1
|
Yan X, Liu D, de Smit SM, Komin V, Buisman CJN, Ter Heijne A. Oxygen-to-ammonium-nitrogen ratio as an indicator for oxygen supply management in microoxic bioanodic ammonium oxidation. WATER RESEARCH 2024; 261:121993. [PMID: 38968732 DOI: 10.1016/j.watres.2024.121993] [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: 04/25/2024] [Revised: 06/16/2024] [Accepted: 06/22/2024] [Indexed: 07/07/2024]
Abstract
Microbial electrolysis cells (MECs) have been proven effective for oxidizing ammonium (NH4+), where the anode acts as an electron acceptor, reducing the energy input by substituting oxygen (O2). However, O2 has been proved to be essential for achieving high removal rates MECs. Thus, precise control of oxygen supply is crucial for optimizing treatment performance and minimizing energy consumption. Unlike previous studies focusing on dissolved oxygen (DO) levels, this study introduces the O2/NH4+-N ratio as a novel control parameter for balancing oxidation rates and the selectivity of NH4+ oxidation towards dinitrogen gas (N2) under limited oxygen condition. Our results demonstrated that the O2/NH4+-N ratio is a more relevant oxygen supply indicator compared to DO level. Oxygen served as a more favorable electron acceptor than the electrode, increasing NH4+ oxidation rates but also resulting in more oxidized products such as nitrate (NO3-). Additionally, nitrous oxide (N2O) and N2 production were higher with the electrode as the electron acceptor compared to oxygen alone. An O2/NH4+-N ratio of 0.5 was found to be optimal, achieving a balance between product selectivity for N2 (51.4 % ± 4.5 %) and oxidation rates (344.6 ± 14.7 mg-N/L*d), with the columbic efficiency of 30.7 % ± 2.0 %. Microbial community analysis revealed that nitrifiers and denitrifiers were the primary bacteria involved, with oxygen promoting the growth of nitrite-oxidizing bacteria, thus facilitating complete NH4+ oxidation to NO3-. Our study provides new insights and guidelines on the appropriate oxygen dosage, offering strategies into optimizing operational conditions for NH4+ removal using MECs.
Collapse
Affiliation(s)
- Xiaofang Yan
- Environmental Technology, Wageningen University & Research, P.O. Box 17, 6700 AA Wageningen, the Netherlands
| | - Dandan Liu
- Paqell B.V., Reactorweg 301, 3542 CE Utrecht, the Netherlands
| | - Sanne M de Smit
- Environmental Technology, Wageningen University & Research, P.O. Box 17, 6700 AA Wageningen, the Netherlands
| | - Vera Komin
- Environmental Technology, Wageningen University & Research, P.O. Box 17, 6700 AA Wageningen, the Netherlands
| | - Cees J N Buisman
- Environmental Technology, Wageningen University & Research, P.O. Box 17, 6700 AA Wageningen, the Netherlands; Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, the Netherlands
| | - Annemiek Ter Heijne
- Environmental Technology, Wageningen University & Research, P.O. Box 17, 6700 AA Wageningen, the Netherlands.
| |
Collapse
|
2
|
Zhang G, Hao Q, Gou Y, Wang X, Chen F, He Y, Liang Z, Jiang C. Changing the order and ratio of substrate filling reduced CH 4 and N 2O emissions from the aerated constructed wetlands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 941:173740. [PMID: 38839002 DOI: 10.1016/j.scitotenv.2024.173740] [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: 04/05/2024] [Revised: 05/27/2024] [Accepted: 06/01/2024] [Indexed: 06/07/2024]
Abstract
Constructed wetlands (CWs) have been used to enhance pollutant removal by filling several types of material as substrates. However, research on substrate filling order remains still limited, particularly regarding the effects of greenhouse gas (GHG) emissions. In this study, six CWs were constructed using zeolite and ferric‑carbon micro-electrolysis (Fe-C) fillers to evaluate the effect of changing the filling order and ratio on pollutant removal, GHGs emissions, and associated microbial structure. The results showed that the order of substrate filling significantly impacted pollutant removal performance on CWs. Specifically, CWs filled with zeolite in the top layer exhibited superior NH4+-N removal compared to those filled in the lower layer. Moreover, the highest NH4+-N removal (95.0 % ± 1.9 %) was observed in CWs with a zeolite to Fe-C volume ratio of 8:2 (CWZe-1). Moreover, zeolite-filled at the top had lower GHGs emissions, with the lowest CH4 (0.22 ± 0.10 mg m-2 h-1) and N2O (167.03 ± 61.40 μg m-2 h-1) fluxes in the CWZe-1. In addition, it is worth noting that N2O is the major contributor to integrated global warming potential (GWP) in the six CWs, accounting for 81.7 %-90.8 %. The upper layer of CWs filled with zeolite exhibited higher abundances of nirK, nirS and nosZ genes. The order in which the substrate was filled affected the microbial community structure and the upper layer of CWs filled with zeolite had higher relative abundance of nitrifying genera (Nitrobacter, Nitrosomonas) and denitrifying genera (Zoogloea, Denitratisoma). Additionally, N2O emission was reduced by approximately 41.2 %-64.4 % when the location of the aeration of the CWs was changed from the bottom to the middle. This study showed that both the order of filling the substrate and the aeration position significantly affected the GHGs emissions from CWs, and that CWs had lower GHGs emissions when zeolites were filled in the upper layer and the aeration position was in the middle.
