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Wang M, He J, Dong X, Zhang R. Effect of gradual increase of salt on performance and microbial community during granulation process. J Environ Sci (China) 2025; 147:404-413. [PMID: 39003058 DOI: 10.1016/j.jes.2023.11.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/21/2023] [Accepted: 11/21/2023] [Indexed: 07/15/2024]
Abstract
Salinity was considered to have effects on the characteristics, performance microbial communities of aerobic granular sludge. This study investigated granulation process with gradual increase of salt under different gradients. Two identical sequencing batch reactors were operated, while the influent of Ra and Rb was subjected to stepwise increments of NaCl concentrations (0-4 g/L and 0-10 g/L). The presence of filamentous bacteria may contribute to granules formed under lower salinity conditions, potentially leading to granules fragmentation. Excellent removal efficiency achieved in both reactors although there was a small accumulation of nitrite in Rb at later stages. The removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) in Ra were 95.31%, 93.70% and 88.66%, while the corresponding removal efficiencies in Rb were 94.19%, 89.79% and 80.74%. Salinity stimulated extracellular polymeric substances (EPS) secretion and enriched EPS producing bacteria to help maintain the integrity and stability of the aerobic granules. Heterotrophic nitrifying bacteria were responsible for NH4+-N and NO2--N oxidation of salinity systems and large number of denitrifying bacteria were detected, which ensure the high removal efficiency of TN in the systems.
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Affiliation(s)
- Mengfei Wang
- School of Environment, Harbin Institute of Technology, Harbin 150090, China; State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Junguo He
- School of Civil Engineering, Guangzhou University, Guangzhou 510006, China
| | - Xiangke Dong
- National Marine Environmental Monitoring Center, Dalian 116023, China
| | - Ruimiao Zhang
- School of Environment, Harbin Institute of Technology, Harbin 150090, China; State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China
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2
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Liu S, Li Y, Lu L, Huang G, Chen F. Efficient nitrogen removal from municipal wastewater using an integrated fixed-film activated sludge process in a novel air-lifting loop reactor: A pilot-scale demonstration. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 360:121108. [PMID: 38754189 DOI: 10.1016/j.jenvman.2024.121108] [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: 12/29/2023] [Revised: 04/12/2024] [Accepted: 05/05/2024] [Indexed: 05/18/2024]
Abstract
A novel air-lifting loop reactor combines anoxic, oxic, and settling zones to achieve organic and nutrient removal, as well as solid-liquid separation. To address sludge settling ability and operation stability issues caused by low dissolved oxygen in aerobic zones, this study proposes using modified polypropylene carriers to establish a fixed-film activated sludge (IFAS) system. A pilot-scale demonstration of the IFAS-based air-lifting loop reactor is conducted, and the results show successful operation for approximately 300 days. The pilot-scale reactor achieves a maximum aerobic granulation ratio of 16% in the bulk liquid. The IFAS system contributes to efficient removal of organic matter (96%) and nitrogen (94%) by facilitating simultaneous nitrification and denitrification, as well as fast solid-liquid separation with a low sludge volume index of 34 mL/g. Microbial analysis reveals enrichment of functional bacteria involved in nitrification, denitrification, and flocculation throughout the operation process.
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Affiliation(s)
- Shujie Liu
- Qingyan Environmental Technology Co. Ltd., Shenzhen, 51800, China; State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University, Beijing 100084, China
| | - Yun Li
- Qingyan Environmental Technology Co. Ltd., Shenzhen, 51800, China.
