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Hou J, Zhu Y, Liu J, Lin L, Zheng M, Yang L, Wei W, Ni BJ, Chen X. Competitive enrichment of comammox Nitrospira in floccular sludge. WATER RESEARCH 2024; 251:121151. [PMID: 38246075 DOI: 10.1016/j.watres.2024.121151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 01/11/2024] [Accepted: 01/15/2024] [Indexed: 01/23/2024]
Abstract
The discovery of complete ammonium oxidation (comammox) has subverted the traditional perception of two-step nitrification, which plays a key role in achieving biological nitrogen removal from wastewater. Floccular sludge-based treatment technologies are being applied at the majority of wastewater treatment plants in service where detection of various abundances and activities of comammox bacteria have been reported. However, limited efforts have been made to enrich and subsequently characterize comammox bacteria in floccular sludge. To this end, a lab-scale sequencing batch reactor (SBR) in the step-feeding mode was applied in this work to enrich comammox bacteria through controlling appropriate operational conditions (dissolved oxygen of 0.5 ± 0.1 g-O2/m3, influent ammonium of 40 g-N/m3 and uncontrolled longer sludge retention time). After 215-d operation, comammox bacteria gradually gained competitive advantages over counterparts in the SBR with a stable nitrification efficiency of 92.2 ± 2.2 %: the relative abundance of Nitrospira reached 42.9 ± 1.3 %, which was 13 times higher than that of Nitrosomonas, and the amoA gene level of comammox bacteria increased to 7.7 ± 2.1 × 106 copies/g-biomass, nearly 50 times higher than that of conventional ammonium-oxidizing bacteria. The enrichment of comammox bacteria, especially Clade A Candidatus Nitrospira nitrosa, in the floccular sludge led to (i) apparent affinity constants for ammonium and oxygen of 3.296 ± 0.989 g-N/m3 and 0.110 ± 0.004 g-O2/m3, respectively, and (ii) significantly low N2O and NO production, with emission factors being 0.136 ± 0.026 % and 0.023 ± 0.013 %, respectively.
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Affiliation(s)
- Jiaying Hou
- College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China
| | - Ying Zhu
- College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China
| | - Jinzhong Liu
- College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China
| | - Limin Lin
- School of Engineering, Westlake University, Hangzhou, Zhejiang 310030, China
| | - Min Zheng
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Linyan Yang
- School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Xueming Chen
- College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China.
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2
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Liu Y, Liu Y, Zhao T, He Y, Zhu T, Chai H, Peng L. Smaller Aerobic Granules Significantly Reduce N 2O Production by Ammonia-Oxidizing Bacteria: Evidences from Biochemical and Isotopic Analyses. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:545-556. [PMID: 38111342 DOI: 10.1021/acs.est.3c06246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
The mitigation of nitrous oxide (N2O) is of primary significance to offset carbon footprints in aerobic granular sludge (AGS) systems. However, a significant knowledge gap still exists regarding the N2O production mechanism and its pathway contribution. To address this issue, the impact of varying granule sizes, dissolved oxygen (DO), and nitrite (NO2-) levels on N2O production by ammonia-oxidizing bacteria (AOB) during nitrification in AGS systems was comprehensively investigated. Biochemical and isotopic experiments revealed that increasing DO or decreasing NO2- levels reduced N2O emission factors (by 13.8 or 19.5%) and production rates (by 0.08 or 0.35 mg/g VSS/h) via weakening the role of the AOB denitrification pathway since increasing DO competed for more electrons required for AOB denitrification. Smaller granules (0.5 mm) preferred to diminish N2O production via enhancing the role of NH2OH pathway (i.e., 59.4-100% in the absence of NO2-), while larger granules (2.0 mm) induced conspicuously higher N2O production via the AOB denitrification pathway (approximately 100% at higher NO2- levels). Nitrifying AGS systems with a unified size of 0.5 mm achieved 42% N2O footprint reduction compared with the system with mixed sizes (0.5-2.0 mm) under optimal conditions (DO = 3.0 mg-O2/L and NO2- = 0 mg-N/L).
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Affiliation(s)
- Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yingrui Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Tianhang Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yanying He
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Hongxiang Chai
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Lai Peng
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070, China
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070, China
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Liu S, Wu F, Guo M, Zeng M, Liu W, Wang Z, Wu N, Cao J. A comprehensive literature mining and analysis of nitrous oxide emissions from different innovative mainstream anammox-based biological nitrogen removal processes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166295. [PMID: 37586540 DOI: 10.1016/j.scitotenv.2023.166295] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 08/09/2023] [Accepted: 08/12/2023] [Indexed: 08/18/2023]
Abstract
The biological nitrogen removal (BNR) process in wastewater treatment plants generates a substantial volume of nitrous oxide (N2O), which possesses a potent greenhouse gas effect. A limited number of studies have systematically investigated the N2O emissions of anammox-based systems with different BNR processes under mainstream conditions. Based on extensive big data statistical analysis, it had been revealed that simultaneous nitritation, anammox and denitrification (SNAD), partial nitritation anammox (PNA) and partial denitrification anammox (PDA), exhibit significantly lower N2O emission factors when compared to traditional BNR processes. The median values for N2O emission factors were determined to be 1.01 %, 1.15 % and 1.43 % for SNAD, PNA and PDA, respectively. Based on nitrogen removal data and N2O emission factors, the N2O emissions from PNA, SNAD and PDA processes were calculated to be 0.016 g·d-1, 0.037 g·d-1 and 0.008 g·d-1, respectively. Furthermore, the machine learning models (SVM and ANN) exhibited excellent predictive performance for N2O emissions in the BNR processes. However, after removing environmental factors, the R2 value of the SVM model sharply decreased. The SHAP feature analysis demonstrated the significant impact of environmental factors on the accuracy of predictive performance in machine learning models. Spearman correlation analysis was employed to investigate the relationship between N2O emissions and operational factors as well as microbial communities. The results demonstrated a negative correlation between HRT, temperature and C/N with N2O emissions. Moreover, strong associations were observed between Nitrosomonas, Nitrospira, Denitratisoma, Thauera species and N2O emissions. The contribution of N2O production via AOB pathways played a key role that was quantitatively calculated to be 93 %, 80 % and 48 % in the PNA, SNAD and PDA processes, respectively. These findings highlight the potential of these innovative BNR processes in mitigating N2O emissions.
