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Liu WX, Wang J, Liu SY, Chen YP, Fang F, Yan P. Potential role of quorum quenching activity of silver nanoparticles in controlling non-filamentous bulking within activated sludge process. CHEMOSPHERE 2023:139324. [PMID: 37356593 DOI: 10.1016/j.chemosphere.2023.139324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 06/20/2023] [Accepted: 06/23/2023] [Indexed: 06/27/2023]
Abstract
The effective prevention and control of non-filamentous bulking is a significant challenge. In this study, the underlying effect of quorum sensing (QS) on inducing non-filamentous bulking and the maintenance effect of silver nanoparticles (AgNPs) on sludge floc stability, aggregation and settleability based on the quorum quenching (QQ) activity during non-filamentous bulking were investigated. The results showed that the concentration of N-acyl homoserine lactone (AHL) increased significantly in the activated sludge system at a high organic load rate (OLR), triggering the AHL-mediated QS. Additionally, the triggered QS promoted exopolysaccharide secretion, reducing the surface charge and hydrophobicity of the sludge aggregates, and further deteriorating the settleability of the sludge aggregates. AgNPs, a quorum sensing inhibitor (QSI), inhibited the AHL-QS based on QQ activity under high OLR, which maintained the physicochemical properties of extracellular polymeric substances (EPS). AgNPs-QQ maintained the surface energy barrier and electrostatic barrier of sludge aggregates and the gel properties of exopolysaccharides, which is favorable for microbial aggregation. The appropriate concentrations of AgNPs (≤10 mg/L) had no negative effect on biological nutrient removal in the sequencing batch reactors (SBRs) at the high organic loading. Therefore, AgNPs effectively prevent and control non-filamentous bulking by their QQ activity in the activated sludge process. Thus, the present study provided new insights into controlling non-filamentous bulking during the activated sludge process.
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Affiliation(s)
- Wei-Xin Liu
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Jing Wang
- Chongqing Jianzhu College, Chongqing, 400072, China
| | - Shao-Yang Liu
- Department of Chemistry and Physics, Troy University, Troy, AL, 36082, USA
| | - You-Peng Chen
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China
| | - Fang Fang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China; College of Environment and Ecology, 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; College of Environment and Ecology, Chongqing University, Chongqing, 400045, China.
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Wang S, Wang G, Yan P, Chen Y, Fang F, Guo J. Non-filamentous sludge bulking induced by exopolysaccharide variation in structure and properties during aerobic granulation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 876:162786. [PMID: 36907402 DOI: 10.1016/j.scitotenv.2023.162786] [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: 11/11/2022] [Revised: 02/13/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
The forming mechanism of non-filamentous sludge bulking during aerobic granulation were investigated basing on three feeding strategies (R1 direct aeration after fast feeding, R2 anaerobic stirring after fast feeding and R3 anaerobic plug-flow slow feeding). Results showed that strong selection stress (shortening settling time) led to a sharp flocs washout and the subsequent increase of food to microorganisms (F/M) in R1 and R3 reactors, but not found in R2 due to the different strategies of feeding modes. With the increase of F/M, zeta potential and hydrophobicity of sludge surfaces significantly decreased and thus leading to an enhanced repulsive force and energy barriers for sludge aggregation. Particularly, when F/M exceeded 1.2 kgCOD/(kgMLSS·d), non-filamentous sludge bulking was ultimately triggered in R1 and R3. Further analysis showed that massive extracellular exopolysaccharide (PS) accumulated on the surfaces of non-filamentous bulking sludge due to the increased abundance of the microorganisms related to PS secretion during sludge bulking. In addition, significantly increased intracellular second messenger (c-di-GMP), a key substance regulating PS biosynthesis, was confirmed via its concentration determination as well as microbial function prediction analysis, which played a critical role in sludge bulking. Combing with the systematic detection from surface plasmon resonance system, rheometer and size-exclusion chromatography-multiangle laser light detection-refractive index system, higher molecular weight, compact conformation, higher viscosity and higher hydrophilicity was determined in sludge bulking PS relative to PS extracted from non-filamentous bulking sludge. Clearly, the changes of PS (content, structures and properties) driven by c-di-GMP are the dominant mechanism for the formation of non-filamentous sludge bulking during aerobic granulation. This work could provide theoretical support for successful start-up and application of aerobic granular sludge technology.
