基于群体感应的自然光诱导藻-菌颗粒污泥稳态运行机制及调控策略

Algal-bacterial granular sludge technology is a promising approach for simultaneous organic carbon, nitrogen and phosphorus removal, biomass energy recovery, and reduction in CO2 emission in wastewater treatment, combing the advantages of fast settling ability of aerobic granules and energy-efficiency of algae. Since this concept is newly established, the understanding for the granulation and operation of the algal-bacterial symbiosis is not clear, nor the inner mechanisms for the interactions between algae and bacteria. The present project is proposed to present the behavioral patterns of key functional sensing signals by identifying and revealing their species and relevant concentrations during the granulation and operation of algal-bacterial granules induced by sunlight exposure. Exogenous sensing signals are to add into the sequencing batch reactors (SBR) to elucidate their impacts on the interactions between algae and bacteria, for looking into the dynamic process and mechanism for algal-bacterial cooperation. The inner relations among sensing signal, characteristics of algal-bacterial granules, microbial communities, extracellular polymeric substances (EPS), and the reactor performance are evaluated to explicate the mechanism for granulation and stable operation of granules through quorum sensing (QS), thus establishing the manipulation procedures for fast start-up and long-term stable operation of the algal-bacterial granular system by chemical sensing signals. The research findings will aid the application of algal-bacterial granular process theoretically and technologically.

藻-菌颗粒污泥技术结合了好氧颗粒污泥沉降速度快和微藻低能耗可持续的优势，能在高效去除有机物及氮、磷污染的同时，实现生物质能源的回收并减少CO2排放，有望成为一种极具潜力的城市污水处理新技术。但目前藻-菌颗粒污泥的形成及稳态运行机制、藻-菌相互作用关系等尚不明确。本项目拟探索自然光诱导的藻-菌颗粒污泥启动和稳态运行过程，通过检测不同阶段系统产生的信号分子，揭示其在藻-菌颗粒污泥运行过程中的行为方式。在此基础上，研究外源信号分子对藻-菌聚集体形成及藻-菌相互作用的影响，深入认识藻-菌互作的动态过程和共生机理。并探寻信号分子与工艺参数、耦合颗粒特性、微生物种群结构、胞外聚合物（EPS）、除污效果之间的响应关系，从群体感应角度解析藻-菌颗粒污泥快速形成及稳态运行机制，从而建立信号分子介导的藻-菌颗粒污泥系统快速启动和长期稳定运行调控策略。研究成果可为藻-菌颗粒污泥工艺的实际应用提供理论和技术指导。

对藻-菌颗粒污泥的形成过程及稳态运行机制缺乏足够的认识一直是限制藻-菌颗粒污泥技术实际应用的主要问题。本申请课题实现了藻-菌颗粒污泥的快速造粒，采用模拟自然光诱导藻类生长的方式，利用共生的微藻和细菌形成包含普通异养菌、除磷菌、硝化/反硝化菌和藻类在内的藻-菌颗粒污泥，使微藻和细菌在相互协作过程中利用外界的有机物和氮、磷等物质，减少多形态碳（污泥、CO2）的排放，促进了微藻和细菌的除污能力，从而实现稳定、高效的污水处理过程。本研究重点探索藻-菌颗粒污泥的形成过程，研究不同光照条件以及不同种类外源信号分子作用下体系的启动特性，阐明藻-菌颗粒污泥的稳态化机制及关键控制因素，分析藻-菌耦合体系的协同除污机理，并利用色谱-质谱检测等技术对藻-菌颗粒污泥体系中影响和调控藻-菌相互关系的关键信号分子种类进行分析和测定。具体方法为在SBR反应器中控制不同的光照强度（0，40，80μmol/m2·s）与光照周期（0，6/18，12/12h），通过沉降选择压的方式实现藻-菌颗粒污泥耦合系统的快速启动；对藻-菌颗粒污泥耦合系统的运行条件进行优化，并研究有机负荷和pH等因素对耦合系统的影响，同时考察了不同信号分子对藻-菌共生体的生长代谢、EPS分泌、污染物降解效率的长期影响以及藻-菌颗粒污泥在长期静置条件下抵抗恶劣环境冲击的能力和活性重启恢复潜力。从污泥特征、生物量积累、叶绿素（Chl）含量、耦合颗粒理化特性、EPS分泌、信号分子和脂质的成分含量以及微生物群落结构变化等方面对耦合系统的稳定性进行了分析和调控，构建了系统稳定维持调控策略，指导藻-菌颗粒污泥系统的快速构建及长期稳定运行。