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Yang F, Li H, Wang S, Zhao F, Fang F, Guo J, Long M, Shen Y. Differences in exopolysaccharides of three microbial aggregates. ENVIRONMENTAL TECHNOLOGY 2022; 43:2909-2921. [PMID: 33769231 DOI: 10.1080/09593330.2021.1909658] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
Different microbial aggregates show substantial differences in morphology, and extracellular polymer substances have been confirmed to play a key role in the formation of aggregates. In this study, three different microbial aggregates and their exopolysaccharides were compared. The results show that the granular sludge was largest in size and the most compact in shape. Biofilms with a certain thickness had the next greatest density, and flocculent sludge, with the smallest particle size, was the loosest. The extended Derjaguin-Landau-Verwey-Overbeek analysis shows that hydrogen bonding, hydrophobic and electrostatic interactions affect the aggregation of microorganisms. A comparison of exopolysaccharides shows that granular sludge exopolysaccharides show the highest hydrophobicity (38.08%) and lowest surface charge (-20.5 mV), followed by biofilm exopolysaccharides (27.9% and -24.8 mV respectively). The results of Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy show that the contents of hydrophilic and hydrophobic functional groups and charged functional groups of exopolysaccharides affect the above properties of exopolysaccharides, thereby affecting microbial aggregation. In addition, the hydrogen bond content of exopolysaccharides in granular sludge (19.3%), biofilm (19.2%) and activated sludge (18.9%) decreased sequentially. This also affects the cross-linking of microbial exopolysaccharides to form hydrogels. Finally, the results of confocal laser scanning microscopy showed that, different from the other two aggregates, the extracellular α-polysaccharides of granular sludge are mainly distributed in the nucleus, which is more conducive to aggregation. The research results of this thesis provide a new understanding of the differences in the aggregation morphology of different aggregates from the perspective of exopolysaccharides.
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Affiliation(s)
- Fan Yang
- College of Environment and Ecology, Chongqing University, Chongqing, People's Republic of China
| | - Hanxiang Li
- College of Environment and Ecology, Chongqing University, Chongqing, People's Republic of China
| | - Shuai Wang
- College of Environment and Ecology, Chongqing University, Chongqing, People's Republic of China
| | - Fan Zhao
- College of Environment and Ecology, Chongqing University, Chongqing, People's Republic of China
| | - Fang Fang
- College of Environment and Ecology, Chongqing University, Chongqing, People's Republic of China
| | - Jinsong Guo
- College of Environment and Ecology, Chongqing University, Chongqing, People's Republic of China
| | - Man Long
- College of Environment and Ecology, Chongqing University, Chongqing, People's Republic of China
| | - Yu Shen
- National Base of International Science and Technology Cooperation for Intelligent Manufacturing Service, Chongqing Key Laboratory of Catalysis & New Environmental Materials, Chongqing Technology and Business University, Chongqing, People's Republic of China
- Chongqing South-to-Thais Environmental Protection Technology Research Institute Co., Ltd., Chongqing, People's Republic of China
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Li Z, Li H, Tang R, Wan C, Zhang C, Tan X, Liu X. Understanding the dependence of start-up and stability of aerobic granule on pH from the perspective of adhesion behavior and properties of extracellular polymeric substances. ENVIRONMENTAL RESEARCH 2021; 198:111311. [PMID: 33989628 DOI: 10.1016/j.envres.2021.111311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 03/08/2021] [Accepted: 05/07/2021] [Indexed: 06/12/2023]
Abstract
The start-up and stability of aerobic granular sludge (AGS) could be greatly influenced by pH variation. The inner core in the aerobic granules provided adhesion sites for microbes by extracellular polymeric substances (EPS) adhesion, the adhesion behavior of EPS and the properties of adhesion layer formed by EPS with pH changes might directly affect the start-up efficiency and stability of AGS. In this study, the adhesion behavior of EPS at an inorganic surface and the viscoelasticity of the EPS adhesion layer with pH variation was investigated by quartz crystal microbalance with dissipation monitoring, and the response of functional groups and intermolecular interactions to pH changes was explored. Based on the interaction energy calculation, it was found that the charge repulsion between substances dominated the interactions between EPS components and between EPS and the surface by regulating protonation and deprotonation of the functional groups of EPS with pH variation. A lower energy barrier between EPS and the surface at a lower pH value could facilitate the adhesion of EPS at the surface, which favored the rapid start-up of AGS. Moreover, the high ratio of both α-helix and intermolecular hydrogen bond at an acid condition could enhance the gel-strength of EPS, which provide AGS the resistance ability against external disturbance. This study revealed the mechanism of the interactions in EPS adhesion process with the variation of pH and provided useful information for a better understanding of the stability of the AGS.