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Affiliation(s)
- Shuang Liu
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, 300457 Tianjin, China
| | - Fan Wu
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, 300457 Tianjin, China
| | - Mingzhu Guo
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, 300457 Tianjin, China
| | - Ming Zeng
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, 300457 Tianjin, China.
| | - Wei Liu
- Department F.A. Forel for Environmental and Aquatic Sciences, Faculty of Sciences, University of Geneva, Carl-Vogt 66, CH-1211 Geneva, Switzerland.
| | - Zhiqiang Wang
- College of Engineering and Technology, Tianjin Agricultural University, Tianjin 300384, China
| | - Nan Wu
- College of Engineering and Technology, Tianjin Agricultural University, Tianjin 300384, China
| | - Jingguo Cao
- College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, 300457 Tianjin, China
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Xiong W, Ye Y, He D, He S, Xiang Y, Xiao J, Feng W, Wu M, Yang Z, Wang D. Deregulation of Ribosome Biogenesis in Nitrite-Oxidizing Bacteria Leads to Nitrite Accumulation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:16673-16684. [PMID: 37862695 DOI: 10.1021/acs.est.3c06002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2023]
Abstract
Nitrite (NO2-) accumulation caused by nitrite-oxidizing bacteria (NOB) inhibition in nitrification is a double-edged sword, i.e., a disaster in aquatic environments but a hope for innovating nitrogen removal technology in wastewater treatment. However, little information is available regarding the molecular mechanism of NOB inhibition at the cellular level. Herein, we investigate the response of NOB inhibition on NO2- accumulation established by a side-stream free ammonia treatment unit in a nitrifying reactor using integrated metagenomics and metaproteomics. Results showed that compared with the baseline, the relative abundance and activity of NOB in the experimental stage decreased by 91.64 and 68.66%, respectively, directly resulting in a NO2- accumulation rate of 88%. Moreover, RNA polymerase, translation factors, and aa-tRNA ligase were significantly downregulated, indicating that protein synthesis in NOB was interfered during NO2- accumulation. Further investigations showed that ribosomal proteins and GTPases, responsible for bindings between either ribosomal proteins and rRNA or ribosome subunits, were remarkably downregulated. This suggests that ribosome biogenesis was severely disrupted, which might be the key reason for the inhibited protein synthesis. Our findings fill a knowledge gap regarding the underlying mechanisms of NO2- accumulation, which would be beneficial for regulating the accumulation of NO2- in aquatic environments and engineered systems.
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Affiliation(s)
- Weiping Xiong
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Yuhang Ye
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Dandan He
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Siying He
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Yinping Xiang
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Jun Xiao
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Wenyi Feng
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Mengru Wu
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Zhaohui Yang
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
| | - Dongbo Wang
- College of Environmental Science and Engineering and Key Laboratory of Environmental Biology and Pollution Control (Ministry of Education), Hunan University, Changsha 410082, PR China
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Zhu Y, Hou J, Liu J, Huo P, Yang L, Zheng M, Wei W, Ni BJ, Chen X. Model-based development of strategies enabling effective enrichment and application of comammox bacteria in floccular sludge under mainstream conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 895:165051. [PMID: 37391158 DOI: 10.1016/j.scitotenv.2023.165051] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/11/2023] [Accepted: 06/19/2023] [Indexed: 07/02/2023]
Abstract
The discovery of complete ammonium oxidation (comammox) has redefined the perception of the nitrification process which plays a vital part in biological nitrogen removal (BNR) from wastewater. Despite the reported detection or cultivation of comammox bacteria in biofilm or granular sludge reactors, limited attempts have been made to enrich or assess comammox bacteria in floccular sludge reactors with suspended growth of microbes, which are most extensively applied at wastewater treatment plants. Therefore, through making use of a comammox-inclusive bioprocess model reliably evaluated using batch experimental data with joint contributions of different nitrifying guilds, this work probed into the proliferation and functioning of comammox bacteria in two commonly-used floccular sludge reactor configurations, i.e., continuous stirred tank reactor (CSTR) and sequencing batch reactor (SBR), under mainstream conditions. The results indicated that compared with the studied SBR, the CSTR was observed to favor the enrichment of comammox bacteria through maintaining a sufficient sludge retention time (40-100 d) while avoiding an extremely low DO level (e.g., 0.05 g-O2/m3), irrespective of the varied influent NH4+-N of 10-100 g-N/m3. Meanwhile, the inoculum sludge was found to greatly influence the start-up process of the studied CSTR. By inoculating the CSTR with a sufficient amount of sludge, finally enriched floccular sludge with a high abundance of comammox bacteria (up to 70.5 %) could be rapidly obtained. These results not only benefitted further investigation and application of comammox-inclusive sustainable BNR technologies but also explained, to some extent, the discrepancy in the reported presence and abundance of comammox bacteria at wastewater treatment plants adopting floccular sludge-based BNR technologies.