Collapse
Affiliation(s)
- Guosheng Zhang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Qingju Hao
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yongxiang Gou
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Xunli Wang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Fanghui Chen
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yangjian He
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Zhenghao Liang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Changsheng Jiang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing 400715, China.
| |
Collapse
|
3
|
Zhang G, Hao Q, Xu S, Li Y, Zhang W, Liang Z, Jiang C. Mitigating nitrous oxide emissions from low carbon to nitrogen ratio wastewater treatment: Utilizing sugarcane bagasse fermentation liquid for constructed wetlands. BIORESOURCE TECHNOLOGY 2024; 406:131088. [PMID: 38981553 DOI: 10.1016/j.biortech.2024.131088] [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: 05/10/2024] [Revised: 07/02/2024] [Accepted: 07/06/2024] [Indexed: 07/11/2024]
Abstract
Sugarcane bagasse was recycled to produce fermentation liquid (FL) as a supplementary carbon source that was added to constructed wetlands (CWs) for regulating influent carbon to nitrogen ratio (C/N), and then being applied to investigate nitrogen transformations and greenhouse gas emissions. Results showed that this FL achieved faster NO3--N removal and lower N2O fluxes than sucrose did, and the lowest N2O flux (67.6 μg m-2h-1) was achieved when FL was added to CWs in a C/N of 3. In contrast, CH4 emissions were higher by the FL addition than by the sucrose addition, although the fluxes under both additions were in a lower range of 0.06-0.17 mg m-2h-1. The utilization of FL also induced significant variations in microbial communities and increased the abundance of denitrification genes. Results showed the application of FL from sugarcane bagasse can be an effective strategy for improving nitrogen removal and mitigating N2O emissions in CWs.
Collapse
Affiliation(s)
- Guosheng Zhang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Qingju Hao
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China; Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Shiwen Xu
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yanxun Li
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Wenxiao Zhang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Zhenghao Liang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Changsheng Jiang
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China; Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing 400715, China.
| |
Collapse
|
4
|
Lee S, Choi J, Choi H, Oh H, Lee S. Assessment and optimization of wastewater treatment plant in terms of effluent quality, energy footprint, and greenhouse gas emissions: An integrated modeling approach. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 283:116820. [PMID: 39094454 DOI: 10.1016/j.ecoenv.2024.116820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 07/25/2024] [Accepted: 07/28/2024] [Indexed: 08/04/2024]
Abstract
Wastewater treatment plants (WWTPs) can benefit from utilizing digital technologies to reduce greenhouse gas (GHG) emissions and to comply with effluent quality standards. In this study, the GHG emissions and electricity consumption of a WWTP were evaluated via computer simulation by varying the dissolved oxygen (DO), mixed liquor recirculation (MLR), and return activated sludge (RAS) parameters. Three different measures, namely, effluent water quality, GHG emissions, and energy consumption, were combined as water-energy-carbon coupling index (WECCI) to compare the effects of the parameters on WWTPs, and the optimal operating condition was determined. The initial conditions of the A2O process were set to 4.0 mg/L of DO, 100 % MLR, and 90.7 % RAS. Eighty scenarios with various DO, MLR, and RAS were simulated under steady-state condition to optimize the biological treatment process. The optimal operating conditions were found to be 1.5 mg/L of DO, 190 % MLR, and 90.9 % RAS, which had the highest WECCI of 2.40 when compared to the WECCI of the initial condition (1.07). This optimal condition simultaneously reduced GHG emissions by 1348 kg CO2-eq/d and energy consumption by 11.64 MWh/d. This implies that controlling DO, MLR, and RAS through sensors, valves, and pumps offers a promising approach to operating WWTPs with reduced electricity consumption and GHG emissions while attaining effluent quality standards. Additionally, the nitrous oxide stripping rate exhibited linear relationships with the effluent total ammonia and nitrite concentrations in the aerobic reactor, suggesting that monitoring dissolved nitrogen compounds in the effluent and reactor could be a viable strategy to control MLR and DO in the biological reactor. The digital-based assessment and optimization tools developed in this study are expected to hold promise for application in broader environmental management efforts.
Collapse
Affiliation(s)
- Seojun Lee
- Department of Environmental Engineering, The University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul 02504, the Republic of Korea
| | - Jaeyoung Choi
- Department of Environmental Engineering, The University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul 02504, the Republic of Korea
| | - Hyeonsoo Choi
- Department of Environmental Engineering, The University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul 02504, the Republic of Korea
| | - Heekyong Oh
- Department of Environmental Engineering, The University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul 02504, the Republic of Korea.