| | - Lanlan Lu
- Qingyan Environmental Technology Co. Ltd., Shenzhen, 51800, China
| | - Guangrong Huang
- Qingyan Environmental Technology Co. Ltd., Shenzhen, 51800, China
| | - Fuming Chen
- Qingyan Environmental Technology Co. Ltd., Shenzhen, 51800, China
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3
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Du B, Zhan X, Lens PNL, Zhang Y, Wu G. Deciphering anaerobic ethanol metabolic pathways shaped by operational modes. WATER RESEARCH 2024; 249:120896. [PMID: 38006787 DOI: 10.1016/j.watres.2023.120896] [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: 09/10/2023] [Revised: 11/01/2023] [Accepted: 11/17/2023] [Indexed: 11/27/2023]
Abstract
Efficient anaerobic digestion requires the syntrophic cooperation among diverse microorganisms with various metabolic pathways. In this study, two operational modes, i.e., the sequencing batch reactor (SBR) and the continuous-flow reactor (CFR), were adopted in ethanol-fed systems with or without the supplement of powdered activated carbon (PAC) to examine their effects on ethanol metabolic pathways. Notably, the operational mode of SBR and the presence of CO2 facilitated ethanol metabolism towards propionate production. This was further evidenced by the dominance of Desulfobulbus, and the increased relative abundances of enzymes (EC: 1.2.7.1 and 1.2.7.11) involved in CO2 metabolism in SBRs. Moreover, SBRs exhibited superior biomass-based rates of ethanol degradation and methanogenesis, surpassing those in CFRs by 53.1% and 22.3%, respectively. Remarkably, CFRs with the extended solids retention time enriched high relative abundances of Geobacter of 71.7% and 70.4% under conditions with and without the addition of PAC, respectively. Although both long-term and short-term PAC additions led to the increased sludge conductivity and a reduced methanogenic lag phase, only the long-term PAC addition resulted in enhanced rates of ethanol degradation and propionate production/degradation. The strategies by adjusting operational mode and PAC addition could be adopted for modulating the anaerobic ethanol metabolic pathway and enriching Geobacter.
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Affiliation(s)
- Bang Du
- Civil Engineering, School of Engineering, College of Science and Engineering, University of Galway, Galway H91 TK33, Ireland
| | - Xinmin Zhan
- Civil Engineering, School of Engineering, College of Science and Engineering, University of Galway, Galway H91 TK33, Ireland
| | - Piet N L Lens
- Microbiology, School of Biological and Chemical Sciences, College of Science and Engineering, University of Galway, Galway H91 TK33, Ireland
| | - Yifeng Zhang
- Department of Environmental and Resource Engineering, Technical University of Denmark, Lyngby DK-2800, Denmark
| | - Guangxue Wu
- Civil Engineering, School of Engineering, College of Science and Engineering, University of Galway, Galway H91 TK33, Ireland.
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4
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Du B, Wang Z, Lens PNL, Zhan X, Wu G. New insights into syntrophic ethanol oxidation: Effects of operational modes and solids retention times. ENVIRONMENTAL RESEARCH 2024; 241:117607. [PMID: 37939810 DOI: 10.1016/j.envres.2023.117607] [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: 08/01/2023] [Revised: 10/21/2023] [Accepted: 11/04/2023] [Indexed: 11/10/2023]
Abstract
Anaerobic ethanol oxidation relies on syntrophic interactions among functional microorganisms to become thermodynamically feasible. Different operational modes (sequencing batch reactors, SBRs, and continuous flow reactors, CFRs) and solids retention times (SRT, 25 days and 10 days) were employed in four ethanol-fed reactors, named as SBR25d, SBR10d, CFR25d, and CFR10d, respectively. System performance, syntrophic relationships, microbial communities, and metabolic pathways were examined. During the long-term operation, 2002.7 ± 56.0 mg COD/L acetate was accumulated in CFR10d due to the washout of acetotrophic methanogens. Microorganisms with high half-saturation constants were enriched in reactors of 25-day SRT. Moreover, ethanol oxidizing bacteria and acetotrophic methanogens with high half-saturation constants could be acclimated in SBRs. In SBRs, Syner-01 and Methanothrix dominated, and the low SRT of 10 days increased the relative abundance of Geobacter to 38.0%. In CFRs, the low SRT of 10 days resulted in an increase of Desulfovibrio among syntrophic bacteria, and CFR10d could be employed in enriching hydrogenotrophic methanogens like Methanobrevibacter.
