Understanding diversity and assembly patterns of microbial communities in activated sludge (AS) is pivotal for addressing fundamental ecological questions and wastewater treatment engineering. Recent applications of molecular methods especially high-throughput sequencing (HTS) have led to the explosion of information about AS community diversity, including the identification of uncultured taxa, and characterization of low-abundance but environmentally important populations such as antibiotic resistant bacteria and pathogens. Those progresses have facilitated the leverage of ecological theories in describing AS community assembly. The lognormal species abundance curve has been applied to estimate AS microbial richness. Taxa-area and taxa-time relationships (TAR and TTR) have been observed for AS microbial communities. Core AS microbial communities have been identified. Meanwhile, the roles of both deterministic and stochastic processes in shaping AS community structures have been examined. Nonetheless, it remains challenging to define tempo-spatial scales for reliable identification of community turnover, and find tight links between AS microbial structure and wastewater treatment plant (WWTP) functions. To solve those issues, we expect that future research will focus on identifying active functional populations in AS using omics- methods integrated with stable-isotope probing (SIP) with the development of bioinformatics tools. Developing mathematic models to understand AS community structures and utilize information on AS community to predict the performance of WWTPs will also be vital for advancing knowledge of AS microbial ecology and environmental engineering.

了解活性污泥（AS）中微生物群落的多样性和组装模式对于解决基本的生态问题和废水处理工程至关重要。分子方法尤其是高通量测序（HTS）的最新应用已导致有关AS群落多样性的信息激增，包括未培养的分类单元的鉴定，以及表征低丰度但对环境重要的种群（如抗生素抗性细菌和病原体）的特征。这些进展促进了生态学理论在描述AS社区集会中的作用。已使用对数正态物种的丰度曲线来估计AS微生物的丰富度。已观察到AS微生物群落的分类面积和分类时间关系（TAR和TTR）。已经确定了核心AS微生物群落。同时，已经研究了确定性过程和随机过程在塑造AS社区结构中的作用。尽管如此，定义时空尺度以可靠地识别社区营业额，在AS微生物结构与废水处理厂（WWTP）功能之间找到紧密联系仍然是一项挑战。为解决这些问题，我们希望未来的研究将集中于通过使用结合了稳定同位素探测（SIP）的组学方法和生物信息学工具的开发来识别AS中的活跃功能群体。