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Birch H, Teixeira A, van Egmond R, Mayer P. Closed aerobic biodegradation kinetics test with activated sludge and low concentration chemical mixtures. CHEMOSPHERE 2023; 330:138752. [PMID: 37086980 DOI: 10.1016/j.chemosphere.2023.138752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/03/2023]
Abstract
The activated sludge process at wastewater treatment plants is important to prevent discharge of organic pollutants to the environment. Determination of biodegradation kinetics in activated sludge is challenging for mixtures that cover a diverse range of structures. The aims of this study were to (1) design a closed aerobic biodegradation batch test with activated sludge and (2) develop a sample preparation procedure that is compatible with LC-MS and Solid Phase Microextraction (SPME) coupled to GC-MS. A headspace:sludge ratio of 4:1 was sufficient to ensure aerobic conditions in activated sludge for 7 days at co-solvent concentrations <0.01%. Ethanol was added to sub-samples (50%) to stop biodegradation, extract sorbed chemicals and allow storage at -18 °C without ice formation. The ethanol extracted the chemicals from the sludge before filtration (0.2 μm). The filtrate was diluted in ultrapure water to <12% ethanol before analysis by SPME GC-MS/MS and was suitable for direct injection on LC-MS/MS. Biodegradation was distinguished from sorption through abiotic controls using autoclaved poisoned sludge. Linalool, naphthalene, α-isomethylionone, phenanthrene, citronellol, drometrizole, 2-ethylhexyl 4-methoxycinnamate, dicyclohexyl phthalate, BP-1, BP-3, methyl-, ethyl-, propylparaben, alkyl sulfates and isethionates degraded within 48 h in activated sludge, while musk ketone, tonalide and 1,3,5-trichlorobenzene did not. A 10 times reduction of sludge density did not markedly affect the microbial diversity but slowed biodegradation kinetics (partly explained by theory). This study demonstrated a 'cold' alternative to an OECD 314b test and how biodegradation kinetics can be determined for mixtures of diverse chemicals in closed batch tests with activated sludge.
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Affiliation(s)
- Heidi Birch
- Technical University of Denmark, Department of Environmental and Resource Engineering, Bygningstorvet, Building 115, 2800, Kgs. Lyngby, Denmark.
| | - Alexandre Teixeira
- Unilever, Safety & Environmental Assurance Centre, Bedford, MK44 1LQ, UK
| | - Roger van Egmond
- Unilever, Safety & Environmental Assurance Centre, Bedford, MK44 1LQ, UK
| | - Philipp Mayer
- Technical University of Denmark, Department of Environmental and Resource Engineering, Bygningstorvet, Building 115, 2800, Kgs. Lyngby, Denmark
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Hong Y, Tu Q, Cheng H, Huangfu X, Chen Z, He Q. Chronic high-dose silver nanoparticle exposure stimulates N 2O emissions by constructing anaerobic micro-environment. WATER RESEARCH 2022; 225:119104. [PMID: 36155009 DOI: 10.1016/j.watres.2022.119104] [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: 05/20/2022] [Revised: 09/05/2022] [Accepted: 09/10/2022] [Indexed: 06/16/2023]
Abstract
Silver nanoparticles (Ag-NPs) were found to be responsible for nitrous oxide (N2O) generation; however, the mechanism of Ag-NP induced N2O production remains controversial and needs to be elucidated. In this study, chronic Ag-NP exposure experiments were conducted in five independent sequencing batch biofilm reactors to systematically assess the effects of Ag-NPs on N2O emission. The results indicated that a low dose of Ag-NPs (< 1 mg/L) slightly suppressed N2O generation by less than 22.99% compared with the no-Ag-NP control method. In contrast, a high dose (5 mg/L) of Ag-NPs stimulated N2O emission by 67.54%. ICP-MS and SEM-EDS together revealed that high Ag-NP content accumulated on the biofilm surface when exposed to 5 mg/L Ag-NPs. N2O and DO microelectrodes, as well as N2O isotopic composition analyses, further demonstrated that the accumulated Ag-NPs construct the anaerobic zone in the biofilm, which is the primary factor for the stimulation of the nitrite reduction pathway to release N2O. A metagenomic analysis further attributed the higher N2O emissions under exposure to a high dose of Ag-NPs to the higher relative abundance of narB and nirK genes (i.e. 1.52- and 1.29-fold higher, respectively). These findings collectively suggest that chronic exposure to high doses of Ag-NPs could enhance N2O emissions by forming anaerobic micro-environments in biofilms.
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Affiliation(s)
- Yiyihui Hong
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing 400044, China
| | - Qianqian Tu
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing 400044, China; China TieGong Investment & Construction Group Co., Ltd, Beijing 101300, China
| | - Hong Cheng
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing 400044, China.
| | - Xiaoliu Huangfu
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing 400044, China
| | - Ziwei Chen
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing 400044, China
| | - Qiang He
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, College of Environment and Ecology, Chongqing University, Chongqing 400044, China
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Wang YC, Lin YT, Wang C, Tong Z, Hu XR, Lv YH, Jiang GY, Han MF, Deng JG, Hsi HC, Lee CH. Microbial community regulation and performance enhancement in gas biofilters by interrupting bacterial communication. MICROBIOME 2022; 10:150. [PMID: 36117217 PMCID: PMC9484056 DOI: 10.1186/s40168-022-01345-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 08/10/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Controlling excess biomass accumulation and clogging is important for maintaining the performance of gas biofilters and reducing energy consumption. Interruption of bacterial communication (quorum quenching) can modulate gene expression and alter biofilm properties. However, whether the problem of excess biomass accumulation in gas biofilters can be addressed by interrupting bacterial communication remains unknown. RESULTS In this study, parallel laboratory-scale gas biofilters were operated with Rhodococcus sp. BH4 (QQBF) and without Rhodococcus sp. BH4 (BF) to explore the effects of quorum quenching (QQ) bacteria on biomass accumulation and clogging. QQBF showed lower biomass accumulation (109 kg/m3) and superior operational stability (85-96%) than BF (170 kg/m3; 63-92%) at the end of the operation. Compared to BF, the QQBF biofilm had lower adhesion strength and decreased extracellular polymeric substance production, leading to easier detachment of biomass from filler surface into the leachate. Meanwhile, the relative abundance of quorum sensing (QS)-related species was found to decrease from 67 (BF) to 56% (QQBF). The QS function genes were also found a lower relative abundance in QQBF, compared with BF. Moreover, although both biofilters presented aromatic compounds removal performance, the keystone species in QQBF played an important role in maintaining biofilm stability, while the keystone species in BF exhibited great potential for biofilm formation. Finally, the possible influencing mechanism of Rhodococcus sp. BH4 on biofilm adhesion was demonstrated. Overall, the results of this study achieved excess biomass control while maintaining stable biofiltration performance (without interrupting operation) and greatly promoted the use of QQ technology in bioreactors. Video Abstract.
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Affiliation(s)
- Yong-Chao Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, 300072, China
| | - Yu-Ting Lin
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, 300072, China
| | - Can Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, 300072, China.
| | - Zhen Tong
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, 300072, China
| | - Xu-Rui Hu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, 300072, China
| | - Ya-Hui Lv
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, 300072, China
| | - Guan-Yu Jiang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, 300072, China
| | - Meng-Fei Han
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China
- Tianjin Key Lab of Indoor Air Environmental Quality Control, Tianjin, 300072, China
| | - Ji-Guang Deng
- College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, 100124, China
| | - Hsing-Cheng Hsi
- Graduate Institute of Environmental Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd, Taipei, 106, Taiwan
| | - Chung-Hak Lee
- School of Chemical and Biological Engineering, Seoul National University, Seoul, 08826, Republic of Korea
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Salvador DG, Pavoni JF, Tessaro IC. The influence of aeration rate on the sorption of emerging pharmaceuticals in activated sludge. ENVIRONMENTAL TECHNOLOGY 2022:1-14. [PMID: 35107039 DOI: 10.1080/09593330.2022.2036246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
The sorption of pharmaceuticals on activated sludge during the wastewater treatment process has been widely studied and considered one of the main mechanisms for the removal of these micropollutants from domestic sewage. Understanding the removal mechanism is important to reduce the environmental risk associated with these compounds. To the best of our knowledge, no data are reporting the influence of the aeration rate and, consequently, of the physicochemical properties of the sludge flocs, on the sorption of pharmaceutical compounds. In this context, the influence of the aeration rate (2, 5, and 8 L min-1) on the physical properties of the sludge and the sorption of two emerging pharmaceuticals, 17-alpha-ethynylestradiol (EE2) and diclofenac (DCF), was evaluated. The pharmaceuticals were analyzed by Solid Phase Extraction and Liquid Chromatography, and the sludge by Laser Particle Size Analyzer and Settling Curves. As a result, higher sorption for 17-alpha-ethinylestradiol (78-96%) in comparison to diclofenac (23-43%) was observed, corroborating the greater hydrophobicity of EE2. Higher pharmaceuticals removal rates were observed for the highest aeration (10.02 µgEE2 gSST-1 and 3.99 µgDCF gSST-1) in comparison to the lowest one (7.81 µgEE2 gSST-1 and 2.58 µgDCF gSST-1), what can be attributed to structural and surface changes in flocs. Smaller and more dispersed flocs were observed when aeration was increased (104.4 µm for 8 L min-1 and 63.8 µm for 2 L min-1). The results suggest that the increase in aeration seems to be promising for the removal of pharmaceuticals by sorption in sewage sludge, especially for the hydrophobic ones.
