1
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Guo B, Frigon D. Cellular RNA levels define heterotrophic substrate-uptake rate sub-guilds in activated sludge microbial communities. Interface Focus 2023; 13:20220080. [PMID: 37303744 PMCID: PMC10251117 DOI: 10.1098/rsfs.2022.0080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 01/23/2023] [Indexed: 06/13/2023] Open
Abstract
A heterotrophic-specialist model was proposed previously to divide wastewater treatment plant (WWTP) heterotrophs into sub-guilds of consumers of readily or slowly degradable substrates (RDS or SDS, respectively). The substrate degradation rate model coupled to metabolic considerations predicted that RNA and polyhydroxyalkanoate (PHA) levels would be positively correlated in the activated sludge communities with high RNA and PHA occurring in RDS-consumers, and low RNA with no PHA accumulation occurring in SDS-consumers because their external substrates are always present. This prediction was verified in previous studies and in the current one. Thus, RNA and PHA levels were used as biomarkers of the RDS- and SDS-consumer sub-guilds for cell sorting using flow cytometry of samples from three WWTPs. Subsequently, 16S rRNA gene amplicon sequencing revealed that the sorted groups were highly similar over time and among WWTPs, and demonstrated a clear segregation by RNA levels. Predicted ecophysiological traits based on 16S rRNA phylogeny suggested that the high-RNA population showed RDS-consumer traits such as higher rrn copy numbers per genome. Using a mass-flow immigration model, it appeared that the high-RNA populations exhibited high immigration rates more frequently than low-RNA populations, but the differences in frequencies were less with increasing solids residence times.
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Affiliation(s)
- Bing Guo
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, Canada H3A 0C3
- Centre for Environmental Health and Engineering (CEHE), Department of Civil and Environmental Engineering, University of Surrey, Guildford GU2 7XH, UK
| | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, Canada H3A 0C3
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2
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Rioux MD, Guillemette F, Lemarchand K, Doiron K, Lemay JF, Maere T, Dolcé P, Quessy P, Abonnenc N, Vanrolleghem PA, Frigon D. Wastewater-based epidemiology: the crucial role of viral shedding dynamics in small communities. Front Public Health 2023; 11:1141837. [PMID: 37601171 PMCID: PMC10433918 DOI: 10.3389/fpubh.2023.1141837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 06/30/2023] [Indexed: 08/22/2023] Open
Abstract
Background Wastewater surveillance (WWS) of pathogens is a rapidly evolving field owing to the 2019 coronavirus disease pandemic, which brought about a paradigm shift in public health authorities for the management of pathogen outbreaks. However, the interpretation of WWS in terms of clinical cases remains a challenge, particularly in small communities where large variations in pathogen concentrations are routinely observed without a clear relation to clinical incident cases. Methods Results are presented for WWS from six municipalities in the eastern part of Canada during the spring of 2021. We developed a numerical model based on viral kinetics reduction functions to consider both prevalent and incident cases to interpret the WWS data in light of the reported clinical cases in the six surveyed communities. Results The use of the proposed numerical model with a viral kinetics reduction function drastically increased the interpretability of the WWS data in terms of the clinical cases reported for the surveyed community. In line with our working hypothesis, the effects of viral kinetics reduction modeling were more important in small communities than in larger communities. In all but one of the community cases (where it had no effect), the use of the proposed numerical model led to a change from a +1.5% (for the larger urban center, Quebec City) to a +48.8% increase in the case of a smaller community (Drummondville). Conclusion Consideration of prevalent and incident cases through the proposed numerical model increases the correlation between clinical cases and WWS data. This is particularly the case in small communities. Because the proposed model is based on a biological mechanism, we believe it is an inherent part of any wastewater system and, hence, that it should be used in any WWS analysis where the aim is to relate WWS measurement to clinical cases.
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Affiliation(s)
- Marc-Denis Rioux
- Department of Mathematics and Engineering, Université du Québec à Rimouski, Quebec, QC, Canada
| | - François Guillemette
- Department of Environmental Science, Université du Québec à Trois-Rivière, Quebec, QC, Canada
| | - Karine Lemarchand
- Institut des Sciences de la Mer, Université du Québec à Rimouski, Quebec, QC, Canada
| | - Kim Doiron
- Northern Institute for Research in Environment and Occupational Health and Safety, Quebec, QC, Canada
| | - Jean-François Lemay
- Centre National en Électrochimie et Technologies Environnementales, Cegep of Shawinigan, Quebec, QC, Canada
| | - Thomas Maere
- modelEAU, Département de génie civil et de génie des eaux, Université Laval, Quebec, QC, Canada
| | - Patrick Dolcé
- Centre Intégré de Santé et de services sociaux du Bas-Saint-Laurent, Quebec, QC, Canada
| | - Patrik Quessy
- Centre National en Électrochimie et Technologies Environnementales, Cegep of Shawinigan, Quebec, QC, Canada
| | - Nanouk Abonnenc
- Centre National en Électrochimie et Technologies Environnementales, Cegep of Shawinigan, Quebec, QC, Canada
| | - Peter A. Vanrolleghem
- modelEAU, Département de génie civil et de génie des eaux, Université Laval, Quebec, QC, Canada
| | - Dominic Frigon
- Department of Civil Engineering, McGill University, Quebec, QC, Canada
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3
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Manoukian L, Stein RS, Correa JA, Frigon D, Omelon S. Short-chain polyphosphates: Extraction effects on migration and size estimation of Saccharomyces cerevisiae extracts with polyacrylamide gel electrophoresis. Electrophoresis 2023; 44:1197-1205. [PMID: 37353918 DOI: 10.1002/elps.202300055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/09/2023] [Accepted: 05/12/2023] [Indexed: 06/25/2023]
Abstract
Polyacrylamide gel electrophoresis is commonly used to characterize the chain length of polyphosphates (polyP), more generally called condensed phosphates. After separation, nonradioactive, optical polyP staining is limited to chain lengths greater than 15PO 3 - ${\rm{PO}}_3^ - $ monomers with toluidine blue or 4',6-diamidino-2-phenylindole. PolyP chain lengths longer than 62PO 3 - $\;{\rm{PO}}_3^ - $ monomers were correlated to the shortest DNA ladders. In this study, synthetic linear polyPs (Sigma-Aldrich "Type 45", estimated mean length of 45PO 3 - ${\rm{PO}}_3^ - $ monomers), trimetaphosphate (trimetaP: 3PO 3 - ${\rm{PO}}_3^ - $ ring), tripolyphosphate (tripolyP), pyrophosphate (PPi ), and inorganic orthophosphate (o-Pi ) were visualized after separation by an in situ hydrolytic degradation process to o-Pi that was subsequently stained with methyl green. Statistically insignificant migration reduction of synthetic short-chain polyP after perchloric acid or phenol-chloroform extraction was confirmed with the Friedman test. 31 P diffusion-ordered NMR spectroscopy confirmed that extraction also reduced PPi diffusivity by <10%. Linear regression between the Rf peak migration value and the logarithm of synthetic polyP molecular weights enabled estimation of extracted polyP chain lengths from 2 to 45PO 3 - ${\rm{PO}}_3^ - $ monomers. Linear polyP extracts from Saccharomyces cerevisiae grown in aerobic conditions were generally shorter than extracts cultured in anaerobic conditions. Extractions from both aerobic and anaerobic S. cerevisiae included tripolyP and o-Pi , but no PPi .