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Affiliation(s)
- Zhengwen Li
- Department of Environmental Science and Engineering, Fudan University, Shanghai, 200438, China
| | - Huiqi Li
- Department of Environmental Science and Engineering, Fudan University, Shanghai, 200438, China
| | - Rui Tang
- Department of Environmental Science and Engineering, Fudan University, Shanghai, 200438, China
| | - Chunli Wan
- Department of Environmental Science and Engineering, Fudan University, Shanghai, 200438, China.
| | - Chen Zhang
- Shanghai Municipal Engineering Design General Institute, Shanghai, 200092, China
| | - Xuejun Tan
- Shanghai Municipal Engineering Design General Institute, Shanghai, 200092, China
| | - Xiang Liu
- Department of Environmental Science and Engineering, Fudan University, Shanghai, 200438, China.
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Shahebrahimi Y, Fazlali A. Phase equilibria, physical and rheological properties of extracellular polymeric substances in the aqueous urea solutions at different temperatures and concentrations. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 284:112103. [PMID: 33567355 DOI: 10.1016/j.jenvman.2021.112103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 01/17/2021] [Accepted: 01/30/2021] [Indexed: 06/12/2023]
Abstract
Extracellular polymeric substances (EPS) were extracted from aerobic granule sludge (AGS) using 8 M aqueous urea solution. It seems that the knowledge of these multi-component systems properties and the ability to predict their phase behavior is necessary for the extraction units design as well as process optimization. In this regard, water activity using the Dynamic Vapor Sorption (DVS) method, viscosity and shear stress, pH, and conductivity were measured at 283.15-343.15 K and 0.0108 to 0.0375 wt fraction of EPS. The salting effects in ternary systems assessed and the results were interpreted in terms of solute-water and solute-solute interactions. It was found these systems were not semi-ideal and except at 283.15 K, had a positive deviation from ideal solution behavior and only at this temperature as the optimum extraction temperature, the salting-in effect was observed for each concentration of EPS. The ternary solutions behave like pseudo-plastic fluids while aqueous urea solution is a Newtonian fluid. Increasing the temperature causes a decrease and increase in pH and conductivity of ternary solutions, respectively and the presence of EPS increases those of 8 M urea solution significantly.
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Affiliation(s)
- Yasaman Shahebrahimi
- Department of Chemical Engineering, Faculty of Engineering, Arak University, Arak, 38156879, Iran.
| | - Alireza Fazlali
- Department of Chemical Engineering, Faculty of Engineering, Arak University, Arak, 38156879, Iran
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Wang S, Liu Z, Yang M, Zhou Y, Yang M, Long M, Fang F, Guo J. The differences in characteristics of extracellular polymeric substances of flocs and anammox granules impacted aggregation. Bioprocess Biosyst Eng 2021; 44:1711-1720. [PMID: 33768321 DOI: 10.1007/s00449-021-02554-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 03/16/2021] [Indexed: 10/21/2022]
Abstract
Extracellular polymeric substances (EPS) are considered crucial components in the formation of microbial aggregates such as biofilms, flocs and granules. However, the role of EPS in sludge aggregation is still unclear. In this study, the differences in EPS characteristics of anammox granular sludge (AG), anammox floc sludge (AF) and activated floc sludge (AS) were investigated to clarify its role in granular aggregation. The results showed that the flocculation ability of EPS extracted from AG (62.8 ± 2.3%) was notably higher than that of EPS extracted from AF (35.7 ± 1.7%) and AS (17.3 ± 1.5%). The zeta potential and hydrophobicity of EPS showed the same tendency. In addition, the PN/PS ratio of AG, AF and AS were 7.66, 4.62 and 3.93, respectively. FTIR, XPS and 3D-EEM fluorescence spectra results revealed that anammox granular sludge has a higher ratio of hydrophobic groups, α-helixs/(β-sheets and random coils), intermolecular hydrogen bonds, and aromatic amino acids, and a lower ratio of electronegative groups. Anammox granular sludge exhibited high aggregation ability, because its EPS had higher zeta potential, hydrophobicity and intermolecular hydrogen bond ratio. This work provides a better understanding of the high aggregation ability of anammox granules and a theoretical basis for improving granules proportion and retention ability of microbes in reactor system.