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Affiliation(s)
- Débora Guerra Salvador
- Chemical Engineering Department, Laboratory of Membrane Separation Processes (LASEM), Federal Univesity of Rio Grande do Sul, Porto Alegre, Brazil
| | - Julia Frick Pavoni
- Chemical Engineering Department, Laboratory of Membrane Separation Processes (LASEM), Federal Univesity of Rio Grande do Sul, Porto Alegre, Brazil
| | - Isabel Cristina Tessaro
- Chemical Engineering Department, Laboratory of Membrane Separation Processes (LASEM), Federal Univesity of Rio Grande do Sul, Porto Alegre, Brazil
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Biological treatment of coke plant effluents: from a microbiological perspective. Biol Futur 2021; 71:359-370. [PMID: 34554459 DOI: 10.1007/s42977-020-00028-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 07/01/2020] [Indexed: 10/23/2022]
Abstract
During coke production, large volume of effluent is generated, which has a very complex chemical composition and contains several toxic and carcinogenic substances, mainly aromatic compounds, cyanide, thiocyanate and ammonium. The composition of these high-strength effluents is very diverse and depends on the quality of coals used and the operating and technological parameters of coke ovens. In general, after initial physicochemical treatment, biological purification steps are applied in activated sludge bioreactors. This review summarizes the current knowledge on the anaerobic and aerobic transformation processes and describes key microorganisms, such as phenol- and thiocyanate-degrading, floc-forming, nitrifying and denitrifying bacteria, which contribute to the removal of pollutants from coke plant effluents. Providing the theoretical basis for technical issues (in this case the microbiology of coke plant effluent treatment) aids the optimization of existing technologies and the design of new management techniques.
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Jiang H, Yang P, Wang Z, Ren S, Qiu J, Liang H, Peng Y, Li X, Zhang Q. Efficient and advanced nitrogen removal from mature landfill leachate via combining nitritation and denitritation with Anammox in a single sequencing batch biofilm reactor. BIORESOURCE TECHNOLOGY 2021; 333:125138. [PMID: 33895670 DOI: 10.1016/j.biortech.2021.125138] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 06/12/2023]
Abstract
A novel combined partial nitrification-Anammox and partial denitrification-Anammox (PnA/PdA) single sequencing batch biofilm reactor (SBBR) was established to realize efficient and advanced nitrogen removal from mature landfill leachate with low biodegradability. Nitrogen removal rate and nitrogen removal efficiency were increased to 2.83 ± 0.06 kgN/(m3∙d) and 98.6 ± 0.2% by stepwise increase of dissolved oxygen (DO, from 0.5 to 3.5 mg/L) and continuous carbon source feeding. Comparable activities of ammonia oxidation bacteria and Anammox bacteria were realized during aerobic period. More organic carbon was redirected from complete denitrification to partial denitrification during anoxic period. The main pathway PnA jointly synergized with PdA, which contributed to 76.04% and 19.44% nitrogen removal, respectively. Nitrosomonas, Thauera, and Kuenenia dominated in floc sludge (0.78%, 5.38%, and 1.14%, respectively) and biofilm (0.34%, 5.18%, and 0.98%, respectively). Overall, this study provides new insight into the high-efficiency treatment of landfill leachate at full-scale landfill sites.
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Affiliation(s)
- Hao Jiang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Pei Yang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China; Engineering Technology Research Center of Beijing MSW Comprehensive Treatment and Utilization, Environmental Engineering Technology Co, Ltd., Beijing, PR China
| | - Zhong Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, PR China
| | - Shang Ren
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Jingang Qiu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Haoran Liang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China.
| | - Xiyao Li
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
| | - Qiong Zhang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China
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Abstract
Aerobic granular sludge (AGS) with oversized diameter commonly affects its stability and pollutant removal. In order to effectively restrict the particle size of AGS, a sequencing batch reactor (SBR) with a spiny aeration device was put forward. A conventional SBR (R1) and an SBR (R2) with the spiny aeration device treating tannery wastewater were compared in the laboratory. The result indicates that the size of the granular sludge from R2 was smaller than that from R1 with sludge granulation. The spines and air bubbles could effectively restrict the particle size of AGS by collision and abrasion. Nevertheless, there was no significant change in mixed liquor suspended solids (MLSS) and the sludge volume index (SVI) in either bioreactors. The removal (%) of chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N) in these two bioreactors did not differ from each other greatly. The analysis of biological composition displays that the proportion of Proteobacteria decreased slightly in R2. The X-ray fluorescence (XRF) analysis revealed less accumulation of Fe and Ca in smaller granules. Furthermore, a pilot-scale SBR with a spiny aeration device was successfully utilized to restrict the diameter of granules at about 300 μm.
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Burdsall AC, Xing Y, Cooper CW, Harper WF. Bioaerosol emissions from activated sludge basins: Characterization, release, and attenuation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 753:141852. [PMID: 32891995 PMCID: PMC7439818 DOI: 10.1016/j.scitotenv.2020.141852] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/15/2020] [Accepted: 08/19/2020] [Indexed: 05/19/2023]
Abstract
This article presents a critical review of the peer-reviewed literature related to bioaerosol generation from activated sludge basins. Characterization techniques include a variety of culture- and nonculture-based techniques, each with unique features. Bioaerosols contain a variety of clinical pathogens including Staphylococcus saprophyticus, Clostridium perfringens, and Salmonella enteritidis; exposure to these microorganisms increases human health risks. Release mechanisms involve splashing and bubble burst dynamics. Larger bubbles emit more aerosol particles than smaller ones. Attenuation strategies include covering sources with lids, adjusting the method and intensity of aeration, and using free-floating carrier media. Future studies should combine culture and non-culture based methods, and expand chemical databases and spectral libraries in order to realize the full power of real-time online monitoring.
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Affiliation(s)
- Adam C Burdsall
- Air Force Institute of Technology, Environmental Engineering and Science Program, Department of Systems Engineering and Management, 2950 Hobson Way, Wright-Patterson AFB, OH 45433, USA
| | - Yun Xing
- Air Force Institute of Technology, Environmental Engineering and Science Program, Department of Systems Engineering and Management, 2950 Hobson Way, Wright-Patterson AFB, OH 45433, USA
| | - Casey W Cooper
- Air Force Institute of Technology, Environmental Engineering and Science Program, Department of Systems Engineering and Management, 2950 Hobson Way, Wright-Patterson AFB, OH 45433, USA
| | - Willie F Harper
- Air Force Institute of Technology, Environmental Engineering and Science Program, Department of Systems Engineering and Management, 2950 Hobson Way, Wright-Patterson AFB, OH 45433, USA.
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Zheng X, Zhang J, Li M, Zhuang LL. Optimization of the pollutant removal in partially unsaturated constructed wetland by adding microfiber and solid carbon source based on oxygen and carbon regulation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 752:141919. [PMID: 32898802 DOI: 10.1016/j.scitotenv.2020.141919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/20/2020] [Accepted: 08/22/2020] [Indexed: 06/11/2023]
Abstract
The partially unsaturated constructed wetland was demonstrated to be able to enhance the oxygen supplement for the microbial nitrification. However, the fast gravity flow of wastewater on the smooth surface of substrate in unsaturated zone led to a short contact time between wastewater and biofilm on the surface of substrate for the microbial pollutant oxidation process. While, the strengthened oxygen supplement also consumed organic carbon, intensifying the shortage of electron donator for the denitrification process. To further enhance the efficiency of both nitrification and denitrification processes, two strategies were conducted as follows: (1) adding microfiber in unsaturated zone to extend the hydraulic retention time (HRT) and improve the oxygenating efficiency; (2) adding slow-release carbon source (Poly butylenes succinate, PBS) as electron donor in saturated zone for denitrification. Results showed that the ammonia oxidation efficiency reached up to 97.0% in the microfiber-enhanced constructed wetland. Additionally, adding microfiber provided more sites for microbes and increased the total number of microbes in unsaturated zone. The addition of PBS in the saturated zone obviously improved the denitrification efficiency with the total nitrogen (TN) removal rate raising from 20.6 ± 4.0% to 90.4 ± 2.7%, which excellently solved the problem of poor denitrification efficiency caused by low ratio of carbon to nitrogen (C/N). In conclusion, the association of microfiber and PBS in partially unsaturated constructed wetland finally accomplished the thorough nitrogen removal.
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Affiliation(s)
- Xinhui Zheng
- Institute of Marine Science and Technology, Shandong University, Qingdao 266237, China.
| | - Jian Zhang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Qingdao 266237, China.
| | - Mengting Li
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Qingdao 266237, China
| | - Lin-Lan Zhuang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science & Engineering, Shandong University, Qingdao 266237, China.
