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Ma X, Yang W, Zhao H, Tan Q. Effects of aeration control strategies on nitrous oxide emissions in alternating anoxic-oxic sequencing batch reactor systems. ENVIRONMENTAL RESEARCH 2024; 260:119591. [PMID: 39002633 DOI: 10.1016/j.envres.2024.119591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 06/28/2024] [Accepted: 07/09/2024] [Indexed: 07/15/2024]
Abstract
Reducing N2O emissions is key to controlling greenhouse gases (GHG) in wastewater treatment plants (WWTPs). Although studies have examined the effects of dissolved oxygen (DO) on N2O emissions during nitrogen removal, the precise effects of aeration rate remain unclear. This study aimed to fill this research gap by investigating the influence of dynamic aeration rates on N2O emissions in an alternating anoxic-oxic sequencing batch reactor system. The emergence of DO breakthrough points indicated that the conversion of ammonia nitrogen to nitrite and the release of N2O were nearly complete. Approximately 91.73 ± 3.35% of N2O was released between the start of aeration and the DO breakthrough point. Compared to a fixed aeration rate, dynamically adjusting the aeration rates could reduce N2O production by up to 48.6%. Structural equation modeling revealed that aeration rate and total nitrogen directly or indirectly had significant effects on the N2O production. A novel regression model was developed to estimate N2O production based on energy consumption (aeration flux), water quality (total nitrogen), and GHG emissions (N2O). This study emphasizes the potential of optimizing aeration strategies in WWTPs to significantly reduce GHG and improve environmental sustainability.
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Affiliation(s)
- Xiao Ma
- Guangdong Basic Research Center of Excellence for Ecological Security and Green Development, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China; Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China
| | - Wei Yang
- Department of Ecological Sciences and Engineering, Chongqing University, Chongqing, 400045, China
| | - Haixiao Zhao
- Guangdong Basic Research Center of Excellence for Ecological Security and Green Development, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China; Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China
| | - Qian Tan
- Guangdong Basic Research Center of Excellence for Ecological Security and Green Development, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China; Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou, 510006, China.
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2
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Xu H, Fu G, Ye Q, Lyu M, Yan X. Life cycle environmental impacts of urban water systems in China. WATER RESEARCH 2024; 266:122350. [PMID: 39217644 DOI: 10.1016/j.watres.2024.122350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 08/01/2024] [Accepted: 08/26/2024] [Indexed: 09/04/2024]
Abstract
Urban water systems in China are facing multiple challenges, including rapid urbanisation, climate change and infrastructure ageing. It is crucial to evaluate their environmental performance from a holistic perspective in planning and management processes. To the best of our knowledge, there is a lack of nationwide life cycle assessment (LCA) studies on China's urban water systems that cover all system stages. Therefore, this study aims to present a comprehensive and nationwide LCA analysis that pinpoints the environmental hotspots and their major sources across China. This study was conducted based on water utility databases at the province level, covering water abstraction and treatment, waterwork sludge treatment, water distribution, sewage collection, stormwater drainage, wastewater treatment and sewage sludge treatment. Nine environmental impact categories were calculated and analysed. The results reveal the inequity of environmental impacts across provinces, with overall impacts geographically higher in the east and south, lower in the west and north. However, at the functional unit level, the impacts in the northern and northeastern provinces are higher than other regions. Most environmental categories are dominated by multiple water system stages. The analyses of underlying drivers found that purchased electricity is the primary source of several environmental impacts. This study provides a holistic understanding of the environmental performance of China's urban water systems, offers some insights for comprehensive decision-making support on sustainable water system management, and can also serve as a benchmark for future scenario analysis to explore options for reducing environmental impact.
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Affiliation(s)
- Hao Xu
- Environment and Sustainability Institute, Faculty of Environment, Science and Economy, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK; Renewable Energy Group, Engineering Department, Faculty of Environment, Science and Economy, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK
| | - Guangtao Fu
- Centre for Water Systems, Faculty of Environment, Science and Economy, University of Exeter, Exeter EX4 4QF, UK
| | - Qian Ye
- School of Civil Engineering, University of Leeds, Leeds LS2 9JT, UK
| | - Mei Lyu
- North China Municipal Engineering Design & Research Institute Co., Ltd., Beijing 100097, China
| | - Xiaoyu Yan
- Environment and Sustainability Institute, Faculty of Environment, Science and Economy, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK; Renewable Energy Group, Engineering Department, Faculty of Environment, Science and Economy, University of Exeter, Penryn Campus, Penryn TR10 9FE, UK.
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3
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Lancioni N, Szelag B, Sgroi M, Barbusiński K, Fatone F, Eusebi AL. Novel extended hybrid tool for real time control and practically support decisions to reduce GHG emissions in full scale wastewater treatment plants. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 365:121502. [PMID: 38936025 DOI: 10.1016/j.jenvman.2024.121502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 04/08/2024] [Accepted: 06/15/2024] [Indexed: 06/29/2024]
Abstract
In this paper, a novel methodology and extended hybrid model for the real time control, prediction and reduction of direct emissions of greenhouse gases (GHGs) from wastewater treatment plants (WWTPs) is proposed to overcome the lack of long-term data availability in several full-scale case studies. A mechanistic model (MCM) and a machine learning (ML) model are combined to real time control, predict the emissions of nitrous oxide (N2O) and carbon dioxide (CO2) as well as effluent quality (COD - chemical oxygen demand, NH4-N - ammonia, NO3-N - nitrate) in activated sludge method. For methane (CH4), using the MCM model, predictions are performed on the input data (VFA, CODs for aerobic and anaerobic compartments) to the MLM model. Additionally, scenarios were analyzed to assess and reduce the GHGs emissions related to the biological processes. A real WWTP, with a population equivalent (PE) of 125,000, was studied for the validation of the hybrid model. A global sensitivity analysis (GSA) of the MCM and a ML model were implemented to assess GHGs emission mechanisms the biological reactor. Finally, an early warning tool for the prediction of GHGs errors was implemented to assess the accuracy and the reliability of the proposed algorithm. The results could support the wastewater treatment plant operators to evaluate possible mitigation scenarios (MS) that can reduce direct GHG emissions from WWTPs by up to 21%, while maintaining the final quality standard of the treated effluent.
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Affiliation(s)
- Nicola Lancioni
- Dipartimento SIMAU, Università Politecnica Delle Marche, Via Brecce Bianche, 60131, Ancona, Italy.
| | - Bartosz Szelag
- Dipartimento SIMAU, Università Politecnica Delle Marche, Via Brecce Bianche, 60131, Ancona, Italy; Department of Geotechnics and Water Engineering, Kielce University of Technology, Al. Tysiąclecia Pa' nstwa Polskiego 7, 25-314, Kielce, Poland.
| | - Massimiliano Sgroi
- Dipartimento SIMAU, Università Politecnica Delle Marche, Via Brecce Bianche, 60131, Ancona, Italy.
| | - Krzysztof Barbusiński
- Department of Water and Wastewater Engineering, Silesian University of Technology, Konarskiego 18 St., 44-100, Gliwice, Poland
| | - Francesco Fatone
- Dipartimento SIMAU, Università Politecnica Delle Marche, Via Brecce Bianche, 60131, Ancona, Italy
| | - Anna Laura Eusebi
- Dipartimento SIMAU, Università Politecnica Delle Marche, Via Brecce Bianche, 60131, Ancona, Italy
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4
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Jiang Y, Ma D, Wang J, Xu Q, Fang J, Yue Z. Regulatory of salinity on assembly of activated sludge microbial communities and nitrogen transformation potential in industrial plants of the lower Yangtze River basin. ENVIRONMENTAL RESEARCH 2024; 251:118769. [PMID: 38518918 DOI: 10.1016/j.envres.2024.118769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 03/24/2024]
Abstract
This study aims to thoroughly investigate the impact mode of salinity carried by industrial wastewater on the anaerobic-anoxic-oxic (A2O) sludge in wastewater treatment plants (WWTPs). Through comprehensive investigation of the A2O stage activated sludge (AS) from 19 industrial WWTPs in the downstream area of the Yangtze River, China, A total of 38 samples of anaerobic sludge and oxic sludge were collected and analyzed. We found that salinity stress significantly inhibits the growth of the AS community, particularly evident in the anaerobic sludge community. Furthermore, the high-saline environment induces changes in the structure and functional patterns of the AS community, leading to intensive interactions and resource exchanges among microorganisms. Halophilic microorganisms may play a crucial role in this process, significantly impacting the overall community structure, especially in the oxic sludge community. Additionally, salinity stress not only suppresses the nitrogen transformation potential of the AS but also leads to the accumulation of nitrite, thereby increasing the emission potential of both NO and N2O, exacerbating the greenhouse effect of the A2O process in industrial WWTPs. The findings of this study provide necessary theoretical support for maintaining the long-term stable operation of the A2O sludge system in industrial WWTPs, reducing carbon footprint, and improving nitrogen removal efficiency.
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Affiliation(s)
- Yifan Jiang
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui, 230009, China
| | - Ding Ma
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui, 230009, China; Anhui Engineering Research Center of Industrial Wastewater Treatment and Resource Recovery, Hefei University of Technology, Hefei, Anhui, 230009, China
| | - Jin Wang
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui, 230009, China; Anhui Engineering Research Center of Industrial Wastewater Treatment and Resource Recovery, Hefei University of Technology, Hefei, Anhui, 230009, China; Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei, Anhui, 230009, China
| | - Qingsheng Xu
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui, 230009, China
| | - Jintao Fang
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui, 230009, China
| | - Zhengbo Yue
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui, 230009, China; Anhui Engineering Research Center of Industrial Wastewater Treatment and Resource Recovery, Hefei University of Technology, Hefei, Anhui, 230009, China; Key Laboratory of Nanominerals and Pollution Control of Anhui Higher Education Institutes, Hefei University of Technology, Hefei, Anhui, 230009, China.
