基于膜结构对MBfR异向传质及生物膜影响机制的甲烷氧化反硝化脱氮效能研究

电子供体显著影响污水生物脱氮中反硝化的完成与效能。甲烷作为一种较高应用潜质的替代电子供体，可在膜生物膜反应器（MBfR）中通过甲烷氧化耦合反硝化过程完成生物脱氮。然而，目前仍存在MBfR异向扩散传质影响因素复杂、膜结构与特性影响机制不明确、功能菌群协同机理有待深入解析等科学问题。本申请利用原位OCT、在线显微PIV与微电极检测等方法研究膜结构与表面特性对异向传质、生物膜附着生长及气体利用转化的影响；通过静电纺丝方法构建双层膜结构，结合水力剪切力等影响效应优化膜表面特性，获得内外层功能专一、生物膜结构可控的新型膜界面，实现气体传质均匀稳定、生物量富集、生物膜结构合理与稳定性提升；在新型MBfR较高生物富集条件下，研究强化功能菌群协同作用与提高甲烷利用转化率的路径，促进体系高效稳定脱氮。课题的开展可深入认知MBfR异向传质与生物膜代谢等机理，突破其应用于甲烷基质利用、污水脱氮等方面的技术瓶颈。

Electron donors substantially affect accomplishment and efficiency of denitrification in biological nitrogen removal process for wastewater treatment. Methane is an alternative electron donor with great application potential, which can be attributed to biological denitrification by aerobic methane oxidation coupled to denitrification (AME-D) process in membrane biofilm reactor (MBfR). However, there are still several challenging scientific issues in MBfR for AME-D, especially the complexity of factors affecting counter-diffusional mass transfer, the uncertainty of influential mechanisms of membrane configuration and surface properties, as well as the unclear synergistic effect of functional microbes. This project will comprehensively analyze the effects of membrane configuration and surface morphological properties on counter-diffusional mass transfer, biofilm attachment and growth, and gaseous substrate mass transfer and utilization, by means of in-situ optical coherence tomography (OCT) observation, on-line micro-particle image velocimetry (PIV) characterization and micro-sensor multi-meter detection. A simple electrostatic spinning method will be employed to fabricate a dual-layer membrane configuration by covering the surface of conventional hollow-fiber hydrophobic base membrane, and the membrane surface morphological properties will be optimized based on the strengthening effect from local hydraulic shear force onto biofilm structure. As a result, an innovative membrane interface, whose inner and outer layer provide specific exclusive function, and that could manipulate biofilm structure, is highly expected to be obtained. Accordingly, the MBfR employed this innovative membrane allows stable and uniform gaseous substrate transfer, and helps to effectively enrich biomass to achieve reasonable biofilm structure and high stability, all which will significantly favor functional microbes abundance enhancement and spatial distribution, and hence result to be stably high-efficient in methane substrate utilization and denitrification. Finally, the possible ways for synergistic effect of functional microbes to elevate methane utilization and transformation rates, in this new MBfR with the enriched biomass, will be investigated. The system cost-effectiveness and stability will also be evaluated. The obtained results in this project will be very useful to in-depth understand the counter-diffusion mass transfer behaviors, biofilm growth and metabolism mechanisms in MBfR, and to break the bottleneck during MBfR applications in gaseous methane utilization and biological nitrogen removal for wastewater treatment.