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Yan X, Zheng S, Yang J, Ma J, Han Y, Feng J, Su X, Sun J. Effects of hydrodynamic shear stress on sludge properties, N 2O generation, and microbial community structure during activated sludge process. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 274:111215. [PMID: 32814212 DOI: 10.1016/j.jenvman.2020.111215] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/06/2020] [Accepted: 08/07/2020] [Indexed: 06/11/2023]
Abstract
Sludge properties are critical to the treatment performance and potentially correlate with nitrous oxide (N2O) generation during activated sludge processes. The hydrodynamic shear stress induced by aeration has a significant influence on sludge properties and is inevitable for wastewater treatment plants (WWTPs). In this study, the effects of aerobic induced hydrodynamic shear stress on sludge properties, N2O generation, and microbial community structure were investigated using three parallel sequencing batch reactors (SBRs) with identical dissolved oxygen (DO) concentrations. Results showed that with a shear stress increase from 1.5 × 10-2 N/m2 to 5.0 × 10-2 N/m2, the COD and NH4+-N removal rates were enhanced from 89.4% to 94.0% and from 93.9% to 98.0%, respectively, while the TN removal rate decreased from 66.0% to 56.5%. Settleability of the activated sludge flocs (ASFs) also increased with the enhancement of shear stress, due to variation in sludge properties including particle size, regularity, compactibility, and EPS (extracellular polymeric substances) composition. The increase in shear stress promoted oxygen diffusion within the ASFs and mitigated NO2--N accumulation, leading to a decrease in the N2O-N conversion rate from (4.8 ± 0.3)% to (2.2 ± 0.6)% (based on TN removal). Microbial analysis results showed that the functional bacteria involved in the biological nitrogen removal was closely related with shear stress. The increase in shear stress favored the enrichment of nitrite oxidizing bacteria (NOB) while suppressed the accumulation of ammonia-oxidizing bacteria (AOB) and denitrifying bacteria (DNB).
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Affiliation(s)
- Xu Yan
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China.
| | - Shikan Zheng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jie Yang
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jiahui Ma
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Yunping Han
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Jinglan Feng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Xianfa Su
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jianhui Sun
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
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Yan X, Zheng S, Huo Z, Shi B, Huang J, Yang J, Ma J, Han Y, Wang Y, Cheng K, Feng J, Sun J. Effects of exogenous N-acyl-homoserine lactones on nutrient removal, sludge properties and microbial community structures during activated sludge process. CHEMOSPHERE 2020; 255:126945. [PMID: 32388260 DOI: 10.1016/j.chemosphere.2020.126945] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
This study investigated the effects of exogenous N-acyl-homoserine lactone (AHL) signal molecules, N-hexanoyl-l-homoserine lactone (C6-HSL) and N-octanoyl-l-homoserine lactone (C8-HSL), on treatment performance, sludge properties and microbial community structures in activated sludge systems. Results showed that the nitrification and denitrification efficiencies were enhanced with the addition of signal molecules. The particle size, irregularity, and internal mass transfer resistance of activated sludge flocs (ASFs) increased, primarily because dosing AHLs led to a content increase and chemical composition variation of extracellular polymeric substances (EPS) in sludge. Microbial analysis indicated an increase in both the bacterial richness and diversity of the systems. The relative abundances of the key functional groups, including bacteria related to C and N removal and EPS production, varied correspondingly. This study presents an insight into the comprehensive understanding of the effects of AHL-based quorum sensing on activated sludge treatment process.
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Affiliation(s)
- Xu Yan
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China.
| | - Shikan Zheng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Zhaoman Huo
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Bowen Shi
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jiajun Huang
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jie Yang
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jiahui Ma
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Yunping Han
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Yan Wang
- School of Public Health, Xinxiang Medical University, Xinxiang, 453003, China
| | - Ke Cheng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jinglan Feng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jianhui Sun
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
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12
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Seasonality and Community Separation of Fungi in a Municipal Wastewater Treatment Plant. Appl Environ Microbiol 2020; 86:AEM.00991-20. [PMID: 32651202 DOI: 10.1128/aem.00991-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/30/2020] [Indexed: 11/20/2022] Open
Abstract
Fungi are known to play important roles in pollutant transformation in activated sludge-based wastewater treatment plants (WWTPs). However, the seasonality and distributions of fungal populations in different-sized flocs have still remained largely unknown. In this study, seasonal population dynamics and community separation of fungi in a municipal WWTP across a 1-year period were investigated. We classified all taxa into six categories based on abundances to assess their roles and contributions to the whole community. The results showed that the rare taxa (<0.01%) contributed greatly to species richness (95.27%). Conversely, although low in species diversity, abundant taxa (≥1%) accounted for the majority (89.45%) of the total relative abundance, which suggested that a few core abundant fungi existed in the activated sludge ecosystem. The abundant, conditionally rare, and rare taxa contributed 30.14%, 31.11%, and 38.75%, respectively, to temporal shifts in community structure, and their abundances responded differently to environmental variables, suggesting that these three subcommunities exhibited a large difference in environmental sensitivity. Importantly, the results revealed seasonal dynamics of the whole fungal community and the subcommunities of all the microbial taxon categories, resulting in significant differences in community structures between warm and cold seasons. Furthermore, fungal diversity and the compositions of the whole community and subcommunities differed significantly among flocs of different sizes, which underlined the size-based fungal community separation in activated sludge of WWTPs. The findings of this work improved our understanding of fungal population dynamics and community separation in WWTPs.IMPORTANCE Fungi are important contributors to the various functions of activated sludge in wastewater treatment plants (WWTPs). Unlike previous studies, this work demonstrated the seasonality of the fungal community over a longer time span while it also systematically assessed the contributions of abundant, conditionally rare, and rare taxa to the whole community. Importantly, in the present study, we considered sludge flocs of a certain size range rather than the whole sludge flocs as a community. Our results revealed significant differences in fungal community structure among different-sized flocs, which supported the idea that size-based fungal community segregation is occurring in activated sludge ecosystems. The findings provide new insights into the dynamic changes or distribution of fungi in the bioaggregates of sludge flocs in WWTPs.
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Effects of Sludge Retention Time on the Performance of Anaerobic Ceramic Membrane Bioreactor Treating High-Strength Phenol Wastewater. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2020; 2020:8895321. [PMID: 32831644 PMCID: PMC7422917 DOI: 10.1155/2020/8895321] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 05/29/2020] [Accepted: 06/05/2020] [Indexed: 11/22/2022]
Abstract
Anaerobic ceramic membrane bioreactor (AnCMBR) is an attractive alternative for the treatment of high-strength phenol wastewater, but the effects of sludge retention time (SRT) on the performance and membrane fouling are still unclear. The results indicated that the AnCMBR was successfully employed to treat high-strength wastewater containing 5 g phenol L−1. The removal efficiencies of phenol and chemical oxygen demand (COD) reached over 99.5% and 99%, respectively, with long SRT and short SRT. SRT had no obvious effect on the performance of the AnCMBR treating high-strength phenol wastewater with long time operation. The strong performance robustness of AnCMBR benefited from the enrichment of hydrogenotrophic methanogens and syntrophic phenol-degrading bacteria. However, the decline of SRT led to a more severe membrane fouling in the AnCMBR, which was caused by the small size of sludge flocs and high concentration of protein in the biopolymers. Therefore, this work presented a comprehensive insight to the feasibility and robustness of the AnCMBR for treating high-strength phenol wastewater.
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14
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Zhang S, Li B, Yu Z, Meng F. Aggregate size-dependence of bacterial community separation in a full-scale membrane bioreactor plant. FEMS Microbiol Ecol 2020; 96:5818762. [PMID: 32275301 DOI: 10.1093/femsec/fiaa060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 04/02/2020] [Indexed: 11/13/2022] Open
Abstract
The size of bacterial aggregates can determine both nutrient removal and sludge/water separation in activated sludge processes. In this study, the bacterial community structures and network associations of different sized aggregates obtained from a full-scale membrane bioreactor plant over a one-year period were investigated. Our results showed that biodiversity of larger sized aggregates was significantly higher than that of smaller ones and that the bacterial compositions of different sized aggregates differed significantly from each other. Bacteria related to nutrient removal (e.g. denitrification, hydrolysis and fermentation) were found to be significantly more abundant in larger aggregates than smaller ones. Network analysis revealed significant difference in species-species interactions, topological roles of individual OTU and keystone populations among different sized aggregates. Moreover, the occurrence of keystone OTUs affiliated with denitrifiers (Thermomonas) in networks of large and medium aggregates may suggest that denitrification influences bacterial interactions in large and medium aggregates. Overall, our results indicate the aggregates size-dependence of bacterial community separation in activated sludge. The current findings not only can provide guidance for process design and operation optimization, but also highlight the necessity for paying more attentions to the aggregate-based community, metabolic function and gene expression of activated sludge in future studies.