| | - Sangyoup Lee
- Institute of Convergence Science, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, the Republic of Korea
| |
Collapse
|
5
|
Chrysochoidis V, Andersen MH, Remigi EU, Faragó M, Smets BF, Domingo-Félez C, Valverde-Pérez B. Critical evaluation of different mass transfer equations to model N 2O emissions from water resource recovery facilities with diffuse aeration. ENVIRONMENTAL TECHNOLOGY 2024; 45:3339-3353. [PMID: 37191950 DOI: 10.1080/09593330.2023.2215454] [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: 12/23/2022] [Accepted: 05/04/2023] [Indexed: 05/17/2023]
Abstract
N2O measurements by liquid sensors in aerated tanks are an input to gas-liquid mass-transfer models for the prediction of N2O off-gas emissions. The prediction of N2O emissions from Water Resource Recovery Facilities (WRRFs) was evaluated by three different mass-transfer models using Benchmark Simulation Model 1 (BSM1) as a reference model. Inappropriate selection of mass-transfer model may result in miscalculation of carbon footprints based on soluble N2O online measurements. The film theory considers a constant mass-transfer expression, while more complex models suggest that emissions are affected by the aeration type, efficiency, and tank design characteristics. The differences among model predictions were 10-16% at dissolved oxygen (DO) concentration of 0.6 g/m3, when biological N2O production was the highest, while the flux of N2O was 20.0-24 kg N2O-N/d. At lower DO, the nitrification rate was low, while at DO higher than 2 g/m3, the N2O production was reduced leading to higher rates of complete nitrification and a flux of 5 kg N2O-N/d. The differences increased to 14-26% in deeper tanks, due to the pressure assumed in the tanks. The predicted emissions are also affected by the aeration efficiency when KLaN2O depends on the airflow instead of the KLaO2. Increasing the nitrogen loading rate under DO concentration of 0.50-0.65 g/m3 increased the differences in predictions by 10-20% in both alpha 0.6 and 1.2. A sensitivity analysis indicated that the selection of different mass-transfer models did not affect the selection of biochemical parameters for N2O model calibration.
Collapse
Affiliation(s)
| | | | | | - Maria Faragó
- Climate Adaptation and Green Infrastructure, Ramboll, Denmark
| | - Barth F Smets
- Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Denmark
| | - Carlos Domingo-Félez
- Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Denmark
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Lyngby, Denmark
- Infrastructure and Environment, School of Engineering, University of Glasgow, University Avenue, Glasgow, UK
| | - Borja Valverde-Pérez
- Department of Environmental Engineering, Technical University of Denmark, Miljøvej, Denmark
| |
Collapse
|
6
|
Zhang B, Mao W, Chen S, Wang X. Characteristics and key driving factors of nitrous oxide emissions from a full-scale landfill leachate treatment system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 931:172821. [PMID: 38688376 DOI: 10.1016/j.scitotenv.2024.172821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/01/2024] [Accepted: 04/25/2024] [Indexed: 05/02/2024]
Abstract
The characteristics of N2O emission from a full-scale landfill leachate treatment system were investigated by in-situ monitoring over 1.4 years and driving factors responsible for these emissions were identified by statistical analysis of multidimensional environmental variables. The results showed that the maximum N2O emission flux of 2.21 × 107 mg N·h-1 occurred in the nitrification tanks, where 98.5 % of the total N2O was released, with only 1.5 % of the total N2O emitted from the denitrification tanks. Limited oxygen in nitrification tank was responsible for N2O hotspot. The N2O emissions from the parallel lines A and B (both comprising the primary biochemical system) accounted for 52.6 % and 46.6 %, respectively, while the secondary biochemical system contributed only 0.8 % to the total emissions. Higher nitrite concentration in line A and lower nitrogen loading in the secondary biochemical system caused these discrepancies. We found that during the steady state of leachate treatment, intensive N2O emissions of 253.4-1270.5 kg N·d-1 were measured. The corresponding N2O emission factor (EF) ranged from 8.86 to 49.6 %, much higher than those of municipal wastewater treatment. But N2O EF was inconceivably as low as 0.42 % averagely after system maintenance. Influent with low salinity was the key reason, followed by the high MLSS and varying microbial community after maintenance. The dominant genus shifted from Lentimicrobium and Thauera to Norank-F-Anaerolineaceae and Unclassified-F-Rhodocyclaceae. This study underscores the significance of landfill leachate treatment in urban nitrogen management and provides valuable insights into the characteristics and driving factors of N2O emissions from such systems. The findings offer important references for greenhouse gas emission inventories and strategies for N2O control in full-scale wastewater treatment plants.
Collapse
Affiliation(s)
- Bo Zhang
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Wenlong Mao
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315830, China.
| | - Shaohua Chen
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Xiaojun Wang
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| |
Collapse
|
7
|
Abasi S, Tarre S, Green M. Nitrous Oxide Emissions from Nitritation Reactors under Hypersaline Conditions. BIORESOURCE TECHNOLOGY 2024; 399:130639. [PMID: 38552863 DOI: 10.1016/j.biortech.2024.130639] [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: 12/13/2023] [Revised: 03/12/2024] [Accepted: 03/25/2024] [Indexed: 04/07/2024]
Abstract
This study focuses on nitrous oxide (N2O) emissions during hypersaline (4 % salinity) nitritation in continuously fed and mixed fixed bed reactors. In the presence of high concentrations of nitrite and ammonium, the percent yield of N2O emissions from ammonium removed decreased with increasing dissolved oxygen (DO). However, N2O production continued even at a high DO of 15 mg/L. Bulk ammonium concentration (not ammonia) was found to be the main controlling factor for N2O emissions under high and low DO during both nitritation and nitrification. Reducing bulk ammonium concentrations below 1 mg N/L in the nitritation reactor under both high and low DO conditions resulted in a reduction of N2O emissions of approximately 90 %. Under full nitrification and low DO, reducing nitrite concentrations below 0.3 mg N/L resulted in a 60 % reduction in N2O emissions. Similar results were observed in a low salinity reactor.