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Affiliation(s)
- Bang Du
- Civil Engineering, School of Engineering, College of Science and Engineering, University of Galway, Galway, H91 TK33, Ireland
| | - Zhongzhong Wang
- Civil Engineering, School of Engineering, College of Science and Engineering, University of Galway, Galway, H91 TK33, Ireland
| | - Piet N L Lens
- Microbiology, School of Biological and Chemical Sciences, College of Science and Engineering, University of Galway, Galway, H91 TK33, Ireland
| | - Xinmin Zhan
- Civil Engineering, School of Engineering, College of Science and Engineering, University of Galway, Galway, H91 TK33, Ireland
| | - Guangxue Wu
- Civil Engineering, School of Engineering, College of Science and Engineering, University of Galway, Galway, H91 TK33, Ireland.
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Li Y, Liu S, Lu L, Wang J, Huang G, Chen F, Zuo JE. Non-uniform dissolved oxygen distribution and high sludge concentration enhance simultaneous nitrification and denitrification in a novel air-lifting reactor for municipal wastewater treatment: A pilot-scale study. BIORESOURCE TECHNOLOGY 2023:129306. [PMID: 37328012 DOI: 10.1016/j.biortech.2023.129306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/01/2023] [Accepted: 06/07/2023] [Indexed: 06/18/2023]
Abstract
Achieving simultaneous carbon and nitrogen removal with sludge-liquid separation in a single reactor offers a solution to land shortages and improves treatment efficiency in municipal wastewater treatment plants of megacities. This study proposes a novel air-lifting continuous-flow reactor configuration with an alternative-aeration strategy that creates multi-functional zones for anoxic, oxic, and settlement processes. The optimal operational conditions for the reactor include a long anoxic hydraulic retention time, low dissolved oxygen (DO) in the oxic zone, and no specific reflux for external nitrifying liquid, which exhibit a high nitrogen removal efficiency of over 90% in treating real sewage with C/N < 4 in the pilot-scale study. Results show that a high sludge concentration and a low DO concentration facilitate simultaneous nitrification and denitrification, and a well mixing of sludge and substrate in different reaction zones promotes nitrogen removal. The long-term operation enriches functional microbes for carbon storage and nutrient removal.
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Affiliation(s)
- Yun Li
- Qingyan Environmental Technology Co. Ltd, Shenzhen 51800, China; Research Centre of Environmental Microbial Resource Development and Application Engineering, Research Institute of Tsinghua University in Shenzhen, Guangdong 518000, China.
| | - Shujie Liu
- Qingyan Environmental Technology Co. Ltd, Shenzhen 51800, China; State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University, Beijing 100084, China
| | - Lanlan Lu
- Qingyan Environmental Technology Co. Ltd, Shenzhen 51800, China
| | - Jinghou Wang
- Qingyan Environmental Technology Co. Ltd, Shenzhen 51800, China
| | - Guangrong Huang
- Qingyan Environmental Technology Co. Ltd, Shenzhen 51800, China
| | - Fuming Chen
- Qingyan Environmental Technology Co. Ltd, Shenzhen 51800, China
| | - Jian-E Zuo
- State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University, Beijing 100084, China; Tsinghua Shenzhen International Graduate School, Shenzhen 518055, China
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6
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Samaei SHA, Chen J, Xue J. Current progress of continuous-flow aerobic granular sludge: A critical review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 875:162633. [PMID: 36889385 DOI: 10.1016/j.scitotenv.2023.162633] [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: 08/21/2022] [Revised: 02/12/2023] [Accepted: 02/28/2023] [Indexed: 06/18/2023]
Abstract