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Affiliation(s)
- Shuai Wang
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China; College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Gonglei Wang
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Peng Yan
- College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Youpeng Chen
- 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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Wang J, Wu S, Yang Q, Liu B, Yang M, Fei W, Tang Y, Zhang X. Effect of the degradation performance on carbon tetrachloride by anaerobic co-metabolism under different external energy sources. CHEMOSPHERE 2022; 308:136262. [PMID: 36055587 DOI: 10.1016/j.chemosphere.2022.136262] [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: 05/13/2022] [Revised: 07/22/2022] [Accepted: 08/27/2022] [Indexed: 06/15/2023]
Abstract
In this research, a comprehensive study was carried out on the removal of carbon tetrachloride (CT) in the anaerobic co-metabolism (ACM) reactor. The experiments showed that when the hydraulic retention time (HRT) was 36 h, pH was 7, and influent CT was 2.5mg/L, the average removal efficiency reached 82.45 ± 2.56% in the glucose co-metabolism substrate reactor, exhibiting a dramatic excellent difference in reaction performance from the other two reactors (p < 0.05) and a favorable tolerance on the CT shock loading. The content of extracellular polymeric substances (EPS) and volatile fatty acids (VFA) demonstrated that glucose could supply more energy to protect the microorganisms, which was the appropriate external energy source. Moreover, microbial community structure and biostatistics analysis demonstrated that Pseudomonas was the most important dechlorination bacteria in ACM reactors, which might via dehalogenation process mediate the transformation of CT. The succession of methanogenic bacteria further demonstrated that CT degradation using co-digestion require to destroy hydrogenotrophic methane generation pathway and the external energy substances could make up the lack of hydrogen in the treatment of CT. The change of intermediate products hinted that anaerobic dechlorination process of CT in an ACM reactor was a sequential dechlorination process, and major transformation products measured were CF. Overall, this study has improved our understanding of the roles of CT degradation process in ACM reactors.
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Affiliation(s)
- Jia Wang
- MOK Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China; Industrial Technology Office, Ministry of Environmental Protection Center for Foreign Cooperation, Beijing, 100035, PR China
| | - Shuangrong Wu
- School of Civil Engineering, Tangshan University, Tangshan, 063000, PR China
| | - Qi Yang
- MOK Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China.
| | - Bingyang Liu
- MOK Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, PR China
| | - Ming Yang
- Industrial Technology Office, Ministry of Environmental Protection Center for Foreign Cooperation, Beijing, 100035, PR China
| | - WeiLiang Fei
- Industrial Technology Office, Ministry of Environmental Protection Center for Foreign Cooperation, Beijing, 100035, PR China
| | - Yandong Tang
- Industrial Technology Office, Ministry of Environmental Protection Center for Foreign Cooperation, Beijing, 100035, PR China
| | - XiaoLan Zhang
- Industrial Technology Office, Ministry of Environmental Protection Center for Foreign Cooperation, Beijing, 100035, PR China
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Zuo R, Shi J, Han K, Xu D, Li Q, Zhao X, Xue Z, Xu Y, Wu Z, Wang J. Response relationship of environmental factors caused by toluene concentration during leaching of capillary zone. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 317:115366. [PMID: 35636110 DOI: 10.1016/j.jenvman.2022.115366] [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: 12/18/2021] [Revised: 05/07/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
Due to the leaching of capillary water, the petroleum pollutants initially trapped in vadose zone may migrate to lower aquifer, thus increasing the risk of groundwater pollution. In order to explore the effect of capillary leaching on toluene-contaminated soil and the relationship between toluene concentration (TC) and environmental factors (EFs) during the leaching process, the sterilized and non-sterilized soil column experiments were designed. The EFs were used to estimate TC. The results showed that the difference between leaching and volatilization rates directly determined the changing trend of toluene concentration in capillary water. The toluene concentration in the medium always showed decreasing trend due to leaching. The indigenous microbial community structure of the non-sterilized soil column was analyzed by 16S rRNA sequencing. It was found that indigenous microorganisms could degrade toluene after 33.0 days of acclimatation. The microbial population was dominated by bacteria, among them the Ellin6055 strain and Pseudomonas, Pseudoxanthomonas, Cupriavidus, Bdellovibrio, Sphingobium, Phenylobacterium, Ramlibacter, Bradyrhizobium, Shinella genera. The Pseudomonas was the most crucial bacterial genus that degraded toluene. Indigenous microbial degradation was the fundamental reason for strong response relationship. Furthermore, we suggested a relationship of function between environmental factors (pH, DO, ORP) and time (t) for toluene attenuation: C0+ln(eAtαBγCβ)=CToluene, (α, β, γ represent the pH, DO, and ORP in leaching capillary water, respectively; A, B, and C represent undetermined coefficients), and the fitting coefficient R2 > 0.950. This relationship can only characterize the attenuation process of capillary zone leaching on toluene. However, it may still be utilized to give a theoretical foundation for understanding the dynamic of pollutant concentration change processes under specific environmental factors.