Collapse
Affiliation(s)
- Samah Abasi
- Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
| | - Sheldon Tarre
- Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
| | - Michal Green
- Faculty of Civil and Environmental Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
| |
Collapse
|
8
|
Pedroza-Camacho LD, Ospina-Sánchez PA, Romero-Perdomo FA, Infante-González NG, Paredes-Céspedes DM, Quevedo-Hidalgo B, Gutiérrez-Romero V, Rivera-Hoyos CM, Pedroza-Rodríguez AM. Wastewater treatment from a science faculty during the COVID-19 pandemic by using ammonium-oxidising and heterotrophic bacteria. 3 Biotech 2024; 14:129. [PMID: 38601881 PMCID: PMC11003938 DOI: 10.1007/s13205-024-03961-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 02/22/2024] [Indexed: 04/12/2024] Open
Abstract
During and after the pandemic caused by the SARS-CoV-2 virus, the use of personal care products and disinfectants increased in universities worldwide. Among these, quaternary ammonium-based products stand out; these compounds and their intermediates caused substantial changes in the chemical composition of the wastewater produced by these institutions. For this reason, improvements and environmentally sustainable biological alternatives were introduced in the existing treatment systems so that these institutions could continue their research and teaching activities. For this reason, the objective of this study was to develop an improved culture medium to cultivate ammonium oxidising bacteria (AOB) to increase the biomass and use them in the treatment of wastewater produced in a faculty of sciences in Bogotá, D.C., Colombia. A Plackett Burman Experimental Design (PBED) and growth curves served for oligotrophic culture medium, and production conditions improved for the AOB. Finally, these bacteria were used with total heterotrophic bacteria (THB) for wastewater treatment in a pilot plant. Modification of base ammonium broth and culture conditions (6607 mg L-1 of (NH4)2SO4, 84 mg L-1 CaCO3, 40 mg L-1 MgSO4·7H2O, 40 mg L-1 CaCl2·2H2O and 200 mg L-1 KH2PO4, 10% (w/v) inoculum, no copper addition, pH 7.0 ± 0.2, 200 r.p.m., 30 days) favoured the growth of Nitrosomonas europea, Nitrosococcus oceani, and Nitrosospira multiformis with values of 8.23 ± 1.9, 7.56 ± 0.7 and 4.2 ± 0.4 Log10 CFU mL-1, respectively. NO2- production was 0.396 ± 0.0264, 0.247 ± 0.013 and 0.185 ± 0.003 mg L-1 for Nitrosomonas europea, Nitrosococcus oceani and Nitrosospira multiformis. After the 5-day wastewater treatment (WW) by co-inoculating the three studied bacteria in the wastewater (with their self-microorganisms), the concentrations of AOB and THB were 5.92 and 9.3 Log10 CFU mL-1, respectively. These values were related to the oxidative decrease of Chemical Oxygen Demand (COD), (39.5 mg L-1), Ammonium ion (NH4+), (6.5 mg L-1) Nitrite (NO2-), (2.0 mg L-1) and Nitrate (NO3-), (1.5 mg L-1), respectively in the five days of treatment. It was concluded, with the improvement of a culture medium and production conditions for three AOB through biotechnological strategies at the laboratory scale, being a promising alternative to bio-augment of the biomass of the studied bacteria under controlled conditions that allow the aerobic removal of COD and nitrogen cycle intermediates present in the studied wastewater. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-024-03961-4.