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Affiliation(s)
- Lori Manoukian
- Department of Mining and Materials Engineering, McGill University, Montreal, Quebec, Canada
| | - Robin S Stein
- Department of Chemistry, McGill University, Montreal, Quebec, Canada
| | - José A Correa
- Department of Mathematics and Statistics, McGill University, Montreal, Quebec, Canada
| | - Dominic Frigon
- Department of Civil Engineering, McGill University, Montreal, Quebec, Canada
| | - Sidney Omelon
- Department of Mining and Materials Engineering, McGill University, Montreal, Quebec, Canada
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4
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Yin X, Chen X, Jiang XT, Yang Y, Li B, Shum MHH, Lam TTY, Leung GM, Rose J, Sanchez-Cid C, Vogel TM, Walsh F, Berendonk TU, Midega J, Uchea C, Frigon D, Wright GD, Bezuidenhout C, Picão RC, Ahammad SZ, Nielsen PH, Hugenholtz P, Ashbolt NJ, Corno G, Fatta-Kassinos D, Bürgmann H, Schmitt H, Cha CJ, Pruden A, Smalla K, Cytryn E, Zhang Y, Yang M, Zhu YG, Dechesne A, Smets BF, Graham DW, Gillings MR, Gaze WH, Manaia CM, van Loosdrecht MCM, Alvarez PJJ, Blaser MJ, Tiedje JM, Topp E, Zhang T. Toward a Universal Unit for Quantification of Antibiotic Resistance Genes in Environmental Samples. Environ Sci Technol 2023. [PMID: 37310875 DOI: 10.1021/acs.est.3c00159] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Surveillance of antibiotic resistance genes (ARGs) has been increasingly conducted in environmental sectors to complement the surveys in human and animal sectors under the "One-Health" framework. However, there are substantial challenges in comparing and synthesizing the results of multiple studies that employ different test methods and approaches in bioinformatic analysis. In this article, we consider the commonly used quantification units (ARG copy per cell, ARG copy per genome, ARG density, ARG copy per 16S rRNA gene, RPKM, coverage, PPM, etc.) for profiling ARGs and suggest a universal unit (ARG copy per cell) for reporting such biological measurements of samples and improving the comparability of different surveillance efforts.
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Affiliation(s)
- Xiaole Yin
- Environmental Microbiome Engineering and Biotechnology Laboratory, Center for Environmental Engineering Research, Department of Civil Engineering, The University of Hong Kong, Pokfulam, 99077 Hong Kong, China
| | - Xi Chen
- Environmental Microbiome Engineering and Biotechnology Laboratory, Center for Environmental Engineering Research, Department of Civil Engineering, The University of Hong Kong, Pokfulam, 99077 Hong Kong, China
| | - Xiao-Tao Jiang
- Microbiome Research Centre, St George and Sutherland Clinical School, University of New South Wales, 2052 Sydney, Australia
| | - Ying Yang
- School of Marine Sciences, Sun Yat-sen University, 519082 Zhuhai, China
| | - Bing Li
- State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, Tsinghua Shenzhen International Graduate School, Tsinghua University, F518055 Shenzhen, China
| | - Marcus Ho-Hin Shum
- State Key Laboratory of Emerging Infectious Diseases, School of Public Health, The University of Hong Kong, Pokfulam, 999077 Hong Kong, China
| | - Tommy T Y Lam
- State Key Laboratory of Emerging Infectious Diseases, School of Public Health, The University of Hong Kong, Pokfulam, 999077 Hong Kong, China
| | - Gabriel M Leung
- Laboratory of Data Discovery for Health, Hong Kong Science & Technology Parks, New Territories, 99077 Hong Kong, China
| | - Joan Rose
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, 48824 Michigan, United States
| | - Concepcion Sanchez-Cid
- Environmental Microbial Genomics, CNRS UMR 5005 Laboratoire Ampère, École Centrale de Lyon, Université Claude Bernard Lyon1, Université de Lyon, 69130 Écully, France
| | - Timothy M Vogel
- Environmental Microbial Genomics, CNRS UMR 5005 Laboratoire Ampère, École Centrale de Lyon, Université Claude Bernard Lyon1, Université de Lyon, 69130 Écully, France
| | - Fiona Walsh
- Department of Biology, Maynooth University, Maynooth, R51 Co. Kildare, Ireland
| | - Thomas U Berendonk
- Faculty of Environmental Sciences, Technische Universität Dresden, Institute for Hydrobiology, 01217 Dresden, Germany
| | | | | | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, H3A 0C3 Quebec, Canada
| | - Gerard D Wright
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, L8N 3Z5 Ontario, Canada
| | - Carlos Bezuidenhout
- Unit for Environmental Sciences and Management (UESM)-Microbiology, North-West University, 2531 Potchefstroom, South Africa
| | - Renata C Picão
- Medical Microbiology Department, Paulo de Góes Microbiology Institute of the Federal University of Rio de Janeiro, 21941-902 Rio de Janeiro, Brazil
| | - Shaikh Z Ahammad
- Department of Biochemical Engineering & Biotechnology, Indian Institute of Technology Delhi, Hauz Khas, 110016 New Delhi, India
| | - Per Halkjær Nielsen
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9210 Aalborg, Denmark
| | - Philip Hugenholtz
- School of Chemistry and Molecular Biosciences, Australian Centre for Ecogenomics, The University of Queensland, Brisbane, 4072 Queensland, Australia
| | - Nicholas J Ashbolt
- Faculty of Science and Engineering, Southern Cross University, Bilinga, 4225 Queensland, Australia
| | - Gianluca Corno
- Molecular Ecology Group (MEG), Water Research Institute, National Research Council of Italy (CNR-IRSA), 28922 Verbania, Italy
| | - Despo Fatta-Kassinos
- Department of Civil and Environmental Engineering and Nireas International Water Research Center, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus
| | - Helmut Bürgmann
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 6047 Kastanienbaum, Switzerland
| | - Heike Schmitt
- Centre for Zoonoses and Environmental Microbiology-Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), 3721 Bilthoven, The Netherlands
- Department of Biotechnology, Delft University of Technology, 2628 Delft, the Netherlands
| | - Chang-Jun Cha
- Department of Systems Biotechnology and Center for Antibiotic Resistome, Chung-Ang University, 17546 Anseong, Republic of Korea
| | - Amy Pruden
- The Charles Edward Via, Jr., Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, 24060 Virginia, United States
| | - Kornelia Smalla
- Julius Kühn Institute (JKI) Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, 38104 Braunschweig, Germany
| | - Eddie Cytryn
- Department of Soil Chemistry, Plant Nutrition and Microbiology, Institute of Soil, Water and Environmental Sciences, The Volcani Institute, Agricultural Research Organization, 7528809 Rishon LeZion, Israel
| | - Yu Zhang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085 Beijing, China
| | - Min Yang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085 Beijing, China
| | - Yong-Guan Zhu
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 361021 Xiamen, China
| | - Arnaud Dechesne
- Department of Environmental and Resource Engineering, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Barth F Smets
- Department of Environmental and Resource Engineering, Technical University of Denmark, 2800 Lyngby, Denmark
| | - David W Graham
- School of Engineering, Newcastle University, NE1 7RU Newcastle Upon Tyne, U.K
| | - Michael R Gillings
- School of Natural Sciences and ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, 2109 New South Wales, Australia
| | - William H Gaze
- University of Exeter Medical School, Environment and Sustainability Institute, University of Exeter, TR10 9FE Cornwall, U.K
| | - Célia M Manaia
- Universidade Católica Portuguesa, CBQF-Centro de Biotecnologia e Química Fina-Laboratório Associado, Escola Superior de Biotecnologia, 4169-005 Porto, Portugal
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Pedro J J Alvarez
- Department of Civil and Environmental Engineering, Rice University, Houston, 77005 Texas, United States
| | - Martin J Blaser
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, 08854 New Jersey, United States
| | - James M Tiedje
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, 48824 Michigan, United States
| | - Edward Topp
- London Research and Development Centre (LRDC), Agriculture and Agri-Food Canada, London, N5V 4T3 Ontario, Canada
| | - Tong Zhang
- Environmental Microbiome Engineering and Biotechnology Laboratory, Center for Environmental Engineering Research, Department of Civil Engineering, The University of Hong Kong, Pokfulam, 99077 Hong Kong, China
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5
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Gibson C, Kraemer SA, Klimova N, Guo B, Frigon D. Antibiotic resistance gene sequencing is necessary to reveal the complex dynamics of immigration from sewers to activated sludge. Front Microbiol 2023; 14:1155956. [PMID: 37228381 PMCID: PMC10204801 DOI: 10.3389/fmicb.2023.1155956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/03/2023] [Indexed: 05/27/2023] Open
Abstract
Microbial community composition has increasingly emerged as a key determinant of antibiotic resistance gene (ARG) content. However, in activated sludge wastewater treatment plants (AS-WWTPs), a comprehensive understanding of the microbial community assembly process and its impact on the persistence of antimicrobial resistance (AMR) remains elusive. An important part of this process is the immigration dynamics (or community coalescence) between the influent and activated sludge. While the influent wastewater contains a plethora of ARGs, the persistence of a given ARG depends initially on the immigration success of the carrying population, and the possible horizontal transfer to indigenously resident populations of the WWTP. The current study utilized controlled manipulative experiments that decoupled the influent wastewater composition from the influent microbial populations to reveal the fundamental mechanisms involved in ARG immigration between sewers and AS-WWTP. A novel multiplexed amplicon sequencing approach was used to track different ARG sequence variants across the immigration interface, and droplet digital PCR was used to quantify the impact of immigration on the abundance of the targeted ARGs. Immigration caused an increase in the abundance of over 70 % of the quantified ARGs. However, monitoring of ARG amplicon sequence variants (ARG-ASVs) at the immigration interface revealed various immigration patterns such as (i) suppression of the indigenous mixed liquor ARG-ASV by the immigrant, or conversely (ii) complete immigration failure of the influent ARG-ASV. These immigration profiles are reported for the first time here and highlight the crucial information that can be gained using our novel multiplex amplicon sequencing techniques. Future studies aiming to reduce AMR in WWTPs should consider the impact of influent immigration in process optimisation and design.