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Affiliation(s)
- Ying Zhu
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China
| | - Jiaying Hou
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China
| | - Jinzhong Liu
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China
| | - Pengfei Huo
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China
| | - Linyan Yang
- School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Min Zheng
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Xueming Chen
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China.
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6
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He Y, Liu Y, Li X, Zhu T, Liu Y. Unveiling the roles of biofilm in reducing N 2O emission in a nitrifying integrated fixed-film activated sludge (IFAS) system. WATER RESEARCH 2023; 243:120326. [PMID: 37454457 DOI: 10.1016/j.watres.2023.120326] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 06/07/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023]
Abstract
Biofilm process such as integrated fixed-film activated sludge (IFAS) system has been preliminarily found to produce less nitrous oxide (N2O) than suspended sludge system. However, the N2O emission behaviors and underlying N2O mitigation mechanism in such hybrid system remain unclear. This study therefore aims to fully unveil the roles of biofilm in reducing N2O emission in a nitrifying IFAS system with the aid of some advanced technologies such as N2O microsensor and site-preference analysis. It was found that ammonia oxidation occurred mostly in the sludge flocs (˃ 86%) and biofilm could reduce N2O emission by 43.77% in a typical operating cycle. Biofilm not only reduced nitrite accumulation in nitrification process, inhibiting N2O production via nitrifier denitrification pathway, but also served as a N2O sink, promoting the reduction of N2O via endogenous denitrification. As a result, N2O emissions from the IFAS system were 50%-83% lower than those from the solo sludge flocs. Further, more N2O emission was reduced in the presence of biofilm with decreasing the dissolved oxygen level in the range of 0.5-3.0 mg O2/L. Microbial community and key enzyme analyses revealed that biofilm had relatively high microbial diversity and unique enzyme composition, providing a reasonable explanation for the changed contributions of different N2O production pathways and reduced N2O emission.
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Affiliation(s)
- Yanying He
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yingrui Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Xuecheng Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China.
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7
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Lu H, Wang H, Wu Q, Luo H, Zhao Q, Liu B, Si Q, Zheng S, Guo W, Ren N. Automatic control and optimal operation for greenhouse gas mitigation in sustainable wastewater treatment plants: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 855:158849. [PMID: 36122730 DOI: 10.1016/j.scitotenv.2022.158849] [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: 06/30/2022] [Revised: 09/01/2022] [Accepted: 09/14/2022] [Indexed: 06/15/2023]
Abstract
In order to promote low-carbon sustainable operational management of the wastewater treatment plants (WWTPs), automatic control and optimal operation technologies, which devote to improving effluent quality, operational costs and greenhouse gas (GHG) emissions, have flourished in recent years. There is no consensus on the design procedure for optimal control/operation of sustainable WWTPs. In this review, we summarize recent researches on developing control and optimization strategies for GHG mitigation in WWTPs. Faced with the fact that direct carbon dioxide (CO2) emissions (considered biological origin) are generally not included in the carbon footprint of WWTPs, direct emissions (nitrous oxide (N2O), methane (CH4)) and indirect emissions are paid much attention. Firstly, the plant-wide models with GHG dynamic simulation, which are employed to design and evaluate the automatic control schemes as well as representative studies on identifying key factors affecting GHG emissions or comprehensive performance are outlined. Then, both traditional and advanced control methods commonly used in GHG mitigation are reviewed in detail, followed by the multi-objective optimization practices of control/operational parameters. Based on the mentioned control and (or) optimization strategies, a novel design framework for the optimal control/operation of sustainable WWTPs is proposed. The findings and design framework proposed in the paper will provide guidance for GHG mitigation and sustainable operation in WWTPs. It is foreseeable that more accurate and appropriate plant-wide models together with flexible control methods and intelligent optimization strategies will be developed to satisfy the upgrading requirements of WWTPs in the future.
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Affiliation(s)
- Hao Lu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Huazhe Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qinglian Wu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Haichao Luo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qi Zhao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Banghai Liu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qishi Si
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shanshan Zheng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Wanqian Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
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8
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Zhang X, Deng J, Yang C, Wang Z, Liu Y. Selective reduction of nitrite to nitrogen by polyaniline-carbon nanotubes composite at neutral pH. ENVIRONMENTAL RESEARCH 2022; 214:114203. [PMID: 36030923 DOI: 10.1016/j.envres.2022.114203] [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: 06/24/2022] [Revised: 08/17/2022] [Accepted: 08/21/2022] [Indexed: 06/15/2023]
Abstract
The selective reduction of nitrite (NO2-) to nitrogen by chemical reductant is a desirable strategy to remove NO2- from polluted water and wastewater. However, the residue and reuse of chemical reductant are two main issues to be addressed. Herein, a novel polyaniline-carbon nanotubes composite (PANI-CNTs) was developed by in-situ polymerization to selectively reduce NO2- to nitrogen gas (N2). The used PANI-CNTs could be reused after regeneration with NaBH4. The PANI-CNTs could reduce NO2- with 93.9% N2 selectivity at initial pH of 6.8. The NO2- removal efficiency only decreased by 12.08% after five cycles of reduction/regeneration. The interconversion between imine nitrogen (-N) and amine nitrogen (-NH-) groups induced the chemical reduction of NO2- and regeneration of PANI-CNTs. PANI-CNTs exhibited an excellent performance for the removal of NO2- in the presence of competitive ions and in actual water and wastewater samples. This new PANI-CNTs composite may have great potential for water purification and wastewater denitrification.