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5
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Wang J, Li Z, Xiong P, Li Z, Liu H, Zhang Y, Lei Z, Liu X, Lee DJ, Qian X. Reduction of greenhouse gas emissions from closed activated sludge- to aerobic granular sludge-based biosystems via gas circulation. BIORESOURCE TECHNOLOGY 2024; 401:130748. [PMID: 38677387 DOI: 10.1016/j.biortech.2024.130748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Revised: 04/08/2024] [Accepted: 04/25/2024] [Indexed: 04/29/2024]
Abstract
Greenhouse gas (GHG) emissions from biological treatment units are challenging wastewater treatment plants (WWTPs) due to their wide applications and global warming. This study aimed to reduce GHG emissions (especially N2O) using a gas circulation strategy in a closed sequencing-batch reactor when the biological unit varies from activated sludge (AS) to aerobic granular sludge (AGS). Results show that gas circulation lowers pH to 6.3 ± 0.2, facilitating regular granules but elevating total N2O production. From AS to AGS, N2O emission factor increased (0.07-0.86 %) due to decreasing ammonia-oxidizing rates while the emissions of CO2 (0.3 ± 0.1 kg-CO2/kg-chemical oxygen demand) and CH4 remained in the closed biosystem. The gas circulation decreased N2O emission factor by 63 ± 15 % after granulation higher than 44 ± 34 % before granulation, which is implemented by heterotrophic denitrification. This study provides a feasible strategy to enhance heterotrophic N2O elimination in the biological WWTPs.
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Affiliation(s)
- Jixiang Wang
- Shanghai Academy of Environmental Sciences, Shanghai 200233, China; Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China
| | - Zejiao Li
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Pengyu Xiong
- Shanghai Academy of Environmental Sciences, Shanghai 200233, China; Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China
| | - Zhengwen Li
- Shanghai Academy of Environmental Sciences, Shanghai 200233, China; Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China
| | - Hui Liu
- Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Yili Zhang
- Shanghai Academy of Environmental Sciences, Shanghai 200233, China
| | - Zhongfang Lei
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | - Xiang Liu
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China
| | - Duu-Jong Lee
- Department of Mechanical Engineering, City University of Hong Kong, Kowloon Tang, Hong Kong; Department of Chemical Engineering & Materials Science, Yuan-Ze University, Chungli 320, Taiwan
| | - Xiaoyong Qian
- Shanghai Academy of Environmental Sciences, Shanghai 200233, China.
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6
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Wang Q, Sheng Y, Zhang Y, Zhong X, Liu H, Huang Z, Li D, Wu H, Ni Y, Zhang J, Lin W, Qiu K, Qian X. Complete long-term monitoring of greenhouse gas emissions from a full-scale industrial wastewater treatment plant with different cover configurations. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 360:121206. [PMID: 38776658 DOI: 10.1016/j.jenvman.2024.121206] [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: 02/29/2024] [Revised: 05/13/2024] [Accepted: 05/18/2024] [Indexed: 05/25/2024]
Abstract
The greenhouse gas (GHG) emissions from wastewater treatment plants (WWTPs), consisting mainly of methane (CH4) and nitrous oxide (N2O), have been constantly increasing and become a non-negligible contributor towards carbon neutrality. The precise evaluation of plant-specific GHG emissions, however, remains challenging. The current assessment approach is based on the product of influent load and emission factor (EF), of which the latter is quite often a single value with huge uncertainty. In particular, the latest default Tier 1 value of N2O EF, 0.016 ± 0.012 kgN2O-N kgTN-1, is estimated based on the measurement of 30 municipal WWTPs only, without involving any industrial wastewater. Therefore, to resolve the pattern of GHG emissions from industrial WWTPs, this work conducted a 14-month monitoring campaign covering all the process units at a full-scale industrial WWTP in Shanghai, China. The total CH4 and N2O emissions from the whole plant were, on average, 447.7 ± 224.5 kgCO2-eq d-1 and 1605.3 ± 2491.0 kgCO2-eq d-1, respectively, exhibiting a 5.2- or 3.9-times more significant deviation than the influent loads of chemical oxygen demand (COD) or total nitrogen (TN). The resulting EFs, 0.00072 kgCH4 kgCOD-1 and 0.00211 kgN2O-N kgTN-1, were just 0.36% of the IPCC recommended value for CH4, and 13.2% for N2O. Besides, the parallel anoxic-oxic (A/O) lines of this industrial WWTP were covered in two configurations, allowing the comparison of GHG emissions from different odor control setup. Unit-specific analysis showed that the replacement of enclosed A/open O with enclosed A/O reduced the CH4 EF by three times, from 0.00159 to 0.00051 kgCH4 kgCOD-1, and dramatically decreased the N2O EF by an order of magnitude, from 0.00376 to 0.00032 kgN2O-N kgTN-1, which was among the lowest of all full-scale WWTPs.
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Affiliation(s)
- Qinyi Wang
- Shanghai Academy of Environmental Sciences, Shanghai, 200233, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Yangyue Sheng
- Shanghai Academy of Environmental Sciences, Shanghai, 200233, China; State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Yili Zhang
- Shanghai Academy of Environmental Sciences, Shanghai, 200233, China
| | - Xinrun Zhong
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Hui Liu
- Shanghai Academy of Environmental Sciences, Shanghai, 200233, China
| | - Zhengfeng Huang
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Dan Li
- Shanghai Academy of Environmental Sciences, Shanghai, 200233, China
| | - Hao Wu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Yuanzhi Ni
- Shanghai Academy of Environmental Sciences, Shanghai, 200233, China
| | - Junqi Zhang
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Weiqing Lin
- Shanghai Academy of Environmental Sciences, Shanghai, 200233, China
| | - Kaipei Qiu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China; Shanghai Environmental Protection Key Laboratory for Environmental Standard and Risk Management of Chemical Pollutants, Shanghai, 200237, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200292, China.
| | - Xiaoyong Qian
- Shanghai Academy of Environmental Sciences, Shanghai, 200233, China.
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7
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Nativ P, Weisbrod A, Lahav O. Should wastewater treatment plants' operational mode radically change to minimize GHG emissions? THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 926:171835. [PMID: 38513861 DOI: 10.1016/j.scitotenv.2024.171835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 02/20/2024] [Accepted: 03/18/2024] [Indexed: 03/23/2024]
Abstract
The operation of municipal wastewater treatment plants (WWTPs) invariably results in significant emission of greenhouse gases (i.e., CH4, N2O, and CO2) into the atmosphere. We propose to consider a radical change in the way municipal WWTPs are operated, with the aim of minimizing GHG emissions while recycling most of the nutrient mass. The means to this end are to reduce the WWTP energy demand while maximizing the recovery of resources (phosphorus, ammonia, methane). The suggested concept involves operating the activated sludge process at a low sludge retention time (SRT < 2 d), i.e., under conditions that maximize the heterotrophic mass yield and eliminate nitrification. The ammonia concentration that remains in the water (considering N in the excess sludge and struvite production in the sludge-dewatering supernatant line) would be separated from the WWTP effluents using a unique ion-exchange material (ZnHCF), which would be regenerated using a low-volume 4 M NaCl solution. The ammonia would be then stripped at high pH and re-adsorbed by an acidic solution for reuse as fertilizer. The high bacterial yield and lack of nitrification in the aerobic step are expected to boost methane yield 3-4-fold, induce lower oxygen consumption, and most importantly, yield much lower N2O release. An approximate energy mass balance shows the concept to merit further consideration, owing to the potential significant reduction in N2O(g) emissions and recovery of resources. Empirical work followed by LCA is required to corroborate the hypothesis presented herein.
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Affiliation(s)
- Paz Nativ
- Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology
| | - Anat Weisbrod
- Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology
| | - Ori Lahav
- Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology.
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8
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Shang Z, Cai C, Guo Y, Huang X, Peng K, Guo R, Wei Z, Wu C, Cheng S, Liao Y, Hung CY, Liu J. Direct and indirect monitoring methods for nitrous oxide emissions in full-scale wastewater treatment plants: A critical review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 358:120842. [PMID: 38599092 DOI: 10.1016/j.jenvman.2024.120842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 03/17/2024] [Accepted: 04/02/2024] [Indexed: 04/12/2024]
Abstract
Mitigation of nitrous oxide (N2O) emissions in full-scale wastewater treatment plant (WWTP) has become an irreversible trend to adapt the climate change. Monitoring of N2O emissions plays a fundamental role in understanding and mitigating N2O emissions. This paper provides a comprehensive review of direct and indirect N2O monitoring methods. The techniques, strengths, limitations, and applicable scenarios of various methods are discussed. We conclude that the floating chamber technique is suitable for capturing and interpreting the spatiotemporal variability of real-time N2O emissions, due to its long-term in-situ monitoring capability and high data acquisition frequency. The monitoring duration, location, and frequency should be emphasized to guarantee the accuracy and comparability of acquired data. Calculation by default emission factors (EFs) is efficient when there is a need for ambiguous historical N2O emission accounts of national-scale or regional-scale WWTPs. Using process-specific EFs is beneficial in promoting mitigation pathways that are primarily focused on low-emission process upgrades. Machine learning models exhibit exemplary performance in the prediction of N2O emissions. Integrating mechanistic models with machine learning models can improve their explanatory power and sharpen their predictive precision. The implementation of the synergy of nutrient removal and N2O mitigation strategies necessitates the calibration and validation of multi-path mechanistic models, supported by long-term continuous direct monitoring campaigns.
