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Saini JS, Adler A, Cardona L, Rodilla Ramírez PN, Pei R, Holliger C. Microbial genome collection of aerobic granular sludge cultivated in sequencing batch reactors using different carbon source mixtures. Microbiol Resour Announc 2024; 13:e0010224. [PMID: 38534152 PMCID: PMC11080561 DOI: 10.1128/mra.00102-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 03/18/2024] [Indexed: 03/28/2024] Open
Abstract
Aerobic granular sludge (AGS) consists of a microbial consortium that has an important role in wastewater treatment. This study investigates AGS microorganisms cultivated in a laboratory-scale sequencing batch reactor. Metagenomic sequencing was conducted using PacBio and Illumina, resulting in 759 metagenome-assembled genomes, 331 of which remained after dereplication.
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Affiliation(s)
- Jaspreet S. Saini
- Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Aline Adler
- Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Laëtitia Cardona
- Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | | | - Ruizhe Pei
- Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Christof Holliger
- Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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2
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Liébana R, Modin O, Persson F, Hermansson M, Wilén BM. Resistance of aerobic granular sludge microbiomes to periodic loss of biomass. Biofilm 2023; 6:100145. [PMID: 37575957 PMCID: PMC10415711 DOI: 10.1016/j.bioflm.2023.100145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/07/2023] [Accepted: 07/26/2023] [Indexed: 08/15/2023] Open
Abstract
Granular sludge is a biofilm process used for wastewater treatment which is currently being implemented worldwide. It is important to understand how disturbances affect the microbial community and performance of reactors. Here, two acetate-fed replicate reactors were inoculated with acclimatized sludge and the reactor performance, and the granular sludge microbial community succession were studied for 149 days. During this time, the microbial community was challenged by periodically removing half of the reactor biomass, subsequently increasing the food-to-microorganism (F/M) ratio. Diversity analysis together with null models show that overall, the microbial communities were resistant to the disturbances, observing some minor effects on polyphosphate-accumulating and denitrifying microbial communities and their associated reactor functions. Community turnover was driven by drift and random granule loss, and stochasticity was the governing ecological process for community assembly. These results evidence the aerobic granular sludge process as a robust system for wastewater treatment.
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Affiliation(s)
- Raquel Liébana
- Division of Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, Sven Hultins gata 6, SE 412 96, Gothenburg, Sweden
- AZTI, Marine Research Division, Basque Research Technology Alliance (BRTA), Txatxarramendi Ugartea z/g, 48395, Sukarrieta, Bizkaia, Spain
| | - Oskar Modin
- Division of Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, Sven Hultins gata 6, SE 412 96, Gothenburg, Sweden
| | - Frank Persson
- Division of Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, Sven Hultins gata 6, SE 412 96, Gothenburg, Sweden
| | - Malte Hermansson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9E, SE-413 90, Gothenburg, Sweden
| | - Britt-Marie Wilén
- Division of Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, Sven Hultins gata 6, SE 412 96, Gothenburg, Sweden
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Liu Z, Yang R, Zhang D, Wang J, Gao M, Zhang A, Liu W, Liu Y. Insight into the effect of particulate organic matter on sludge granulation at the low organic load: Sludge characteristics, extracellular polymeric substances and microbial communities response. BIORESOURCE TECHNOLOGY 2023; 388:129791. [PMID: 37730138 DOI: 10.1016/j.biortech.2023.129791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/17/2023] [Accepted: 09/17/2023] [Indexed: 09/22/2023]
Abstract
This paper investigated the effect of particulate organic matter (POM) on sludge granulation under low organic load. The results showed that POM promoted the formation of aerobic granular sludge (AGS) with a chemical oxygen demand (COD) fraction of 25%, and POM also enhanced the sludge settleability and biomass retention. However, when the COD fraction of POM increased to 50% and 75%, the AGS performance deteriorated. The analysis of extracellular polymeric substances revealed that the POM (accounted for ≤ 50% of COD in the influent) suppressed the secretion of extracellular protein. Analysis of the microbial community showed that species diversity was lower in the POM-fed system, with Rhodocyclaceae being the predominant bacteria responsible for carbon source degradation. Additionally, molecular ecological network analysis demonstrated that when the COD fraction of the POM exceeded 50%, the connectivity and modularity between microbial species decreased, which may explain the sludge performance deterioration.