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Affiliation(s)
- Shuai Wang
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Zihan Liu
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Mingming Yang
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, China.,Yangtze Ecology and Environment Co., Ltd, Wuhan, 430062, China
| | - Yang Zhou
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Mansu Yang
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Man Long
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Fang Fang
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, China.
| | - Jinsong Guo
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
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Shen Y, Huang DM, Chen YP, Yan P, Gao X. New insight into filamentous sludge bulking during wastewater treatment: Surface characteristics and thermodynamics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 712:135795. [PMID: 31866048 DOI: 10.1016/j.scitotenv.2019.135795] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 11/22/2019] [Accepted: 11/25/2019] [Indexed: 06/10/2023]
Abstract
Although there have been many studies on filamentary bulking of activated sludge, it has been revealed that there is still a gap in the microscopic mechanism of filamentary bulking. In this study, the surface characteristics and thermodynamics of sludge floc were investigated to reveal the mechanism of filamentous sludge bulking. The results showed that the EPS content gradually decreased from 71.09 mg/g VSS to 40.00 mg/g VSS and the protein (PN) content of the EPS significantly decreased from 64.10 mg/g VSS to 35.85 mg/g VSS during sludge bulking. The variation in the EPS and its components led to a decrease in the relative hydrophobicity of sludge and an increase in surface negative charge; then, deterioration of the flocculation setteability of sludge flocs occurred. The electric double layer (WR) was the main force determining the aggregation of sludge during sludge bulking. The total energy of the interaction (WT) increased during sludge bulking, which led to an increase in the difficulty of sludge accumulation. This study is useful for understanding the filamentous bulking of sludge within an activated sludge process.
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Affiliation(s)
- Yu Shen
- National Research Base of Intelligent Manufacturing Service, Chongqing Key Laboratory of Catalysis and New Environmental Materials, Chongqing Technology and Business University, Chongqing 400067, China; Chongqing South-to-Thais Environmental Protection Technology Research Institute Co., Ltd., Chongqing 400067, China
| | - Dong-Mei Huang
- National Research Base of Intelligent Manufacturing Service, Chongqing Key Laboratory of Catalysis and New Environmental Materials, Chongqing Technology and Business University, Chongqing 400067, China; Chongqing South-to-Thais Environmental Protection Technology Research Institute Co., Ltd., Chongqing 400067, China
| | - You-Peng Chen
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Peng Yan
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China.
| | - Xu Gao
- National Research Base of Intelligent Manufacturing Service, Chongqing Key Laboratory of Catalysis and New Environmental Materials, Chongqing Technology and Business University, Chongqing 400067, China
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Tian X, Shen Z, Han Z, Zhou Y. The effect of extracellular polymeric substances on exogenous highly toxic compounds in biological wastewater treatment: An overview. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2018.11.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Pino-Herrera DO, Pechaud Y, Huguenot D, Esposito G, van Hullebusch ED, Oturan MA. Removal mechanisms in aerobic slurry bioreactors for remediation of soils and sediments polluted with hydrophobic organic compounds: An overview. JOURNAL OF HAZARDOUS MATERIALS 2017; 339:427-449. [PMID: 28715703 DOI: 10.1016/j.jhazmat.2017.06.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/04/2017] [Accepted: 06/06/2017] [Indexed: 06/07/2023]
Abstract
Hydrophobic organic compound (HOC)-contaminated soils are a great environmental and public health concern nowadays. Further research is necessary to develop environmental friendly biotechnologies that allows public and private sectors to implement efficient and adaptable treatment approaches. Aerobic soil-slurry bioreactor technology has emerged as an effective and feasible technique with a high remediation potential, especially for silt and clay soil fractions, which often contain the highest pollutant concentration levels and are usually difficult to remove by implementing conventional methods. However, the mechanisms involved in the HOC removal in bioslurry reactor are still not completely understood. Gas-liquid and solid-liquid mass transfer, mass transport and biodegradation phenomena are the main known processes taking place in slurry bioreactors. This review compiles the most up-to-date information available about these phenomena and tries to link them, enlightening the possible interactions between parameters. It gathers the basic information needed to understand the complex bioremediation technology and raises awareness of some considerations that should be made.
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Affiliation(s)
- Douglas O Pino-Herrera
- Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, Marne-la-Vallée, 77454, France
| | - Yoan Pechaud
- Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, Marne-la-Vallée, 77454, France.
| | - David Huguenot
- Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, Marne-la-Vallée, 77454, France
| | - Giovanni Esposito
- University of Cassino and Southern Lazio, Department of Civil Engineering, Via di Biasio, 43, Cassino, 03043 FR, Italy
| | - Eric D van Hullebusch
- Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, Marne-la-Vallée, 77454, France; IHE Delft Institute for Water Education, Department of Environmental Engineering and Water Technology, Westvest 7, 2611 AX Delft, The Netherlands
| | - Mehmet A Oturan
- Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, Marne-la-Vallée, 77454, France
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Cao F, Bourven I, van Hullebusch ED, Pechaud Y, Lens PN, Guibaud G. Hydrophobic molecular features of EPS extracted from anaerobic granular sludge treating wastewater from a paper recycling plant. Process Biochem 2017. [DOI: 10.1016/j.procbio.2017.04.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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