菌藻共生序批式泥膜系统构建及氮磷去除强化机制研究

The algal-bacterial symbiosis (ABS) system is a promising biological-ecological coupled wastewater treatment technology to simultaneously achieve nitrogen (N) and phosphorus (P) removal. However, until now, both the performance improvement and stable regulation of the ABS system have not been solved. Thus, it is urgently needed to develop a high-efficiency, stable and controllable ABS technology for the enhanced N and P removal. In this project, an innovative ABS system building in sequencing batch sludge-biofilm reactor is constructed by coupling ABS-sludge system with ABS-biofilm system, that is, the light-blocking limitation can be broken by both suspended carrier floating and sludge setting at non-aeration stage while the suspended carriers are introduced into sequencing batch ABS-sludge system, and the ecological conditions for the growth and metabolism of microalgae is established, then the ABS biofilm is formed. Focusing on the N and P removal from municipal wastewater, the aim of this project is to investigate the removal efficiency of N and P and the equilibrium condition of the interaction between bacteria and microalgae in this constructed system, and the corresponding assimilation and transformation ways of N and P by bacteria and microalgae are studied. Also, both the structure and composition of functional microbial community are revealed, as well as the key functional genes and metabolic characteristics related to N and P removal, and the collaboration mechanisms between bacteria and microalgae for N and P removal are clarified. Based on the above research findings, the regulation strategies for N and P removal in this constructed system are proposed. The project will provide some theoretical and technical support for the development and application of wastewater treatment technology based on ABS system.

菌藻共生系统同步去除氮磷是一种具有发展前景的生物-生态耦合污水处理技术，但是，目前菌藻共生系统的运行提效及稳定调控问题尚未得到解决。因此亟待开发一种高效稳定与可控性强的菌藻共生强化氮磷去除技术。本研究通过将菌藻共生污泥系统和菌藻共生生物膜系统进行耦合，构建了一种菌藻共生序批式泥膜新型系统，即在序批式菌藻共生污泥系统中引入悬浮性载体，利用非曝气阶段悬浮载体上浮和污泥下沉状态突破遮光限制，建立微藻生长代谢的生态学条件，进而形成菌藻共生生物膜。以城市污水中的无机氮磷为研究对象，重点探讨菌藻共生序批式泥膜系统氮磷去除效率及菌藻相互作用的平衡稳定条件，明确菌藻同化、转化氮磷的途径。同时，揭示系统中功能微生物群落的结构和组成以及与氮磷去除相关的关键功能基因和代谢特征，阐明菌藻协作去除氮磷的机制，并掌握系统去除氮磷的调控策略，为菌藻共生系统污水处理技术的开发和应用提供理论和技术支撑。

菌藻共生（ABS）系统是一种可同步脱氮除磷污水处理技术，其与传统活性污泥工艺的耦合有望为污水深度处理增效。然而，污泥的遮光效应显著抑制微藻光合作用。因此，微藻在传统生物污水处理系统中的强化生长及菌藻稳定互作关系调控成为ABS研究领域的重要方向之一。本研究以强化微藻生长代谢为目标，在具体解析微藻关键生长参数的基础上，提出微藻生长强化方法，即在序批式菌藻共生污泥系统中引入密度小于水的悬浮性载体，通过间歇曝气模式和载体悬浮性质建立光能接收和微藻附着场所，在载体表面形成微藻优势生长的菌藻共生生物膜，从而强化微藻活性和生物量积累。在此新型菌藻共生序批式泥膜系统中，通过比较悬浮污泥相和生物膜相中絮体性状差异和微生物活性、种群差异和相关性等，确定微藻生长强化和菌藻互作机制。研究表明，生物膜相微藻富集生长过程可通过同化作用促进氮磷去除，并有助于创造富氧微环境，促进周围好氧细菌活性；好氧细菌活性的增强可促进更多胞外聚合物（EPS）的分泌，强化微藻粘附。此外，微藻对钙镁等无机阳离子的主动吸收可部分中和EPS的表面负电性，促进其对含氮磷的阴离子的吸附，进一步强化污水氮磷去除。本项目已发表学术论文6篇，其中ESI高被引论文1篇，SCI论文6篇；申请发明专利1件；培养硕士研究生8名，毕业1名。