Aerobic granular sludge (AGS) is promising for water resource recovery. Despite the mature granulation strategies in sequencing batch reactor (SBR), the application of AGS-SBR in wastewater treatment is usually costly as it requires extensive infrastructure conversion (e.g., from continuous-flow reactor to SBR). In contrast, continuous-flow AGS (CAGS) that does not require such infrastructure conversion is a more cost-effective strategy to retrofit existing wastewater treatment plants (WWTPs). Formation of aerobic granules in both batch and continuous-flow mode depends on many factors, including selection pressure, feast/famine conditions, extracellular polymeric substances (EPS), and environmental conditions. Compared with AGS in SBR, creating proper conditions to facilitate granulation in continuous-flow mode is challenging. Researchers have been seeking to tackle this bottleneck by studying the impacts of selection pressure, feast/famine conditions, and operating parameters on granulation and granule stability in CAGS. This review paper summarizes the state-of-the-art knowledge regarding CAGS for wastewater treatment. Firstly, we discuss the CAGS granulation process and effective parameters (i.e., selection pressure, feast/famine conditions, hydrodynamic shear force, reactor configuration, the role of EPS, and other operating factors). Then, we evaluate CAGS performance in removing COD, nitrogen, phosphorus, emerging pollutants, and heavy metals from wastewater. Finally, the applicability of the hybrid CAGS systems is presented. At last, we suggest that integrating CAGS with other treatment methods such as membrane bioreactor (MBR) or advanced oxidation processes (AOP) can benefit the performance and stability of granules. However, future research should address unknowns including the relationship between feast/famine ratio and stability of the granules, the effectiveness of applying particle size-based selection pressure, and the CAGS performance at low temperatures.
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Affiliation(s)
- Seyed Hesam-Aldin Samaei
- Cold-Region Water Resource Recovery Laboratory, Environmental Systems Engineering, Faculty of Engineering and Applied Science, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - Jianfei Chen
- Cold-Region Water Resource Recovery Laboratory, Environmental Systems Engineering, Faculty of Engineering and Applied Science, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - Jinkai Xue
- Cold-Region Water Resource Recovery Laboratory, Environmental Systems Engineering, Faculty of Engineering and Applied Science, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada.
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7
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Wang Y, Wang H, Chen H. Response of aerobic activated sludge to edible oil exposure: Extracellular polymeric substance (EPS) characteristics and microbial community. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 335:117571. [PMID: 36871358 DOI: 10.1016/j.jenvman.2023.117571] [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: 12/18/2022] [Revised: 02/13/2023] [Accepted: 02/21/2023] [Indexed: 06/18/2023]
Abstract
Aerobic activated sludge is widely used to degrade edible oil wastewater in wastewater treatment plants. During this process, the observed poor organics removal performance might be caused by poor sludge settling performance, which might be influenced by extracellular polymeric substances (EPS) and the structure of the microbial community. However, this hypothesis was not confirmed. Thus, this study investigated the response of activated sludge to 50% and 100% edible oil exposure in comparison to glucose, focusing on organics removal performance, characteristics of sludge, EPS, and microbial community structure. Results showed that both concentrations of edible oil influenced the systems' performance, although 100% edible oil showed more significant negative effects than 50% edible oil. The mechanisms behind the influence of edible oil on the aerobic activated sludge system and the differences between the different concentrations of edible oil were revealed. The worse system performance in the edible oil exposure system was due to the worse sludge settling performance, which was significantly affected by edible oil (p < 0.05). The sludge settling performance was mainly inhibited by promoting the formation of floating particles and the enrichment of filamentous bacteria in the 50% edible oil exposure system; biosurfactant secretion was also speculated as the reason, in addition to the above factors, in the 100% edible oil exposure system. The macroscopic largest floating particles, highest total relative abundance of foaming bacteria and biosurfactant production genera (34.32%), lowest surface tension (43.7 mN/m), and highest emulsifying activity (E24 = 25%) of EPS in 100% edible oil exposure systems provide strong evidence.