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Affiliation(s)
- Zhe Liu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an 710055, China; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China; Yulin Ecological Environment Monitoring Station, High-tech Zone Xingda Road, Yulin 719000, China.
| | - Rushuo Yang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an 710055, China
| | - Dan Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an 710055, China
| | - Jiaxuan Wang
- School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Yan Ta Road, No. 58, Xi'an 710054, China
| | - Min Gao
- School of Environmental and Chemical Engineering, Xi an Polytechnic University, Jin Hua Nan Road. No.19, Xi'an 710048, China
| | - Aining Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an 710055, China
| | - Wenlong Liu
- Yulin Ecological Environment Monitoring Station, High-tech Zone Xingda Road, Yulin 719000, China
| | - Yongjun Liu
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Yan Ta Road. No.13, Xi'an 710055, China; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China
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4
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Xu J, Gao Y, Bi X, Li L, Xiang W, Liu S. Positive effects of lignocellulose on the formation and stability of aerobic granular sludge. Front Microbiol 2023; 14:1254152. [PMID: 37670989 PMCID: PMC10475587 DOI: 10.3389/fmicb.2023.1254152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 07/31/2023] [Indexed: 09/07/2023] Open
Abstract
Introduction Lignocellulose is one of the major components of particulate organic matter in sewage, which has a significant influence on biological wastewater treatment process. However, the effect of lignocellulose on aerobic granular sludge (AGS) system is still unknown. Methods In this study, two reactors were operated over 5 months to investigate the effect of lignocellulose on granulation process, structure stability and pollutants removal of AGS. Results and discussion The results indicated that lignocellulose not only promoted the secretion of tightly bound polysaccharide in extracellular polymeric substances, but also acted as skeletons within granules, thereby facilitating AGS formation, and enhancing structural strength. Lignocellulose imposed little effect on the removal efficiency of pollutants, with more than 95, 99, and 92% of COD, NH4+-N, and PO43--P were removed in both reactors. However, it did exhibit a noticeable influence on pollutants conversion processes. This might be due to that the presence of lignocellulose promoted the enrichment of functional microorganisms, including Candidatus_Accumulibacter, Candidatus_Competibacter, Nitrosomonas, and Nitrospira, etc. These findings might provide valuable insights into the control strategy of lignocellulose in practical AGS systems.
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Affiliation(s)
- Jie Xu
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, China
| | - Yuan Gao
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, China
| | - Xuejun Bi
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, China
| | - Lin Li
- Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing, China
| | - Wenjuan Xiang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, China
| | - Shichang Liu
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, China
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Deng X, Yuan J, Chen L, Chen H, Wei C, Nielsen PH, Wuertz S, Qiu G. CRISPR-Cas phage defense systems and prophages in Candidatus Accumulibacter. WATER RESEARCH 2023; 235:119906. [PMID: 37004306 DOI: 10.1016/j.watres.2023.119906] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 02/27/2023] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
Candidatus Accumulibacter plays a major role in enhanced biological phosphorus removal (EBPR) from wastewater. Although bacteriophages have been shown to represent fatal threats to Ca. Accumulibacter organisms and thus interfere with the stability of the EBPR process, little is known about the ability of different Ca. Accumulibacter strains to resist phage infections. We conducted a systematic analysis of the occurrence and characteristics of clustered regularly interspaced short palindromic repeats and associated proteins (CRISPR-Cas) systems and prophages in Ca. Accumulibacter lineage members (43 in total, including 10 newly recovered genomes). Results indicate that 28 Ca. Accumulibacter genomes encode CRISPR-Cas systems. They were likely acquired via horizontal gene transfer, conveying a distinct adaptivity to phage predation to different Ca. Accumulibacter members. Major differences in the number of spacers show the unique phage resistance of these members. A comparison of the spacers in closely related Ca. Accumulibacter members from distinct geographical locations indicates that habitat isolation may have resulted in the acquisition of resistance to different phages by different Ca. Accumulibacter. Long-term operation of three laboratory-scale EBPR bioreactors revealed high relative abundances of Ca. Accumulibacter with CRISPSR-Cas systems. Their specific resistance to phages in these reactors was indicated by spacer analysis. Metatranscriptomic analyses showed the activation of the CRISPR-Cas system under both anaerobic and aerobic conditions. Additionally, 133 prophage regions were identified in 43 Ca. Accumulibacter genomes. Twenty-seven of them (in 19 genomes) were potentially active. Major differences in the occurrence of CRISPR-Cas systems and prophages in Ca. Accumulibacter will lead to distinct responses to phage predation. This study represents the first systematic analysis of CRISPR-Cas systems and prophages in the Ca. Accumulibacter lineage, providing new perspectives on the potential impacts of phages on Ca. Accumulibacter and EBPR systems.