Collapse
Affiliation(s)
- Lucas D. Pedroza-Camacho
- Laboratorio de Microbiología Ambiental y Suelos, Unidad de Investigaciones Agropecuarias (UNIDIA), Grupo de Biotecnología Ambiental e Industrial (GBAI), Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7ma No 43-82, Edifício 50 Lab. 106, P.O. Box 110-23, Bogotá, DC Colombia
| | - Paula A. Ospina-Sánchez
- Laboratorio de Microbiología Ambiental y Suelos, Unidad de Investigaciones Agropecuarias (UNIDIA), Grupo de Biotecnología Ambiental e Industrial (GBAI), Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7ma No 43-82, Edifício 50 Lab. 106, P.O. Box 110-23, Bogotá, DC Colombia
| | - Felipe A. Romero-Perdomo
- Laboratorio de Microbiología Ambiental y Suelos, Unidad de Investigaciones Agropecuarias (UNIDIA), Grupo de Biotecnología Ambiental e Industrial (GBAI), Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7ma No 43-82, Edifício 50 Lab. 106, P.O. Box 110-23, Bogotá, DC Colombia
| | - Nury G. Infante-González
- Laboratorio de Microbiología Ambiental y Suelos, Unidad de Investigaciones Agropecuarias (UNIDIA), Grupo de Biotecnología Ambiental e Industrial (GBAI), Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7ma No 43-82, Edifício 50 Lab. 106, P.O. Box 110-23, Bogotá, DC Colombia
| | - Diana M. Paredes-Céspedes
- Laboratorio de Microbiología Ambiental y Suelos, Unidad de Investigaciones Agropecuarias (UNIDIA), Grupo de Biotecnología Ambiental e Industrial (GBAI), Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7ma No 43-82, Edifício 50 Lab. 106, P.O. Box 110-23, Bogotá, DC Colombia
| | - Balkys Quevedo-Hidalgo
- Laboratorio de Biotecnología Aplicada, Grupo de Biotecnología Ambiental e Industrial (GBAI), Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, P.O. Box 110-23, Bogotá, DC Colombia
| | | | - Claudia M. Rivera-Hoyos
- Laboratorio de Biotecnología Molecular, Grupo de Biotecnología Ambiental e Industrial (GBAI), Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, P.O. Box 110-23, Bogotá, DC Colombia
| | - Aura M. Pedroza-Rodríguez
- Laboratorio de Microbiología Ambiental y Suelos, Unidad de Investigaciones Agropecuarias (UNIDIA), Grupo de Biotecnología Ambiental e Industrial (GBAI), Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7ma No 43-82, Edifício 50 Lab. 106, P.O. Box 110-23, Bogotá, DC Colombia
| |
Collapse
|
9
|
Ren Z, Li D, Zhang Z, Sun W, Liu G. Enhancing the relative abundance of comammox nitrospira in ammonia oxidizer community decreases N 2O emission in nitrification exponentially. CHEMOSPHERE 2024; 356:141883. [PMID: 38583528 DOI: 10.1016/j.chemosphere.2024.141883] [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: 01/13/2024] [Revised: 03/28/2024] [Accepted: 04/01/2024] [Indexed: 04/09/2024]
Abstract
Comammox Nitrospira and canonical ammonia-oxidizing bacteria (cAOB) generally coexist in activated sludge. In present study, the effect of comammox Nitrospira on N2O production during nitrification of activated sludge was investigated. Comammox Nitrospira and cAOB were separately enriched in two nitrifying reactors, with respective relative abundance of approximately 98% in ammonia oxidizer community. The N2O emission factor (EF) of nitrification in comammox Nitrospira dominated reactor was 0.35%, consistently lower than that (2.2%) in cAOB dominated reactor. When increasing the relative abundance of comammox Nitrospira in ammonia oxidizer community, the N2O EF of nitrification decreased exponentially, which suggested that comammox Nitrospira not only decreased N2O production directly but also might have reduced N2O yield by cAOB. When cAOB dominated the ammonia oxidizer community of sludge, decreasing pH to 6.3, lowering DO to less than 0.5 mg/L, and increasing nitrite concentration enhanced N2O EF dramatically. When comammox Nitrospira became the dominant ammonia oxidizer, however, the N2O EF correlated to nitrite insignificantly and a low DO of 0.2 mg/L and weakly acidic pH (6.3) decreased N2O EF by approximately 70% and 60%, respectively. These results imply that enhancing the relative abundance of comammox Nitrospira in sludge is an effective way to reducing N2O emissions and can also offset the promoting effects of acidic pH, low DO, and high nitrite concentration on N2O production during nitrification.
Collapse
Affiliation(s)
- Zhichang Ren
- Guangdong Engineering Research Center of Water Treatment Processes and Materials, Guangdong Key Laboratory of Environmental Pollution and Health, and School of Environment, Jinan University, Guangzhou 510632, And Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China
| | - Deyong Li
- Guangdong Engineering Research Center of Water Treatment Processes and Materials, Guangdong Key Laboratory of Environmental Pollution and Health, and School of Environment, Jinan University, Guangzhou 510632, And Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China
| | - Zhuang Zhang
- Guangdong Engineering Research Center of Water Treatment Processes and Materials, Guangdong Key Laboratory of Environmental Pollution and Health, and School of Environment, Jinan University, Guangzhou 510632, And Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China
| | - Weimin Sun
- Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou, 510650, China
| | - Guoqiang Liu
- Guangdong Engineering Research Center of Water Treatment Processes and Materials, Guangdong Key Laboratory of Environmental Pollution and Health, and School of Environment, Jinan University, Guangzhou 510632, And Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China.
