粒子电极界面自组装杂化生物膜强化反硝化作用机制与调控原理

地下水硝酸盐污染严重威胁公众健康。三维电极生物膜法是一种新型的将电化学法与生物膜法相耦合的反硝化方法，自养反硝化菌利用电解产生的氢气作为电子供体将硝酸盐还原为氮气，反硝化效率高且无需外加碳源，适合于低碳氮比的地下水中的硝酸盐脱除。在三维电极生物膜反应器中，粒子电极界面的生物膜是硝酸盐还原的主体，决定了系统的脱氮效果，但由于自养菌生长较慢，生物膜的挂膜启动时间较长。因此，本项目提出将导电性和生物兼容性良好的纳米α-Fe2O3与反硝化菌在粒子电极界面进行自组装，培育纳米杂化生物膜，从而加速生物膜形成并提高生物膜的电活性。项目拟研究纳米α-Fe2O3对粒子电极界面挂膜过程的影响，解析纳米材料-微生物自组装杂化生物膜及其胞外聚合物的特征，探索杂化生物膜参与反硝化过程的作用机制，调控工艺参数提高生物膜活性，优化反应器脱氮性能，为推动三维电极生物膜技术应用于地下水硝酸盐污染修复提供理论基础和技术支持。

Nitrate pollution in groundwater has seriously threatened the public health. Three-dimensional biofilm electrode reactor (3DBER) is a new denitrification technology integrating the processes of electrolysis and biofilm metabolism. Hydrogen produced by electrolysis is utilized by autotrophic denitrifying bacteria as the electron donor to reduce nitrates to nitrogen. The denitrification efficiency of 3DBER is quite high without supplying external carbon source, that is very suitable for remedying nitrates in groundwater with low ratio of carbon to nitrogen. In the 3DBER, the electroactive biofilm at the interface of particle electrodes implement the process of nitrates reduction, directly determining the denitrification efficiency of the reactor. However, the time for biofilm cultivation and acclimation is as long as several months. In this project, nano α-Fe2O3 of excellent conductivity and biocompatibility is assembled with denitrifying microorganisms at the interface of particle electrodes to form hybrid biofilm, aiming to accelerate the maturation of biofilm and to improve the electrochemical activity of the biofilm. Roles of nano α-Fe2O3 in the process of biofilm culturing on particle electrodes are investigated. The characteristics of the hybrid biofilm assembled by nano particles and microorganisms as well as extracellular polymeric substances are analyzed. Mechanisms for enhanced denitrification by the hybrid biofilm are explored. Operation parameters are optimized to improve the activity of the biofilm for elevated denitrification performance of the 3DBER. Results would provide theoretical basis and technical support for the application of 3DBER in remedying nitrates pollution in groundwater.