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Affiliation(s)
- Xuemei Zhang
- College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China
| | - Jinhua Deng
- College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China
| | - Congling Yang
- College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China
| | - Zhaoli Wang
- Chengdu Academy of Environmental Sciences, Sichuan, Chengdu, 610072, China
| | - Yong Liu
- College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China; Key Laboratory of Treatment for Special Wastewater of Sichuan Province Higher Education System, Sichuan, Chengdu, 610066, China.
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9
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Di Capua F, Iannacone F, Sabba F, Esposito G. Simultaneous nitrification-denitrification in biofilm systems for wastewater treatment: Key factors, potential routes, and engineered applications. BIORESOURCE TECHNOLOGY 2022; 361:127702. [PMID: 35905872 DOI: 10.1016/j.biortech.2022.127702] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/20/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Simultaneous nitrification-denitrification (SND) is an advantageous bioprocess that allows the complete removal of ammonia nitrogen through sequential redox reactions leading to nitrogen gas production. SND can govern nitrogen removal in single-stage biofilm systems, such as the moving bed biofilm reactor and aerobic granular sludge system, as oxygen gradients allow the development of multilayered biofilms including nitrifying and denitrifying bacteria. Environmental and operational conditions can strongly influence SND performance, biofilm development and biochemical pathways. Recent advances have outlined the possibility to reduce the carbon and energy consumption of the process via the "shortcut pathway", and simultaneously remove both N and phosphorus under specific operational conditions, opening new possibilities for wastewater treatment. This work critically reviews the factors influencing SND and its application in biofilm systems from laboratory to full scale. Operational strategies to enhance SND efficiency and hints to reduce nitrous oxide emission and operational costs are provided.
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Affiliation(s)
- Francesco Di Capua
- Department of Civil, Environmental, Land, Building Engineering and Chemistry, Polytechnic University of Bari, Bari 70125, Italy.
| | | | | | - Giovanni Esposito
- Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, Naples 80125, Italy
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10
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Dockx L, Caluwé M, Dobbeleers T, Dries J. Nitrous oxide formation during simultaneous phosphorus and nitrogen removal in aerobic granular sludge treating different carbon substrates. BIORESOURCE TECHNOLOGY 2022; 345:126542. [PMID: 34906707 DOI: 10.1016/j.biortech.2021.126542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/05/2021] [Accepted: 12/06/2021] [Indexed: 06/14/2023]
Abstract
The impact of different substrates on N2O dynamics and gene expression of marker enzymes (nirS, nirK and nosZ) involved in denitrifying enhanced biological phosphorus removal (d-EBPR) was investigated. Aerobic granular sludge fed with VFAs led to an anoxic P-uptake (27.7 ± 1.2 mg PO43--P.gVSS-1) and N2O emissions up to 80.7 ± 3.4% N2O-N. A decisive role of Accumulibacter in N2O formation was observed. Dosage of amino acids (12.0 ± 1.2 mg PO43--P.gVSS-1) and glucose (1.5 ± 0.9 mg PO43--P.gVSS-1) as sole substrate did not support d-EBPR activity. Presence of NO2- resulted in higher N2O formation in comparison to nitrate and a nosZ/(nirS + nirK) ratio lower than 0.3. A linear correlation (R2 > 0.95) between the nosZ/(nirS + nirK) ratio and the N2O reductase rate was found only when dosing the same type of substrate. This suggests an interplay between the microbial community composition and different polyhydroxyalkanoates derivatives, when dosing different substrates.