| |
Collapse
|
10
|
Han K, Yu P, Lu J, Hao Z, Jiao Y, Ren Y, Zhao Y, Jiang H, Wang J, Hu Z. Nitrogen and nitrous oxides emission characteristics of anoxic/oxic wastewater treatment process under different oxygen regulation strategies. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 919:170802. [PMID: 38342469 DOI: 10.1016/j.scitotenv.2024.170802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/15/2024] [Accepted: 02/06/2024] [Indexed: 02/13/2024]
Abstract
Nitrous oxide (N2O) and nitrogen oxides (NOx) (i.e., nitric oxide (NO) and nitrogen dioxide (NO2)), which could be produced in wastewater treatment process and result in greenhouse effect and atmospheric pollution, respectively, have been studied limitedly in their emission characteristics and transformation mechanisms. In this study, intelligent oxygen regulation was applied in anoxic/oxic wastewater treatment process (I-A/O), and its effects on regulating NOx and N2O transformations were extensively explored by comparing it with conventional A/O process (C-A/O). Results showed that the average emission amounts of N2O and NOx in I-A/O were 7.45 ± 0.66 mg and 1.88 ± 0.10 mg, respectively. Satisfactory reduction of N2O by 29.28 %-45.08 % was achieved in I-A/O compared to that of C-A/O, but together with increased NOx emission by 83.19 %-120.57 %. Pearson correlation and transcriptional analysis suggested that NO2--N reduction in the anoxic phase dominated N2O production, while no significant N2O production in the oxic phase was found. Hence, the reduced N2O production in I-A/O was mainly attributed to its efficient denitrification process. On the other hand, both the anoxic and oxic phases played important roles in NO production. More importantly, sufficient oxygen in I-A/O promoted the ammonia oxidation process, resulting in higher NO emission in I-A/O in the oxic phase. The imbalance in NO and N2O emissions was then amplified by the NOR enzyme, which mediates the conversion of NO to N2O in both the anoxic and oxic phases. Besides, carbon emission reduction by 31.32 %-36.50 % was obtained in I-A/O due to aeration consumption savings and greenhouse gas emissions reduction compared to C-A/O. Overall, intelligent oxygen regulation optimized the nitrogen transformation and achieved carbon emission reduction in A/O process, but special attention should be paid to the associated risk caused by increased NO emissions.
Collapse
Affiliation(s)
- Ke Han
- School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Peihan Yu
- School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Jiaxing Lu
- School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Zeyu Hao
- School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Yang Jiao
- Environment Research Institute, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Yangang Ren
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Yanhui Zhao
- School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Huiqi Jiang
- School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Jinhe Wang
- Resources and Environment Research Institute, School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, China
| | - Zhen Hu
- School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
| |
Collapse
|
11
|
Liu Y, Liu Y, Zhao T, He Y, Zhu T, Chai H, Peng L. Smaller Aerobic Granules Significantly Reduce N 2O Production by Ammonia-Oxidizing Bacteria: Evidences from Biochemical and Isotopic Analyses. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:545-556. [PMID: 38111342 DOI: 10.1021/acs.est.3c06246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
The mitigation of nitrous oxide (N2O) is of primary significance to offset carbon footprints in aerobic granular sludge (AGS) systems. However, a significant knowledge gap still exists regarding the N2O production mechanism and its pathway contribution. To address this issue, the impact of varying granule sizes, dissolved oxygen (DO), and nitrite (NO2-) levels on N2O production by ammonia-oxidizing bacteria (AOB) during nitrification in AGS systems was comprehensively investigated. Biochemical and isotopic experiments revealed that increasing DO or decreasing NO2- levels reduced N2O emission factors (by 13.8 or 19.5%) and production rates (by 0.08 or 0.35 mg/g VSS/h) via weakening the role of the AOB denitrification pathway since increasing DO competed for more electrons required for AOB denitrification. Smaller granules (0.5 mm) preferred to diminish N2O production via enhancing the role of NH2OH pathway (i.e., 59.4-100% in the absence of NO2-), while larger granules (2.0 mm) induced conspicuously higher N2O production via the AOB denitrification pathway (approximately 100% at higher NO2- levels). Nitrifying AGS systems with a unified size of 0.5 mm achieved 42% N2O footprint reduction compared with the system with mixed sizes (0.5-2.0 mm) under optimal conditions (DO = 3.0 mg-O2/L and NO2- = 0 mg-N/L).
Collapse
Affiliation(s)
- Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yingrui Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Tianhang Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yanying He
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Hongxiang Chai
- Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing 400045, China
| | - Lai Peng
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070, China
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070, China
| |
Collapse
|
12
|
Wang JF, Huang JW, Cai ZX, Li QS, Sun YY, Zhou HZ, Zhu H, Song XS, Wu HM. Differential Nitrous oxide emission and microbiota succession in constructed wetlands induced by nitrogen forms. ENVIRONMENT INTERNATIONAL 2024; 183:108369. [PMID: 38070437 DOI: 10.1016/j.envint.2023.108369] [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: 07/25/2023] [Revised: 11/26/2023] [Accepted: 12/03/2023] [Indexed: 01/25/2024]
Abstract
Nitrous oxide (N2O) emission during the sewage treatment process is a serious environmental issue that requires attention. However, the N2O emission in constructed wetlands (CWs) as affected by different nitrogen forms in influents remain largely unknown. This study investigated the N2O emission profiles driven by microorganisms in CWs when exposed to two typical nitrogen sources (NH4+-N or NO3--N) along with different carbon source supply (COD/N ratios: 3, 6, and 9). The results showed that CWs receiving NO3--N caused a slight increase in total nitrogen removal (by up to 11.8 %). This increase was accomplished by an enrichment of key bacteria groups, including denitrifiers, dissimilatory nitrate reducers, and assimilatory nitrate reducers, which enhanced the stability of microbial interaction. Additionally, it led to a greater abundance of denitrification genes (e.g., nirK, norB, norC, and nosZ) as inferred from the database. Consequently, this led to a gradual increase in N2O emission from 66.51 to 486.77 ug-N/(m2·h) as the COD/N ratio increased in CWs. Conversely, in CWs receiving NH4+-N, an increasing influent COD/N ratio had a negative impact on nitrogen biotransformation. This resulted in fluctuating trend of N2O emissions, which decreased initially, followed by an increase at later stage (with values of 122.87, 44.00, and 148.59 ug-N/(m2·h)). Furthermore, NH4+-N in the aquatic improved the nitrogen uptake by plants and promoted the production of more root exudates. As a result, it adjusted the nitrogen-transforming function, ultimately reducing N2O emissions in CWs. This study highlights the divergence in microbiota succession and nitrogen transformation in CWs induced by nitrogen form and COD/N ratio, contributing to a better understanding of the microbial mechanisms of N2O emission in CWs with NH4+-N or NO3--N at different COD/N ratios.