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Affiliation(s)
- Zhenxin Shang
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China
| | - Chen Cai
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China; Institute of Carbon Neutrality, Tongji University, Shanghai, 200092, PR China.
| | - Yanli Guo
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China
| | - Xiangfeng Huang
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China; Institute of Carbon Neutrality, Tongji University, Shanghai, 200092, PR China
| | - Kaiming Peng
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China; Institute of Carbon Neutrality, Tongji University, Shanghai, 200092, PR China
| | - Ru Guo
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China; Institute of Carbon Neutrality, Tongji University, Shanghai, 200092, PR China
| | - Zhongqing Wei
- Fuzhou Water Group Co., Ltd, Fuzhou, 350000, PR China
| | - Chenyuan Wu
- Fuzhou Water Group Co., Ltd, Fuzhou, 350000, PR China
| | - Shunjian Cheng
- Fuzhou City Construction Design & Research Institute Co., Ltd, Fuzhou, 350000, PR China
| | - Youxiang Liao
- Fuzhou City Construction Design & Research Institute Co., Ltd, Fuzhou, 350000, PR China
| | - Chih-Yu Hung
- Environment and Climate Change, 351 Saint-Joseph Blvd., 9th Floor. Gatineau, Quebec, K1A 0H3, Canada
| | - Jia Liu
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, PR China; Institute of Carbon Neutrality, Tongji University, Shanghai, 200092, PR China
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9
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Gao Z, Bi X, Zhao J, Ding X, Li Y, Shi J, Pan X, Bai M, Miao Y, Zhang J. Self-cultivating anammox granules for enhancing wastewater nitrogen removal in nitrification-denitrification flocculent sludge system. BIORESOURCE TECHNOLOGY 2024; 397:130458. [PMID: 38373506 DOI: 10.1016/j.biortech.2024.130458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 02/02/2024] [Accepted: 02/14/2024] [Indexed: 02/21/2024]
Abstract
The feasibility of self-cultivating anammox granules for enhancing wastewater nitrogen removal was investigated in a nitrification-denitrification flocculent sludge system. Desirable nitrogen removal efficiency of 84 ± 4 % was obtained for the influent carbon to nitrogen ratio of 1-1.3 (NH4+-N: 150-200 mg N/L) via alternate anaerobic/oxic/anoxic mode. Meanwhile, some red granular sludge was formed in the system. The abundance and activity of anaerobic ammonia oxidation bacteria (AnAOB) increased from 'not detected' in seed sludge to 0.57 % and 29.4 ± 0.7 mg N/(g mixed liquor volatile suspended solids·h) in granules, respectively, suggesting successful cultivation of anammox granules. Furthermore, some denitrifying bacteria with capability of partial denitrification were enriched, such as Candidatus Competibacter (2.45 %) and Thauera (5.75 %), which could cooperate with AnAOB, facilitating AnAOB enrichment. Anammox was dominant in nitrogen removal with the contribution to nitrogen removed above 68.8 ± 0.3 %. The strategy of self-cultivating anammox granules could promote the application of anammox.
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Affiliation(s)
- Zhongxiu Gao
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, PR China
| | - Xuejun Bi
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, PR China
| | - Jixiang Zhao
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, PR China
| | - Xiang Ding
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, PR China
| | - Yitong Li
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, PR China
| | - Junhui Shi
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, PR China
| | - Xinlei Pan
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, PR China
| | - Meng Bai
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, PR China
| | - Yuanyuan Miao
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, PR China
| | - Jianhua Zhang
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, PR China.
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10
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Wang H, Miao J, Sun Y. Aerobic nitrous oxide emission in anoxic/aerobic and intermittent aeration sequencing batch reactors. ENVIRONMENTAL TECHNOLOGY 2024; 45:1449-1458. [PMID: 36331189 DOI: 10.1080/09593330.2022.2144467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 10/28/2022] [Indexed: 06/16/2023]
Abstract
This study characterized nitrogen removal and nitrous oxide (N2O) emissions from lab-scale anoxic/aerobic sequencing batch reactor (AOSBR) and intermittent aeration sequencing batch reactor (IASBR), respectively, for treating synthetic municipal wastewater. The N2O emission was evaluated in a simulated cycle, and batch conditions of aerobic nitrification, simultaneous nitrification and denitrification (SND), and aerobic denitrification. The results show that nitrogen removal was enhanced in IASBR compared to AOSBR, with 94.2% and 67.9% of total inorganic nitrogen removal efficiency in IASBR and AOSBR, respectively. In the simulated cycle, the emission factors (of oxidized ammonium) were 4.9% and 0.6% in AOSBR and IASBR, respectively. Under batch conditions, the N2O emission factors during SND were obviously higher than that during aerobic nitrification and denitrification. The N2O emission factors during SND ranging 0.68-11.68% in AOSBR and 1.25-5.13% in IASBR. Furthermore, N2O emission under batch conditions was affected by the aeration ratios. Moderate and high aeration ratios used in this study stimulated the N2O emission from SND. The N2O emission was enhanced with the nitrite accumulation during aerobic nitrification when the nitrite-oxidizing bacteria was inhibited by a chemical inhibitor. Aerobic denitrification via nitrite could be the main pathway of N2O generation from SND processes. The findings from our study can help further understand N2O emission mechanisms and guide the optimization of the current wastewater treatment process for minimizing N2O emission.
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Affiliation(s)
- Huoqing Wang
- State Environmental Protection Key Laboratory of Drinking Water Source Management and Technology, Shenzhen Academy of Environmental Science, Shenzhen, People's Republic of China
| | - Jia Miao
- Japan Research Center for Environmental Quality Management, Graduate School of Engineering, Kyoto University, Kyoto, Japan
| | - Yuepeng Sun
- Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA, USA
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Roothans N, Gabriëls M, Abeel T, Pabst M, van Loosdrecht MCM, Laureni M. Aerobic denitrification as an N2O source from microbial communities. THE ISME JOURNAL 2024; 18:wrae116. [PMID: 38913498 PMCID: PMC11272060 DOI: 10.1093/ismejo/wrae116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 04/26/2024] [Accepted: 06/21/2024] [Indexed: 06/26/2024]
Abstract
Nitrous oxide (N2O) is a potent greenhouse gas of primarily microbial origin. Oxic and anoxic emissions are commonly ascribed to autotrophic nitrification and heterotrophic denitrification, respectively. Beyond this established dichotomy, we quantitatively show that heterotrophic denitrification can significantly contribute to aerobic nitrogen turnover and N2O emissions in complex microbiomes exposed to frequent oxic/anoxic transitions. Two planktonic, nitrification-inhibited enrichment cultures were established under continuous organic carbon and nitrate feeding, and cyclic oxygen availability. Over a third of the influent organic substrate was respired with nitrate as electron acceptor at high oxygen concentrations (>6.5 mg/L). N2O accounted for up to one-quarter of the nitrate reduced under oxic conditions. The enriched microorganisms maintained a constitutive abundance of denitrifying enzymes due to the oxic/anoxic frequencies exceeding their protein turnover-a common scenario in natural and engineered ecosystems. The aerobic denitrification rates are ascribed primarily to the residual activity of anaerobically synthesised enzymes. From an ecological perspective, the selection of organisms capable of sustaining significant denitrifying activity during aeration shows their competitive advantage over other heterotrophs under varying oxygen availabilities. Ultimately, we propose that the contribution of heterotrophic denitrification to aerobic nitrogen turnover and N2O emissions is currently underestimated in dynamic environments.
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Affiliation(s)
- Nina Roothans
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Minke Gabriëls
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Thomas Abeel
- Delft Bioinformatics Lab, Delft University of Technology, van Mourik Broekmanweg 6, Delft 2628 XE, the Netherlands
- Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, United States
| | - Martin Pabst
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, the Netherlands
| | - Michele Laureni
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629 HZ Delft, the Netherlands
- Department of Water Management, Delft University of Technology, Stevinweg 1, 2628 CN Delft, the Netherlands
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12
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Zhang J, Ma G, Bi X, Zhao X, Li J, Zhang Y, Gao Z, Li Y, Miao Y. Achieving advanced nitrogen removal and excess sludge treatment via single nitritation/anammox-fermentation combined system. BIORESOURCE TECHNOLOGY 2023; 387:129550. [PMID: 37495158 DOI: 10.1016/j.biortech.2023.129550] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 07/17/2023] [Accepted: 07/23/2023] [Indexed: 07/28/2023]
Abstract
The feasibility of treating wastewater and excess sludge via simultaneous nitritation, anammox, denitrification and fermentation (SNADF) was investigated in three parallel sequencing batch reactors (SBRs). SBR2 and SBR3 received exogenous nitrification-denitrification sludge and thermal hydrolysis sludge, respectively. Nitrogen removal efficiencies of 92.8 ± 5.9%, 94.6 ± 4.1%, 93.4 ± 4.8% were achieved in SBR1, SBR2, and SBR3, respectively (influent ammonium: 56.0-74.0 mg N/L), with low observed sludge yield of 0.02-0.15, -0.06-0.11, -0.17-0.05 kg mixed liquor suspended solids (MLSS)/kg chemical oxygen demand (COD). Anammox bacterial abundances increased from 3.6 × 109 ± 2.8 × 108 to 8.1 × 109 ± 2.3 × 108, 1.5 × 1010 ± 1.1 × 108, and 1.4 × 1010 ± 2.9 × 108 copies/L in SBR1-SBR3, respectively. The abundances of Nitrosomonas, genes (amo, hao) for partial nitrification, and narGHI genes (nitrate → nitrite) in dominant partial denitrifying bacteria (Candidatus Competibacter) were higher in SBR2 and SBR3 than that in SBR1. These results suggested that adding excess sludge promoted sludge reduction, nitrite production and anammox bacterial enrichment. The SNADF system could treat excess sludge, meanwhile, achieve advanced nitrogen removal.