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Affiliation(s)
- Shaoqing Zhang
- 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
| | - Bing Li
- Division of Energy and Environment, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, PR China
| | - Zhong Yu
- 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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15
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Al-Dawery SK, Ahmed A, Reddy SS, Al-Hadhrami O, Al-Lamki K. Cost-effective treatment of sludge conditioning using supernatant fluid polyelectrolyte. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:10790-10801. [PMID: 31950420 DOI: 10.1007/s11356-020-07694-8] [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: 10/23/2019] [Accepted: 01/09/2020] [Indexed: 06/10/2023]
Abstract
Treatment of activated sludge using pure polyelectrolyte and its supernatant fluids for sludge dewatering was examined. The supernatant was used for treatment of fresh sludge for reducing the total cost of sludge conditioning by almost 50% and had great impact on wastewater treatment especially on that with large flow rate. The utilization of supernatant can be considered as a sustainable and economical method for pollution reduction especially in the developing countries. This would overcome the problem of imperfect mixing, difficulties in operated sludge conditioning, and utilized wasted polyelectrolyte. A slightly high positively charged polyelectrolyte was selected during this study. The results showed this polymer and the supernatant had significant influence on the sludge volume index (SVI) and sludge settling. The SVI and settling were improved by 50% and 60%, respectively. We found the sludge treated with supernatant showed a highest sludge settling properties compared with using pure polyelectrolyte especially for sludge samples with low total suspended solid (TSS) and SVI. Using mixed supernatant with pure polyelectrolyte showed higher settling compared to second treatment. Zeta potentials were measured, and increases in zeta potentials were observed for use of both pure polymer and supernatant fluids. The experiments of using supernatants for sludge treatment were found to reflect the use of waste for waste and principle of circulation cleaning; thus it can be a valuable reference for the researchers working in the field of sludge treatment.
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Affiliation(s)
- Salam K Al-Dawery
- Department of Chemical Engineering, College of Engineering and Architecture, University of Nizwa, Nizwa, Sultanate of Oman.
| | - Anwar Ahmed
- Department of Civil and Environmental Engineering, College of Engineering and Architecture, University of Nizwa, Nizwa, Sultanate of Oman
| | - Sajjala S Reddy
- Department of Civil and Environmental Engineering, College of Engineering and Architecture, University of Nizwa, Nizwa, Sultanate of Oman
| | - Omaima Al-Hadhrami
- Department of Chemical Engineering, College of Engineering and Architecture, University of Nizwa, Nizwa, Sultanate of Oman
| | - Kareema Al-Lamki
- Department of Chemical Engineering, College of Engineering and Architecture, University of Nizwa, Nizwa, Sultanate of Oman
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16
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Xu R, Zhang S, Meng F. Large-sized planktonic bioaggregates possess high biofilm formation potentials: Bacterial succession and assembly in the biofilm metacommunity. WATER RESEARCH 2020; 170:115307. [PMID: 31786395 DOI: 10.1016/j.watres.2019.115307] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/22/2019] [Accepted: 11/12/2019] [Indexed: 05/06/2023]
Abstract
Wanted and unwanted surface-attached growth of bacteria is ubiquitous in natural and engineered settings. Normally, attachment of planktonic cells to media surfaces initiates biofilm formation and fundamentally regulates biofilm assembly processes. Here, culturing biofilm with planktonic sludge as source community, we found distinct succession profiles of biofilm communities sourced from the size-fractionated sludge flocs (<25; 25-120; >120 μm). Null model analyses revealed that deterministic process dominated in biofilm community assemblies but decreased with decreasing floc size. Additionally, the relative importance of environmental selection increased with increasing floc size of the source sludge, whereas homogenizing dispersal and ecological drift followed opposite trends. Phylogenetic molecular ecological networks (pMENs) indicated that species interactions were intensive in biofilm microbiota developed from large-sized flocs (>120 μm), as evidenced by the low modularity and harmonic geodesic distance and the high average degree. Intriguingly, the keystone taxa in these biofilm ecological networks were controlled by distinct interaction patterns but all showed strong habitat characteristics (e.g., facultative anaerobic, motile, hydrophobic and involved in extracellular polymeric substance metabolism), corroborating the crucial roles of environmental filtering in structuring biofilm community. Taken together, our findings highlight the role of planktonic floc properties in biofilm community assembly and advance our understanding of microbial ecology in biofilm-based systems.
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Affiliation(s)
- Ronghua Xu
- 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
| | - Shaoqing Zhang
- 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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17
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Yan X, Zheng S, Qiu D, Yang J, Han Y, Huo Z, Su X, Sun J. Characteristics of N 2O generation within the internal micro-environment of activated sludge flocs under different dissolved oxygen concentrations. BIORESOURCE TECHNOLOGY 2019; 291:121867. [PMID: 31376671 DOI: 10.1016/j.biortech.2019.121867] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/18/2019] [Accepted: 07/20/2019] [Indexed: 06/10/2023]
Abstract
Nitrous oxide (N2O) is a strong greenhouse gas that is produced in significant quantities through biological nitrogen removal processes in wastewater treatment plants; however, N2O generation within the internal micro-environment of activated sludge flocs (ASFs) is poorly understood. In this study, microelectrodes and molecular techniques were employed to investigate the concentrations of N2O and other chemicals and the composition and distribution of microbes within ASFs, respectively. The results showed that N2O generation was correlated with the ASF micro-environment, and was significantly influenced by the dissolved oxygen (DO) concentration of the bulk wastewater. Equal N2O, DO, NH4+-N, and NO3--N concentrations were found in small flocs (<100 μm). By contrast, higher N2O generation rates and lower DO, NH4+-N, and NO3--N concentrations were detected in the center of large flocs (>200 μm) compared with those at their surfaces. Microbial structures of varying particle sizes were distinct and depended on the micro-environmental characteristics.
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Affiliation(s)
- Xu Yan
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang 453007, Henan, China.
| | - Shikan Zheng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang 453007, Henan, China
| | - Dezhi Qiu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jie Yang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yunping Han
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Zhaoman Huo
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xianfa Su
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jianhui Sun
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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18
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Zhang S, He Z, Meng F. Floc-size effects of the pathogenic bacteria in a membrane bioreactor plant. ENVIRONMENT INTERNATIONAL 2019; 127:645-652. [PMID: 30991220 DOI: 10.1016/j.envint.2019.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 03/29/2019] [Accepted: 04/01/2019] [Indexed: 06/09/2023]
Abstract
The size nature of sludge flocs could affect the occurrence and distribution of bacterial pathogens in wastewater treatment plants (WWTPs). In this study, the floc-size dependence of bacterial pathogens in the activated sludge of a WWTP was investigated using high-throughput metagenomic sequencing approaches. The results showed that a total of 423 pathogenic species belonging to 123 genera were identified in the three size-fractionated flocs. Also, we found that all the pathogens on the WHO's global priority pathogens list were detected in the size-fractionated flocs, with relative abundance of 0.4%, 0.3% and 0.3% for large-size, medium-size and small-size flocs, respectively, indicating the severe human and environmental health risks of activated sludge. Importantly, our results revealed that the pathogenic species showed a clear floc-size dependent distribution manner, leading to significant differences (P < 0.05) of pathogenic communities among the size-fractionated flocs. Additionally, by partitioning pathogens based on the occurrence and significant difference in abundances, we suggested the following distribution features: 1) large flocs-associated pathogens, such as Borrelia recurrentis, Actinobacillus ureae and Campylobacter gracilis; 2) medium flocs-associated pathogens, such as Mycobacterium szulgai and Ureaplasma urealyticum; and 3) small flocs-associated pathogens, such as Rickettsia akari, Staphylococcus anginosus and Helicobacter cinaedi. Overall, this study provides a comprehensive understanding of pathogens in activated sludge, which is expected to aid in assessment and management of pathogen risks.
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Affiliation(s)
- Shaoqing Zhang
- 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
| | - Zhili He
- 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; College of Agronomy, Hunan Agricultural University, Changsha 410128, 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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19
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Han Y, Zhang W, Yu X, Yu P, Xiao B, Yi H. Effects of tetrakis (hydroxymethyl) phosphonium sulfate pretreatment on characteristics of sewage sludge. J Environ Sci (China) 2019; 78:174-182. [PMID: 30665636 DOI: 10.1016/j.jes.2018.09.013] [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: 04/24/2018] [Revised: 08/24/2018] [Accepted: 09/12/2018] [Indexed: 06/09/2023]
Abstract
Recently, tetrakis(hydroxymethyl)phosphonium sulfate (THPS) was found to play an important role in the sludge pretreatment process. However, the effects of THPS pretreatment on the characteristics of sewage sludge are still insufficiently understood. The properties of sludge after pretreatment with different concentrations of THPS were investigated in this study. The results showed that pH, dewatering ability, and particle size of sludge decreased with increase in THPS concentration. The volatile suspended solids (VSS) and total suspended solids (TSS) of sludge also decreased slightly with increase in THPS concentration. The specific oxygen uptake rate (SOUR) results suggested that lower THPS concentrations (≤1.87 mg/g VSS) enhanced the activity of sludge, but higher concentrations (≥1.87 mg/g VSS) inhibited it. Gram-negative bacteria with peritrichous flagellation (such as Pseudomonas, Escherichia, and Faecalibacterium) were extremely sensitive to THPS. The decrease in specific most probable numbers (MPNs) of pathogens (total coliforms and Escherichia coli) with the increase in THPS concentration also proved the sterilization ability of THPS in the sludge pretreatment process. Pretreatment of sludge with concentrations of THPS higher than 37.41 mg/g VSS would meet the pathogen requirements for land application of Class A biosolids.
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Affiliation(s)
- Yunping Han
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenzhe Zhang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao Yu
- College of Textiles and Clothing, Qingdao University, Qingdao 266071, China
| | - Panfen Yu
- College of Textiles and Clothing, Qingdao University, Qingdao 266071, China
| | - Benyi Xiao
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Hao Yi
- South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou 510655, China.