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Affiliation(s)
- Lennert Dockx
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium
| | - Michel Caluwé
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium
| | - Thomas Dobbeleers
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium
| | - Jan Dries
- BioWAVE, Biochemical Wastewater Valorization and Engineering, Faculty of Applied Engineering, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
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11
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Yang R, Yuan LJ, Wang R, Wang G, Zhu M. Role of nitrite reductase in N2O production under aerobic conditions: An index for predicting the intensity of N2O production. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2021.108242] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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12
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Gruber W, von Känel L, Vogt L, Luck M, Biolley L, Feller K, Moosmann A, Krähenbühl N, Kipf M, Loosli R, Vogel M, Morgenroth E, Braun D, Joss A. Estimation of countrywide N 2O emissions from wastewater treatment in Switzerland using long-term monitoring data. WATER RESEARCH X 2021; 13:100122. [PMID: 34661091 PMCID: PMC8503907 DOI: 10.1016/j.wroa.2021.100122] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 09/24/2021] [Accepted: 09/24/2021] [Indexed: 05/21/2023]
Abstract
Nitrous oxides (N2O) emissions contribute to climate change and stratospheric ozone depletion. Wastewater treatment is an important, yet likely underestimated, source of N2O emissions, as recent, long-term monitoring campaigns have demonstrated. However, the available data are insufficient to representatively estimate countrywide emission due to the brevity of most monitoring campaigns. This study showed that the emission estimates can be significantly improved using an advanced approach based on multiple continuous, long-term monitoring campaigns. In monitoring studies on 14 full-scale wastewater treatment plants (WWTPs), we found a strong variability in the yearly emission factors (EFs) (0.1 to 8% of the incoming nitrogen load) which exhibited a good correlation with effluent nitrite. But countrywide data on nitrite effluent concentrations is very limited and unavailable for emission estimation in many countries. Hence, we propose a countrywide emission factor calculated from the weighted EFs of three WWTP categories (carbon removal, EF: 0.1-8%, nitrification only: 1.8%, and full nitrogen removal: 0.9%). However, EF of carbon removal WWTPs are still highly uncertain given the expected variability in performance. The newly developed approach allows representative, country-specific estimations of the N2O emissions from WWTP. Applied to Switzerland, the estimations result in an average EF of 0.9 to 3.6% and total emissions of 410 to 1690 tN2O-N/year, which corresponds to 0.3-1.4% of the total greenhouse gas emissions in Switzerland. Our results demonstrate that better data availability and an improved understanding of long-term monitoring campaigns is crucial to improve current emission estimations. Finally, our results confirm several measures to mitigate N2O emissions from wastewater treatment; year-round denitrification, limiting nitrite accumulation, and stringent control of sludge age in carbon removal plants.
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Affiliation(s)
- Wenzel Gruber
- Eawag, Swiss Federal Institute for Aquatic Science and Technology, 8600 Duebendorf, Switzerland
- Institute of Environmental Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Luzia von Känel
- Institute of Environmental Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Liliane Vogt
- Eawag, Swiss Federal Institute for Aquatic Science and Technology, 8600 Duebendorf, Switzerland
- Institute of Environmental Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Manuel Luck
- Eawag, Swiss Federal Institute for Aquatic Science and Technology, 8600 Duebendorf, Switzerland
- Institute of Environmental Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Lucien Biolley
- Institute of Environmental Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Kilian Feller
- Eawag, Swiss Federal Institute for Aquatic Science and Technology, 8600 Duebendorf, Switzerland
| | - Andrin Moosmann
- Eawag, Swiss Federal Institute for Aquatic Science and Technology, 8600 Duebendorf, Switzerland
| | - Nikita Krähenbühl
- Eawag, Swiss Federal Institute for Aquatic Science and Technology, 8600 Duebendorf, Switzerland
| | - Marco Kipf
- Eawag, Swiss Federal Institute for Aquatic Science and Technology, 8600 Duebendorf, Switzerland
| | - Reto Loosli
- Institute of Environmental Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Michael Vogel
- Institute of Environmental Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Eberhard Morgenroth
- Eawag, Swiss Federal Institute for Aquatic Science and Technology, 8600 Duebendorf, Switzerland
- Institute of Environmental Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Daniel Braun
- Institute of Environmental Engineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Adriano Joss
- Eawag, Swiss Federal Institute for Aquatic Science and Technology, 8600 Duebendorf, Switzerland
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13
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Pereira TDS, Spindola RH, Rabelo CABS, Silveira NC, Adorno MAT, Kunz A, Pires EC, Damianovic MHRZ. A predictive model for N 2O production in anammox-granular sludge reactors: Combined effects of nitrite/ammonium ratio and organic matter concentration. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 297:113295. [PMID: 34311258 DOI: 10.1016/j.jenvman.2021.113295] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/29/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
Once the use of anammox reactors has been increasing on a global scale, it is important to understand the mechanisms of N2O emissions and how to minimise the emissions by optimising the operating conditions. In this study, the influence of chemical oxygen demand (COD) (from 0 mgO2 L-1 to 100 mgO2 L-1) and nitrite/ammonium ratio from 0.79 to 2.21 (maintaining ammonium at 100 mgN L-1 and varying nitrite from 79 mgN L-1 to 221 mgN L-1) in the N2O emissions from anammox-granular sludge reactor was investigated in two steps. Step 1 consisted of batch tests, using central composite design, and Step 2, long-term operation of a 6.5 L continuous up-flow reactor. The results showed that the N2O emissions were minimized by controlling, in the influent, the NO2--N/NH4+-N ratio from 1.1 to 1.3 and maintaining the COD concentration below 100 mgO2 L-1. TN removal efficiencies were higher than 70% in all conditions tested".
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Affiliation(s)
- T D S Pereira
- Laboratory of Biological Processes, Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Av. João Dagnone, 1100, Jd. Santa Angelina, 13563-120, São Carlos, SP, Brazil.