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Affiliation(s)
- Claire Gibson
- Department of Civil Engineering and Applied Mechanics, McGill University, Montreal, QC, Canada
| | - Susanne A. Kraemer
- Department of Civil Engineering and Applied Mechanics, McGill University, Montreal, QC, Canada
- Aquatic Contaminants Research Division, Environment and Climate Change Canada, Montreal, QC, Canada
| | - Natalia Klimova
- Department of Civil Engineering and Applied Mechanics, McGill University, Montreal, QC, Canada
| | - Bing Guo
- Department of Civil and Environmental Engineering, Centre for Environmental Health and Engineering, University of Surrey, Surrey, United Kingdom
| | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, Montreal, QC, Canada
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6
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Manoukian L, Correa JA, Stein RS, Frigon D, Omelon S. Extraction processes reduce polyphosphate ion migration, dispersion and diffusion as detected with gel electrophoresis and
31
P DOSY NMR. Electrophoresis 2022; 43:2014-2022. [DOI: 10.1002/elps.202100364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 07/10/2022] [Accepted: 08/08/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Lori Manoukian
- Department of Mining and Materials Engineering McGill University Montreal Quebec Canada
| | - José A. Correa
- Department of Mathematics and Statistics McGill University Montreal Quebec Canada
| | - Robin S. Stein
- Department of Chemistry McGill University Montreal Quebec Canada
| | - Dominic Frigon
- Department of Civil Engineering McGill University Montreal Quebec Canada
| | - Sidney Omelon
- Department of Mining and Materials Engineering McGill University Montreal Quebec Canada
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7
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Navab-Daneshmand T, Guo B, Gehr R, Frigon D. Impact of pH and removed filtrate on E. coli regrowth and microbial community during storage of electro-dewatered biosolids. Sci Total Environ 2022; 814:152544. [PMID: 34952058 DOI: 10.1016/j.scitotenv.2021.152544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/15/2021] [Accepted: 12/15/2021] [Indexed: 06/14/2023]
Abstract
Residual biosolids can be land applied if they meet microbiological requirements at the time of application. Electro-dewatering technology is shown to reduce biosolids bacterial counts to detection limits with little potential for bacterial regrowth during incubations. Here, we investigated the impacts on Escherichia coli regrowth and microbial communities of biosolids pH, removed nutrients via the filtrate, and inhibitory compounds produced in electro-dewatered biosolids. Findings suggest pH as the primary mechanism impacting E. coli regrowth in electro-dewatered biosolids. Propidium monoazide treatments were effective at removing DNA from dead cells, based on the removal of obligate anaerobes observed after anaerobic incubation. Analyses of high throughput sequenced data showed lower alpha-diversities associated with electro-dewatering treatment and incubation time. Moreover, biosolids pH and incubation period were the main factors contributing to the variations in microbial community compositions after incubation. Results highlight the role of electro-dewatered biosolids' low pH on inhibiting the regrowth of culturable bacteria as well as reducing the microbial community variance.
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Affiliation(s)
- Tala Navab-Daneshmand
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, 105 SW 26th St., Corvallis, OR 97331, USA; Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, Quebec H3A 0C3, Canada
| | - Bing Guo
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, Quebec H3A 0C3, Canada; Centre for Environmental Health and Engineering, Department of Civil and Environmental Engineering, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
| | - Ronald Gehr
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, Quebec H3A 0C3, Canada
| | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, Quebec H3A 0C3, Canada.
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Quintela-Baluja M, Frigon D, Abouelnaga M, Jobling K, Romalde JL, Gomez Lopez M, Graham DW. Dynamics of integron structures across a wastewater network - Implications to resistance gene transfer. Water Res 2021; 206:117720. [PMID: 34673462 PMCID: PMC8626773 DOI: 10.1016/j.watres.2021.117720] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/14/2021] [Accepted: 09/24/2021] [Indexed: 05/19/2023]
Abstract
Class 1 and other integrons are common in wastewater networks, often being associated with antibiotic resistance genes (ARGs). However, the importance of different integron structures in ARG transfer within wastewater systems has only been implied, especially between community and hospital sources, among wastewater treatment plant compartments, and in receiving waters. This uncertainty is partly because current clinical class 1 integron qPCR assays (i.e., that target human-impacted structures, i.e., clintI1) poorly delineate clintI1 from non-impacted class 1 integron structures. They also say nothing about their ARG content. To fill these technical gaps, new real-time qPCR assays were developed for "impacted" class 1 structures (called aint1; i.e., anthropogenic class 1 integrons) and empty aint1 structures (i.e., carry no ARGs; called eaint1). The new assays and other integron assays then were used to examine integron dynamics across a wastewater network. 16S metagenomic sequencing also was performed to characterise associated microbiomes. aint1 abundances per bacterial cell were about 10 times greater in hospital wastewaters compared with other compartments, suggesting aint1 enrichment with ARGs in hospital sources. Conversely, the relative abundance of eaint1 structures were over double in recycled activated sludge compared with other compartments, except receiving waters (RAS; ∼30% of RAS class 1 structures did not carry ARGs). Microbiome analysis showed that human-associated bacterial taxa with mobile integrons also differed in RAS and river sediments. Further, class 1 integrons in RAS bacteria appear to have released ARGs, whereas hospital bacteria have accumulated ARGs. Results show that quantifying integron dynamics can help explain where ARG transfer occurs in wastewater networks, and should be considered in future studies on antibiotic resistance in the environment.
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Affiliation(s)
- Marcos Quintela-Baluja
- School of Engineering, Cassie Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; Department of Analytical Chemistry, Nutrition and Bromatology, University of Santiago de Compostela, Spain.
| | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, Montréal (QC), Canada
| | - M Abouelnaga
- Department of Analytical Chemistry, School of Veterinary Sciences, Suez Canel University, Ismailia, Egypt
| | - Kelly Jobling
- School of Engineering, Cassie Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Jesús L Romalde
- Departamento de Microbiología y Parasitología, CIBUS-Facultad de Biología & Institute CRETUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | | | - David W Graham
- School of Engineering, Cassie Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
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9
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Bürgmann H, Frigon D, H Gaze W, M Manaia C, Pruden A, Singer AC, F Smets B, Zhang T. Water and sanitation: an essential battlefront in the war on antimicrobial resistance. FEMS Microbiol Ecol 2019; 94:5033400. [PMID: 29878227 DOI: 10.1093/femsec/fiy101] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 05/06/2018] [Indexed: 12/15/2022] Open
Abstract
Water and sanitation represent a key battlefront in combatting the spread of antimicrobial resistance (AMR). Basic water sanitation infrastructure is an essential first step towards protecting public health, thereby limiting the spread of pathogens and the need for antibiotics. AMR presents unique human health risks, meriting new risk assessment frameworks specifically adapted to water and sanitation-borne AMR. There are numerous exposure routes to AMR originating from human waste, each of which must be quantified for its relative risk to human health. Wastewater treatment plants play a vital role in centralized collection and treatment of human sewage, but there are numerous unresolved issues in terms of the microbial ecological processes occurring within them and the extent to which they attenuate or amplify AMR. Research is needed to advance understanding of the fate of resistant bacteria and antibiotic resistance genes in various waste management systems, depending on the local constraints and intended reuse applications. World Health Organization and national AMR action plans would benefit from a more holistic 'One Water' understanding. In this article we provide a framework for research, policy, practice and public engagement aimed at limiting the spread of AMR from water and sanitation in low-, medium- and high-income countries.