Collapse
Affiliation(s)
- Jun-Feng Wang
- 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
| | - 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
| | - Yun-Yun Sun
- 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
| | - Hui Zhu
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
| | - Xin-Shan Song
- State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, College of Environmental Science and Engineering, Donghua University, Shanghai 201600, China
| | - Hai-Ming Wu
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
| |
Collapse
|
13
|
Liu S, Wu F, Guo M, Zeng M, Liu W, Wang Z, Wu N, Cao J. A comprehensive literature mining and analysis of nitrous oxide emissions from different innovative mainstream anammox-based biological nitrogen removal processes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166295. [PMID: 37586540 DOI: 10.1016/j.scitotenv.2023.166295] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 08/09/2023] [Accepted: 08/12/2023] [Indexed: 08/18/2023]
Abstract
The biological nitrogen removal (BNR) process in wastewater treatment plants generates a substantial volume of nitrous oxide (N2O), which possesses a potent greenhouse gas effect. A limited number of studies have systematically investigated the N2O emissions of anammox-based systems with different BNR processes under mainstream conditions. Based on extensive big data statistical analysis, it had been revealed that simultaneous nitritation, anammox and denitrification (SNAD), partial nitritation anammox (PNA) and partial denitrification anammox (PDA), exhibit significantly lower N2O emission factors when compared to traditional BNR processes. The median values for N2O emission factors were determined to be 1.01 %, 1.15 % and 1.43 % for SNAD, PNA and PDA, respectively. Based on nitrogen removal data and N2O emission factors, the N2O emissions from PNA, SNAD and PDA processes were calculated to be 0.016 g·d-1, 0.037 g·d-1 and 0.008 g·d-1, respectively. Furthermore, the machine learning models (SVM and ANN) exhibited excellent predictive performance for N2O emissions in the BNR processes. However, after removing environmental factors, the R2 value of the SVM model sharply decreased. The SHAP feature analysis demonstrated the significant impact of environmental factors on the accuracy of predictive performance in machine learning models. Spearman correlation analysis was employed to investigate the relationship between N2O emissions and operational factors as well as microbial communities. The results demonstrated a negative correlation between HRT, temperature and C/N with N2O emissions. Moreover, strong associations were observed between Nitrosomonas, Nitrospira, Denitratisoma, Thauera species and N2O emissions. The contribution of N2O production via AOB pathways played a key role that was quantitatively calculated to be 93 %, 80 % and 48 % in the PNA, SNAD and PDA processes, respectively. These findings highlight the potential of these innovative BNR processes in mitigating N2O emissions.
Collapse
Affiliation(s)
- Shuang Liu
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, 300457 Tianjin, China
| | - Fan Wu
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, 300457 Tianjin, China
| | - Mingzhu Guo
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, 300457 Tianjin, China
| | - Ming Zeng
- College of Marine and Environmental Sciences, Tianjin University of Science & Technology, 300457 Tianjin, China.
| | - Wei Liu
- Department F.A. Forel for Environmental and Aquatic Sciences, Faculty of Sciences, University of Geneva, Carl-Vogt 66, CH-1211 Geneva, Switzerland.
| | - Zhiqiang Wang
- College of Engineering and Technology, Tianjin Agricultural University, Tianjin 300384, China
| | - Nan Wu
- College of Engineering and Technology, Tianjin Agricultural University, Tianjin 300384, China
| | - Jingguo Cao
- College of Chemical Engineering and Materials Science, Tianjin University of Science & Technology, 300457 Tianjin, China
| |
Collapse
|
14
|
Wang JF, Cai ZX, Li YH, Sun YY, Wu HM, Song XS, Zhu H. Microbiota and genetic potential for reducing nitrous oxide emissions by biochar in constructed wetlands. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166489. [PMID: 37611707 DOI: 10.1016/j.scitotenv.2023.166489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/26/2023] [Accepted: 08/20/2023] [Indexed: 08/25/2023]
Abstract
The denitrification process in constructed wetlands (CWs) is responsible for most of the nitrous oxide (N2O) emissions, which is an undesired impact on the ecology of sewage treatment systems. This study compared three types of CWs filled with gravel (CW-B), gravel mixed with natural pyrite (CW-BF), or biochar (CW-BC) to investigate their impact on microbiota and genetic potential for N2O generation during denitrification under varying chemical oxygen demand (COD) to nitrate (NO3--N) ratios. The results showed that natural pyrite and biochar were superior in enhancing COD (90.6-91.2 %) and NO3--N removal (90.0-93.5 %) in CWs with a COD/NO3--N ratio of 9. The accumulation of NO2--N during the denitrification process was the primary cause of N2O emission, with the fluxes ranging from 95.6-472.0 μg/(m2·h) in CW-B, 92.9-400 μg/(m2·h) in CW-BF, and 54.0-293.3 μg/(m2·h) in CW-BC. The addition of biochar significantly reduced N2O emissions during denitrification, while natural pyrite had a lesser inhibitory effect on N2O emissions. The three types of substrates also influenced the structure of microbiota in the biofilm, with natural pyrite enriched nitrogen transformation microorganisms, especially for denitrifiers. Notably, biochar significantly enhanced the abundance of nosZ and the ratio of nosZ/(norB + norC), which are critical factors in reducing N2O emissions from CWs. Overall, the results suggest that the biochar-induced changes in microbiota and genetic potential during denitrification play a significant role in preventing N2O production in CWs, especially when treating sewage with a relatively high COD/NO3--N ratio.