| | - R H Spindola
- Laboratory of Biological Processes, Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Av. João Dagnone, 1100, Jd. Santa Angelina, 13563-120, São Carlos, SP, Brazil
| | - C A B S Rabelo
- Laboratory of Biological Processes, Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Av. João Dagnone, 1100, Jd. Santa Angelina, 13563-120, São Carlos, SP, Brazil
| | - N C Silveira
- Laboratory of Biological Processes, Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Av. João Dagnone, 1100, Jd. Santa Angelina, 13563-120, São Carlos, SP, Brazil
| | - M A T Adorno
- Laboratory of Biological Processes, Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Av. João Dagnone, 1100, Jd. Santa Angelina, 13563-120, São Carlos, SP, Brazil
| | - A Kunz
- Embrapa Suínos e Aves, 89715-899, Concórdia, SC, Brazil
| | - E C Pires
- Laboratory of Biological Processes, Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Av. João Dagnone, 1100, Jd. Santa Angelina, 13563-120, São Carlos, SP, Brazil
| | - M H R Z Damianovic
- Laboratory of Biological Processes, Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Av. João Dagnone, 1100, Jd. Santa Angelina, 13563-120, São Carlos, SP, Brazil
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14
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Duan H, Zhao Y, Koch K, Wells GF, Zheng M, Yuan Z, Ye L. Insights into Nitrous Oxide Mitigation Strategies in Wastewater Treatment and Challenges for Wider Implementation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:7208-7224. [PMID: 33975433 DOI: 10.1021/acs.est.1c00840] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nitrous oxide (N2O) emissions account for the majority of the carbon footprint of wastewater treatment plants (WWTPs). Many N2O mitigation strategies have since been developed while a holistic view is still missing. This article reviews the state-of-the-art of N2O mitigation studies in wastewater treatment. Through analyzing existing studies, this article presents the essential knowledge to guide N2O mitigations, and the logics behind mitigation strategies. In practice, mitigations are mainly carried out by aeration control, feed scheme optimization, and process optimization. Despite increasingly more studies, real implementation remains rare, which is a combined result of unclear climate change policies/incentives, as well as technical challenges. Five critical technical challenges, as well as opportunities, of N2O mitigations were identified. It is proposed that (i) quantification methods for overall N2O emissions and pathway contributions need improvement; (ii) a reliable while straightforward mathematical model is required to quantify benefits and compare mitigation strategies; (iii) tailored risk assessment needs to be conducted for WWTPs, in which more long-term full-scale trials of N2O mitigation are urgently needed to enable robust assessments of the resulting operational costs and impact on nutrient removal performance; (iv) current mitigation strategies focus on centralized WWTPs, more investigations are warranted for decentralised systems, especially decentralized activated sludge WWTPs; and (v) N2O may be mitigated by adopting novel strategies promoting N2O reduction denitrification or microorganisms that emit less N2O. Overall, we conclude N2O mitigation research is reaching a maturity while challenges still exist for a wider implementation, especially in relation to the reliability of N2O mitigation strategies and potential risks to nutrient removal performances of WWTPs.
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Affiliation(s)
- Haoran Duan
- School of Chemical Engineering, the University of Queensland, St. Lucia, Queensland 4072, Australia
- Advanced Water Management Centre (AWMC), the University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Yingfen Zhao
- School of Chemical Engineering, the University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Konrad Koch
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany
| | - George F Wells
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Min Zheng
- Advanced Water Management Centre (AWMC), the University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre (AWMC), the University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Liu Ye
- School of Chemical Engineering, the University of Queensland, St. Lucia, Queensland 4072, Australia
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15
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Chen H, Zeng L, Wang D, Zhou Y, Yang X. Recent advances in nitrous oxide production and mitigation in wastewater treatment. WATER RESEARCH 2020; 184:116168. [PMID: 32683143 DOI: 10.1016/j.watres.2020.116168] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/17/2020] [Accepted: 07/10/2020] [Indexed: 05/21/2023]
Abstract
Nitrous oxide (N2O) emitted from wastewater treatment plants has caused widespread concern. Over the past decade, people have made tremendous efforts to discover the microorganisms responsible for N2O production, elucidate metabolic pathways, establish production models and formulate mitigation strategies. The ultimate goal of all these efforts is to shed new light on how N2O is produced and how to reduce it, and one of the best ways is to find key opportunities by integrating the information obtained. This review article critically evaluates the knowledge gained in the field within a decade, especially in N2O production microbiology, biochemistry, models and mitigation strategies, with a focus on denitrification. Previous research has greatly deepened the understanding of the N2O generation mechanism, but further efforts are still needed due to the lack of standardized methodology for establishing N2O mitigation strategies in full-scale systems. One of the challenges seems to be to convert the denitrification process from a net N2O source into an effective sink, which is recommended as a key opportunity to reduce N2O production in this review.
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Affiliation(s)
- Hongbo Chen
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China.
| | - Long Zeng
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Dongbo Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China.
| | - Yaoyu Zhou
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Xiao Yang
- Korea Biochar Research Center, O-Jeong Eco-Resilience Institute & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, South Korea
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16
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Liu Y, Zhao T, Su Z, Zhu T, Ni BJ. Evaluating the roles of coexistence of sludge flocs on nitrogen removal and nitrous oxide production in a granule-based autotrophic nitrogen removal system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 730:139018. [PMID: 32413601 DOI: 10.1016/j.scitotenv.2020.139018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/24/2020] [Accepted: 04/24/2020] [Indexed: 06/11/2023]
Abstract
Certain levels of sludge flocs would always coexist in granule-based reactors due to the biomass detachment from granules. Such inevitable coexistence could affect both total nitrogen (TN) removal and nitrous oxide (N2O) production in autotrophic nitrogen removal systems. This work utilized a mathematical approach to systematically study the influence of the coexisting sludge flocs on TN removal and N2O production in a granular nitritation-anaerobic ammonium oxidation (Anammox) process for the first time, based on a 2-pathway N2O production model concept. The modelling results reveal that the highest TN removal efficiency decreases from ca. 87-88% to ca. 41-49% as the fraction of sludge flocs in the system increases from 10% to 40%, while the N2O production rate gradually increases with such increase. Meanwhile, both bulk dissolved oxygen (DO, 0.05-0.3 mg/L) and the size of granule (200-400 μm) could also influence the TN removal efficiency and N2O production. As the fraction of sludge flocs increases from 10% to 40%, the contribution of granular biomass to total N2O production is reduced due to increase of N2O-producing ammonia-oxidizing bacteria (AOB) in the sludge flocs, and the increase of granule size could intensify such decrease. In addition, the hydroxylamine oxidation pathway dominates the nitrifier denitrification pathway in both granules and sludge flocs under various testing conditions, whereas the increasing contribution of the latter would occur at a certain DO range, higher fraction of sludge flocs and smaller granule size. These results disclose an important influence of the coexisting sludge flocs on the performance of granular nitritation-Anammox systems.