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Affiliation(s)
- Helmut Bürgmann
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Seestrasse 79, Kastanienbaum, 6047, Switzerland
| | - Dominic Frigon
- Department of Civil Engineering, McGill University, 817 Sherbrooke Street West, Room 492, Montreal, Quebec, H3A 0C3, Canada
| | - William H Gaze
- European Center for Environment and Human Health, University of Exeter Medical School, Truro, TR1 3HD, UK
| | - Célia M Manaia
- Universidade Católica Portuguesa, CBFQ- Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Robão Vital, Apartado 2511, 4202-401 Porto, Portugal
| | - Amy Pruden
- Via Department of Civil & Environmental Engineering, Virginia Tech, 418 Durham Hall, 1145 Perry Street, Blacksburg, Virginia, 24061, USA
| | - Andrew C Singer
- Centre for Ecology & Hydrology, NERC Centre for Ecology & Hydrology, Maclean Building, Benson Lane, Wallingford, OX10 8BB, UK
| | - Barth F Smets
- Department of Environmental Engineering, Technical University of Denmark, Miljøvej, DK 2800 Kgs., Lyngby, Denmark
| | - Tong Zhang
- Department of Civil Engineering, The University of Hong Kong, Environmental Biotechnology Laboratory, The University of Hong Kong, Hong Kong
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Guo B, Liu C, Gibson C, Frigon D. Wastewater microbial community structure and functional traits change over short timescales. Sci Total Environ 2019; 662:779-785. [PMID: 30708293 DOI: 10.1016/j.scitotenv.2019.01.207] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 12/31/2018] [Accepted: 01/16/2019] [Indexed: 05/06/2023]
Abstract
Wastewater contains microorganisms coming from various sources, e.g. feces discharges, soil infiltrations and sewer biofilms and sediments. The primary objective of this work was to determine if end-of-pipe wastewater microbial community structures exhibits short-timescale variation, and assess possible microbial origins. To this end, we measured hourly physicochemical characteristics of wastewater influent for 2 days and analyzed the microbial community at 4-h intervals using 16S rRNA gene amplicon sequencing. Results showed large variations in the microbial community composition at phylum and genus levels, i.e. Proteobacteria ranged from 44 to 63% of the total relative abundance and Arcobacter ranged from 11 to 22%. Diurnal patterns were observed in the alpha-diversity, beta-diversity and the prevalence of several taxa. Wastewater physicochemical characteristics explained 61% of the total microbial community variance by Canonical Correspondence Analysis (CCA), with flow rate being the main explanatory variable exhibiting a clear diurnal profile. Comparison with public databases using closed reference OTUs revealed that only 7.3% of the sequences were shared with human gut microbiota and 21.7% with soil microbiota, the majority being from the sewer biofilms and sediments. The functional trait, weighted average ribosomal RNA operon (rrn) copy number per genome, was found to be relatively high in the wastewater microbiota (average 3.6, soil 2.1, and human gut 2.6) and significantly correlated with flow, inferring active microbial enrichments in the sewer. The prevalence of Methylophilaceae, methanol oxidation genes and denitrification genes were related to high influent methanol and NO3- concentration in the influent wastewater. These functional organisms and genes indicate important carbon and nutrient removal related functions in the sewer. Together, the observed temporal patterns of the microbial community and functional traits suggest that high wastewater flow causes greater transport of active sewer microorganisms which are functionally important.
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Affiliation(s)
- Bing Guo
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada
| | - Chenxiao Liu
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada
| | - Claire Gibson
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada
| | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada.
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Guo B, Manchester M, Luby T, Frigon D. Composition of heterotrophic specialized sub-guilds defined by a positive RNA and polyhydroxyalkanoate correlation in activated sludge. Water Res 2018; 144:561-571. [PMID: 30081336 DOI: 10.1016/j.watres.2018.07.059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 06/20/2018] [Accepted: 07/24/2018] [Indexed: 06/08/2023]
Abstract
Microbial heterotrophic guilds in activated sludge wastewater treatment systems have complex population structures and functions. A previously proposed heterotrophic-specialist model states that heterotrophs consist of sub-guilds specialized in consuming specific classes of compounds, either readily degradable substrate (RDS) or slowly degradable substrate (SDS) according to current mathematical modeling practices for wastewater treatment processes. It follows from metabolic considerations that the levels of RNA and polyhydroxyalkanoate (PHA) are correlated for strains of the same species growing in different environments; a conjecture previously tested. The proposed classification of heterotrophs into RDS or SDS consumers predicts that the same correlation would also be found across heterotrophic species in conventional activated sludge systems; this prediction was tested in the current study. The positive correlation between the RNA and PHA levels was observed in 9 conventional activated sludge plants in two independent sampling times and it was also found stable over a 6-month regular sampling period at one of these plants. Together, these results imply that the levels of RNA and PHA can be used to define heterotrophic-specialist sub-guilds. In order to gain insight in the species composition of the defined sub-guilds, flow cytometry cell sorting was used to further analyze one of the activated sludge samples. Four sorted sub-samples were obtained (high-RNA/high-PHA, low-RNA/high-PHA, high-RNA/low-PHA, and low-RNA/low-PHA), and the phylogenetic composition of each was determined using 16S rRNA gene amplicon pyrosequencing. Heterotrophic genera were identified across 12 phyla, and their representation in each sorted sub-sample showed that the high-RNA/high-PHA and low-RNA/low-PHA groups were most dissimilar. The enriched genera in these sorted sub-samples are suggested to represent the composition of heterotrophic-specialized sub-guilds defined by the kinetics of substrate consumption.
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Affiliation(s)
- Bing Guo
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, H3A 0C3, Canada
| | - Marie Manchester
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, H3A 0C3, Canada; Story Environmental and Geomatics, 332 Main St, Haileybury, Ontario, P0J 1K0, Canada
| | - Theresa Luby
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, H3A 0C3, Canada; Stantec, 200-325 25, Street SE, Calgary, Alberta, T2A 7H8, Canada
| | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, H3A 0C3, Canada.
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12
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Tajparast M, Frigon D. Predicting the accumulation of storage compounds by Rhodococcus jostii RHA1 in the feast-famine growth cycles using genome-scale flux balance analysis. PLoS One 2018; 13:e0191835. [PMID: 29494607 PMCID: PMC5832212 DOI: 10.1371/journal.pone.0191835] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 01/11/2018] [Indexed: 01/18/2023] Open
Abstract
Feast-famine cycles in biological wastewater resource recovery systems select for bacterial species that accumulate intracellular storage compounds such as poly-β-hydroxybutyrate (PHB), glycogen, and triacylglycerols (TAG). These species survive better the famine phase and resume rapid substrate uptake at the beginning of the feast phase faster than microorganisms unable to accumulate storage. However, ecophysiological conditions favouring the accumulation of either storage compounds remain to be clarified, and predictive capabilities need to be developed to eventually rationally design reactors producing these compounds. Using a genome-scale metabolic modelling approach, the storage metabolism of Rhodococcus jostii RHA1 was investigated for steady-state feast-famine cycles on glucose and acetate as the sole carbon sources. R. jostii RHA1 is capable of accumulating the three storage compounds (PHB, TAG, and glycogen) simultaneously. According to the experimental observations, when glucose was the substrate, feast phase chemical oxygen demand (COD) accumulation was similar for the three storage compounds; when acetate was the substrate, however, PHB accumulation was 3 times higher than TAG accumulation and essentially no glycogen was accumulated. These results were simulated using the genome-scale metabolic model of R. jostii RHA1 (iMT1174) by means of flux balance analysis (FBA) to determine the objective functions capable of predicting these behaviours. Maximization of the growth rate was set as the main objective function, while minimization of total reaction fluxes and minimization of metabolic adjustment (environmental MOMA) were considered as the sub-objective functions. The environmental MOMA sub-objective performed better than the minimization of total reaction fluxes sub-objective function at predicting the mixture of storage compounds accumulated. Additional experiments with 13C-labelled bicarbonate (HCO3−) found that the fluxes through the central metabolism reactions during the feast phases were similar to the ones during the famine phases on acetate due to similarity in the carbon sources in the feast and famine phases (i.e., acetate and poly-β-hydroxybutyrate, respectively); this suggests that the environmental MOMA sub-objective function could be used to analyze successive environmental conditions such as the feast and famine cycles while the metabolically similar carbon sources are taken up by microorganisms.
