基于生态调控的菌-藻共生好氧颗粒污泥体系强化构建机制研究

Rapid construction of stable and efficient bacterial-algal symbiotic aerobic granule system is the key and difficult point to promote the development of bacterial-algal symbiotic wastewater treatment system. In this project, based on the analysis of microalgae enrichment conditions and aggregation behavior between bacteria and algae, the formation and growth mechanism of bacterial-algal symbiotic aerobic granules will be clarified. Furthermore, the piecewise controlling strategy will also be proposed to ascertain the construction process principle of bacterial-algal symbiotic aerobic granules system. Molecular biology methods will be adopted to investigate the spatial-temporal succession of bacterial-algal symbiotic ecosystem during the sludge granulation process, as well as the molecular ecological network of bacterial-algal consortia will be constructed. By analyzing its influence on aggregation behavior, structural stability and functional performance of bacterial-algal symbiotic granules, the action mechanism of bacterial-algal ecological shift on the granulation process will be revealed. In this case, the dominate factors influencing the bacterial-algal community in symbiotic aerobic granules will be identified and the relationship between them will also be determined. According to the evaluation of construction efficiency, structural stability and functional performance, the strengthening construction strategy for bacterial-algal symbiotic aerobic granules system which is based on the ecological regulation will be proposed. The research results will provide necessary theoretical basis and technical support for the engineering application of bacterial-algal symbiotic aerobic granules.

快速构建稳定、高效的菌-藻共生好氧颗粒污泥体系，是推进菌-藻共生污水处理系统发展的关键与难点。本项目基于对微藻富集条件及菌-藻聚集行为的研究，明确菌-藻共生好氧颗粒污泥的形成及成长机制，并提出分段控制策略，以探明菌-藻共生好氧颗粒污泥体系构建的工艺原理；应用分子生物学手段，考察污泥颗粒化进程中菌-藻共营生态系统在时间和空间维度下的演替规律并构建菌-藻分子生态网络；分析菌-藻生态演替对共生体聚集行为、结构稳态及功能特性的影响，揭示其在污泥颗粒化进程中的作用机制。基于以上研究，识别影响共生颗粒污泥中菌-藻群落结构的主导因素，并判明两者间的映射关系，最终以系统的构建效率、结构稳态及功能特性为评价指标，提出基于生态调控的菌-藻共生好氧颗粒污泥体系强化构建策略。研究成果将为菌-藻共生体颗粒化技术的工程化应用提供必要的理论基础与技术支撑。

对于好氧颗粒污泥而言，系统启动周期长是限制其工程化应用的主要问题之一。同样，如何快速构建稳定、高效的菌-藻共生颗粒污泥体系，是推进菌-藻共生污水处理系统与污泥颗粒化技术结合的关键与难点。本项目在探明菌-藻共生颗粒污泥体系构建工艺原理的基础上，考察了菌-藻共营生态系统在污泥颗粒化进程中的演替规律，并判明环境因素与菌-藻群落结构间的映射关系，明确菌-藻生态演替在污泥颗粒化进程中作用机制，最终提出基于生态调控的菌-藻共生颗粒污泥体系强化构建策略。研究发现，接种外源藻可以加快藻类在系统中的富集，提高污染物去除效能，而内生藻与污泥微生物之间有更好的相容性，从而最先实现污泥颗粒化，且颗粒沉降性更好。高通量测序结果表明，藻类的生长能够提高共生颗粒污泥中细菌种群的多样性及丰富度，而不同于好氧颗粒污泥中的脱氯菌属（Dechloromonas），成熟菌-藻共生颗粒污泥中的优势菌属为嗜酸聚塑料菌属（Plasticicumulans）。而且，颗粒化过程中，藻类的α多样性提高，但群落结构无显著变化。对比不同光照强度对菌-藻生态演替的影响，发现中低光强下，微生物群落结构相近，而且光强对藻类种群的影响要比细菌显著。通过对比发现，有机碳源类型对菌-藻共生颗粒污泥的群落也有影响，且对细菌的作用大于藻类，颗粒性碳源有助于Plasticicumulans的富集。另外，在菌-藻共生颗粒污泥形成过程中，存在着对藻类的定向选择，及时接种藻源不同。在菌-藻生态演替过程中，Gammaproteobacteria菌纲可促进污泥EPS分泌，而Goniomonadaceae藻纲可以提高污泥的沉降性能，Selenastraceae藻纲则能够增加系统中的污泥浓度。本项目研究成果可为菌-藻共生颗粒污泥的快速培养提供理论基础和技术指导。