厌氧膜生物反应器中微细颗粒物的识别与调控及膜污染机理研究

Anaerobic membrane bioreactor (AnMBR) technology is being considered as a very appealing and sustainable alternative for wastewater treatment due to the significant advantages such as lower sludge production, lower energy consumption and resource recovery over conventional anaerobic systems and aerobic MBR. Similar to aerobic MBR, however, the biggest challenge in scaling up this technology is preventing the membrane from becoming clogged. Previous studies mainly focused on the influence of sludge properties and dissolved organic matter characteristics but less understanding on the roles of sub-visible micro-particles in membrane fouling. The major aim of this project is to explore the composition and formation of micro-particles in AnMBRs and their fouling behaviors. The detailed objectives are to (i) determine the composition of micro-particles from the aspects of biopolymers and microorganisms by confocal laser scanning microscopy and scan electron microscope observation; (ii) to make clear the influence of sludge property and microbial physiology/community on origins and production of micro-particles in AnMBRs under different operating conditions; finally (iii) to reveal the interactions between micro-particles and membranes by using quartz crystal microbalance and their fouling behaviors by dead-end filtration tests. The conduction of this project could add new knowledge of micro-particles from the perspectives of fouling mechanisms and control strategies.

厌氧膜生物反应器（AnMBR），因具有污泥产量少、能耗低和资源回收等优势，成为一种很有潜力的污水处理技术。然而，与好氧MBR相似，膜污染一直以来阻碍着该项技术的发展。关于膜污染，先前研究主要集中在污泥性状和溶解性有机物两个方面的影响，而对微细颗粒物（0.1-10 µm）的膜污染角色尚未明了。因此，本项目以AnMBR中微细颗粒物为研究对象，系统研究其组成特性、形成机制和膜污染机理。采用激光共聚焦显微镜和荧光原位杂交技术，揭示微细颗粒物中细菌和生物聚合物的共存关系。通过改变关键运行参数和借助批式实验，明确污泥性状和细菌生理状况对微细颗粒物形成的影响；同时，采用分子生物学技术探索微细颗粒物中细菌群落结构差异，并构建与膜污染的联系；最后，借助石英晶体微天平和死端膜过滤实验，阐明微细颗粒物与膜之间的相互作用机制。本项目的研究有助于拓展对微细颗粒物的认识，为AnMBR工艺优化和膜污染调控提供科学依据。

厌氧膜生物反应器（AnMBR）因产泥少、能耗低和资源回收等优势，在城市污水处理工艺中扮演着重要角色。然而，与好氧MBR（AeMBR）类似，膜污染是阻碍该技术发展的重要瓶颈。尽管膜污染在AeMBR中已被研究数十年，但AnMBR膜污染机理是否与其一致值得商榷，有必要进行新的阐释。首先，研究通过对比An和Ae-MBR运行情况及污泥混合液中各组分的膜过滤性能发现，AnMBR上清液中微细颗粒物（0.45-10 μm）是主要的膜污染物；且不论是有机物和微生物组成，AnMBR上清液中微细颗粒物在膜污染过程中扮演着非常重要的角色，这与AeMBR膜污染物的组成和性质显著不同。其次，针对AnMBR中微细颗粒物全面解析了其组成和形态分布（如：多糖、蛋白和DNA染色）以及微生物菌群结构，探明了不同膜通量下微细颗粒物（如：5-10，1-5，和0.45-1 μm）的膜污染行为（过滤性能和生物膜形成潜能），并构建了微细颗粒物菌群与其膜污染之间的相关关系。进一步，通过研究了不同进水水质AnMBR中微细颗粒物的尺寸分布和菌群组成及膜过滤行为，明确了进水多糖和蛋白的比例对微细颗粒物形成和AnMBR膜污染机制的影响机制。最后，借助二维相关红外光谱分析研究了膜污染控制过程中常用化学清洗药剂NaOCl对一种商用复合膜PES/PVP的破坏或老化机制。总体上，本文研究结果扩展了人们对AnMBR膜污染物组成和主要来源以及膜清洗过程膜的老化机制的认识和理解，可为进一步提出AnMBR膜污染的有效防治措施提供了理论支撑。