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Affiliation(s)
- Jianhua Zhang
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, Qingdao University of Technology, Qingdao 266520, PR China
| | - Guocheng Ma
- School of Environmental Science and Engineering, Qingdao University, Qingdao 266071, PR China
| | - Xuejun Bi
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, Qingdao University of Technology, Qingdao 266520, PR China
| | - Xinchao Zhao
- School of Environmental Science and Engineering, Qingdao University, Qingdao 266071, PR China
| | - Jiawen Li
- School of Environmental Science and Engineering, Qingdao University, Qingdao 266071, PR China
| | - Yu Zhang
- School of Environmental Science and Engineering, Qingdao University, Qingdao 266071, PR China
| | - Zhongxiu Gao
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, Qingdao University of Technology, Qingdao 266520, PR China
| | - Yitong Li
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, Qingdao University of Technology, Qingdao 266520, PR China
| | - Yuanyuan Miao
- State and Local Joint Engineering Research Centre of Urban Wastewater Treatment and Reclamation, Qingdao University of Technology, Qingdao 266520, PR China; School of Environmental Science and Engineering, Qingdao University, Qingdao 266071, PR China.
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Sabia G, Mattioli D, Langone M, Petta L. Methodology for a preliminary assessment of water use sustainability in industries at sub-basin level. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 343:118163. [PMID: 37247546 DOI: 10.1016/j.jenvman.2023.118163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 04/30/2023] [Accepted: 05/11/2023] [Indexed: 05/31/2023]
Abstract
The sustainability of industrial production, especially for highly water-demanding processes, is strictly related to water resource availability and to the dynamic interactions between natural and anthropogenic requirements over the spatial and temporal scales. The increase in industrial water demand raises the need to assess the related environmental sustainability, facing the occurrence of global and local water stress issues. The identification of reliable methodologies, based on simple indices and able to consider the impact on local water basins, may play a basilar role in water sustainability diagnosis and decision-making processes for water management and land use planning. The present work focalized on the definition of a methodology based on the calculation of indicators and indices in the view of providing a synthetic, simple, and site-specific assessment tool for industrial water cycle sustainability. The methodology was built starting from geo-referenced data on water availability and sectorial uses derived for Italian sub-basins. According to the data monthly time scale, the proposed indices allowed for an industrial water-related impacts assessment, able to take into account the seasonal variability of local resources. Three industrial factories, located in northern (SB1, SB2) and central (SB3) Italian sub-basins, were selected as case studies (CS1, CS2, CS3) to validate the methodology. The companies were directly involved and asked to provide some input data. The methodology is based on the calculation of three synthetic indexes: the Withdrawal and Consumption water Stress Index (WCSI) allowed for deriving a synthetic water stress level assessment at the sub-basin scale, also considering the spatial and temporal variations; the industrial water use sustainability assessment was achieved by calculating the Overall Factory-to-Basin Impact (OFBI) and the Internal Water Reuse (IWR) indices, which allowed a preliminary evaluation of the factories' impacts on the sub-basin water status, considering the related water uses and the overall pressures on the reference territorial context. The WCSI values highlighted significant differences between the northern sub-basins, characterised by limited water stress (WCSISB1 = 0.221; WCSISB2 = 0.047), and the central ones, more subjected to high stress (WCSISB3 = 0.413). The case studies CS1 and CS3 showed to exert a more significant impact on the local water resource (OFBICS1 = 0.18%; OFBICS2 = 0.192%) with respect to CS2 (OFBI = 0.002%), whereas the IWR index revealed the different company's attitude in implementing water reuse practices (IWRCS1 = 40%; IWRCS1 = 27%; IWRCS1 = 99%). The proposed methodology and the indices may also contribute to assessing the effectiveness of river basin management actions to pursue sustainable development goals.
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Affiliation(s)
- G Sabia
- ENEA Italian National Agency for New Technologies, Department for Sustainability, Division Resource Efficiency, Research Centre of Bologna (BO), Italy.
| | - D Mattioli
- ENEA Italian National Agency for New Technologies, Department for Sustainability, Division Resource Efficiency, Research Centre of Bologna (BO), Italy
| | - M Langone
- ENEA Italian National Agency for New Technologies, Department for Sustainability, Division Resource Efficiency, Research Centre of Casaccia (RM), Italy
| | - L Petta
- ENEA Italian National Agency for New Technologies, Department for Sustainability, Division Resource Efficiency, Research Centre of Bologna (BO), Italy
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Li Q, Xu Y, Liang C, Peng L, Zhou Y. Nitrogen removal by algal-bacterial consortium during mainstream wastewater treatment: Transformation mechanisms and potential N 2O mitigation. WATER RESEARCH 2023; 235:119890. [PMID: 36958220 DOI: 10.1016/j.watres.2023.119890] [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: 10/20/2022] [Revised: 02/08/2023] [Accepted: 03/17/2023] [Indexed: 06/18/2023]
Abstract
This work investigated nitrogen transformation pathways of the algal-bacterial consortium as well as its potential in reducing nitrous oxide (N2O) emission in enclosed, open and aerated reactors. The results confirmed the superior ammonium removal performance of the algal-bacterial consortium relative to the single algae (Chlorella vulgaris) or the activated sludge, achieving the highest efficiency at 100% and the highest rate of 7.34 mg N g MLSS-1 h-1 in the open reactor with glucose. Enhanced total nitrogen (TN) removal (to 74.6%) by the algal-bacterial consortium was achieved via mixotrophic algal assimilation and bacterial denitrification under oxygen-limited and glucose-sufficient conditions. Nitrogen distribution indicated that ammonia oxidation (∼41.8%) and algal assimilation (∼43.5%) were the main pathways to remove ammonium by the algal-bacterial consortium. TN removal by the algal-bacterial consortium was primarily achieved by algal assimilation (28.1-40.8%), followed by bacterial denitrification (2.9-26.5%). Furthermore, the algal-bacterial consortium contributed to N2O mitigation compared with the activated sludge, reducing N2O production by 35.5-55.0% via autotrophic pathways and by 81.0-93.6% via mixotrophic pathways. Nitrogen assimilation by algae was boosted with the addition of glucose and thus largely restrained N2O production from nitrification and denitrification. The synergism between algae and bacteria was also conducive to an enhanced N2O reduction by denitrification and reduced direct/indirect carbon emissions.
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Affiliation(s)
- Qi Li
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Yifeng Xu
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Chuanzhou Liang
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Lai Peng
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China.
| | - Yan Zhou
- School of Civil and Environmental Engineering, Nanyang Technological University 639798, Singapore
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Bai M, Wang Z, Lloyd J, Seneviratne D, Flesch T, Yuan Z, Chen D. Long-term onsite monitoring of a sewage sludge drying pan finds methane emissions consistent with IPCC default emission factor. WATER RESEARCH X 2023; 19:100184. [PMID: 37274752 PMCID: PMC10236450 DOI: 10.1016/j.wroa.2023.100184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/19/2023] [Accepted: 05/24/2023] [Indexed: 06/06/2023]
Abstract
As the wastewater sector moves towards achieving net zero greenhouse gas (GHG) emissions, quantifying and understanding fugitive emissions from various sewage treatment steps is crucial for developing effective GHG abatement strategies. Methane (CH4) emissions from a sludge drying pan (SDP) were measured at a wastewater treatment plant in Australia for more than a year, using a micrometeorological technique paired with open-path lasers. The emission rate was tightly associated with sludge additions, climatology, and operational processes. The mean emission rate during the 90 weeks after initial sludge addition was 2.3 (± 0.8) g m-2 d-1, with cumulative emissions of approximately 32 t of CH4. A dynamic temporal pattern of emissions was observed, highlighting the importance of continuous (or near-continuous) measurements for quantifying SDP emissions. A Methane Correction Factor (MCF) expressed as a fraction of the measured chemical oxygen demand of the sludge, was determined to be 0.17 after 63 weeks (the median operational cycle duration at the facility). This is broadly consistent with, albeit slightly less than, the IPCC default value of 0.2 for shallow anaerobic lagoons. These emission measurements will support wastewater utilities that employ open air sludge drying processes to develop effective GHG abatement strategies.