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Affiliation(s)
- Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; Academy of Environment and Ecology, Tianjin University, Tianjin 300072, China
| | - Tianhang Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Zhongxian Su
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Bing-Jie Ni
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
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17
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Chen H, Zeng L, Wang D, Zhou Y, Yang X. Exploring the linkage between free nitrous acid accumulation and nitrous oxide emissions in a novel static/oxic/anoxic process. BIORESOURCE TECHNOLOGY 2020; 304:123011. [PMID: 32088627 DOI: 10.1016/j.biortech.2020.123011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/08/2020] [Accepted: 02/11/2020] [Indexed: 06/10/2023]
Abstract
In this work, four batch tests were conducted to comprehensively explore the effects of free nitrous acid (FNA) accumulation on nitrous oxide (N2O) emissions in a novel energy-saving and N2O-reducing static/oxic/anoxic (SOA) process. With the accumulation of FNA, the N2O emission factor increased from 1.51% to 4.32%, and the N2O emission ratio contributed by ammonia-oxidizing bacteria (AOB) increased from 74.0% to 78.6%, accordingly. Mechanism studies show that produced FNA and weakened aerobic metabolism bring synergy to competition between reductases. Aeration conditions and FNA cytotoxicity exert a greater impact on nitrite-oxidizing bacteria than on AOB, thus enhancing the potential for nitrite accumulation. Considering the removal of nitrogen and phosphorus and the reduction of N2O emissions in the SOA process, it is feasible to keep the average dissolved oxygen above 2.0 mg/L under the premise of nitrite accumulation.
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Affiliation(s)
- Hongbo Chen
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Long Zeng
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Dongbo Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China
| | - Yaoyu Zhou
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Xiao Yang
- Korea Biochar Research Center, O-Jeong Eco-Resilience Institute (OJERI) & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea.
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18
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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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19
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Liu Y, Ngo HH, Guo W, Wang D, Peng L, Wei W, Ni BJ. Impact of coexistence of sludge flocs on nitrous oxide production in a granule-based nitrification system: A model-based evaluation. WATER RESEARCH 2020; 170:115312. [PMID: 31760359 DOI: 10.1016/j.watres.2019.115312] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 10/20/2019] [Accepted: 11/14/2019] [Indexed: 06/10/2023]
Abstract
A common operational status of granule-based reactor is the inevitable coexistence of sludge flocs. Such hybrid system could have a profound impact on nitrous oxide (N2O) production in nitrifying process. In this work, a mathematical model is employed to evaluate the key role of the coexistence of sludge flocs on N2O production in a granule-based nitrifying system for the first time, by considering both nitrifier denitrification and hydroxylamine oxidation pathways. The modelling results show that the N2O production gradually decreases with the increase of the percentage of sludge flocs in the total biomass (10-60%). More N2O is tended to be generated in sludge flocs which has lower N2O production capacity compared to granular biomass, thus lowering the total N2O production. The relative contributions of two N2O production pathways are only affected by bulk dissolved oxygen (DO) for the sludge flocs in the hybrid system, whereas those are affected by both bulk DO and the fractions of sludge flocs for the granular biomass. The results reveal a substantial effect of the coexistence of sludge flocs on N2O production in granule-based nitrifying process, which should not be ignored in future design and operation.
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Affiliation(s)
- Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China; Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Huu Hao Ngo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia.
| | - Wenshan Guo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Dongbo Wang
- College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha, 410082, China
| | - Lai Peng
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia.
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20
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Chen X, Mielczarek AT, Habicht K, Andersen MH, Thornberg D, Sin G. Assessment of Full-Scale N 2O Emission Characteristics and Testing of Control Concepts in an Activated Sludge Wastewater Treatment Plant with Alternating Aerobic and Anoxic Phases. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:12485-12494. [PMID: 31593443 DOI: 10.1021/acs.est.9b04889] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This work aims to obtain full-scale N2O emission characteristics translatable into viable N2O control strategies and conduct full-scale testing of the proposed N2O control concepts. Data of a long-term monitoring campaign was first used to quantify full-scale N2O emission and probe into the seasonal pattern. Then trends between N2O production/emission and process variables/conditions during typical operating cycles were revealed to explore the dynamic N2O emission behavior. A multivariate statistical analysis was performed to find the dependency of N2O emission on relevant process variables. The results show for the first time that relatively low/high N2O emission took place in seasons with a decreasing/increasing trend of water temperature, respectively. Aerobic phase contributed to N2O production/emission probably mainly through the hydroxylamine pathway. Comparatively, heterotrophic bacteria had a dual role in the anoxic phase and could be responsible for both net N2O production and consumption. Incomplete denitrification might contribute mainly to the N2O production/emission in the anoxic phase and the accumulation of N2O to be significantly emitted in the following cycle due to the competition between different denitrification steps for electron donors. Therefore, properly extending the length of anoxic phase could serve as a potential control means to regulate N2O accumulation in the anoxic phase. The full-scale testing not only verified the efficacy of reduced dissolved oxygen set-point in reducing N2O emission by 60%, but also confirmed the proposed concepts of control over the aerobic and anoxic phases collectively.