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Affiliation(s)
- Yanqiong Wang
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Hongwu Wang
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Key Laboratory of Urban Water Supply, Water Saving and Water Environment Governance in the Yangtze River Delta of Ministry of Water Resources, Shanghai, 200092, China.
| | - Hongbin Chen
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; National Engineering Research Center for Urban Pollution Control, Tongji University, Shanghai, 200092, China
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8
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Li J, Ma J, Liao H, Li X, Shen L, Lin H, Sun L, Ou R, He D. Hot-pressed membrane assemblies enhancing the biofilm formation and nitrogen removal in a membrane-aerated biofilm reactor. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 833:155003. [PMID: 35390370 DOI: 10.1016/j.scitotenv.2022.155003] [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: 02/07/2022] [Revised: 03/23/2022] [Accepted: 03/30/2022] [Indexed: 06/14/2023]
Abstract
Membrane-aerated biofilm reactor (MABR) is gaining popularity in wastewater treatment as a result of the low-energy delivery of oxygen from the carrier side and reduced sludge waste production, although its wider application suffers from the difficulty in microbial colonization on the smooth, hydrophobic membrane surface. In this study, a newly designed membrane/non-woven fabric assembly, prepared via a facile hot-pressing method, is demonstrated to be efficient in promoting the biofilm formation and nitrogen removal in MABR. The assembly achieved rough surface structure to retain biomass whilst sustained the surface hydrophobicity for a high oxygen transfer ability, which is crucial to support a resilient biofilm. Compared with the slower biomass growth and severe detachment of biofilm in the control, a thicker biofilm was quickly developed on the hot-pressed membrane assembly. High loading rates of organic matter, ammonia nitrogen and total nitrogen (TN) in the MABR using the hot-pressed membrane were 154.9 ± 5.4 g COD/(m2·d), 25.5 ± 0.6 g N/(m2·d) and 22.6 ± 0.7 g N/(m2·d), respectively. Particularly, the removal efficiency of TN was up to 82.8%, which was 2.5 times higher than the control. Furthermore, the biofilm grown on the hot-pressed membrane assembly organized a stable microbial community structure with a steady evolution to achieve a synergistic denitrifying function. Among the bacterial phylotypes, OLB8 might be crucial in denitrification. This study highlighted the significance of this facile membrane modification method to improve the process performance of MABR in wastewater treatment.
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Affiliation(s)
- Jibin Li
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Jinxing Ma
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China
| | - Huaiyu Liao
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Xianhui Li
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China
| | - Liguo Shen
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, PR China
| | - Hongjun Lin
- College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, PR China
| | - Li Sun
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Rui Ou
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Di He
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, PR China.
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9
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Yuan S, Guo S, Huang X, Meng F. Time-lagged interspecies interactions prevail during biofilm development in moving bed biofilm reactor. Biotechnol Bioeng 2022; 119:2770-2783. [PMID: 35837838 DOI: 10.1002/bit.28177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 06/27/2022] [Accepted: 07/10/2022] [Indexed: 11/09/2022]
Abstract
Clarifying the essential succession dynamics of interspecies interactions during biofilm development is crucial for the regulation and application of biofilm-based processes. In this study, regular and time-series phylogenetic molecular ecological networks (pMENs) were constructed to investigate ordinary and time-lagged interspecies interactions during biofilm development in a moving bed biofilm reactor (MBBR). Positive interactions dominated both regular (89.78%) and time-series (77.04%) ecological networks, suggesting that extensive cooperative behaviors facilitated biofilm development. The pronounced directional interactions (72.52%) in the time-series network further indicated that time-lagged interspecies interactions prevailed in the biofilm development process. Specifically, the proportion of directional negative interactions was higher than that of positive interactions, implying that interspecific competition preferred to be time-lagged. The time-series network revealed that module hubs exhibited extensive time-lagged positive interactions with their neighbors, and most of them exhibited altruistic behaviors. Keystone species possessing more positive interactions were positively correlated with biofilm biomass, NO3 - -N concentrations, and the removal efficiencies of NH4 + -N and COD. However, keystone species and peripherals that were negatively targeted by their neighbors showed positive correlations with the concentrations of NO2 - -N, polysaccharides, and proteins in the soluble microbial products. The data highlight that the time-series network can provide directional microbial interactions along with the biofilm development process, which would help to predict the tendency of community shifts and propose efficient strategies for the regulation of biofilm-based processes. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Shasha Yuan