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Affiliation(s)
- Mei Bai
- School of Agriculture and Food Science, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Zhiyao Wang
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, Brisbane, Queensland 4067, Australia
| | - James Lloyd
- Sewerage Planning – Service Futures, Melbourne Water, Dockland, Victoria 3008, Australia
| | - Dilini Seneviratne
- Sewerage Planning – Service Futures, Melbourne Water, Dockland, Victoria 3008, Australia
| | - Thomas Flesch
- School of Agriculture and Food Science, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Zhiguo Yuan
- Australian Centre for Water and Environmental Biotechnology (ACWEB, formerly AWMC), The University of Queensland, Brisbane, Queensland 4067, Australia
| | - Deli Chen
- School of Agriculture and Food Science, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
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16
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Zhang Y, Ni X, Wang H. Visual analysis of greenhouse gas emissions from sewage treatment plants based on CiteSpace: from the perspective of bibliometrics. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:45555-45569. [PMID: 36807038 DOI: 10.1007/s11356-023-25582-9] [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: 05/19/2022] [Accepted: 01/23/2023] [Indexed: 06/18/2023]
Abstract
With the global reduction actions of greenhouse gas (GHG) emissions, environmental facilities, including sewage treatment plants (STPs), need to reduce pollutants while minimizing GHG emissions. Therefore, more and more publications revealed the formation mechanism of GHGs in STPs and committed to finding better reduction schemes. From the perspective of bibliometrics, this study used CiteSpace to conduct quantitative and visual analysis based on 1,543 publications retrieved from Web of Science between 2000 and 2021 around the world. We have systematically evaluated the structure, development trend, hot spots, and research frontier in the field of GHG emissions from STPs and compared with the contents of top journals to verify the scientificity of the analysis. The results show that the number of publications has increased year by year, and the networks of authors and institutions show a strong correlation. Among them, the clusters of nitrous oxide, anaerobic digestion, and life cycle assessment (LCA) started earlier and received extensive attention, which derived other clusters in the research process. With the development of the field, researchers have gradually changed from single water treatment facilities to multi-carriers that can realize energy regeneration and utilization simultaneously. Accordingly, the GHG reduction of STPs through energy regeneration and resource recovery has become a hot point and frontier direction, which also challenges the breakthroughs in relevant technologies. Furthermore, it provides scientific support for the formulation of relevant incentive policies and economic subsidy systems, so as to alleviate the pressure of global warming and realize the sustainable development of STPs concurrently.
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Affiliation(s)
- Yidi Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, 1239 Siping Rd, Shanghai, 200092, China
| | - Xiaohang Ni
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, 1239 Siping Rd, Shanghai, 200092, China
| | - Hongtao Wang
- State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, 1239 Siping Rd, Shanghai, 200092, China.
- Shanghai Institute of Pollution Control and Ecological Security, Tongji University, 1239 Siping Rd, Shanghai, 200092, China.
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Wang Q, Li X, Liu W, Zhai S, Xu Q, Huan C, Nie S, Ouyang Q, Wang H, Wang A. Carbon source recovery from waste sludge reduces greenhouse gas emissions in a pilot-scale industrial wastewater treatment plant. ENVIRONMENTAL SCIENCE AND ECOTECHNOLOGY 2023; 14:100235. [PMID: 36660739 PMCID: PMC9843262 DOI: 10.1016/j.ese.2022.100235] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 12/28/2022] [Accepted: 12/28/2022] [Indexed: 05/13/2023]
Abstract
Carbon cycle regulation and greenhouse gas (GHG) emission abatement within wastewater treatment plants (WWTPs) can theoretically improve sustainability. Currently, however, large amounts of external carbon sources used for deep nitrogen removal and waste sludge disposal aggravate the carbon footprint of most WWTPs. In this pilot-scale study, considerable carbon was preliminarily recovered from primary sludge (PS) through short-term (five days) acidogenic fermentation and subsequently utilized on-site for denitrification in a wool processing industrial WWTP. The recovered sludge-derived carbon sources were excellent electron donors that could be used as additional carbon supplements for commercial glucose to enhance denitrification. Additionally, improvements in carbon and nitrogen flow further contributed to GHG emission abatement. Overall, a 9.1% reduction in sludge volatile solids was achieved from carbon recovery, which offset 57.4% of external carbon sources, and the indirect GHG emissions of the target industrial WWTP were reduced by 8.05%. This study demonstrates that optimizing the allocation of carbon mass flow within a WWTP has numerous benefits.
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Affiliation(s)
- Qiandi Wang
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China
- University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Xiqi Li
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, PR China
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China
| | - Wenzong Liu
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, PR China
- Corresponding author.
| | - Siyuan Zhai
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China
| | - Qiongying Xu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, PR China
| | - Chang'an Huan
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, PR China
| | - Shichen Nie
- Shandong Shenshui Hynar Water Environmental Protection Co., Ltd., Shandong, 274000, PR China
| | - Qinghua Ouyang
- Shenshui Hynar Water Group Co., Ltd., Shenzhen, 518055, PR China
| | - Hongcheng Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, PR China
| | - Aijie Wang
- CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China
- University of Chinese Academy of Sciences, Beijing, 100049, PR China
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, PR China
- Corresponding author. CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, PR China.
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18
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Han H, Kim DD, Song MJ, Yun T, Yoon H, Lee HW, Kim YM, Laureni M, Yoon S. Biotrickling Filtration for the Reduction of N 2O Emitted during Wastewater Treatment: Results from a Long-Term In Situ Pilot-Scale Testing. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:3883-3892. [PMID: 36809918 DOI: 10.1021/acs.est.2c08818] [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: 06/18/2023]
Abstract
Wastewater treatment plants (WWTPs) are a major source of N2O, a potent greenhouse gas with 300 times higher global warming potential than CO2. Several approaches have been proposed for mitigation of N2O emissions from WWTPs and have shown promising yet only site-specific results. Here, self-sustaining biotrickling filtration, an end-of-the-pipe treatment technology, was tested in situ at a full-scale WWTP under realistic operational conditions. Temporally varying untreated wastewater was used as trickling medium, and no temperature control was applied. The off-gas from the covered WWTP aerated section was conveyed through the pilot-scale reactor, and an average removal efficiency of 57.9 ± 29.1% was achieved during 165 days of operation despite the generally low and largely fluctuating influent N2O concentrations (ranging between 4.8 and 96.4 ppmv). For the following 60-day period, the continuously operated reactor system removed 43.0 ± 21.2% of the periodically augmented N2O, exhibiting elimination capacities as high as 5.25 g N2O m-3·h-1. Additionally, the bench-scale experiments performed abreast corroborated the resilience of the system to short-term N2O starvations. Our results corroborate the feasibility of biotrickling filtration for mitigating N2O emitted from WWTPs and demonstrate its robustness toward suboptimal field operating conditions and N2O starvation, as also supported by analyses of the microbial compositions and nosZ gene profiles.
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Affiliation(s)
- Heejoo Han
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Daehyun D Kim
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Min Joon Song
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Taeho Yun
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
| | - Hyun Yoon
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
- School of Civil & Environmental Engineering, Cornell University, Ithaca, New York 14853, United States
| | | | - Young Mo Kim
- Department of Civil and Environmental Engineering, Hanyang University, Seoul 04763, South Korea
| | - Michele Laureni
- Department of Geoscience and Engineering, Delft University of Technology, 2628 CN Delft, The Netherlands
| | - Sukhwan Yoon
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea
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19
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Peng L, Qiu H, Li S, Xu Y, Liang C, Wang N, Liu Y, Ni BJ. The mitigation effect of free ammonia and free nitrous acid on nitrous oxide production from the full-nitrification and partial-nitritation systems. BIORESOURCE TECHNOLOGY 2023; 372:128564. [PMID: 36592867 DOI: 10.1016/j.biortech.2022.128564] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/27/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
The potentials of using endogenous free ammonia (FA) and free nitrous acid (FNA) as nitrous oxide (N2O) mitigators were investigated in treatment of both mainstream and sidestream wastewater. Although the N2O emission factor of a sidestream partial-nitritation (PN) reactor (averaged 1.70 % ± 0.39 %, n = 30) was about 2.4 times higher than a mainstream full-nitrification (FN) reactor (averaged 0.72 % ± 0.24 %, n = 30) (P < 0.01), one-hour exposure of PN sludge to 1.5 mg HNO2-N/L FNA could virtually abolish N2O emission. As for FN sludge, both 45 mg NH3-N/L FA and 0.015 mg HNO2-N/L FNA successfully mitigated N2O production at varying dissolved oxygen (DO) levels (50 % vs 61 %), while 1.5 mg HNO2-N/L FNA not only reduced more N2O (92 %) but also altered the N2O dependency on DO. Both FNA and FA sludge treatment were effective N2O mitigation strategies with FNA toward the end of carbon neutrality and FA being more economically appealing (2 % cost saving).
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Affiliation(s)
- Lai Peng
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; Shenzhen Research Institute of Wuhan University of Technology, Shenzhen 518000, Guangdong, China
| | - Huiling Qiu
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; Shenzhen Research Institute of Wuhan University of Technology, Shenzhen 518000, Guangdong, China
| | - Shengjun Li
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; Shenzhen Research Institute of Wuhan University of Technology, Shenzhen 518000, Guangdong, China.
| | - Yifeng Xu
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Chuanzhou Liang
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Ning Wang
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Yiwen Liu
- University of Technology Sydney, Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, Sydney, NSW 2007, Australia
| | - Bing-Jie Ni
- University of Technology Sydney, Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, Sydney, NSW 2007, Australia
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20
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Lu X, Wang Z, Duan H, Wu Z, Hu S, Ye L, Yuan Z, Zheng M. Significant production of nitric oxide by aerobic nitrite reduction at acidic pH. WATER RESEARCH 2023; 230:119542. [PMID: 36603308 DOI: 10.1016/j.watres.2022.119542] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 12/20/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
The acidic (i.e., pH ∼5) activated sludge process is attracting attention because it enables stable nitrite accumulation and enhances sludge reduction and stabilization, compared to the conventional process at neutral pH. Here, this study examined the production and potential pathways of nitric oxide (NO) and nitrous oxide (N2O) during acidic sludge digestion. With continuous operation of a laboratory-scale aerobic digester at high dissolved oxygen concentration (DO>4 mg O2 L-1) and low pH (4.7±0.6), a significant amount of total nitrogen (TN) loss (i.e., 18.6±1.5% of TN in feed sludge) was detected. Notably, ∼40% of the removed TN was emitted as NO, with ∼8% as N2O. A series of batch assays were then designed to explain the observed TN loss under aerobic conditions. All assays were conducted with a low concentration of volatile solids (VS), i.e., VS<4.5 g L-1. This VS concentration is commensurate with the values commonly found in the aeration tanks of full-scale wastewater treatment systems, and thus no significant nitrogen loss should be expected when DO is controlled above 4 mg O2 L-1. However, nitrite disappeared at a significant rate (with the chemical decomposition of nitrite excluded), leading to NO production in the batch assays at pH 5. The nitrite reduction could be associated with endogenous microbial activities, e.g., nitrite detoxification. The significant NO production illustrates the importance of aerobic nitrite reduction during acidic aerobic sludge digestion, suggesting this process cannot be neglected in developing acidic activated sludge technology.