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Affiliation(s)
- Xueming Chen
- Process and Systems Engineering Center (PROSYS), Department of Chemical and Biochemical Engineering , Technical University of Denmark , 2800 Kgs. Lyngby , Denmark
| | | | - Kirsten Habicht
- Unisense Environment A/S , Tueager 1 , DK-8200 Aarhus N , Denmark
| | | | | | - Gürkan Sin
- Process and Systems Engineering Center (PROSYS), Department of Chemical and Biochemical Engineering , Technical University of Denmark , 2800 Kgs. Lyngby , Denmark
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21
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Zhou G, Li N, Rene ER, Liu Q, Dai M, Kong Q. Chemical composition of extracellular polymeric substances and evolution of microbial community in activated sludge exposed to ibuprofen. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 246:267-274. [PMID: 31181475 DOI: 10.1016/j.jenvman.2019.05.044] [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: 01/16/2019] [Revised: 04/27/2019] [Accepted: 05/10/2019] [Indexed: 06/09/2023]
Abstract
Ibuprofen (IBU) containing wastewater with a concentration of 1-5 mg/L was treated in an activated sludge sequencing batch reactor (SBR), for 60 days, in order to investigate the overall performance of the SBR, the parameter variations during a typical cycle, the chemical composition and content of extracellular polymeric substances (EPS) and the evolution of microbial community. The average removal efficiencies of COD, NH4+-N and TN were >85%, while >40% of the IBU was removed and the removal efficiencies of TP fluctuated around ~ 75%. The EPS content increased significantly with IBU addition (p < 0.01). Fulvic acid-like substances in the chemical composition of EPS increased during the stable operation phase. Proteobacteria associated with nitrogen removal was the dominant phylum, which can also resist IBU stress. For the denitrifying bacteria, the OTUs of both Rhodobacter and Pseudomonas increased from day 1-30 and reduced on day 60 (p < 0.01), which was opposite to the results observed for Rhodocyclaceae (phosphorus-accumulating bacteria). The OTUs of Acidovorax showed an increasing trend (p < 0.01), whereas the OTUs for Nitrospira (nitrite oxidizers) and Nitrosomonas (ammonia oxidizers) decreased significantly (p < 0.05).
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Affiliation(s)
- Guangqing Zhou
- College of Life Science, Shandong Normal University, 88 Wenhua Donglu, Jinan, 250014, Shandong, PR China; College of Geography and Environment, Collaborative Innovation Center of Human-Nature and Green Development in the Universities of Shandong, Shandong Normal University, Jinan, 250014, PR China
| | - Na Li
- College of Life Science, Shandong Normal University, 88 Wenhua Donglu, Jinan, 250014, Shandong, PR China
| | - Eldon R Rene
- Department of Environmental Engineering and Water Technology, UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX, Delft, the Netherlands
| | - Qi Liu
- College of Life Science, Shandong Normal University, 88 Wenhua Donglu, Jinan, 250014, Shandong, PR China
| | - Meixue Dai
- College of Life Science, Shandong Normal University, 88 Wenhua Donglu, Jinan, 250014, Shandong, PR China.
| | - Qiang Kong
- College of Life Science, Shandong Normal University, 88 Wenhua Donglu, Jinan, 250014, Shandong, PR China; College of Geography and Environment, Collaborative Innovation Center of Human-Nature and Green Development in the Universities of Shandong, Shandong Normal University, Jinan, 250014, PR China; Department of Civil and Environmental Engineering, National University of Singapore, Singapore, 117576, Singapore.
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22
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Ren Y, Ngo HH, Guo W, Ni BJ, Liu Y. Linking the nitrous oxide production and mitigation with the microbial community in wastewater treatment: A review. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2019.100191] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Chen X, Ni B, Sin G. Nitrous oxide production in autotrophic nitrogen removal granular sludge: A modeling study. Biotechnol Bioeng 2019; 116:1280-1291. [DOI: 10.1002/bit.26937] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/19/2019] [Accepted: 01/24/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Xueming Chen
- Process and Systems Engineering Center (PROSYS), Department of Chemical and Biochemical Engineering Technical University of Denmark Lyngby Denmark
| | - Bing‐Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney Sydney New South Wales Australia
| | - Gürkan Sin
- Process and Systems Engineering Center (PROSYS), Department of Chemical and Biochemical Engineering Technical University of Denmark Lyngby Denmark
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Sabba F, Terada A, Wells G, Smets BF, Nerenberg R. Nitrous oxide emissions from biofilm processes for wastewater treatment. Appl Microbiol Biotechnol 2018; 102:9815-9829. [DOI: 10.1007/s00253-018-9332-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 08/13/2018] [Accepted: 08/15/2018] [Indexed: 01/21/2023]
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