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20
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Cohen Y, Pasternak Z, Johnke J, Abed‐Rabbo A, Kushmaro A, Chatzinotas A, Jurkevitch E. Bacteria and microeukaryotes are differentially segregated in sympatric wastewater microhabitats. Environ Microbiol 2019; 21:1757-1770. [DOI: 10.1111/1462-2920.14548] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 01/20/2019] [Accepted: 01/28/2019] [Indexed: 01/22/2023]
Affiliation(s)
- Yossi Cohen
- Department of Plant Pathology and Microbiology, Faculty of Agriculture, Food and EnvironmentThe Hebrew University of Jerusalem Rehovot, 76100 Israel
| | - Zohar Pasternak
- Department of Plant Pathology and Microbiology, Faculty of Agriculture, Food and EnvironmentThe Hebrew University of Jerusalem Rehovot, 76100 Israel
| | - Julia Johnke
- Department of Environmental MicrobiologyHelmholtz Centre for Environmental Research – UFZ Permoserstrasse 15, Leipzig, 04318 Germany
| | - Alfred Abed‐Rabbo
- Faculty of ScienceBethlehem University, Palestinian National Authority, Bethlehem, Israel
| | - Ariel Kushmaro
- Avram and Stella Goldstein‐Goren, The Department of Biotechnology Engineering, Faculty of Engineering SciencesBen‐Gurion University of the Negev P.O. Box 653, Beer‐Sheva Israel
- The Ilse Katz Centre for Meso and Nanoscale Science and TechnologyBen‐Gurion University of the Negev Beer‐Sheva Israel
| | - Antonis Chatzinotas
- Department of Environmental MicrobiologyHelmholtz Centre for Environmental Research – UFZ Permoserstrasse 15, Leipzig, 04318 Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig Deutscher Platz 5e, Leipzig, 04103 Germany
| | - Edouard Jurkevitch
- Department of Plant Pathology and Microbiology, Faculty of Agriculture, Food and EnvironmentThe Hebrew University of Jerusalem Rehovot, 76100 Israel
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21
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Fu L, Zhang F, Bai YN, Lu YZ, Ding J, Zhou D, Liu Y, Zeng RJ. Mass transfer affects reactor performance, microbial morphology, and community succession in the methane-dependent denitrification and anaerobic ammonium oxidation co-culture. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 651:291-297. [PMID: 30236845 DOI: 10.1016/j.scitotenv.2018.09.184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/13/2018] [Accepted: 09/14/2018] [Indexed: 06/08/2023]
Abstract
Denitrifying anaerobic methane oxidation (DAMO) combining anaerobic ammonium oxidation (Anammox) process is a novel nitrogen removal technology. However, the roles of methane transfer (gas phase) and nitrogen transfer (liquid phase) in the heterogeneous process remain unclear. In this study, granular DAMO and Anammox co-cultures were inoculated from a hollow-fiber membrane bioreactor into a sequence batch reactor (SBR). Since the methane transfer became limited in SBR, the nitrate removal rate first decreased and then increased to 10 mg/(L∙day), while the ammonium removal rate did not recover and was around 2 mg/(L∙day). The activity of DAMO archaea and Anammox bacteria decreased noticeably. Furthermore, granular aggregates dispersed into small granules and ultimately became flocs with poor settleability in SBR. The content of extracellular polymeric substances decreased, especially that of proteins and humics. DAMO archaea decreased by 94.6% and Anammox bacteria decreased by 72%. In summary, the limitation of methane transfer affected DAMO and Anammox processes more notably than nitrogen transfer, resulting in lower nitrogen removal, granule disruption, and microbial community succession.
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Affiliation(s)
- Liang Fu
- School of Environment, Northeast Normal University, Changchun 130117, China; CAS Key Laboratory for Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Fang Zhang
- Centre of Wastewater Resource Recovery, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.
| | - Ya-Nan Bai
- CAS Key Laboratory for Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Yong-Ze Lu
- CAS Key Laboratory for Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Jing Ding
- CAS Key Laboratory for Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Dandan Zhou
- School of Environment, Northeast Normal University, Changchun 130117, China
| | - Yue Liu
- School of Environment, Northeast Normal University, Changchun 130117, China
| | - Raymond Jianxiong Zeng
- CAS Key Laboratory for Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei 230026, China; Centre of Wastewater Resource Recovery, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.
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22
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Li L, Xue S, Xi J. Anaerobic oxidation of methane coupled to sulfate reduction: Consortium characteristics and application in co-removal of H 2S and methane. J Environ Sci (China) 2019; 76:238-248. [PMID: 30528014 DOI: 10.1016/j.jes.2018.05.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/09/2018] [Accepted: 05/09/2018] [Indexed: 06/09/2023]
Abstract
Anaerobic sludge from a sewage treatment plant was used to acclimatize microbial colonies capable of anaerobic oxidation of methane (AOM) coupled to sulfate reduction. Clone libraries and fluorescence in situ hybridization were used to investigate the microbial population. Sulfate-reducing bacteria (SRB) (e.g., Desulfotomaculum arcticum and Desulfobulbus propionicus) and anaerobic methanotrophic archaea (ANME) (e.g., Methanosaeta sp. and Methanolinea sp.) coexisted in the enrichment. The archaeal and bacterial cells were randomly or evenly distributed throughout the consortia. Accompanied by sulfate reduction, methane was oxidized anaerobically by the consortia of methane-oxidizing archaea and SRB. Moreover, CH4 and SO42- were consumed by methanotrophs and sulfate reducers with CO2 and H2S as products. The H3CSH produced by methanotrophy was an intermediate product during the process. The methanotrophic enrichment was inoculated in a down-flow biofilter for the treatment of methane and H2S from a landfill site. On average, 93.33% of H2S and 10.71% of methane was successfully reduced in the biofilter. This study tries to provide effective method for the synergistic treatment of waste gas containing sulfur compounds and CH4.
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Affiliation(s)
- Lin Li
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, China.
| | - Song Xue
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, China
| | - Jingru Xi
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China; National Engineering Laboratory for VOCs Pollution Control Material & Technology, University of Chinese Academy of Sciences, Beijing 101408, China
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23
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Wang G, Wang Y, Liu L, Jin Y, Zhu N, Li X, Wang G, Chen G. Comprehensive assessment of microbial aggregation characteristics of activated sludge bioreactors using fuzzy clustering analysis. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 162:296-303. [PMID: 30005402 DOI: 10.1016/j.ecoenv.2018.06.096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/14/2018] [Accepted: 06/30/2018] [Indexed: 06/08/2023]
Abstract
Understanding microbial aggregation dynamics in response to the often violent environmental fluctuations is important for activated sludge wastewater biotreatment practice, yet remains poorly understood. We investigated microbial aggregation process of an activated sludge reactor in response to various operating conditions of resource limitations, disinfectant and pH stresses, and quantified aggregation characteristics by employing a fuzzy clustering analysis (FCA) method. The results revealed that the FCA provided a means for comprehensive assessment of microbial aggregation dynamics of the bioreactor relying solely on simple parameter estimation. Proper disinfectant stress (of NaClO 1.00% or 2.00%) is a promising strategy to improve the comprehensive performance of microbial aggregation and sludge settleability. Nitrogen- (of C/N ratio > 40) and dissolved oxygen-limitations (of DO < 0.2 mg/L) had medium influence on the comprehensive performance of the activated sludge system, while little impacts for acidic and alkaline conditions. These quantitative estimations offer insights into the underlying bio-physicochemical processes of an activated sludge bioreactor in response to practical fluctuations that is often beyond typical assessment practice. In addition, it may represent a step towards uncoupling the complex biophysical interactions that is essential for optimized designing and proper engineering practice of biological wastewater treatment reactors.
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Affiliation(s)
- Gang Wang
- Department of Water & Soil Sciences, China Agricultural University, Beijing 100193, China
| | - Yan Wang
- Department of Water & Soil Sciences, China Agricultural University, Beijing 100193, China
| | - Li Liu
- Department of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Yan Jin
- Department of Plant & Soil Sciences, University of Delaware, Newark, DE 19716, USA
| | - Ning Zhu
- Department of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Xing Li
- Department of Civil Engineering, Hefei University of Technology, Hefei 230009, China
| | - Guoqing Wang
- Nanjing Hydraulic Research Institute, Nanjing 210029, China
| | - Guowei Chen
- Department of Civil Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China.
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Kuśnierz M. Scale of Small Particle Population in Activated Sludge Flocs. WATER, AIR, AND SOIL POLLUTION 2018; 229:327. [PMID: 30294049 PMCID: PMC6153693 DOI: 10.1007/s11270-018-3979-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 09/11/2018] [Indexed: 06/08/2023]
Abstract
The light scattering method is a valuable tool for accessing particle size and structure mainly due to fast and the nonintrusive nature of the measurement. The method is based on a scattered intensity pattern and depends on particle volume, particle morphology, the light wavelength and the scattering angle. The light scattering model, for particles characterised by a fractal structure, is enabled with the use of the Rayleigh-Gans-Debye theory under constrained assumptions. The range of validity of the Rayleigh-Gans-Debye is limited when primary particles constituting aggregate have a size close to the wavelength. In this work, a range of particle sizes was characterised in order to achieve a better understanding of the relationship between flocs size and its fractal dimension. Hence, the width of the power law regime is discussed. What is more, a specific fractal dimension value of activated sludge flocs was found for each of the analysed wastewater treatment plant, which suggests that the spatial structure of suspensions constituting the activated sludge is an individual characteristic of each treatment facility. It has been shown that activated sludge consists of microflocs from the range of 1-10 μm, which constitute approximately 90% of all the population.