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Affiliation(s)
- Mohammad Tajparast
- Microbial Community Engineering Laboratory, Department of Civil Engineering and Applied Mechanics, McGill University, Montreal, Quebec, Canada
| | - Dominic Frigon
- Microbial Community Engineering Laboratory, Department of Civil Engineering and Applied Mechanics, McGill University, Montreal, Quebec, Canada
- * E-mail:
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Isazadeh S, Jauffur S, Frigon D. Bacterial community assembly in activated sludge: mapping beta diversity across environmental variables. Microbiologyopen 2016; 5:1050-1060. [PMID: 27762086 PMCID: PMC5221439 DOI: 10.1002/mbo3.388] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 05/26/2016] [Accepted: 05/30/2016] [Indexed: 11/06/2022] Open
Abstract
Effect of ecological variables on community assembly of heterotrophic bacteria at eight full-scale and two pilot-scale activated sludge wastewater treatment plants (AS-WWTPs) were explored by pyrosequencing of 16S rRNA gene amplicons. In total, 39 samples covering a range of abiotic factors spread over space and time were analyzed. A core bacterial community of 24 families detected in at least six of the eight AS-WWTPs was defined. In addition to the core families, plant-specific families (observed at <50% AS-WWTPs) were found to be also important in the community structure. Observed beta diversity was partitioned with respect to ecological variables. Specifically, the following variables were considered: influent wastewater characteristics, season (winter vs. summer), process operations (conventional, oxidation ditch, and sequence batch reactor), reactor sizes (pilot-scale vs. full-scale reactors), chemical stresses defined by ozonation of return activated sludge, interannual variation, and geographical locations. Among the assessed variables, influent wastewater characteristics and geographical locations contributed more in explaining the differences between AS-WWTP bacterial communities with a maximum of approximately 26% of the observed variations. Partitioning of beta diversity is necessary to interpret the inherent variability in microbial community assembly and identify the driving forces at play in engineered microbial ecosystem.
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Affiliation(s)
- Siavash Isazadeh
- Department of Civil Engineering and Applied MechanicsMcGill UniversityMontrealQuebecCanada
- Present address: Life Sciences GroupAir Liquide Delaware Research & Technology CenterNewarkUSA
| | - Shameem Jauffur
- Department of Civil Engineering and Applied MechanicsMcGill UniversityMontrealQuebecCanada
| | - Dominic Frigon
- Department of Civil Engineering and Applied MechanicsMcGill UniversityMontrealQuebecCanada
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Tajparast M, Frigon D. Genome-scale metabolic model of Rhodococcus jostii RHA1 (iMT1174) to study the accumulation of storage compounds during nitrogen-limited condition. BMC Syst Biol 2015; 9:43. [PMID: 26248853 PMCID: PMC4528721 DOI: 10.1186/s12918-015-0190-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 07/28/2015] [Indexed: 11/20/2022]
Abstract
Background Rhodococcus jostii RHA1 growing on different substrates is capable of accumulating simultaneously three types of carbon storage compounds: glycogen, polyhydroxyalkanoates (PHA), and triacylglycerols (TAG). Under nitrogen-limited (N-limited) condition, the level of storage increases as is commonly observed for other bacteria. The proportion of each storage compound changes with substrate, but it remains unclear what modelling approach should be adopted to predict the relative composition of the mixture of the storage compounds. We analyzed the growth of R. jostii RHA1 under N-limited conditions using a genome-scale metabolic modelling approach to determine which global metabolic objective function could be used for the prediction. Results The R. jostii RHA1 model (iMT1174) produced during this study contains 1,243 balanced metabolites, 1,935 unique reactions, and 1,174 open reading frames (ORFs). Seven objective functions used with flux balance analysis (FBA) were compared for their capacity to predict the mixture of storage compounds accumulated after the sudden onset of N-limitation. Predictive abilities were determined using a Bayesian approach. Experimental data on storage accumulation mixture (glycogen, polyhydroxyalkanoates, and triacylglycerols) were obtained for batch cultures grown on glucose or acetate. The best FBA simulation results were obtained using a novel objective function for the N-limited condition which combined the maximization of the storage fluxes and the minimization of metabolic adjustments (MOMA) with the preceding non-limited conditions (max storage + environmental MOMA). The FBA solutions for the non-limited growth conditions were simply constrained by the objective function of growth rate maximization. Measurement of central metabolic fluxes by 13C-labelling experiments of amino acids further supported the application of the environmental MOMA principle in the context of changing environment. Finally, it was found that the quantitative predictions of the storage mixture during N-limited storage accumulation were fairly sensitive to the biomass composition, as expected. Conclusions The genome-scale metabolic model analysis of R. jostii RHA1 cultures suggested that the intracellular reaction flux profile immediately after the onset of N-limited condition are impacted by the values of the same fluxes during the period of non-limited growth. PHA turned out to be the main storage pool of the mixture in R. jostii RHA1. Electronic supplementary material The online version of this article (doi:10.1186/s12918-015-0190-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mohammad Tajparast
- Microbial Community Engineering Laboratory, Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, QC, H3A 0C3, Canada.
| | - Dominic Frigon
- Microbial Community Engineering Laboratory, Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, QC, H3A 0C3, Canada.
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15
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Abstract
Electro-dewatering (ED) is a novel technology to reduce the overall costs of residual biosolids processing, transport, and disposal. In this study, we investigated Joule heating and pH as parameters controlling the dewaterability limit, dewatering rate, and energy efficiency. Temperature-controlled electrodes revealed that Joule heating enhances water removal by increasing evaporation and electro-osmotic flow. High temperatures increased the dewatering rate, but had little impact on the dewaterability limit and energy efficiency. Analysis of horizontal layers after 15-min ED suggests electro-osmotic flow reversal, as evidenced by a shifting of the point of minimum moisture content from the anode toward the cathode. This flow reversal was also confirmed by the pH at the anode being below the isoelectric point, as ascertained by pH titration. The important role of pH on ED was further studied by adding acid/base solutions to biosolids prior to ED. An acidic pH reduced the biosolids charge while simultaneously increasing the dewatering efficiency. Thus, process optimization depends on trade-offs between speed and efficiency, according to physicochemical properties of the biosolids microstructure.
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Affiliation(s)
- Tala Navab-Daneshmand
- †Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada
| | - Raphaël Beton
- †Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada
| | - Reghan J Hill
- ‡Department of Chemical Engineering, McGill University, 3610 University Street, Montreal, Quebec H3A 0C5, Canada
| | - Dominic Frigon
- †Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada
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Navab-Daneshmand T, Enayet S, Gehr R, Frigon D. Bacterial pathogen indicators regrowth and reduced sulphur compounds' emissions during storage of electro-dewatered biosolids. Chemosphere 2014; 113:109-115. [PMID: 25065797 DOI: 10.1016/j.chemosphere.2014.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 04/03/2014] [Accepted: 04/04/2014] [Indexed: 06/03/2023]
Abstract
Electro-dewatering (ED) increases biosolids dryness from 10-15 to 30-50%, which helps wastewater treatment facilities control disposal costs. Previous work showed that high temperatures due to Joule heating during ED inactivate total coliforms to meet USEPA Class A biosolids requirements. This allows biosolids land application if the requirements are still met after the storage period between production and application. In this study, we examined bacterial regrowth and odour emissions during the storage of ED biosolids. No regrowth of total coliforms was observed in ED biosolids over 7d under aerobic or anaerobic incubations. To mimic on-site contamination during storage or transport, ED samples were seeded with untreated sludge. Total coliform counts decreased to detection limits after 4d in inoculated samples. Olfactometric analysis of ED biosolids odours showed that odour concentrations were lower compared to the untreated and heat-treated control biosolids. Furthermore, under anaerobic conditions, odorous reduced sulphur compounds (methanethiol, dimethyl sulphide and dimethyl disulphide) were produced by untreated and heat-treated biosolids, but were not detected in the headspaces above ED samples. The data demonstrate that ED provides advantages not only as a dewatering technique, but also for producing biosolids with lower microbial counts and odour levels.
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Affiliation(s)
- Tala Navab-Daneshmand
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada
| | - Samia Enayet
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada
| | - Ronald Gehr
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada
| | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, Quebec H3A 0C3, Canada.