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Affiliation(s)
- Xi Lu
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiyao Wang
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Haoran Duan
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Ziping Wu
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Shihu Hu
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Liu Ye
- School of Chemical Engineering, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Zhiguo Yuan
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Min Zheng
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, QLD 4072, Australia.
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21
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Ma G, Yu D, Zhang J, Miao Y, Zhao X, Li J, Zhang Y, Dong G, Zhi J. A novel simultaneous partial nitrification, anammox, denitrification and fermentation process: Enhancing nitrogen removal and sludge reduction in a single reactor. BIORESOURCE TECHNOLOGY 2023; 369:128484. [PMID: 36513309 DOI: 10.1016/j.biortech.2022.128484] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/07/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
This study verified the feasibility of simultaneous partial nitrification, anammox, denitrification and fermentation process under intermittent aeration in a single reactor, and explored the impact of dissolved oxygen (DO) on the synergy between fermentation and nitrogen removal. An advanced nitrogen removal efficiency of 92.8 % and a low observed sludge yield of 0.0268-0.1474 kgMLSS/kgCOD were achieved. In-situ test showed that nitrate and ammonium decreased synchronously in the absence of organic matter, indicating the possibility of simultaneous partial denitrification, anammox and fermentation. Additionally, the abundance of functional genes for acetate production was 66,894 hits, while the key genes relevant to methanogenesis were only 348 hits, which suggested that fermentation might stop at the acid-producing stage and promote partial denitrification-anammox reaction, achieving simultaneous sludge reduction and advanced nitrogen removal performance. When DO increased from 0.1-0.3 to 0.4-0.6 mg/L, the nitrogen removal efficiency was increased (63.9 %→92.8 %) while sludge reduction was negatively affected.
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Affiliation(s)
- Guocheng Ma
- School of Environmental Science & Engineering, Qingdao University, Qingdao 266071, PR China
| | - Deshuang Yu
- School of Environmental Science & Engineering, Qingdao University, Qingdao 266071, PR China
| | - Jianhua Zhang
- School of Environmental & Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China
| | - Yuanyuan Miao
- School of Environmental Science & Engineering, Qingdao University, Qingdao 266071, PR China; Carbon Neutrality and Eco-Environmental Technology Innovation Center of Qingdao, Qingdao 266071, PR China.
| | - Xinchao Zhao
- School of Environmental Science & Engineering, Qingdao University, Qingdao 266071, PR China
| | - Jiawen Li
- School of Environmental Science & Engineering, Qingdao University, Qingdao 266071, PR China
| | - Yu Zhang
- School of Environmental Science & Engineering, Qingdao University, Qingdao 266071, PR China
| | - Guoqing Dong
- School of Environmental Science & Engineering, Qingdao University, Qingdao 266071, PR China
| | - Jiaru Zhi
- School of Environmental Science & Engineering, Qingdao University, Qingdao 266071, PR China
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22
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Yao H, Gao X, Guo J, Wang H, Zhang L, Fan L, Jia F, Guo J, Peng Y. Contribution of nitrous oxide to the carbon footprint of full-scale wastewater treatment plants and mitigation strategies- a critical review. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 314:120295. [PMID: 36181929 DOI: 10.1016/j.envpol.2022.120295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 08/27/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Nitrous oxide (N2O), a potent greenhouse gas, significantly contributes to the carbon footprint of wastewater treatment plants (WWTPs) and contributes significantly to global climate change and to the deterioration of the natural environment. Our understanding of N2O generation mechanisms has significantly improved in the last decade, but the development of effective N2O emission mitigation strategies has lagged owing to the complexity of parameter regulation, substandard monitoring activities, and inadequate policy criteria. Based on critically screened published studies on N2O control in full-scale WWTPs, this review elucidates N2O generation pathway identifications and emission mechanisms and summarizes the impact of N2O on the total carbon footprint of WWTPs. In particular, a linear relationship was established between N2O emission factors and total nitrogen removal efficiencies in WWTPs located in China. Promising N2O mitigation options were proposed, which focus on optimizing operating conditions and implementation of innovative treatment processes. Furthermore, the sustainable operation of WWTPs has been anticipated to convert WWTPs into absolute greenhouse gas reducers as a result of the refinement and improvement of on-site monitoring activities, mitigation mechanisms, regulation of operational parameters, modeling, and policies.
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Affiliation(s)
- Hong Yao
- Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, School of Environment, Beijing Jiaotong University, Beijing, 100044, China.
| | - Xinyu Gao
- Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, School of Environment, Beijing Jiaotong University, Beijing, 100044, China
| | - Jingbo Guo
- School of Civil Engineering and Architecture, Northeast Electric Power University, Jilin, 132012, China
| | - Hui Wang
- SINOPEC Research Institute of Petroleum Processing, Beijing, 100083, China
| | - Liang Zhang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing, 100124, China
| | - Liru Fan
- Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, School of Environment, Beijing Jiaotong University, Beijing, 100044, China
| | - Fangxu Jia
- Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, School of Environment, Beijing Jiaotong University, Beijing, 100044, China
| | - Jianhua Guo
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD, 4072, Australia
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing, 100124, China
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23
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Ye J, Gao H, Wu J, Yang G, Duan L, Yu R. Long-term exposure to nano-TiO 2 interferes with microbial metabolism and electron behavior to influence wastewater nitrogen removal and associated N 2O emission. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 311:119930. [PMID: 35970347 DOI: 10.1016/j.envpol.2022.119930] [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: 06/07/2022] [Revised: 08/04/2022] [Accepted: 08/06/2022] [Indexed: 06/15/2023]
Abstract
The extensive use of nano-TiO2 has caused concerns regarding their potential environmental risks. However, the stress responses and self-recovery potential of nitrogen removal and greenhouse gas N2O emissions after long-term nano-TiO2 exposure have seldom been addressed yet. This study explored the long-term effects of nano-TiO2 on biological nitrogen transformations in a sequencing batch reactor at four levels (1, 10, 25, and 50 mg/L), and the reactor's self-recovery potential was assessed. The results showed that nano-TiO2 exhibited a dose-dependent inhibitory effect on the removal efficiencies of ammonia nitrogen and total nitrogen, whereas N2O emissions unexpectedly increased. The promoted N2O emissions were probably due to the inhibition of denitrification processes, including the reduction of the denitrifying-related N2O reductase activity and the abundance of the denitrifying bacteria Flavobacterium. The inhibition of carbon source metabolism, the inefficient electron transfer efficiency, and the electronic competition between the denitrifying enzymes would be in charge of the deterioration of denitrification performance. After the withdrawal of nano-TiO2 from the influent, the nitrogen transformation efficiencies and the N2O emissions of activated sludge recovered entirely within 30 days, possibly attributed to the insensitive bacteria survival and the microbial community diversity. Overall, this study will promote the current understanding of the stress responses and the self-recovery potential of BNR systems to nanoparticle exposure.
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Affiliation(s)
- Jinyu Ye
- School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, Hangzhou 310023, China; Department of Environmental Science and Engineering, School of Energy and Environment, Wuxi Engineering Research Center of Taihu Lake Water Environment, Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu, 210096, China
| | - Huan Gao
- Department of Environmental Science and Engineering, School of Energy and Environment, Wuxi Engineering Research Center of Taihu Lake Water Environment, Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu, 210096, China
| | - Junkang Wu
- Department of Environmental Science and Engineering, School of Energy and Environment, Wuxi Engineering Research Center of Taihu Lake Water Environment, Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu, 210096, China; Department of Water Supply and Drainage Science and Engineering, College of Civil Engineering, Nanjing Forestry University, Nanjing, Jiangsu, 210037, China
| | - Guangping Yang
- Chinair Envir. Sci-Tech Co., Ltd., Nanjing, Jiangsu, 210019, China
| | - Lijie Duan
- Guangdong Institute of Socialism, Guangzhou, Guangdong, 510499, China
| | - Ran Yu
- Department of Environmental Science and Engineering, School of Energy and Environment, Wuxi Engineering Research Center of Taihu Lake Water Environment, Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu, 210096, China.