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Affiliation(s)
- Magdalena Kuśnierz
- Wroclaw University of Environmental and Life Sciences, Wroclaw, Poland
- Institute of Environmental Engineering, Plac Grunwaldzki 24, 50-363 Wroclaw, Poland
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26
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Wang J, Rong H, Zhang C. Evaluation of the impact of dissolved oxygen concentration on biofilm microbial community in sequencing batch biofilm reactor. J Biosci Bioeng 2018; 125:532-542. [DOI: 10.1016/j.jbiosc.2017.11.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 10/24/2017] [Accepted: 11/14/2017] [Indexed: 01/21/2023]
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State of the art on granular sludge by using bibliometric analysis. Appl Microbiol Biotechnol 2018; 102:3453-3473. [PMID: 29497798 DOI: 10.1007/s00253-018-8844-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 02/02/2018] [Accepted: 02/05/2018] [Indexed: 02/07/2023]
Abstract
With rapid industrialization and urbanization in the nineteenth century, the activated sludge process (ASP) has experienced significant steps forward in the face of greater awareness of and sensitivity toward water-related environmental problems. Compared with conventional flocculent ASP, the major advantages of granular sludge are characterized by space saving and resource recovery, where the methane and hydrogen recovery in anaerobic granular and 50% more space saving, 30-50% of energy consumption reduction, 75% of footprint cutting, and even alginate recovery in aerobic granular. Numerous engineers and scientists have made great efforts to explore the superiority over the last 40 years. Therefore, a bibliometric analysis was desired to trace the global trends of granular sludge research from 1992 to 2016 indexed in the SCI-EXPANDED. Articles were published in 276 journals across 44 subject categories spanning 1420 institutes across 68 countries. Bioresource Technology (293, 11.9%), Water Research (235, 9.6%), and Applied Microbiology and Biotechnology (127, 5.2%) dominated in top three journals. The Engineering (991, 40.3%), China (906, 36.9%), and Harbin Inst Technol, China (114, 4.6%) were the most productive subject category, country, and institution, respectively. The hotspot is the emerging techniques depended on granular reactors in response to the desired removal requirements and bio-energy production (primarily in anaerobic granular sludge). In view of advanced and novel bio-analytical methods, the characteristics, functions, and mechanisms for microbial granular were further revealed in improving and innovating the granulation techniques. Therefore, a promising technique armed with strengthened treatment efficiency and efficient resource and bio-energy recovery can be achieved.
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28
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Zhang J, Li L, Liu J, Wang Y. Effects of oxygen and water content on microbial distribution in the polyurethane foam cubes of a biofilter for SO 2 removal. J Environ Sci (China) 2018; 63:268-276. [PMID: 29406109 DOI: 10.1016/j.jes.2017.03.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/10/2017] [Accepted: 03/13/2017] [Indexed: 06/07/2023]
Abstract
The performance of a biofilter for off-gas treatment relies on the activity of microorganisms and adequate O2 and H2O. In present study, a microelectrode was applied to analyze O2 in polyurethane foam cubes (PUFCs) packed in a biofilter for SO2 removal. The O2 distribution varied with the density and water-containing rate (WCR) of PUFCs. The O2 concentration dropped sharply from 10.2 to 0.8mg/L from the surface to the center of a PUFC with 97.20% of WCR. The PUFCs with high WCR presented aerobic-anoxic-aerobic areas. Three-dimensional simulated images demonstrated that the structure of PUFCs with high WCR consisted of an aerobic "shell" and an anoxic "core", with high-density PUFCs featuring a larger anoxic area than low-density PUFCs. Moreover, the H2O distribution in the PUFC was uneven and affected the O2 concentration. Whereas aerobic bacteria were observed in the PUFC surface, facultative anaerobic microorganisms were found at the PUFC core, where the O2 concentration was relatively low. O2 and H2O distributions differed in the PUFCs, and the distribution of microorganisms varied accordingly.
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Affiliation(s)
- Jingying Zhang
- State key laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Lin Li
- State key laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Junxin Liu
- State key laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanjie Wang
- State key laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
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Yan X, Zheng J, Han Y, Liu J, Sun J. Effect of influent C/N ratio on N 2O emissions from anaerobic/anoxic/oxic biological nitrogen removal processes. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:23714-23724. [PMID: 28864852 DOI: 10.1007/s11356-017-0019-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 08/23/2017] [Indexed: 06/07/2023]
Abstract
The problem of producing strong greenhouse gas of nitrous oxide (N2O) from biological nitrogen removal (BNR) process in wastewater treatment plants (WWTP) has elicited great concern from various sectors. In this study, three laboratory-scale wastewater treatment systems, with influent C/N ratios of 3.4, 5.4, and 7.5, were set up to study the effect of influent C/N ratio on N2O generation in anaerobic/anoxic/oxic (A2O) process. Results showed, with the increased influent C/N ratio, N2O generation from both nitrification and denitrification process was decreased, and the N2O-N conversion ratio of the process was obviously reduced from 2.23 to 0.05%. Nitrification rate in oxic section was reduced, while denitrification rate in anaerobic and anoxic section was elevated and the removal efficiency of COD, NH4+-N, TN, and TP was enhanced in different extent. As the C/N ratio increased from 3.4 to 7.5, activities of three key denitrifying enzymes of nitrate reductase, nitrite reductase, and nitrous oxide reductase were increased. Moreover, microorganism analysis indicated that the relative abundance of ammonium-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) were positively correlated with N2O generation, which was reduced from (8.42 ± 3.65) to (3.61 ± 1.66)% and (10.38 ± 4.12) to (4.67 ± 1.62)%, respectively. NosZ gene copy numbers of the A2O system were increased from (1.19 ± 0.49) × 107 to (2.84 ± 0.54) × 108 copies/g MLSS with the influent C/N ratio elevated from 3.4 to 7.5. Hence, appropriate influent C/N condition of A2O process could optimize the microbial community structure that simultaneously improve treatment efficiency and decrease the N2O generation.
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Affiliation(s)
- Xu Yan
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, Henan, 453007, China.
| | - Jiaxi Zheng
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Yunping Han
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Jianwei Liu
- Beijing Engineering Research Center of Sustainable Urban Sewage System Construction and Risk Control, Beijing University of Civil Engineering and Architecture, Beijing, China
| | - Jianhui Sun
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, Henan, 453007, China
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Wang JH, Chen YP, Dong Y, Wang XX, Guo JS, Shen Y, Yan P, Ma TF, Sun XQ, Fang F, Wang J. A new method to measure and model dynamic oxygen microdistributions in moving biofilms. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 229:199-209. [PMID: 28599204 DOI: 10.1016/j.envpol.2017.05.062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 04/11/2017] [Accepted: 05/18/2017] [Indexed: 06/07/2023]
Abstract
Biofilms in natural environments offer a superior solution to mitigate water pollution. Artificially intensified biofilm reactors represented by rotating biological contactors (RBCs) are widely applied and studied. Understanding the oxygen transfer process in biofilms is an important aspect of these studies, and describing this process in moving biofilms (such as biofilms in RBCs) is a particular challenge. Oxygen transfer in RBCs behaves differently than in other biological reactors due to the special oxygen supply mode that results from alternate exposure of the biofilm to wastewater and air. The study of oxygen transfer in biofilms is indispensable for understanding biodegradation in RBCs. However, the mechanisms are still not well known due to a lack of effective tools to dynamically analyze oxygen diffusion, reaction, and microdistribution in biofilms. A new experimental device, the Oxygen Transfer Modeling Device (OTMD), was designed and manufactured for this purpose, and a mathematical model was developed to model oxygen transfer in biofilm produced by an RBC. This device allowed the simulation of the local environment around the biofilm during normal RBC operation, and oxygen concentrations varying with time and depth in biofilm were measured using an oxygen microelectrode. The experimental data conformed well to the model description, indicating that the OTMD and the model were stable and reliable. Moreover, the OTMD offered a flexible approach to study the impact of a single-factor on oxygen transfer in moving biofilms. In situ environment of biofilm in an RBC was simulated, and dynamic oxygen microdistributions in the biofilm were measured and well fitted to the built model description.