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Isazadeh S, Ozcer PO, Frigon D. Microbial community structure of wastewater treatment subjected to high mortality rate due to ozonation of return activated sludge. J Appl Microbiol 2014; 117:587-96. [PMID: 24738966 DOI: 10.1111/jam.12523] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 03/24/2014] [Accepted: 04/07/2014] [Indexed: 11/30/2022]
Abstract
AIMS This study investigated the effects of return activated sludge (RAS) ozonation, on the bacterial community structure of pilot-scale wastewater treatment systems. METHODS AND RESULTS Two parallel activated sludge reactors were operated to treat real municipal wastewater for 98 days. The RAS of one of the reactors was subjected to increasing doses of ozone during the experimental period, which resulted in higher reduction in biosolids waste production and higher bacterial growth rate. The bacterial community structures were investigated by 16S rRNA gene amplicon high-throughput pyrosequencing and fluorescence in situ hybridization (FISH). The structures remained highly similar throughout the experiment despite the ozone treatment. Comparative analyses between pyrosequencing and FISH revealed clear discrepancies in the proportion of some bacterial populations. CONCLUSIONS The results suggest that RAS ozonation is not a main environmental factor structuring the community composition. Instead, the parallel drifts and slight convergence of the two community structures indicate that other environmental factors such as influent wastewater composition and temperature may be more important. Care should be exercised in interpreting the proportion of sequence reads as pyrosequencing may be biased as compared to FISH. SIGNIFICANCE AND IMPACT OF THE STUDY This study provides new insights on the importance of indiscriminate high mortality rates brought by external factors (here ozonation) on microbial community structures of activated sludge system.
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Affiliation(s)
- S Isazadeh
- Department of Civil Engineering and Applied Mechanics, McGill University, Montreal, QC, Canada
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Isazadeh S, Feng M, Urbina Rivas LE, Frigon D. New mechanistically based model for predicting reduction of biosolids waste by ozonation of return activated sludge. J Hazard Mater 2014; 270:160-168. [PMID: 24572272 DOI: 10.1016/j.jhazmat.2014.01.053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 01/18/2014] [Accepted: 01/29/2014] [Indexed: 06/03/2023]
Abstract
Two pilot-scale activated sludge reactors were operated for 98 days to provide the necessary data to develop and validate a new mathematical model predicting the reduction of biosolids production by ozonation of the return activated sludge (RAS). Three ozone doses were tested during the study. In addition to the pilot-scale study, laboratory-scale experiments were conducted with mixed liquor suspended solids and with pure cultures to parameterize the biomass inactivation process during exposure to ozone. The experiments revealed that biomass inactivation occurred even at the lowest doses, but that it was not associated with extensive COD solubilization. For validation, the model was used to simulate the temporal dynamics of the pilot-scale operational data. Increasing the description accuracy of the inactivation process improved the precision of the model in predicting the operational data.
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Affiliation(s)
- Siavash Isazadeh
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, QC, Canada H3A 0C3
| | - Min Feng
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, QC, Canada H3A 0C3
| | - Luis Enrique Urbina Rivas
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, QC, Canada H3A 0C3
| | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke Street West, Montreal, QC, Canada H3A 0C3.
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Biswal BK, Mazza A, Masson L, Gehr R, Frigon D. Impact of wastewater treatment processes on antimicrobial resistance genes and their co-occurrence with virulence genes in Escherichia coli. Water Res 2014; 50:245-253. [PMID: 24380739 DOI: 10.1016/j.watres.2013.11.047] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 11/29/2013] [Accepted: 11/30/2013] [Indexed: 06/03/2023]
Abstract
An increase in the frequency of antimicrobial resistance genes (ARGs) in bacteria including Escherichia coli could be a threat to public health. This study investigated the impact of activated sludge and physicochemical wastewater treatment processes on the prevalence of ARGs in E. coli isolates. In total, 719 E. coli were isolated from the influent and effluent (prior to disinfection) of two activated sludge and two physicochemical municipal treatment plants, and genotyped using DNA microarrays. Changes in the abundance of ARGs in the E. coli population were different for the two treatment processes. Activated sludge treatment did not change the prevalence of ARG-possessing E. coli but increased the abundance of ARGs in the E. coli genome while physicochemical treatment reduced both the prevalence of ARG-carrying E. coli as well as the frequency of ARGs in the E. coli genome. Most E. coli isolates from the four treatment plants possessed ARGs of multiple antimicrobial classes, mainly aminoglycoside, β-lactams, quinolone and tetracyclines. In addition these isolates harboured DNA insertion sequence elements including integrase and transposase. A significant positive association was found between the occurrence of ARGs and virulence genotypes.
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Affiliation(s)
- Basanta Kumar Biswal
- Department of Civil Engineering and Applied Mechanics, McGill University, Montréal, Québec H3A 0C3, Canada
| | - Alberto Mazza
- National Research Council of Canada, Montréal, Québec H4P 2R2, Canada
| | - Luke Masson
- National Research Council of Canada, Montréal, Québec H4P 2R2, Canada
| | - Ronald Gehr
- Department of Civil Engineering and Applied Mechanics, McGill University, Montréal, Québec H3A 0C3, Canada
| | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, Montréal, Québec H3A 0C3, Canada.
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20
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Jauffur S, Isazadeh S, Frigon D. Should activated sludge models consider influent seeding of nitrifiers? Field characterization of nitrifying bacteria. Water Sci Technol 2014; 70:1526-1532. [PMID: 25401317 DOI: 10.2166/wst.2014.407] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This study revealed the presence of nitrifying bacteria in influent municipal wastewaters reaching full-scale biological wastewater treatment plants. Respirometric assays showed that the influent nitrifiers were active following a 5- to 8-hour period of metabolic induction. Diversity analyses by pyrosequencing of functional gene PCR (polymerase chain reaction) amplicon suggested that the nitrifiers in the influent stream likely seeded activated sludge bioreactors since the most abundant operational taxonomic units in the influent and mixed liquor were the same. Based on the estimated seeding intensity of 0.3 g of nitrifiers per day per gram of nitrifiers already present, the absolute minimum solids retention time (SRT) was reduced by approximately 56% at 5 °C as compared to non-seeding conditions. This can have important repercussions on the design and sizing of bioreactors operating in cold climates and calls for a need to fine-tune process modelling by considering the contribution of autotrophic nitrifying biomass from municipal influent streams.
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Affiliation(s)
- Shameem Jauffur
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, Quebec. Canada H3A 0C3 E-mail:
| | - Siavash Isazadeh
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, Quebec. Canada H3A 0C3 E-mail:
| | - Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, Quebec. Canada H3A 0C3 E-mail:
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21
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Chang W, Akbari A, Snelgrove J, Frigon D, Ghoshal S. Biodegradation of petroleum hydrocarbons in contaminated clayey soils from a sub-arctic site: the role of aggregate size and microstructure. Chemosphere 2013; 91:1620-1626. [PMID: 23453601 DOI: 10.1016/j.chemosphere.2012.12.058] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 12/07/2012] [Accepted: 12/12/2012] [Indexed: 06/01/2023]
Abstract
This study investigates the extent of biodegradation of non-volatile petroleum hydrocarbons (C16-C34) and the associated microbial activity in predominant aggregate sizes during a pilot-scale biopile experiment conducted at 15 °C, with a clayey soil, from a crude oil-impacted site in northern Canada. The in situ aggregate microstructure was characterized by N2 adsorption and X-ray CT scanning. The soils in the nutrient (N)-amended and unamended biopile tanks were comprised of macroaggregates (>2 mm) and mesoaggregates (0.25-2 mm). Nutrient addition significantly enhanced petroleum hydrocarbon biodegradation in macroaggregates, but not in mesoaggregates. At the end of 65-d biopile experiment, 42% of the C16-C34 hydrocarbons were degraded in the nutrient-amended macroaggregates, compared to 13% in the mesoaggregates. Higher microbial activity in the macroaggregates of the nutrient amended biopile was inferred from a larger increase in extractable protein concentrations, compared to the other aggregates. Terminal Restriction Fragment Length Polymorphism (T-RFLP) of 16S rRNA genes showed that there was no selection of bacterial populations in any of the aggregates during biopile treatment, suggesting that the enhanced biodegradation in nutrient-amended macroaggregates was likely due to metabolic stimulation. X-ray micro CT scanning revealed that the number of pores wider than 4 μm, which would be easily accessible by bacteria, were an order of magnitude higher in macroaggregates. Also, N2 adsorption analyses showed that pore surface areas and pore volumes per unit weight were four to five-times larger, compared to the mesoaggregates. Thus the higher porosity microstructure in macroaggregates allowed greater hydrocarbon degradation upon biostimulation by nutrient addition and aeration.