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24
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Cai ZX, Li QS, Bai H, Zhu CY, Tang GH, Zhou HZ, Huang JW, Song XS, Wang JF. Interactive effects of aquatic nitrogen and plant biomass on nitrous oxide emission from constructed wetlands. ENVIRONMENTAL RESEARCH 2022; 213:113716. [PMID: 35718165 DOI: 10.1016/j.envres.2022.113716] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/12/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
Understanding of mechanisms in nitrous oxide (N2O) emission from constructed wetland (CW) is particularly important for the establishment of related strategies to reduce greenhouse gas (GHG) production during its wastewater treatment. However, plant biomass accumulation, microbial communities and nitrogen transformation genes distribution and their effects on N2O emission from CW as affected by different nitrogen forms in aquatic environment have not been reported. This study investigated the interactive effects of aquatic nitrogen and plant biomass on N2O emission from subsurface CW with NH4+-N (CW-A) or NO3--N (CW-B) wastewater. The experimental results show that NH4+-N and NO3--N removal efficiencies from CW mesocosms were 49.4% and 87.6%, which indirectly lead to N2O emission fluxes of CW-A and CW-B maintained at 213 ± 67 and 462 ± 71 μg-N/(m2·h), respectively. Correlation analysis of nitrogen conversion dynamic indicated that NO2--N accumulation closely related to N2O emission from CW. Aquatic NH4+-N could up-regulate plant biomass accumulation by intensifying citric acid cycle, glycine-serine-threonine metabolism etc., resulting in more nitrogen uptake and lower N2O emission/total nitrogen (TN) removal ratio of CW-A compared to CW-B. Although the abundance of denitrifying bacteria and N2O reductase nosZ in CW-B were significantly higher than that of CW-A, after fed with mixed NH4+-N and NO3--N influent, N2O fluxes and N2O emission/TN removal ratio in CW-A were extremely close to that of CW-B, suggesting that nitrogen form rather than nitrogen transformation microbial communities and N2O reductase nosZ determines N2O emission from CW. Hence, the selection of nitrate-loving plants will play an important role in inhibiting N2O emission from CW.
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Affiliation(s)
- Ze-Xiang Cai
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Qu-Sheng Li
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Heng Bai
- Powerchina Beijing Engineering Corporation Limited, Beijing, 100024, China
| | - Cong-Yun Zhu
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Guan-Hui Tang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Huan-Zhan Zhou
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Jia-Wei Huang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China
| | - Xin-Shan Song
- College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China
| | - Jun-Feng Wang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou, 510632, China.
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25
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Abulimiti A, Wang X, Kang J, Li L, Wu D, Li Z, Piao Y, Ren N. The trade-off between N 2O emission and energy saving through aeration control based on dynamic simulation of full-scale WWTP. WATER RESEARCH 2022; 223:118961. [PMID: 35973249 DOI: 10.1016/j.watres.2022.118961] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 08/05/2022] [Accepted: 08/06/2022] [Indexed: 06/15/2023]
Abstract
This study investigated the trade-off between energy saving and N2O emission reduction of WWTP under the precise control of dissolved oxygen (DO) concentration through model simulation. A long-term dynamic model for full-scale WWTP GHG emissions was established and calibrated with monitored year-round hourly water quality data to quantify the annual GHG emissions from WWTP. Results showed that N2O dominated the direct emission, up to 76.1%, and the variability of N2O generation could better be revealed by dynamic simulation. Furthermore, GHG emissions of the WWTP were mainly contributed by electric energy, among which the blower consumes the most electricity. To reduce the electricity consumption of blowers, improve mechanical efficiency and reduce DO concentration should be considered. DO setting played a significant role in the N2O and CH4 emission, electricity consumption and effluent quality, which was challenging to balance. The ultralow-oxygen (0-1/0.2-1 mg/L) and low oxygen (1-2 mg/L) control strategies were proposed, and their effects on total GHG emissions and effluent water quality were discussed. If the anaerobic environment (DO<0.2 mg/L)could be avoided, the control frequency (high and low) of the DO set-point did not have a significant effect on the emissions of N2O and CH4 and the effluent quality. The ultralow-oxygen strategy (0.2-1 mg/L) with a high-frequency control strategy achieved the lowest GHG emissions under the current energy mix. However, by 2050, as the energy supply gets cleaner, the total GHG emissions of WWTPs with ultralow-oxygen aeration (0.2-1 mg/L) will exceed low-oxygen aeration by 3.6%-4.2%, as N2O dominates 61.6%. Therefore, considering the trade-off between N2O emission and energy saving in WWTP, ultralow-oxygen aeration is a transition scheme to cleaner energy.
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Affiliation(s)
- Aliya Abulimiti
- State key Laboratory of urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Xiuheng Wang
- State key Laboratory of urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Jinhao Kang
- State key Laboratory of urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Lanqing Li
- State key Laboratory of urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Dan Wu
- Longjiang Environmental Protection Group Co., Ltd, Harbin 150090, China
| | - Zhe Li
- Longjiang Environmental Protection Group Co., Ltd, Harbin 150090, China
| | - Yitong Piao
- Beijing SequoiaLibra Technology Development Co., Ltd, Beijing 100000, China
| | - Nanqi Ren
- State key Laboratory of urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China
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26
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Mao W, Yang R, Shi H, Feng H, Chen S, Wang X. Identification of key water parameters and microbiological compositions triggering intensive N 2O emissions during landfill leachate treatment process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 833:155135. [PMID: 35405234 DOI: 10.1016/j.scitotenv.2022.155135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 03/16/2022] [Accepted: 04/05/2022] [Indexed: 06/14/2023]
Abstract
Landfill leachate treatment processes tend to emit more N2O compared to domestic wastewater treatment. This discrepancy may be ascribed to leachate water characteristics such as high refractory COD, ammonium (NH4+) content, and salinity. In this work, the leachate influent was varied to examine the N2O emission scenarios. NH4+-N, COD, and Cl- concentrations ranged between 1000-2500, 1000-10,000, and 500-3000 mg L-1, respectively. Simultaneously, we attempted to combine statistical analysis with high-throughput sequencing to understand the microbial mechanism with regards to N2O emission. Results show that the strong N2O emissions occur in the nitrifying tank due to the intensive aeration. The system receiving the lowest COD shows the maximum N2O emission factor of 42.7% of the removed nitrogen. Both redundancy analysis and a structural equation model verify that insufficient degradable organics are the key water parameter triggering intensive N2O emission within the designed influent limits. Furthermore, two essential but non-abundant functional bacteria, Flavobacterium (acting as a denitrifier) and Nitrosomonas (acting as a nitrifier), are identified as the core functional species that dramatically influence N2O emissions. An increase in influent COD promotes the proliferation of Flavobacterium and inhibits Nitrosomonas, which in turn reduce N2O release. Meanwhile, two keystone species of Castellaniella and Saprospiraceae unclassified are recognized. They may supply a suitable niche and integrity of the microbial community for N-cycle functional bacteria. These findings reveal the essential role of non-abundant species in microbial community, and expand the current understanding of microbial interactions underlying N2O dynamics in leachate treatment systems.
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Affiliation(s)
- Wenlong Mao
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Ruili Yang
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Huiqun Shi
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Hualiang Feng
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Shaohua Chen
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Xiaojun Wang
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
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27
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Lin Z, Ma K, Yang Y. Nitrous Oxide Emission from Full-Scale Anammox-Driven Wastewater Treatment Systems. LIFE (BASEL, SWITZERLAND) 2022; 12:life12070971. [PMID: 35888061 PMCID: PMC9317218 DOI: 10.3390/life12070971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/16/2022] [Accepted: 06/27/2022] [Indexed: 11/23/2022]
Abstract
Wastewater treatment plants (WWTPs) are important contributors to global greenhouse gas (GHG) emissions, partly due to their huge emission of nitrous oxide (N2O), which has a global warming potential of 298 CO2 equivalents. Anaerobic ammonium-oxidizing (anammox) bacteria provide a shortcut in the nitrogen removal pathway by directly transforming ammonium and nitrite to nitrogen gas (N2). Due to its energy efficiency, the anammox-driven treatment has been applied worldwide for the removal of inorganic nitrogen from ammonium-rich wastewater. Although direct evidence of the metabolic production of N2O by anammox bacteria is lacking, the microorganisms coexisting in anammox-driven WWTPs could produce a considerable amount of N2O and hence affect the sustainability of wastewater treatment. Thus, N2O emission is still one of the downsides of anammox-driven wastewater treatment, and efforts are required to understand the mechanisms of N2O emission from anammox-driven WWTPs using different nitrogen removal strategies and develop effective mitigation strategies. Here, three main N2O production processes, namely, hydroxylamine oxidation, nitrifier denitrification, and heterotrophic denitrification, and the unique N2O consumption process termed nosZ-dominated N2O degradation, occurring in anammox-driven wastewater treatment systems, are summarized and discussed. The key factors influencing N2O emission and mitigation strategies are discussed in detail, and areas in which further research is urgently required are identified.
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28
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Kirim G, McCullough K, Bressani-Ribeiro T, Domingo-Félez C, Duan H, Al-Omari A, De Clippeleir H, Jimenez J, Klaus S, Ladipo-Obasa M, Mehrani MJ, Regmi P, Torfs E, Volcke EIP, Vanrolleghem PA. Mainstream short-cut N removal modelling: current status and perspectives. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 85:2539-2564. [PMID: 35576252 DOI: 10.2166/wst.2022.131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This work gives an overview of the state-of-the-art in modelling of short-cut processes for nitrogen removal in mainstream wastewater treatment and presents future perspectives for directing research efforts in line with the needs of practice. The modelling status for deammonification (i.e., anammox-based) and nitrite-shunt processes is presented with its challenges and limitations. The importance of mathematical models for considering N2O emissions in the design and operation of short-cut nitrogen removal processes is considered as well. Modelling goals and potential benefits are presented and the needs for new and more advanced approaches are identified. Overall, this contribution presents how existing and future mathematical models can accelerate successful full-scale mainstream short-cut nitrogen removal applications.