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Affiliation(s)
- Jian-Hui Wang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - You-Peng Chen
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China; Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
| | - Yang Dong
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Xi-Xi Wang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Jin-Song Guo
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
| | - Yu Shen
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China; National Base of International Science and Technology Cooperation for Intelligent Manufacturing Service, Chongqing Technology and Business University, Chongqing 400067, China
| | - Peng Yan
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Teng-Fei Ma
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Xiu-Qian Sun
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Fang Fang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Jing Wang
- Chongqing Jianzhu College, Chongqing 400072, China
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31
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Chiu BK, Kato S, McAllister SM, Field EK, Chan CS. Novel Pelagic Iron-Oxidizing Zetaproteobacteria from the Chesapeake Bay Oxic-Anoxic Transition Zone. Front Microbiol 2017; 8:1280. [PMID: 28769885 PMCID: PMC5513912 DOI: 10.3389/fmicb.2017.01280] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 06/26/2017] [Indexed: 01/11/2023] Open
Abstract
Chemolithotrophic iron-oxidizing bacteria (FeOB) could theoretically inhabit any environment where Fe(II) and O2 (or nitrate) coexist. Until recently, marine Fe-oxidizing Zetaproteobacteria had primarily been observed in benthic and subsurface settings, but not redox-stratified water columns. This may be due to the challenges that a pelagic lifestyle would pose for Zetaproteobacteria, given low Fe(II) concentrations in modern marine waters and the possibility that Fe oxyhydroxide biominerals could cause cells to sink. However, we recently cultivated Zetaproteobacteria from the Chesapeake Bay oxic–anoxic transition zone, suggesting that they can survive and contribute to biogeochemical cycling in a stratified estuary. Here we describe the isolation, characterization, and genomes of two new species, Mariprofundus aestuarium CP-5 and Mariprofundus ferrinatatus CP-8, which are the first Zetaproteobacteria isolates from a pelagic environment. We looked for adaptations enabling strains CP-5 and CP-8 to overcome the challenges of living in a low Fe redoxcline with frequent O2 fluctuations due to tidal mixing. We found that the CP strains produce distinctive dreadlock-like Fe oxyhydroxide structures that are easily shed, which would help cells maintain suspension in the water column. These oxides are by-products of Fe(II) oxidation, likely catalyzed by the putative Fe(II) oxidase encoded by the cyc2 gene, present in both CP-5 and CP-8 genomes; the consistent presence of cyc2 in all microaerophilic FeOB and other FeOB genomes supports its putative role in Fe(II) oxidation. The CP strains also have two gene clusters associated with biofilm formation (Wsp system and the Widespread Colonization Island) that are absent or rare in other Zetaproteobacteria. We propose that biofilm formation enables the CP strains to attach to FeS particles and form flocs, an advantageous strategy for scavenging Fe(II) and developing low [O2] microenvironments within more oxygenated waters. However, the CP strains appear to be adapted to somewhat higher concentrations of O2, as indicated by the presence of genes encoding aa3-type cytochrome c oxidases, but not the cbb3-type found in all other Zetaproteobacteria isolate genomes. Overall, our results reveal adaptations for life in a physically dynamic, low Fe(II) water column, suggesting that niche-specific strategies can enable Zetaproteobacteria to live in any environment with Fe(II).
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Affiliation(s)
- Beverly K Chiu
- Department of Geological Sciences, University of Delaware, NewarkDE, United States
| | - Shingo Kato
- Project Team for Development of New-Generation Research Protocol for Submarine Resources, Japan Agency for Marine-Earth Science and TechnologyKanagawa, Japan
| | - Sean M McAllister
- School of Marine Science and Policy, University of Delaware, NewarkDE, United States
| | - Erin K Field
- Department of Biology, East Carolina University, GreenvilleNC, United States
| | - Clara S Chan
- Department of Geological Sciences, University of Delaware, NewarkDE, United States.,School of Marine Science and Policy, University of Delaware, NewarkDE, United States
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Fan H, Liu X, Wang H, Han Y, Qi L, Wang H. Oxygen transfer dynamics and activated sludge floc structure under different sludge retention times at low dissolved oxygen concentrations. CHEMOSPHERE 2017; 169:586-595. [PMID: 27902965 DOI: 10.1016/j.chemosphere.2016.10.137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 10/16/2016] [Accepted: 10/31/2016] [Indexed: 06/06/2023]
Abstract
In activated sludge systems, the aeration process consumes the most energy. The energy cost can be dramatically reduced by decreasing the operating dissolved oxygen (DO) concentration. However, low DO may lead to incomplete nitrification and poor settling performance of activated sludge flocs (ASFs). This study investigates oxygen transfer dynamics and settling performances of activated sludge under different sludge retention times (SRTs) and DO conditions using microelectrodes and microscopic techniques. Our experimental results showed that with longer SRTs, treatment capacity and settling performances of activated sludge improved due to smaller floc size and less extracellular polymeric substances (EPS). Long-term low DO conditions produced larger flocs and more EPS per unit sludge, which produced a more extensive anoxic area and led to low oxygen diffusion performance in flocs. Long SRTs mitigated the adverse effects of low DO. According to the microelectrode analysis and fractal dimension determination, smaller floc size and less EPS in the long SRT system led to high oxygen diffusion property and more compact floc structure that caused a drop in the sludge volume index (SVI). In summary, our results suggested that long SRTs of activated sludge can improve the operating performance under low DO conditions.
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Affiliation(s)
- Haitao Fan
- Research Center for Low carbon technology of water environment, Renmin University of China, Beijing 100872, China
| | - Xiuhong Liu
- Research Center for Low carbon technology of water environment, Renmin University of China, Beijing 100872, China
| | - Hao Wang
- Research Center for Low carbon technology of water environment, Renmin University of China, Beijing 100872, China
| | - Yunping Han
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Lu Qi
- Research Center for Low carbon technology of water environment, Renmin University of China, Beijing 100872, China.
| | - Hongchen Wang
- Research Center for Low carbon technology of water environment, Renmin University of China, Beijing 100872, China.
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33
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Control of ultrafiltration membrane fouling caused by algal extracellular organic matter (EOM) using enhanced Al coagulation with permanganate. Sep Purif Technol 2017. [DOI: 10.1016/j.seppur.2016.07.054] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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34
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Miao L, Wang S, Cao T, Peng Y, Zhang M, Liu Z. Advanced nitrogen removal from landfill leachate via Anammox system based on Sequencing Biofilm Batch Reactor (SBBR): Effective protection of biofilm. BIORESOURCE TECHNOLOGY 2016; 220:8-16. [PMID: 27552718 DOI: 10.1016/j.biortech.2016.06.131] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 06/21/2016] [Accepted: 06/24/2016] [Indexed: 06/06/2023]
Abstract
High levels of organics negatively affect Anammox for treating landfill leachate. To enhance the ability of Anammox to survive against adverse environments, a lab-scale two-stage Anammox system using a Sequencing Biofilm Batch Reactor was applied to treat mature landfill leachate under 35°C. Over 107days, with influent total nitrogen (TN) and chemical oxygen demand (COD) concentrations of 3000±100 and 3000±100mg/L, effluent TN was below 20mg/L. For extracellular polymeric substance (EPS) of Anammox, slime-EPS and loosely-bound-EPS of floccules were both higher than biofilm, while tight-bound-EPS of biofilm was significantly higher, contributing to biofilm formation. Quantitative microbial analysis showed that as influent COD increased, Anammox gene ratios of biofilm increased from 1.34% to 13.28%; the gene ratios of floccule first increased, then decreased to 3.88%. This indicated that Anammox and heterotrophic bacteria could coexist because of the biofilm, leading to stable nitrogen removal performance, even when organics were present.
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Affiliation(s)
- Lei Miao
- Engineering Research Center of Beijing, Beijing University of Technology, Beijing, PR China
| | - Shuying Wang
- Engineering Research Center of Beijing, Beijing University of Technology, Beijing, PR China.
| | - Tianhao Cao
- Engineering Research Center of Beijing, Beijing University of Technology, Beijing, PR China
| | - Yongzhen Peng
- Engineering Research Center of Beijing, Beijing University of Technology, Beijing, PR China
| | - Man Zhang
- Engineering Research Center of Beijing, Beijing University of Technology, Beijing, PR China
| | - Zhaoyuan Liu
- Engineering Research Center of Beijing, Beijing University of Technology, Beijing, PR China
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35
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Sytek-Szmeichel K, Podedworna J, Zubrowska-Sudol M. Efficiency of wastewater treatment in SBR and IFAS-MBSBBR systems in specified technological conditions. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2016; 73:1349-1356. [PMID: 27003075 DOI: 10.2166/wst.2015.611] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The objective of this study is to compare wastewater treatment effectiveness in sequencing batch reactor (SBR) and integrated fixed-film activated sludge-moving-bed sequencing batch biofilm reactor (IFAS-MBSBBR) systems in specific technological conditions. The comparison of these two technologies was based on the following assumptions, shared by both series, I and II: the reactor's active volume was 28 L; 8-hour cycle of reactor's work, with the same sequence and duration of its consecutive phases; and the dissolved oxygen concentration in the aerobic phases was maintained at a level of 3.0 mg O2/L. For both experimental series (I and II), comparable effectiveness of organic compound (chemical oxygen demand (COD)) removal, nitrification and biological phosphorus removal has been obtained at levels of 95.1%, 97% and 99%, respectively. The presence of the carrier improved the efficiency of total nitrogen removal from 86.3% to 91.7%. On the basis of monitoring tests, it has been found that the ratio of simultaneous denitrification in phases with aeration to the total efficiency of denitrification in the cycle was 1.5 times higher for IFAS-MBSBBR.
