氨氧化系统的脱氮效能，基于研究结果提出了基于选择性排泥的限NH4+厌氧氨氧化系统优化运行策略。本项目研究成果为推进厌氧氨氧化的实践应用提供了新思路和理论支撑。