Treating domestic wastewater towards freshwater quality: Bacterial community and antibiotic resistance profiles highlight critical steps and improvement opportunities
Inês Leão , Jorge Antunes , Inês Baptista , Ruben Jorge , Luís Marinheiro , Stefan Löblich , Ivone Vaz-Moreira , Célia M. Manaia
{"title":"Treating domestic wastewater towards freshwater quality: Bacterial community and antibiotic resistance profiles highlight critical steps and improvement opportunities","authors":"Inês Leão , Jorge Antunes , Inês Baptista , Ruben Jorge , Luís Marinheiro , Stefan Löblich , Ivone Vaz-Moreira , Célia M. Manaia","doi":"10.1016/j.jece.2025.116172","DOIUrl":null,"url":null,"abstract":"<div><div>Ideally, wastewater treatment aims to produce water indistinguishable from freshwater, especially for reuse. This study evaluated bacterial community and antibiotic resistance variations throughout treatment and benchmarked these with freshwater sources. Samples collected from six points of a full-scale wastewater treatment plant, pilot-scale advanced treatment options (non-thermal plasma - NTP, ultrafiltration - UF, UF followed by reverse osmosis- UF+RO), two rivers and a borehole were analyzed for quality parameters (BOD5, TSS, turbidity, <em>Escherichia coli</em>), antibiotic resistance genes (quantitative PCR), class 1 integron variable region composition (Oxford Nanopore sequencing), and bacterial community composition (16S rRNA Illumina sequencing).</div><div>Secondary treatment followed by sand filters and coagulants caused the highest reduction (∼2 log-unit/volume) of all analyzed parameters and the sharpest reduction of diversity of antibiotic resistance genes within class 1 integrons’ variable region. Ultraviolet disinfection triggered minimal bacterial or genes reduction, while among advanced treatments, UF+RO caused the highest, and NTP the lowest.</div><div>Principal component analysis suggested significant associations between antibiotic resistance (n = 32) and genetic recombination elements (n = 12) and predominant bacterial families in raw wastewater (<em>Aeromonadaceae</em>, <em>Moraxellaceae</em>, <em>Campylobacteraceae</em>, <em>Lachnospiraceae</em>). For predominant freshwater families (<em>Comamonadaceae</em>, <em>Chitinophagaceae</em>, <em>Flavobacteriaceae</em>) no significant associations were observed. Freshwater differed from UF-treated water by a lower antibiotic resistance abundance, higher bacterial richness (∼4000 vs.1200 operational taxonomic units) and distinct predominant families - <em>Alcaligenaceae</em>, <em>Sphingomonadaceae</em>, <em>Chitinophagaceae</em>, and <em>Microbacteriaceae</em> in UF water. The findings underscore the critical role of secondary/post-secondary treatments in shaping resistance and community profiles and suggest that advanced treatment should balance water quality with bacterial diversity preservation for sustainable reuse.</div></div>","PeriodicalId":15759,"journal":{"name":"Journal of Environmental Chemical Engineering","volume":"13 3","pages":"Article 116172"},"PeriodicalIF":7.4000,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Environmental Chemical Engineering","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2213343725008681","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Ideally, wastewater treatment aims to produce water indistinguishable from freshwater, especially for reuse. This study evaluated bacterial community and antibiotic resistance variations throughout treatment and benchmarked these with freshwater sources. Samples collected from six points of a full-scale wastewater treatment plant, pilot-scale advanced treatment options (non-thermal plasma - NTP, ultrafiltration - UF, UF followed by reverse osmosis- UF+RO), two rivers and a borehole were analyzed for quality parameters (BOD5, TSS, turbidity, Escherichia coli), antibiotic resistance genes (quantitative PCR), class 1 integron variable region composition (Oxford Nanopore sequencing), and bacterial community composition (16S rRNA Illumina sequencing).
Secondary treatment followed by sand filters and coagulants caused the highest reduction (∼2 log-unit/volume) of all analyzed parameters and the sharpest reduction of diversity of antibiotic resistance genes within class 1 integrons’ variable region. Ultraviolet disinfection triggered minimal bacterial or genes reduction, while among advanced treatments, UF+RO caused the highest, and NTP the lowest.
Principal component analysis suggested significant associations between antibiotic resistance (n = 32) and genetic recombination elements (n = 12) and predominant bacterial families in raw wastewater (Aeromonadaceae, Moraxellaceae, Campylobacteraceae, Lachnospiraceae). For predominant freshwater families (Comamonadaceae, Chitinophagaceae, Flavobacteriaceae) no significant associations were observed. Freshwater differed from UF-treated water by a lower antibiotic resistance abundance, higher bacterial richness (∼4000 vs.1200 operational taxonomic units) and distinct predominant families - Alcaligenaceae, Sphingomonadaceae, Chitinophagaceae, and Microbacteriaceae in UF water. The findings underscore the critical role of secondary/post-secondary treatments in shaping resistance and community profiles and suggest that advanced treatment should balance water quality with bacterial diversity preservation for sustainable reuse.
期刊介绍:
The Journal of Environmental Chemical Engineering (JECE) serves as a platform for the dissemination of original and innovative research focusing on the advancement of environmentally-friendly, sustainable technologies. JECE emphasizes the transition towards a carbon-neutral circular economy and a self-sufficient bio-based economy. Topics covered include soil, water, wastewater, and air decontamination; pollution monitoring, prevention, and control; advanced analytics, sensors, impact and risk assessment methodologies in environmental chemical engineering; resource recovery (water, nutrients, materials, energy); industrial ecology; valorization of waste streams; waste management (including e-waste); climate-water-energy-food nexus; novel materials for environmental, chemical, and energy applications; sustainability and environmental safety; water digitalization, water data science, and machine learning; process integration and intensification; recent developments in green chemistry for synthesis, catalysis, and energy; and original research on contaminants of emerging concern, persistent chemicals, and priority substances, including microplastics, nanoplastics, nanomaterials, micropollutants, antimicrobial resistance genes, and emerging pathogens (viruses, bacteria, parasites) of environmental significance.