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Affiliation(s)
- Gamze Kirim
- modelEAU, Université Laval, 1065 avenue de la Médecine, Québec, QC G1 V 0A6, Canada E-mail: ; CentrEau, Quebec Water Research Centre, 1065 avenue de la Médecine, Québec, QC G1 V 0A6, Canada
| | - Kester McCullough
- School of Civil and Environmental Engineering, Cornell University, Ithaca, NY 14853, USA; Hampton Roads Sanitation District, 1434 Air Rail Ave., Virginia Beach, VA 23455, USA
| | - Thiago Bressani-Ribeiro
- BioCo Research Group, Department of Green Chemistry and Technology, Ghent University, Coupure Links 653, Gent 9000, Belgium
| | - Carlos Domingo-Félez
- Department of Environmental Engineering, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Haoran Duan
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Ahmed Al-Omari
- Brown and Caldwell, 1725 Duke St. Suite 250, Alexandria, VA 22314, USA
| | - Haydee De Clippeleir
- DC Water and Sewer Authority, 5000 Overlook Ave., SW., Washington, DC 20032, USA
| | - Jose Jimenez
- Brown and Caldwell, 1725 Duke St. Suite 250, Alexandria, VA 22314, USA
| | - Stephanie Klaus
- Hampton Roads Sanitation District, 1434 Air Rail Ave., Virginia Beach, VA 23455, USA
| | - Mojolaoluwa Ladipo-Obasa
- DC Water and Sewer Authority, 5000 Overlook Ave., SW., Washington, DC 20032, USA; Department of Civil & Environmental Engineering, The George Washington University, 800 22nd Street NW, Washington, DC 20037, USA
| | - Mohamad-Javad Mehrani
- Faculty of Civil and Environmental Engineering, Gdansk University of Technology, Ul. Narutowicza 11/12, Gdansk 80-233, Poland; Department of Urban Water and Waste Management, University of Duisburg-Essen, Universit¨atsstraße 15, 45141, Essen, Germany
| | - Pusker Regmi
- Brown and Caldwell, 1725 Duke St. Suite 250, Alexandria, VA 22314, USA
| | - Elena Torfs
- Centre for Advanced Process Technology for Urban Resource recovery (CAPTURE), Frieda Saeysstraat 1, Gent 9000, Belgium; BIOMATH, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Gent 9000, Belgium
| | - Eveline I P Volcke
- BioCo Research Group, Department of Green Chemistry and Technology, Ghent University, Coupure Links 653, Gent 9000, Belgium; Centre for Advanced Process Technology for Urban Resource recovery (CAPTURE), Frieda Saeysstraat 1, Gent 9000, Belgium
| | - Peter A Vanrolleghem
- modelEAU, Université Laval, 1065 avenue de la Médecine, Québec, QC G1 V 0A6, Canada E-mail: ; CentrEau, Quebec Water Research Centre, 1065 avenue de la Médecine, Québec, QC G1 V 0A6, Canada
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29
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Li K, Duan H, Liu L, Qiu R, van den Akker B, Ni BJ, Chen T, Yin H, Yuan Z, Ye L. An Integrated First Principal and Deep Learning Approach for Modeling Nitrous Oxide Emissions from Wastewater Treatment Plants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:2816-2826. [PMID: 35107268 DOI: 10.1021/acs.est.1c05020] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Mathematical modeling plays a critical role toward the mitigation of nitrous oxide (N2O) emissions from wastewater treatment plants (WWTPs). In this work, we proposed a novel hybrid modeling approach by integrating the first principal model with deep learning techniques to predict N2O emissions. The hybrid model was successfully implemented and validated with the N2O emission data from a full-scale WWTP. This hybrid model is demonstrated to have higher accuracy for N2O emission modeling in the WWTP than the mechanistic model or pure deep learning model. Equally important, the hybrid model is more applicable than the pure deep learning model due to the lower requirement of data and the pure mechanistic model due to the less calibration requirement. This superior performance was due to the hybrid nature of the proposed model. It integrated the essential wastewater treatment knowledge as the first principal component and the less understood N2O production processes by the data-driven deep learning approach. The developed hybrid model was also successfully implemented under different circumstances for the prediction of N2O flux, which showed the generalizability of the model. The hybrid model also showed great potential to be applied for the N2O mitigation work. Nevertheless, the capability of the hybrid model in evaluating N2O mitigation strategies still requires validation with experiments. Going beyond N2O modeling in WWTP, the novel hybridization modeling concept can potentially be applied to other environmental systems.
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Affiliation(s)
- Kaili Li
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Haoran Duan
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Linfeng Liu
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Ruihong Qiu
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Ben van den Akker
- South Australian Water Corporation, Adelaide, South Australia 5000, Australia
- School of Natural and Built Environments, University of South Australia, Adelaide, South Australia 5001, Australia
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5042, Australia
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Tong Chen
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Hongzhi Yin
- School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Zhiguo Yuan
- Australian Centre for Water and Environmental Biotechnology (formerly AWMC), The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Liu Ye
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
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30
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Dias DFC, Marques R, Martins C, Martins A, Oehmen A. The impact of a seasonal change in loading rate on the nitrous oxide emissions at the WWTP of a tourist region. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 804:149987. [PMID: 34517330 DOI: 10.1016/j.scitotenv.2021.149987] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/23/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
Nitrous oxide (N2O) is a powerful greenhouse gas (GHG) whose production and emission must be minimised from wastewater treatment plants (WWTPs) to avoid undesirable impacts to climate change and the ozone layer. WWTPs operated in tourist regions undergo large seasonal changes to the influent loading rates of organic matter, nitrogen and phosphorus, which operators must respond to by changing their operational conditions. This study examines the impact of a change in low to high season on the N2O emissions of an activated sludge WWTP in a well-known tourist region in the Algarve, Portugal. While literature studies have suggested that increases in the nitrogen and organic loading rates can promote increased N2O emissions, we have found higher N2O emissions in the low season (7.4% kgN2O-N·kgNH4-N-1), where these loading rates were lower. It was found that the impact of accompanying operational changes to the WWTP outweighed any change caused by the increased loading rate, where the aeration rate showed a significant correlation with N2O emission dynamics. The location of the N2O fluxes observed as well as the dissolved vs gaseous N2O levels suggested that the hydroxylamine oxidation pathway was likely to be of higher relevance towards N2O production as compared to nitrifier denitrification. This study contributes towards the understanding of operational factors impacting N2O emissions at full-scale WWTPs and potential mitigation strategies.
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Affiliation(s)
- Daniel F C Dias
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal
| | - Ricardo Marques
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal
| | - Carla Martins
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal
| | - António Martins
- Aguas do Algarve, Rua do Repouso, n°10, 8000-302, Faro, Portugal
| | - Adrian Oehmen
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal; School of Chemical Engineering, The University of Queensland, St. Lucia, Qld 4072, Australia.
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31
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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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32
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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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33
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Thwaites BJ, Stuetz R, Short M, Reeve P, Alvarez-Gaitan JP, Dinesh N, Philips R, van den Akker B. Analysis of nitrous oxide emissions from aerobic granular sludge treating high saline municipal wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 756:143653. [PMID: 33310220 DOI: 10.1016/j.scitotenv.2020.143653] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/02/2020] [Accepted: 11/03/2020] [Indexed: 06/12/2023]
Abstract
Conventional activated sludge (CAS)-based wastewater treatment processes have the potential to emit high concentrations of nitrous oxide (N2O) during nitrification and denitrification, which can significantly impact the environmental performance and carbon footprint of wastewater treatment operations. While N2O emissions from CAS have been extensively studied, there is little knowledge of N2O emissions from aerobic granular sludge (AGS) which is now an increasingly popular secondary treatment alternative. The N2O emissions performance of AGS needs to be investigated to ensure that the positive benefits of AGS, such as increased capacity and stable nutrient removal, are not offset by higher emissions. This study quantified N2O emissions from a pilot-scale AGS reactor operated under a range of organic loading rates. A second CAS pilot plant was operated in parallel and under identical loading rates to allow for side-by-side comparison of N2O emissions from floc-based activated sludge. Under low loadings of <0.6 kg COD/m3/d the N2O emission factor from AGS and CAS were similar, at around 1.46 ± 0.1% g N2Oemitted/g ammonium loaded. A step increase in the organic loading rate increased N2O emissions from AGS more so than CAS which appeared to be attributed to the reactor feeding strategy that was required for AGS formation. The use of a separate anaerobic feeding phase which was followed by the aeration phase, resulted in extended periods of low dissolved oxygen (DO) concentrations combined with an initial high biomass ammonium loading rate, which favours N2O production and was exacerbated at higher organic loads. Conversely, the combined feeding plus aeration operation (aerobic feed) employed by the CAS system enabled a more even biomass ammonium loading rate and DO supply. This work has shown that while AGS has many operational benefits, the impacts that aeration profile, loading rate and feeding strategy have on N2O emissions must be considered.
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Affiliation(s)
- Benjamin J Thwaites
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Richard Stuetz
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Michael Short
- Future Industries Institute, University of South Australia, Mawson Lakes 5095, South Australia, Australia
| | - Petra Reeve
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Juan-Pablo Alvarez-Gaitan
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Nirmala Dinesh
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Renae Philips
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia
| | - Ben van den Akker
- South Australian Water Corporation, Adelaide, 5000, South Australia, Australia; Health and Environment Group, School of the Environment, Flinders University, Bedford Park, 5042, South Australia, Australia; School of Natural and Built Environments, University of South Australia, Mawson Lakes 5095, South Australia, Australia
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