Department of Civil Engineering and Applied Mechanics, McGill University, Montreal, Quebec, Canada.
Department of Civil and Environmental Engineering, Center for Environmental Health and Engineering, University of Surrey, Surrey, United Kingdom.
Appl Environ Microbiol. 2024 Aug 21;90(8):e0059824. doi: 10.1128/aem.00598-24. Epub 2024 Jul 12.
Wastewater treatment plants (WWTPs) are host to diverse microbial communities and receive a constant influx of microbes from influent wastewater. However, the impact of immigrants on the structure and activities of the activated sludge (AS) microbial community remains unclear. To gain insight on this phenomenon known as perpetual community coalescence, the current study utilized controlled manipulative experiments that decoupled the influent wastewater composition from the microbial populations to reveal the fundamental mechanisms involved in immigration between sewers and AS-WWTP. The immigration dynamics of heterotrophs were analyzed by harvesting wastewater biomass solids from three different sewer systems and adding to synthetic wastewater. Immigrating influent populations were observed to contribute up to 14% of the sequencing reads in the AS. By modeling the net growth rate of taxa, it was revealed that immigrants primarily exhibited low or negative net growth rates. By developing a protocol to reproducibly grow AS-WWTP communities in the lab, we have laid down the foundational principles for the testing of operational factors creating community variations with low noise and appropriate replication. Understanding the processes that drive microbial community diversity and assembly is a key question in microbial ecology. In the future, this knowledge can be used to manipulate the structure of microbial communities and improve system performance in WWTPs.IMPORTANCEIn biological wastewater treatment processes, the microbial community composition is essential in the performance and stability of the system. This study developed a reproducible protocol to investigate the impact of influent immigration (or perpetual coalescence of the sewer and activated sludge communities) with appropriate reproducibility and controls, allowing intrinsic definitions of core and immigrant populations to be established. The method developed herein will allow sequential manipulative experiments to be performed to test specific hypothesis and optimize wastewater treatment processes to meet new treatment goals.
污水处理厂（WWTP）是多种微生物群落的宿主，并不断从进水废水中接收微生物。然而，移民对活性污泥（AS）微生物群落的结构和活性的影响尚不清楚。为了深入了解这种被称为永久群落融合的现象，本研究利用受控的操作实验，将进水废水成分与微生物种群分离，以揭示污水管和 AS-WWTP 之间移民所涉及的基本机制。通过从三个不同的污水系统中收获废水生物量固体并添加到合成废水中，分析了异养生物的移民动态。观察到进入的进水种群在 AS 中贡献了高达 14%的测序读数。通过对分类群的净增长率进行建模，发现移民主要表现出低或负的净增长率。通过开发一种可在实验室中重复培养 AS-WWTP 群落的方案，我们为测试产生具有低噪声和适当复制的群落变化的操作因素奠定了基础原则。了解驱动微生物群落多样性和组装的过程是微生物生态学中的一个关键问题。在未来，这些知识可用于操纵微生物群落的结构并提高 WWTP 中的系统性能。
重要性
在生物废水处理过程中，微生物群落组成对于系统的性能和稳定性至关重要。本研究开发了一种可重复的方案，以具有适当的重现性和对照来研究进水移民（或污水管和活性污泥群落的永久融合）的影响，从而可以建立核心和移民种群的内在定义。本文开发的方法将允许进行连续的操作实验，以测试特定的假设并优化废水处理过程以满足新的处理目标。