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Affiliation(s)
- Xuhan Deng
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Jing Yuan
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Liping Chen
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Hang Chen
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
| | - Chaohai Wei
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China
| | - Per H Nielsen
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore; Centre for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg DK-9220, Denmark
| | - Stefan Wuertz
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore.
| | - Guanglei Qiu
- School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou 510006, China.
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6
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Burzio C, Ekholm J, Modin O, Falås P, Svahn O, Persson F, van Erp T, Gustavsson DJI, Wilén BM. Removal of organic micropollutants from municipal wastewater by aerobic granular sludge and conventional activated sludge. JOURNAL OF HAZARDOUS MATERIALS 2022; 438:129528. [PMID: 35999740 DOI: 10.1016/j.jhazmat.2022.129528] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/02/2022] [Accepted: 07/01/2022] [Indexed: 06/15/2023]
Abstract
Removal performances of organic micropollutants by conventional activated sludge (CAS) and aerobic granular sludge (AGS) were investigated at a full-scale wastewater treatment plant. Lab-scale kinetic experiments were performed to assess the micropollutant transformation rates under oxic and anoxic conditions. Transformation rates were used to model the micropollutant removal in the full-scale processes. Metagenomic sequencing was used to compare the microbial communities and antimicrobial resistance genes of the CAS and AGS systems. Higher transformation ability was observed for CAS compared to AGS for most compounds, both at the full-scale plant and in the complementary batch experiments. Oxic conditions supported the transformation of several micropollutants with faster and/or comparable rates compared to anoxic conditions. The estimated transformation rates from batch experiments adequately predicted the removal for most micropollutants in the full-scale processes. While the compositions in microbial communities differed between AGS and CAS, the full-scale biological reactors shared similar resistome profiles. Even though granular biomass showed lower potential for micropollutant transformation, AGS systems had somewhat higher gene cluster diversity compared to CAS, which could be related to a higher functional diversity. Micropollutant exposure to biomass or mass transfer limitations, therefore played more important roles in the observed differences in OMP removal.
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Affiliation(s)
- Cecilia Burzio
- Department of Architecture and Civil Engineering, Chalmers University of Technology, Gothenburg 41296, Sweden.
