Free-living bacteria and potential bacterial pathogens in sewage treatment plants

Abstract

To comprehensively understand the profile of free-living bacteria and potential bacterial pathogens in sewage treatment plants (STPs), this study applied high-throughput sequencing-based metagenomics approaches to investigate the effects of activated sludge (AS) treatment process and ultraviolet (UV) disinfection on the community of bacterial pathogens in two full-scale STPs. A total of 23 bacterial genera were identified as free-living bacteria, and 243 species/OTU were identified as potential bacterial pathogens, 6 of which were confidently detected in the STPs (with the total abundances ranging from 0.02 to 14.19%). Both diversity and relative abundance of the detected bacterial pathogens decreased obviously after AS treatment process (p < 0.05), and increased slightly after sedimentation (p < 0.05). UV disinfection shows no obvious effects on the total relative abundance of the free-living pathogenic bacteria in sewage. Although large amounts of the particle-bound pathogens were eliminated through the sewage treatment process, the STPs could not effectively remove the free-living bacterial pathogens, and some pathogenic bacteria (e.g., Pseudomonas aeruginosa) present in the effluent had higher relative abundance after UV disinfection. Overall, the results extend our knowledge regarding the community of potential pathogens (especially free-living pathogens) in STPs.

Profiling Bacterial Diversity and Potential Pathogens in Wastewater Treatment Plants Using High-Throughput Sequencing Analysis

“…Waterborne infections emanate from the transmission of pathogenic microorganisms (bacteria, viruses, protozoa) by both direct and indirect ingestion of polluted water [1,2,3,4]. Most water-borne pathogens are spread through the fecal–oral route, and find their way to wastewater treatment plants (WWTPs) through excreted feces in raw sewage from infected people or in drinking water, or by eating food exposed to contaminated water, which could lead to serious health complications [4,5,6,7]. In recent years, bacterial pathogens have been recurrently identified in wastewater plants, based on the impression that WWTPs are a major reservoir for the growth of numerous pathogenic microbes [2,6,8].…”

Recycling nutrients contained in human excreta to agriculture: Pathways, processes, and products

“…Instead, energy is recovered in the form of biogas (in anaerobic treatment such as UASB) (Seghezzo et al, 1998), electricity (in microbial fuel cells) or biofuels such as ethanol, methane, or hydrogen (in microbial electrolysis cells). Pathogens tend to only partly accumulate in the sludge (Wen et al, 2009;Li et al, 2015;Huang et al, 2018). In aerobic treatment, heavy metals partition fairly equally between effluent and sludge (Karvelas et al, 2003).…”

Biological HRPs in wastewater

“…Recently, a variety of ARG types (tetracycline, sulfonamide, multidrug, aminoglycoside, bacitracin, chloramphenicol, b-lactam, quinolone, trimethoprim, polymyxin, and vancomycin as well as other types) have been found in medical wastewater, pharmaceutical wastewater, domestic wastewater and wastewater from aquaculture systems, and livestock breeding (Guo et al, 2018;Jia et al, 2017;Tong et al, 2019;Zhao et al, 2018). Furthermore, ARB and multiple ARB, such as Pseudomonas aeruginosa, Escherichia coli, Acinetobacter spp., and Enterobacteriaceae are observed in wastewater (Huang et al, 2018;Kümmerer, 2009). The main sources and distribution of ARGs in wastewater were reviewed:…”