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Affiliation(s)
- Wonjae Chang
- Department of Civil Engineering, McGill University, Montreal, Canada
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Frigon D, Biswal BK, Mazza A, Masson L, Gehr R. Biological and physicochemical wastewater treatment processes reduce the prevalence of virulent Escherichia coli. Appl Environ Microbiol 2013; 79:835-44. [PMID: 23160132 PMCID: PMC3568565 DOI: 10.1128/aem.02789-12] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 11/13/2012] [Indexed: 12/25/2022] Open
Abstract
Effluents discharged from wastewater treatment plants are possible sources of pathogenic bacteria, including Escherichia coli, in the freshwater environment, and determining the possible selection of pathogens is important. This study evaluated the impact of activated sludge and physicochemical wastewater treatment processes on the prevalence of potentially virulent E. coli. A total of 719 E. coli isolates collected from four municipal plants in Québec before and after treatment were characterized by using a customized DNA microarray to determine the impact of treatment processes on the frequency of specific pathotypes and virulence genes. The percentages of potentially pathogenic E. coli isolates in the plant influents varied between 26 and 51%, and in the effluents, the percentages were 14 to 31%, for a reduction observed at all plants ranging between 14 and 45%. Pathotypes associated with extraintestinal pathogenic E. coli (ExPEC) were the most abundant at three of the four plants and represented 24% of all isolates, while intestinal pathogenic E. coli pathotypes (IPEC) represented 10% of the isolates. At the plant where ExPEC isolates were not the most abundant, a large number of isolates were classified as both ExPEC and IPEC; overall, 6% of the isolates were classified in both groups, with the majority being from the same plant. The reduction of the proportion of pathogenic E. coli could not be explained by the preferential loss of one virulence gene or one type of virulence factor; however, the quinolone resistance gene (qnrS) appears to enhance the loss of virulence genes, suggesting a mechanism involving the loss of pathogenicity islands.
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Affiliation(s)
- Dominic Frigon
- Department of Civil Engineering and Applied Mechanics, McGill University, Montréal, Québec, Canada.
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Navab Daneshmand T, Beton R, Hill RJ, Gehr R, Frigon D. Inactivation mechanisms of bacterial pathogen indicators during electro-dewatering of activated sludge biosolids. Water Res 2012; 46:3999-4008. [PMID: 22677501 DOI: 10.1016/j.watres.2012.05.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 04/08/2012] [Accepted: 05/05/2012] [Indexed: 05/15/2023]
Abstract
Electro-dewatering is an energy-efficient technology in which an electric field can increase the dryness of biosolids from secondary wastewater treatment from 15% w/w to 30-50% w/w. Here, we address bacterial pathogen indicators inactivation (total coliforms, Escherichia coli and aerobic endospores) during electro-dewatering, investigating the roles of electrochemically generated oxidants, extreme pH, and high temperature (from Joule heating). Our results demonstrate that temperature is the primary factor affecting total coliforms and E. coli inactivation. First, several electro-dewatering cycles were used to increase sludge temperature to about 100 °C after 6 min, during which time the average pH decreased from 7 to 3.6 after 10 min. Total coliforms and E. coli MPNs reached their detection limits after 6 min (with 4-5 logs of inactivation for total coliforms and 3-4 logs for E. coli). In contrast, aerobic endospores were not inactivated under these conditions; rather, their germination appeared to be stimulated by 6-8 min of electro-dewatering. Second, the dewatering cake was separated into four horizontal layers. After 8 min of electro-dewatering, the pH in the top layers decreased to 3, whereas the pH in the bottom layers increased to 8. Inactivation of total coliforms and E. coli in the sludge cake was similar in all layers, increasing with time, suggesting that oxidants and extreme pH are secondary inactivation factors. Finally, electrodes were cooled to maintain a temperature less than 34 °C. Although pH decreased significantly after 12 min of electro-dewatering, there was no significant bacterial pathogen indicator inactivation at low temperature.
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Affiliation(s)
- Tala Navab Daneshmand
- Department of Civil Engineering and Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, Quebec H3A 0C3, Canada.
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Frigon D, Isazadeh S. Evaluation of a new model for the reduction of excess sludge production by ozonation of return activated sludge: what solids COD fraction is affected? Water Sci Technol 2011; 63:156-163. [PMID: 21245568 DOI: 10.2166/wst.2011.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This paper aims at clarifying the effect of ozone on the RAS solids to model activated sludge systems equipped with RAS-ozonation processes for the reduction of sludge production. A common hypothesis is that ozone only affects active biomass by promoting cryptic growth. Data from a pilot-scale study were used to test this and two other model extensions to IWA-ASM3. All model extensions were able to simulate the observed linear reduction in sludge production with increasing ozone dose when the MLVSS are kept constant. However, model simulations showed the inconsistency of the cryptic growth hypothesis with the extent of sludge reduction. The second tested model extensions assumes that ozone affects all the solids fractions (active biomass, endogenous residue, and influent inert particulate COD) equally. This extension could properly simulate the observed sludge reduction, but it failed to predict the trends in effluent BOD₅, ATP/VSS, and nitrification rates. A third tested model extension, which performed better, assumes that biomass is inactivated at a specific rate higher than the specific rate of transformation by ozone of the other solids fractions. Finally, the predictions from this model extension were most accurate if either (i) the nitrifiers were inactivated at a lower rate then heterotrophs, (ii) the nitrifiers model parameters (e.g., maximum growth rate) were changed under ozone (i.e., metabolic adaptation, (iii) or both.
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Affiliation(s)
- Dominic Frigon
- Dept. of Civil Engineering & Applied Mechanics, McGill University, 817 Sherbrooke St. West, Montreal, QC, H3A 2K6, Canada.
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Lavallée B, Frigon D, Lessard P, Vanrolleghem PA, Yuan Z, van Loosdrecht MCM. Modelling using rRNA-structured biomass models. Water Sci Technol 2009; 59:661-671. [PMID: 19237760 DOI: 10.2166/wst.2009.592] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Models currently used have been developed to describe the storage response in the activated sludge process. In these models the distribution of the substrate flux between growth and storage is an empirical function. rRNA-structured biomass models are proposed to describe the metabolic status of cells in view of predicting the growth response (dmicro/dt) of cells in activated sludge process. The autocatalytic reaction rate of the synthesis of the PSS component (rRNA) can provide a mechanistic explanation for the growth response and the growth lag phase. The proposed models were able to describe and predict properly the growth response of the biomass in various types of reactor. Such models could be more widely applicable by using intrinsic model parameters. This would be a key improvement for as it would lead to improved models for design.
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Affiliation(s)
- B Lavallée
- Département de génie civil, Université Laval, Québec, G1K 7P4, QC, Canada.
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Klein AN, Frigon D, Raskin L. Populations related to Alkanindiges, a novel genus containing obligate alkane degraders, are implicated in biological foaming in activated sludge systems. Environ Microbiol 2007; 9:1898-912. [PMID: 17635538 DOI: 10.1111/j.1462-2920.2007.01307.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Activated sludge mixed liquor and biological foam samples were collected from five full-scale municipal wastewater treatment plants in Illinois, all of which were exhibiting biological foaming at the time of sampling. Oligonucleotide probe hybridization consistently measured higher levels of Gammaproteobacteria rRNA in the foam as compared with the mixed liquor for all treatment plants analysed. Cloning and sequencing of 16S rRNA gene amplicons led to the identification of populations which were abundant in each of the treatment plants. These populations were related to the Alkanindiges/Acinetobacter cluster within the Gammaproteobacteria. Further analysis of the 16S rRNA sequences indicated that they clustered in three phylogenetic groups outside the main Alkanindiges/Acinetobacter cluster, suggesting that these groups may represent new taxa. Terminal-restriction fragment length polymorphism analysis showed that these populations were enriched in the foam compared with the underlying mixed liquor similar to the enrichment of the Gammaproteobacteria measured by oligonucleotide probe membrane hybridization. The observed enrichment in foam samples is suggestive of a role for these populations in foam formation or stabilization, and their presence in all treatment plants analysed in this study may be indicative of their widespread abundance in foaming plants.