| | - Jennifer Ekholm
- Department of Architecture and Civil Engineering, Chalmers University of Technology, Gothenburg 41296, Sweden
| | - Oskar Modin
- Department of Architecture and Civil Engineering, Chalmers University of Technology, Gothenburg 41296, Sweden
| | - Per Falås
- Department of Chemical Engineering, Lund University, PO Box 124, Lund 22100, Sweden
| | - Ola Svahn
- Department of Environmental Science and Bioscience, Kristianstad University, Kristianstad 29139, Sweden
| | - Frank Persson
- Department of Architecture and Civil Engineering, Chalmers University of Technology, Gothenburg 41296, Sweden
| | - Tim van Erp
- Strömstad Municipality, Wastewater Treatment Plant Österröd, Strömstad 45233, Sweden
| | | | - Britt-Marie Wilén
- Department of Architecture and Civil Engineering, Chalmers University of Technology, Gothenburg 41296, Sweden
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Phosphorus Removal from Aerobic Granular Sludge: Proliferation of Polyphosphate-Accumulating Organisms (PAOs) under Different Feeding Strategies. Processes (Basel) 2022. [DOI: 10.3390/pr10071399] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Aerobic granular sludge (AGS) is known for high phosphorus removal from wastewaters, and phosphorus can be recovered from high phosphorus-containing waste sludge granules. This study aimed at determining the feeding strategy that provides the best performance in terms of the proliferation of polyphosphate-accumulating organisms (PAOs) and phosphorus removal. Using three AGS bioreactors, this study compared phosphorus removal and the proliferation dynamics of PAOs under three different feeding strategies: anaerobic slow feeding (R1), pulse feeding + anaerobic mixing (R2), and pulse feeding (R3). Results indicate that R1 and R2 achieved significantly higher phosphorus removal (97.6 ± 3% for R1 and 98.3 ± 1% for R2) than R3 (55 ± 11%). The anaerobic slow feeding procedure (R1) achieved the highest specific phosphorus release rate (SPRR) and specific phosphorus uptake rate (SPUR) as compared to the other two feeding conditions. 16S ribosomal ribonucleic acid (rRNA) gene sequencing assay of the microbial community for the three feeding strategies indicated that although the feeding strategy impacted reactor performance, it did not significantly alter the microbial community. The bacteria community composition maintained a similar degree of diversity. Proteobacteria, Bacteroidetes, and Verrucomicrobia were the dominant bacterial phyla in the system. Dominant PAOs were from the class Betaproteobacteria and the genera Paracoccus and Thauera. Glycogen-accumulating organisms were significantly inhibited while other less-known bacteria such as Wandonia and Hyphomonas were observed in all three reactors.
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8
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Adler A, Poirier S, Pagni M, Maillard J, Holliger C. Disentangle genus microdiversity within a complex microbial community by using a multi-distance long-read binning method: example of Candidatus Accumulibacter. Environ Microbiol 2022; 24:2136-2156. [PMID: 35315560 PMCID: PMC9311429 DOI: 10.1111/1462-2920.15947] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 02/19/2022] [Indexed: 11/26/2022]
Abstract
Complete genomes can be recovered from metagenomes by assembling and binning DNA sequences into metagenome assembled genomes (MAGs). Yet, the presence of microdiversity can hamper the assembly and binning processes, possibly yielding chimeric, highly fragmented and incomplete genomes. Here, the metagenomes of four samples of aerobic granular sludge bioreactors containing Candidatus (Ca.) Accumulibacter, a phosphate-accumulating organism of interest for wastewater treatment, were sequenced with both PacBio and Illumina. Different strategies of genome assembly and binning were investigated, including published protocols and a binning procedure adapted to the binning of long contigs (MuLoBiSC). Multiple criteria were considered to select the best strategy for Ca. Accumulibacter, whose multiple strains in every sample represent a challenging microdiversity. In this case, the best strategy relies on long-read only assembly and a custom binning procedure including MuLoBiSC in metaWRAP. Several high-quality Ca. Accumulibacter MAGs, including a novel species, were obtained independently from different samples. Comparative genomic analysis showed that MAGs retrieved in different samples harbour genomic rearrangements in addition to accumulation of point mutations. The microdiversity of Ca. Accumulibacter, likely driven by mobile genetic elements, causes major difficulties in recovering MAGs, but it is also a hallmark of the panmictic lifestyle of these bacteria.