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Affiliation(s)
- K Sytek-Szmeichel
- Faculty of Environmental Engineering, Warsaw University of Technology, Nowowiejska 20, 00-653 Warsaw, Poland E-mail:
| | - J Podedworna
- Faculty of Environmental Engineering, Warsaw University of Technology, Nowowiejska 20, 00-653 Warsaw, Poland E-mail:
| | - M Zubrowska-Sudol
- Faculty of Environmental Engineering, Warsaw University of Technology, Nowowiejska 20, 00-653 Warsaw, Poland E-mail:
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Zhang J, Li L, Liu J. Temporal variation of microbial population in a thermophilic biofilter for SO₂ removal. J Environ Sci (China) 2016; 39:4-12. [PMID: 26899638 DOI: 10.1016/j.jes.2015.11.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 11/02/2015] [Accepted: 11/04/2015] [Indexed: 06/05/2023]
Abstract
The performance of a biofilter relies on the activity of microorganisms during the gas contaminant treatment process. In this study, SO2 was treated using a laboratory-scale biofilter packed with polyurethane foam cubes (PUFC), on which thermophilic desulfurization bacteria were attached. The thermophilic biofilter effectively reduced SO2 within 10months of operation time, with a maximum elimination capacity of 48.29 g/m(3)/hr. Temporal shifts in the microbial population in the thermophilic biofilter were determined through polymerase chain reaction-denaturing gradient gel electrophoresis and deoxyribonucleic acid (DNA) sequence analysis. The substrate species and environmental conditions in the biofilter influenced the microbial population. Oxygen distribution in the PUFC was analyzed using a microelectrode. When the water-containing rate in PUFC was over 98%, the oxygen distribution presented aerobic-anoxic-aerobic states along the test route on the PUFC. The appearance of sulfate-reducing bacteria was caused by the anaerobic conditions and sulfate formation after 4months of operation.
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Affiliation(s)
- Jingying Zhang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Lin Li
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Junxin Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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37
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Ding Z, Bourven I, Guibaud G, van Hullebusch ED, Panico A, Pirozzi F, Esposito G. Role of extracellular polymeric substances (EPS) production in bioaggregation: application to wastewater treatment. Appl Microbiol Biotechnol 2015; 99:9883-905. [DOI: 10.1007/s00253-015-6964-8] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 08/23/2015] [Accepted: 08/26/2015] [Indexed: 11/28/2022]
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Wang J, Li K, Wei Y, Cheng Y, Wei D, Li M. Performance and fate of organics in a pilot MBR-NF for treating antibiotic production wastewater with recycling NF concentrate. CHEMOSPHERE 2015; 121:92-100. [PMID: 25475971 DOI: 10.1016/j.chemosphere.2014.11.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 11/07/2014] [Accepted: 11/15/2014] [Indexed: 06/04/2023]
Abstract
A double membrane system comprising a membrane bioreactor (MBR) combined with a nanofiltration (NF) membrane was investigated on a pilot scale for the treatment of antibiotic production wastewater over a three-month period at a pharmaceutical company in Wuxi, China. By recycling the NF concentrate, the combined MBR-NF process was shown to be effective for the treatment of antibiotic production wastewater, resulting in excellent water quality and a high water yield of 92±5.6%. The water quality of the pilot-scale MBR-NF process was excellent; e.g., the concentrations of TOC, NH4(+)-N, TP were stable at 5.52, 0.68, 0.34 mg L(-1), respectively, and the values of turbidity and conductivity of the NF permeate were 0.15 NTU and 2.5 mS cm(-1), respectively; these values meet China's water quality standard requirements for industrial use (GB21903-2008). Not only were the antibiotic removal rates of spiramycin (SPM) and new spiramycin (NSPM) over 95%, the acute toxicity was also drastically reduced by the MBR-NF pilot system. The main organics in the MBR effluent were proteins, polysaccharides, and humic-like substances; they were almost completely retained by the NF membrane and further biodegraded in the MBR because the NF concentrate was recycled. The microbial community of the MBR did not significantly change with the recycling of the NF concentrate.
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Affiliation(s)
- Jianxing Wang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
| | - Kun Li
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
| | - Yuansong Wei
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China.
| | - Yutao Cheng
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China; CCID Consulting Co., Ltd, Beijing 100048, China
| | - Dongbin Wei
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China
| | - Mingyue Li
- Wuxi Fortune Pharmaceutical Co. Ltd, Wuxi 214046, China
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Tang B, Zhang Z, Chen X, Bin L, Huang S, Fu F, Yang H, Chen C. Biodiversity and succession of microbial community in a multi-habitat membrane bioreactor. BIORESOURCE TECHNOLOGY 2014; 164:354-361. [PMID: 24874876 DOI: 10.1016/j.biortech.2014.05.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/26/2014] [Accepted: 05/02/2014] [Indexed: 06/03/2023]
Abstract
The present study focused on establishing a multi-habitat membrane bioreactor, as well as exploring its biodiversity and succession of microbial communities. In a long-term operational period (100 days), the dissolved oxygen level of a local zone within the bioreactor decreased consistently from the original oxic state to the final anaerobic state, which led to a continuous succession of the microbial community in the bioreactor. The results revealed that the biodiversity of the microbial community in different zones simultaneously increased, with a similar microbial composition in their final successional stage. The results also indicated that the dominant species during the whole operation were distributed among 6 major phyla. At the initial operational stages, the dominant species in the anoxic-anaerobic and the oxic zones exhibited distinguished difference, whereas at the final operational stage, both zones presented nearly the same dominant microbial species and a rather similar structure in their microbial communities.
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Affiliation(s)
- Bing Tang
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China.
| | - Zi Zhang
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Xuan Chen
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Liying Bin
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Shaosong Huang
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Fenglian Fu
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Huiwen Yang
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Cuiqun Chen
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China
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Tang B, Zhang Z. Essence of disposing the excess sludge and optimizing the operation of wastewater treatment: rheological behavior and microbial ecosystem. CHEMOSPHERE 2014; 105:1-13. [PMID: 24462086 DOI: 10.1016/j.chemosphere.2013.12.067] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 12/25/2013] [Accepted: 12/26/2013] [Indexed: 06/03/2023]
Abstract
Proper disposal of excess sludge and steady maintenance of the high bioactivity of activated sludge in bioreactors are essential for the successful operation of wastewater treatment plants (WWTPs). Since sludge is a non-Newtonian fluid, the rheological behavior of sludge can therefore have a significant impact on various processes in a WWTP, such as fluid transportation, mixing, oxygen diffusion, mass transfer, anaerobic digestion, chemical conditioning and mechanical dewatering. These are key factors affecting the operation efficiency and the energy consumption of the entire process. In the past decade-due to the production of large quantities of excess sludge associated with the extensive construction of WWTPs and the emergence of some newly-developed techniques for wastewater purification characterized by high biomass concentrations-investigations into the rheology of sludge are increasingly important and this topic has aroused considerable interests. We reviewed a number of investigations into the rheology of sludge, with the purpose of providing systematic and detailed analyses on the related aspects of the rheological behavior of sludge. It is clear that, even though considerable research has focused on the rheology of sludge over a long time period, there is still a need for further thorough investigation into this field. Due to the complex process of bio-treatment in all WWTPs, biological factors have a major influence on the properties of sludge. These influences are however still poorly understood, particularly with respect to the mechanisms involved and magnitude of such impacts. When taking note of the conspicuous biological characteristics of sludge, it becomes important that biological factors, such as the species composition and relative abundance of various microorganisms, as well as the microbial community characteristics that affect relevant operating processes, should be considered.
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Affiliation(s)
- Bing Tang
- School of Environmental Science and Engineering, Guangdong University of Technology, 510006 Guangzhou, PR China.
| | - Zi Zhang
- School of Environmental Science and Engineering, Guangdong University of Technology, 510006 Guangzhou, PR China
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Yang Y, Yu K, Xia Y, Lau FTK, Tang DTW, Fung WC, Fang HHP, Zhang T. Metagenomic analysis of sludge from full-scale anaerobic digesters operated in municipal wastewater treatment plants. Appl Microbiol Biotechnol 2014; 98:5709-18. [PMID: 24633414 DOI: 10.1007/s00253-014-5648-0] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 02/24/2014] [Accepted: 02/26/2014] [Indexed: 01/07/2023]
Abstract
This study applied Illumina high-throughput sequencing to explore the microbial communities and functions in anaerobic digestion sludge (ADS) from two wastewater treatment plants based on a metagenomic view. Taxonomic analysis using SILVA SSU database indicated that Proteobacteria (9.52-13.50 %), Bacteroidetes (7.18 %-10.65 %) and Firmicutes (7.53 %-9.46 %) were the most abundant phyla in the ADS. Differences of microbial communities between the two types of ADS were identified. Genera of Methanosaeta and Methanosarcina were the major methanogens. Functional analysis by SEED subsystems showed that the basic metabolic functions of metagenomes in the four ADS samples had no significant difference among them, but they were different from other microbial communities from activated sludge, human faeces, ocean and soil. Abundances of genes in methanogenesis pathway were also quantified using a methanogenesis genes database extracted from KEGG. Results showed that acetotrophic was the major methanogenic pathway in the anaerobic sludge digestion.
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Affiliation(s)
- Ying Yang
- Environmental Biotechnology Laboratory, Department of Civil Engineering, University of Hong Kong, Hong Kong, China
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