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Affiliation(s)
- Adam N Klein
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Frigon D, Muyzer G, van Loosdrecht M, Raskin L. rRNA and poly-beta-hydroxybutyrate dynamics in bioreactors subjected to feast and famine cycles. Appl Environ Microbiol 2006; 72:2322-30. [PMID: 16597926 PMCID: PMC1449019 DOI: 10.1128/aem.72.4.2322-2330.2006] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Feast and famine cycles are common in activated sludge wastewater treatment systems, and they select for bacteria that accumulate storage compounds, such as poly-beta-hydroxybutyrate (PHB). Previous studies have shown that variations in influent substrate concentrations force bacteria to accumulate high levels of rRNA compared to the levels in bacteria grown in chemostats. Therefore, it can be hypothesized that bacteria accumulate more rRNA when they are subjected to feast and famine cycles. However, PHB-accumulating bacteria can form biomass (grow) throughout a feast and famine cycle and thus have a lower peak biomass formation rate during the cycle. Consequently, PHB-accumulating bacteria may accumulate less rRNA when they are subjected to feast and famine cycles than bacteria that are not capable of PHB accumulation. These hypotheses were tested with Wautersia eutropha H16 (wild type) and W. eutropha PHB-4 (a mutant not capable of accumulating PHB) grown in chemostat and semibatch reactors. For both strains, the cellular RNA level was higher when the organism was grown in semibatch reactors than when it was grown in chemostats, and the specific biomass formation rates during the feast phase were linearly related to the cellular RNA levels for cultures. Although the two strains exhibited maximum uptake rates when they were grown in semibatch reactors, the wild-type strain responded much more rapidly to the addition of fresh medium than the mutant responded. Furthermore, the chemostat-grown mutant culture was unable to exhibit maximum substrate uptake rates when it was subjected to pulse-wise addition of fresh medium. These data show that the ability to accumulate PHB does not prevent bacteria from accumulating high levels of rRNA when they are subjected to feast and famine cycles. Our results also demonstrate that the ability to accumulate PHB makes the bacteria more responsive to sudden increases in substrate concentrations, which explains their ecological advantage.
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Affiliation(s)
- Dominic Frigon
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, Environmental Biotechnology Group, Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Gerard Muyzer
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, Environmental Biotechnology Group, Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Mark van Loosdrecht
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, Environmental Biotechnology Group, Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
| | - Lutgarde Raskin
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, Environmental Biotechnology Group, Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
- Corresponding author. Present address: Department of Civil and Environmental Engineering, University of Michigan, 107 EWRE Bldg., 1351 Beal Ave., Ann Arbor, MI 48109-2125. Phone: (734) 647-6920. Fax: (734) 763-2275. E-mail:
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Frigon D, Guthrie RM, Bachman GT, Royer J, Bailey B, Raskin L. Long-term analysis of a full-scale activated sludge wastewater treatment system exhibiting seasonal biological foaming. Water Res 2006; 40:990-1008. [PMID: 16460780 DOI: 10.1016/j.watres.2005.12.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Revised: 12/07/2005] [Accepted: 12/08/2005] [Indexed: 05/06/2023]
Abstract
The seasonal accumulation of biological foam on the activated sludge system of the Urbana-Champaign Sanitary District Northeast (UCSD-NE) wastewater treatment plant was investigated over an 8-year period by statistical analyses including path analysis, multivariate regression, and principal component analysis. Results of these analyses suggested that variation in the activated sludge reactor temperature and the use of a stream bypassing the primary clarifier were the two main factors determining the observed temporal foam profile. Characterization of the primary clarifier influent and effluent suggested the involvement of high lipid loading rates from the bypass stream in foam accumulation. In light of these results, it is hypothesized that increasing temperatures and lipid loading rates are responsible for foam formation through the same mechanism: the foam-forming microbial population is specialized in consuming lipids, substrates classified as slowly degradable. When the temperature increases, the rate of lipid hydrolysis becomes sufficiently high for this population to become abundant, accumulate on the surfaces of the aeration basins, and cause biological foaming.
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Affiliation(s)
- Dominic Frigon
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, USA.
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Gilbride KA, Frigon D, Cesnik A, Gawat J, Fulthorpe RR. Effect of chemical and physical parameters on a pulp mill biotreatment bacterial community. Water Res 2006; 40:775-87. [PMID: 16427115 DOI: 10.1016/j.watres.2005.12.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Revised: 11/23/2005] [Accepted: 12/03/2005] [Indexed: 05/06/2023]
Abstract
The bacterial community composition in an activated sludge plant treatment from a bleached kraft pulp mill was monitored over a period of 209 days. Using DGGE and terminal-Restriction Fragment Length Polymorphism (t-RFLP) analysis we generated community DNA fingerprints over the time period. Both methods produce fingerprints that can be used to monitor stability in the system and generate fragments that can be associated with bacterial taxa. Chemical and physical parameters were also collected during that same time frame. We found a number of significant correlations with influent variables such as temperature, chemical oxygen demand (COD), Biochemical oxygen demand (BOD) and chloroform concentrations suggesting that these were the most likely parameters to influence the bacterial community structure. In addition several taxa correlated to important performance indicators such as COD/BOD removals and SVI. Multivariate analysis also confirmed the strong links between taxa variation and temperature, nutrient loads, chloroform and also one class of filaments. Establishing the identity of these taxa and their ecological preferences will greatly enhance our understanding and management of biological treatment systems.
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Affiliation(s)
- K A Gilbride
- Department of Chemistry and Biology, Ryerson University, 350 Victoria Street, Toronto, Ont., Canada M5B 2K3.
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Frigon D, Oerthe DB, Morgenroth E, Raskin L. Oligonucleotide probe hybridization and modeling results suggest that populations consuming readily degradable substrate have high cellular RNA levels. Water Sci Technol 2002; 45:115-126. [PMID: 11989864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Analyses based on ribosomal RNA (rRNA)-targeted hybridization performed in our laboratory identified two types of bacterial populations: a population with a high RNA level per biomass and a population with a low level of RNA per biomass. To extend these descriptions, the diurnal dynamics of the RNA pool were monitored by rRNA-targeted oligonucleotide probe membrane hybridization. Under the typical diurnal variation in COD loading rate experienced by municipal wastewater treatment plants, the RNA level of the bacterial population with a high level of RNA per biomass varied with changes in the COD loading rate. Under the same conditions, the RNA level of the population with low RNA level per biomass remained constant. A structured biomass model was developed to describe these data. Substrate COD was divided into a readily biodegradable and a slowly biodegradable COD fraction. It was assumed that two specialized populations coexist in municipal activated sludge treatment systems. One population consumes readily degradable COD and the other consumes slowly degradable COD. According to model simulations, the population consuming readily degradable COD has a high level of RNA per biomass under variable substrate concentrations. Comparatively, the population consuming slowly degradable COD has a low level of RNA level per biomass. Furthermore, model simulations reproduced the two diurnal RNA profiles observed in a full-scale municipal activated sludge system. Therefore, we suggest that two populations can be distinguished in municipal activated sludge systems: a population consuming readily degradable substrate and a population consuming slowly degradable substrate.
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Affiliation(s)
- D Frigon
- University of Illinois at Urbana-Champaign, Department of Civil and Environmental Engineering, Urbana 61801, USA
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Frigon D, Arnaiz E, Oerther DB, Raskin L. Who eats what? Classifying microbial populations based on diurnal profiles of rRNA levels. Water Sci Technol 2002; 46:1-9. [PMID: 12216607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Identifying the relationships between various bacterial populations and the substrates they consume is central to the understanding of population dynamics and to the development of process control in activated sludge. However, linking a heterotrophic population to its activity in situ is difficult because ribosomal RNA (rRNA) techniques, while allowing the rapid identification of populations, provide little information about their heterotrophic activity. Activated sludge models describe biodegradation kinetics by classifying substrates into two types: readily and slowly degradable substrates. Assuming that bacterial populations specialize in degrading one type of substrate, their growth rate should be affected differently if the COD loading rate varies diurnally as for a municipal activated sludge system. Modeling results suggested that the growth rates of populations consuming readily degradable substrates vary according to variations in COD loading rate. On the other hand, the growth rates of populations consuming slowly degradable substrates do not change despite the variation in COD loading rate. Since the cellular rRNA level is positively correlated with the growth rate, we hypothesized that the rRNA levels of some populations in municipal activated sludge should increase throughout the day, while they should stay constant for other populations. This hypothesis was verified by monitoring the rRNA level of Acinetobacter (a model population consuming readily degradable substrates) and Gordonia (a model population consuming slowly degradable substrates) in the mixed liquor of a full-scale municipal activated sludge reactor for three weeks.
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Affiliation(s)
- D Frigon
- University of Illinois at Urbana-Champaign, Department of Civil and Environmental Engineering, Urbana 61801, USA
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Dutilleul P, Stockwell JD, Frigon D, Legendre P. The Mantel Test versus Pearson's Correlation Analysis: Assessment of the Differences for Biological and Environmental Studies. Journal of Agricultural, Biological, and Environmental Statistics 2000. [DOI: 10.2307/1400528] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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