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Affiliation(s)
- Aline Adler
- Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Simon Poirier
- Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Marco Pagni
- Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Julien Maillard
- Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,IFP Energie nouvelles, 1 et 4 avenue de Bois-Préau, 92852, Rueil-Malmaison Cedex, France
| | - Christof Holliger
- Laboratory for Environmental Biotechnology, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Dockx L, Caluwé M, Dobbeleers T, Dries J. Nitrous oxide formation during simultaneous phosphorus and nitrogen removal in aerobic granular sludge treating different carbon substrates. BIORESOURCE TECHNOLOGY 2022; 345:126542. [PMID: 34906707 DOI: 10.1016/j.biortech.2021.126542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/05/2021] [Accepted: 12/06/2021] [Indexed: 06/14/2023]
Abstract
The impact of different substrates on N2O dynamics and gene expression of marker enzymes (nirS, nirK and nosZ) involved in denitrifying enhanced biological phosphorus removal (d-EBPR) was investigated. Aerobic granular sludge fed with VFAs led to an anoxic P-uptake (27.7 ± 1.2 mg PO43--P.gVSS-1) and N2O emissions up to 80.7 ± 3.4% N2O-N. A decisive role of Accumulibacter in N2O formation was observed. Dosage of amino acids (12.0 ± 1.2 mg PO43--P.gVSS-1) and glucose (1.5 ± 0.9 mg PO43--P.gVSS-1) as sole substrate did not support d-EBPR activity. Presence of NO2- resulted in higher N2O formation in comparison to nitrate and a nosZ/(nirS + nirK) ratio lower than 0.3. A linear correlation (R2 > 0.95) between the nosZ/(nirS + nirK) ratio and the N2O reductase rate was found only when dosing the same type of substrate. This suggests an interplay between the microbial community composition and different polyhydroxyalkanoates derivatives, when dosing different substrates.
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Affiliation(s)
- Lennert Dockx
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium
| | - Michel Caluwé
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium
| | - Thomas Dobbeleers
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium
| | - Jan Dries
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
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10
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Gonzalez A, van Lier JB, de Kreuk MK. The role of growth media on composition, bioconversion and susceptibility for mild thermal pre-treatment of waste activated sludge. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 298:113491. [PMID: 34375922 DOI: 10.1016/j.jenvman.2021.113491] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/04/2021] [Accepted: 08/05/2021] [Indexed: 06/13/2023]
Abstract
The highly variable characteristics of waste activated sludge (WAS) hinder the comparison of experimental results on WAS bioconversion between the different studies that use excess sludge from different origin. Sludge grown under laboratory conditions with synthetic wastewater as feed showed high resistance to commonly applied pre-treatment techniques, such as thermal pre-treatment. However, a distinctly higher bioconversion of this sludge was recorded compared to WAS from a full-scale wastewater treatment plant (WWTP). The observed results casted concern on the suitability of the experimental laboratory-based data for practice. The physicochemical and biochemical characteristics of both WAS and lab-grown sludge are dependent on the wastewater characteristics or growth media on which the sludges were grown. The objective of this study was to formulate a growth medium that results into a lab-grown sludge which shows high similarity to the WAS coming from a specific full-scale WWTP in response to a pre-treatment technique. More specifically, in this study we targeted the formation of slowly-biodegradable lab-grown sludge that is similarly responsive to mild thermal pre-treatment with H2O2 addition. By comparing real and synthetic wastewaters, we discussed the various wastewater constituents that may lead to a higher degree of recalcitrance of the produced sludge. We then formulated a growth medium, which was fed to a lab-scale activated sludge reactor and evaluated the nutrient removal capacity, as well as the characteristics of the cultivated sludge before and after pre-treatment. Finally, the growth medium was modified to provoke a change in both the bioconversion and in the response to mild thermal pre-treatment. The growth medium proposed in this study resulted in a slowly-biodegradable sludge (195 ± 3.7 NLCH4/kgVSadded) that after thermal pre-treatment resulted in an increase in methane production of 9 %, which was similar to the WAS coming from the full-scale WWTP. It was concluded that not only the bioconversion but also the response to mild thermal pre-treatment of lab-grown sludge was determined by the composition of the growth media.