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Affiliation(s)
- Rui Zuo
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
| | - Jian Shi
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
| | - Kexue Han
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China.
| | - Donghui Xu
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
| | - Qiao Li
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
| | - Xiao Zhao
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
| | - Zhenkun Xue
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
| | - Yunxiang Xu
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
| | - Ziyi Wu
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
| | - Jinsheng Wang
- College of Water Sciences, Beijing Normal University, Beijing, 100875, China; Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing, 100875, China
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Wang J, Yang Z, Wang H, Wu S, Lu H, Wang X. Decomposition process of cefotaxime sodium from antibiotic wastewater by Up-flow Blanket Filter (UBF) reactor: Reactor performance, sludge characteristics and microbial community structure analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 758:143670. [PMID: 33257062 DOI: 10.1016/j.scitotenv.2020.143670] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/28/2020] [Accepted: 11/09/2020] [Indexed: 06/12/2023]
Abstract
In this study, a novel Up-flow Blanket Filter (UBF) reactor was applied to the degradation of antibiotic wastewater. The experiments showed that when the hydraulic retention time (HRT) was 24 h and the ratio of volatile fatty acids (VFA) to alkalinity (ALK) was 0.3, the best removal efficiency was achieved in the combined packing UBF reactor, and the COD removal efficiency reached 80.1%-84.6%, exhibiting a significant difference in reaction performance from the other two reactors (P < 0.05) and a good efficiency of cefotaxime sodium removal. Moreover, the microstructure and surface characteristics of the reactor fillers were studied through scanning electron microscope (SEM) analysis, which showed that three fillers all had biofilm adhesion, but the combined packing gave best performance. Energy dispersive spectrometer (EDS) tests indicated abundant element components in the combined packing. The particle size distribution of sludge was also considered in the experiment, and the result showed the particle size of sludge increased with the operation of the reactor. In addition, microbial community structures of sludge and biofilm with the combined packing were analyzed. High-throughput sequencing confirmed the existence of Pseudomonas, which had good adaptability to antibiotic wastewater and became the dominant bacteria. Decomposition process of cefotaxime sodium after hydrolysis and anaerobic treatment was analyzed through Fourier transform infrared spectroscopy (FTIR). The reactor, which is economical, exhibited favorable performance in degrading the pollutions in the antibiotic wastewater.
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Affiliation(s)
- Jia Wang
- College of Civil and Architectural Engineering, North China University of Science and Technology, Tangshan, PR China
| | - Zhinian Yang
- College of Civil and Architectural Engineering, North China University of Science and Technology, Tangshan, PR China
| | - Hao Wang
- College of Civil and Architectural Engineering, North China University of Science and Technology, Tangshan, PR China.
| | - Shuangrong Wu
- College of Civil and Architectural Engineering, North China University of Science and Technology, Tangshan, PR China
| | - Huan Lu
- College of Civil and Architectural Engineering, North China University of Science and Technology, Tangshan, PR China
| | - Xingguo Wang
- College of Civil and Architectural Engineering, North China University of Science and Technology, Tangshan, PR China
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Real Wastewater Treatment Using a Moving Bed and Wastewater-Borne Algal–Bacterial Consortia with a Short Hydraulic Retention Time. Processes (Basel) 2021. [DOI: 10.3390/pr9010116] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Algal–bacterial consortium is a promising technology, combined with wastewater treatment plants, because algae produce molecular oxygen for nitrification and organic removal and reduce carbon dioxide emissions. However, algal–bacterial consortia based on suspended growth require a relatively long hydraulic retention time (HRT) of 4 d to 6 d for removal of organic matter and nutrients. For the algal–bacterial consortia in a photobioreactor (PBR) containing a moving bed, the organic matter and nutrient removal and the community structure of algal–bacterial consortia were investigated to determine the performance under a relatively short HRT of 2.5 d. Moving media containing algal–bacterial consortia enhanced the photosynthetic oxygen concentration (0.2 mg dissolved oxygen (DO)·L−1 to 5.9 mg DO·L−1), biochemical oxygen demand removal (88.0% to 97.2%), ammoniacal nitrogen removal (33.8% to 95.3%), total nitrogen removal (61.6% to 87.7%), total phosphate removal (66.4% to 88.7%), algal growth (149.3 mg algae·L−1 to 285.4 mg algae·L−1), and settleability (algae removal efficiency of 20.6% to 71.2%) compared with those of a PBR without moving media (SPBR). Although biomass uptake was the main mechanism for nutrient removal in the SPBR, both biomass uptake and denitrification were the main mechanisms in the PBR with moving media (MBPBR). The bacterial community also changed under the moving media condition. This study shows that moving media might be an essential parameter for PBRs with a short HRT to enhance nutrient removal and settleability.
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