The capacity of wastewater treatment plants drives bacterial community structure and its assembly

Abstract

Bacterial communities in wastewater treatment plants (WWTPs) affect plant functionality through their role in the removal of pollutants from wastewater. Bacterial communities vary extensively based on plant operating conditions and influent characteristics. The capacity of WWTPs can also affect the bacterial community via variations in the organic or nutrient composition of the influent. Despite the importance considering capacity, the characteristics that control bacterial community assembly are largely unknown. In this study, we discovered that bacterial communities in WWTPs in Korea and Vietnam, which differ remarkably in capacity, exhibit unique structures and interactions that are governed mainly by the capacity of WWTPs. Bacterial communities were analysed using 16S rRNA gene sequencing and exhibited clear differences between the two regions, with these differences being most pronounced in activated sludge. We found that capacity contributed the most to bacterial interactions and community structure, whereas other factors had less impact. Co-occurrence network analysis showed that microorganisms from high-capacity WWTPs are more interrelated than those from low-capacity WWTPs, which corresponds to the tighter clustering of bacterial communities in Korea. These results will contribute to the understanding of bacterial community assembly in activated sludge processing.

Investigation of the Prevalence of Antibiotic Resistance Genes According to the Wastewater Treatment Scale Using Metagenomic Analysis

“…The results of this study suggest that the microbial communities are generally different according to the capacity of WWTPs, without some exceptions, such as the dominance of Mycrobacterium genera between large- and small-scale WWTPs. This is consistent with previous studies [ 10 , 56 , 57 ]. Although there are many reasons, similar fitness levels of the microbial community from the influent wastewater community may fit the bioreactor despite different WWTP scales.…”

“…However, most previous studies preliminarily focused on the identification of ARGs and ARB during the wastewater treatment process, such as activated sludge and anaerobic digestion processes, not considering the scale and treatment capacity of WWTPs [ 6 , 8 ]. According to a previous study, the capacity of a WWTP can affect the bacterial community via various operation practices, such as influent characteristics, sludge retention time (SRT), hydraulic retention time (HRT), reactor volumes, and physical constraints [ 10 ]. Recent studies have suggested that the bacterial community plays a key role in ARG prevalence and enrichment during the WWTP process [ 11 ].…”

High Diversity and Functional Potential of Undescribed “Acidobacteriota” in Danish Wastewater Treatment Plants

“…Few studies have examined "Acidobacteriota" in WWTPs, and only a couple of key populations have been explored in detail. Geothrix is recognized as an abundant lineage in nutrient removal WWTPs in South Korea and Vietnam (Kim et al, 2019), suggesting Geothrix to be metabolically active and growing in the plants. In a study by Saunders et al (2016), an unknown genus from the "Acidobacteriota" order with the placeholder name "Sva0725" was defined as a member of the abundant core genera also suggesting them growing in the plants and influencing carbon turnover.…”

“…Most characterized taxa in activated sludge WWTPs across the world are from the phyla Proteobacteria, Actinobacteriota, Bacteroidota, Spirochaetota, and Nitrospirota (Wu et al, 2019), but other less well-described phyla are also observed as abundant. For example, almost nothing is known about the potential roles of abundant "Acidobacteriota" members in the wastewater treatment process and only a few studies have visualized (McIlroy et al, 2015a) or evaluated the abundance of "Acidobacteriota" in situ (Juretschko et al, 2002;McIlroy et al, 2015b;Saunders et al, 2016;Kim et al, 2019).…”

Characterization of the Spatial Variation of Microbial Communities in a Decentralized Subtropical Wastewater Treatment Plant Using Passive Methods

“…Other families, like the Bacteroidaceae, Desulfobacteraceae, Geobacteraceae, and Methylocystaceae, were more abundant at the surface (Figures 7b and 8b), indicating that they may include some facultative anaerobic species, the abundance of this families can be enhanced by a slight increase in oxygen levels. In addition to oxygen availability, it has been suggested that substrate availability and competitive interactions between microbial populations shape the distribution of the bacterial communities from inlet to outlet in anaerobic treatment units such as up flow anaerobic sludge blanket reactors [90,91].…”