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Affiliation(s)
- Adrian Gonzalez
- Faculty of Civil Engineering and Geosciences, Department of Water Management, Sanitary Engineering Section, Delft University of Technology, Stevinweg 1, 2628 CN, Delft, the Netherlands.
| | - Jules B van Lier
- Faculty of Civil Engineering and Geosciences, Department of Water Management, Sanitary Engineering Section, Delft University of Technology, Stevinweg 1, 2628 CN, Delft, the Netherlands
| | - Merle K de Kreuk
- Faculty of Civil Engineering and Geosciences, Department of Water Management, Sanitary Engineering Section, Delft University of Technology, Stevinweg 1, 2628 CN, Delft, the Netherlands
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11
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Dockx L, Caluwé M, De Vleeschauwer F, Dobbeleers T, Dries J. Impact of the substrate composition on enhanced biological phosphorus removal during formation of aerobic granular sludge. BIORESOURCE TECHNOLOGY 2021; 337:125482. [PMID: 34320762 DOI: 10.1016/j.biortech.2021.125482] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/25/2021] [Accepted: 06/27/2021] [Indexed: 06/13/2023]
Abstract
Performance of enhanced biological phosphorus removal (EBPR) is often investigated with simple synthetic wastewater containing volatile fatty acids (VFAs). In this study, various (fermentable) substrates, individually and in mixtures, were examined during the application of a granulation strategy. In addition, the microbial community and N2O formation were monitored. Sludge densification was observed in all systems. Stable EBPR, associated with the presence of Accumulibacter and an anaerobic P-release up to 21.9 mgPO43--P.gVSS-1, was only obtained when VFAs were present as sole substrate or in mixture. Systems fed with VFAs were strongly related to the formation of N2O (maximum of 6.25% relative to the total available nitrogen). A moderate anaerobic dissolved organic carbon (DOC) uptake was observed when amino acids (64.27 ± 3.08%) and glucose (75.39 ± 5.79%) as sole carbon source were applied. The substrate/species-specific enrichment of Burkholderiaceae and Saccharimonadaceae respectively, resulted in unstable EBPR in those systems.
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Affiliation(s)
- Lennert Dockx
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Michel Caluwé
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Flinn De Vleeschauwer
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Thomas Dobbeleers
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Jan Dries
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
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12
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Shang J, Zhang W, Chen X, Li Y, Niu L, Wang L, Zhang H. How environmental stress leads to alternative microbiota states in a river ecosystem: A new insight into river restoration. WATER RESEARCH 2021; 203:117538. [PMID: 34416651 DOI: 10.1016/j.watres.2021.117538] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 08/04/2021] [Accepted: 08/05/2021] [Indexed: 06/13/2023]
Abstract
Catastrophic shifts in river ecosystems can abruptly degrade their structures and functions, often reducing the efficacy of traditional remediation targeting physicochemical properties. Alternative stable states theory can not only explain this phenomenon but also provide a new insight into river restoration; however, little is known about the existence and implications of alternative stable states in a river. Considering the important role of benthic microbiota in sustaining river ecosystem structures and functions, ecological theory and high-throughput sequencing were combined to firstly investigate multi-stability in microbial communities and its relationship with environmental factors in river sediments. The Nanjing reach of the Yangtze River was selected as the study area because of its huge spatial heterogeneity and varying degrees of pollution. Bimodal distributions combined with temporal variations of microbiota status provided direct evidence of bistability by showing the instability at the intermediate. In addition, environmental stress, particularly concentrations of NH4+-N and NO3--N, was identified as an important driver of alternative microbiota states from the perspectives of the behavior of bistable ecosystems. Comparison of α-diversity indices and network properties between two alternative microbiota states revealed that the diversity and co-occurrence pattern of microbial communities will be high if they are settled in favorable environments (i.e., comprehensive sediment quality identification index > 3.7). Key taxa, including Clostridiales, Nitrospirales and Myxococcales, were discerned by combining LEfSe and network analysis, and their strong interspecies interactions were believed to be an important factor in triggering alternative microbiota states. This study suggests alternative stable states theory should be considered in river remediation to better understand the response of river ecosystems to environmental stress and the effect of hysteresis, benefiting the implementation of effective monitoring and restoration strategies in a river of urban area.
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Affiliation(s)
- Jiahui Shang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, P.R. China
| | - Wenlong Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, P.R. China.
| | - Xinqi Chen
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, P.R. China
| | - Yi Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, P.R. China.
| | - Lihua Niu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, P.R. China
| | - Longfei Wang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, P.R. China
| | - Huanjun Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, P.R. China
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