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, PR China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, (Sun Yat-sen University), Guangzhou, 510275, PR China
| | - Sixian Guo
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, PR China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, (Sun Yat-sen University), Guangzhou, 510275, PR China
| | - Xihao Huang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, PR China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, (Sun Yat-sen University), Guangzhou, 510275, PR China
| | - Fangang Meng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, PR China.,Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, (Sun Yat-sen University), Guangzhou, 510275, PR China
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Guo Q, Yin Q, Du J, Zuo J, Wu G. New insights into the r/K selection theory achieved in methanogenic systems through continuous-flow and sequencing batch operational modes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 807:150732. [PMID: 34606861 DOI: 10.1016/j.scitotenv.2021.150732] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/28/2021] [Accepted: 09/28/2021] [Indexed: 06/13/2023]
Abstract
Anaerobic digestion is achieved through cooperation among various types of microorganisms, and the regulation of microbial communities is key to achieving stable system operation. In this study, the r/K selection theory was adopted to examine the system performance and microbial characteristics in anaerobic reactors with different operating modes (continuous-flow reactors, CFRs; sequencing batch reactors, SBRs) and sludge retention times (25 and 10 days). Four lab-scale reactors (CFR25d, CFR10d, SBR25d, and SBR10d) were operated. In the cycle reaction, CFR25d achieved the highest methane yield (678.0 mL/L) and methane production rate (140.8 mL/(L·h)); while those in CFR10d were the lowest, which could have been due to an accumulation of volatile fatty acids. CFR could wash out r-strategists efficiently, such as Methanosarcina. CFR25d and CFR10d significantly enriched the K-strategist Geobacter, with the relative abundances of 34.0% and 72.6%, respectively. In addition, the hydrogenotrophic methanogens of Methanolinea and Methanospirillum (K-strategists) dominated in CFR25d and CFR10d. Methanobacterium adapted to the diverse operational conditions, but the slow grower Methanosaeta only accounted for 0.9% in CFR10d. Failure to enrich propionate oxidizers resulted in a functional absence of propionate degradation in the CFRs.
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Affiliation(s)
- Qiannan Guo
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong, China
| | - Qidong Yin
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong, China
| | - Jin Du
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong, China
| | - Jiane Zuo
- Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong, China
| | - Guangxue Wu
- Civil Engineering, School of Engineering, College of Science and Engineering, National University of Ireland, Galway, Galway H91 TK33, Ireland.
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Hang Z, Li Z, Zhu Y, Zhang J, Yang F, Zhang T. A new approach to evaluate and improve the stability of aerobic sludge systems based on maintenance coefficient. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 296:113192. [PMID: 34252857 DOI: 10.1016/j.jenvman.2021.113192] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/31/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Stability is a key issue of wastewater treatment plants using either aerobic granular (AGS) or conventional activated sludge (CAS). The two forms of aerobic sludge were cultivated under different conditions to study the main factors affecting their stability. It was found that maintenance coefficient (m) describing the fraction of non-growth energy of granules increased significantly when the system became more stable during processes with the enhancement of granulation and the periodic short-term shock load. The yield coefficient (YH) was the main factor affecting the m value, and the inhibition in YH value was able to promote the maintenance potential according to the kinetic equation. Therefore, strategies that promote the maintenance coefficient could be applied to improve the stability of sludge systems, including inhibiting the yield rate and taking periodic short-term shock. Evaluation of stability based on the maintenance coefficient is a promising tool for ensuring the stable operation of wastewater treatment processes.
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Affiliation(s)
- Zhenyu Hang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Zhihua Li
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
| | - Yuanmo Zhu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Jing Zhang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Fan Yang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Tianyu Zhang
- Department of Mathematical Sciences, Montana State University, Bozeman, MT, 59717-2400, USA
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