Collapse
Affiliation(s)
- Jun-Feng Wang
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, PR China
| | - Ze-Xiang Cai
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, PR China
| | - Yi-Hao Li
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment (MEE), Guangzhou 510655, PR China
| | - Yun-Yun Sun
- Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, PR China
| | - Hai-Ming Wu
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, PR China
| | - Xin-Shan Song
- State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, College of Environmental Science and Engineering, Donghua University, Shanghai 201600, PR China
| | - Hui Zhu
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China.
| |
Collapse
|
15
|
Zhou X, Fujiwara T, Hidaka T, Nishimura F, Nakanishi T, Terada A, Hori T. Evaluation of nitrous oxide emission during ammonia retention from simulated industrial wastewater by microaerobic activated sludge process. WATER RESEARCH 2023; 247:120780. [PMID: 37950949 DOI: 10.1016/j.watres.2023.120780] [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: 07/24/2023] [Revised: 10/07/2023] [Accepted: 10/22/2023] [Indexed: 11/13/2023]
Abstract
Considering the reciprocating processes of nitrogen gas (N2) fixation to ammonia (NH4-N) and NH4-N removal to N2 through nitrification and denitrification during wastewater treatment, a microaerobic activated sludge process (MAS) is proposed in this study as a pretreatment to retain NH4-N from high-strength nitrogenous wastewater for further NH4-N recovery through membrane technology, that is, inhibit nitrification, with sufficient removal of total organic carbon (TOC). With DO and pH control, the 3-reactor bench-scale MAS systems successfully realized an NH4-N retention rate of over 80 %, with TOC removal rates of over 90 %. In addition, the emissions of carbon dioxide (CO2) and nitrous oxide (N2O) during MAS were evaluated. The total N2O emissions were 407 and 475 mg-N/day when pH was controlled at 6.2 (S1) and 6.8 (S2), respectively, with average emission factors to total nitrogen load over 2 % in both systems. Also, the global warming potential of N2O is one order of magnitude larger than that of CO2, indicating the significance of N2O in the MAS process. Therefore, the mechanisms of N2O emission from each reactor were investigated. The first reactor, where most of the TOC was adsorbed, emitted only 1.98 % (S1) and 2.43 % (S2) of the total N2O emissions through the denitrification of nitrite and nitrate (NOx) from the return sludge. The second reactor emitted 79.9 % (S1) and 69.0 % (S2) of the total N2O with the emission rates the same order of magnitude as the NOx production rates. Multiple pathways were considered to contribute to the high N2O emissions, and biotic NH2OH oxidation was one potential pathway at pH 6.2. Finally, the third reactor emitted 9.98 % (S1) and 16.8 % (S2) of the total N2O by nitrifier denitrification. Overall, this study showed that the large N2O emissions under nitrification-inhibiting conditions of the MAS process owed to the incomplete nitrification under acidic conditions and large abundances of denitrifiers. On the other hand, the lower N2O emissions at pH 6.2 evidenced the potential N2O mitigation under slightly more acidic conditions, underlining the necessity of further study on N2O mitigation when adapting to the trend of NH4-N recovery.
Collapse
Affiliation(s)
- Xinyi Zhou
- Graduate School of Global Environmental Studies, Kyoto University, Kyoto University Katsura, Nishikyo, Kyoto 615-8540, Japan
| | - Taku Fujiwara
- Graduate School of Global Environmental Studies, Kyoto University, Kyoto University Katsura, Nishikyo, Kyoto 615-8540, Japan; Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto University Katsura, Nishikyo, Kyoto 615-8540, Japan.
| | - Taira Hidaka
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto University Katsura, Nishikyo, Kyoto 615-8540, Japan
| | - Fumitake Nishimura
- Research Center for Environmental Quality Management, Graduate School of Engineering, Kyoto University, 1-2 Yumihama, Otsu 520-0811, Japan
| | - Tomohiro Nakanishi
- Department of Environmental Engineering, Graduate School of Engineering, Kyoto University, Kyoto University Katsura, Nishikyo, Kyoto 615-8540, Japan
| | - Akihiko Terada
- Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Tomoyuki Hori
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology, Onogawa 16-1, Tsukuba 305-8569, Japan
| |
Collapse
|
16
|
Zhu W, Van Tendeloo M, De Paepe J, Vlaeminck SE. Comparison of typical nitrite oxidizing bacteria suppression strategies and the effect on nitrous oxide emissions in a biofilm reactor. BIORESOURCE TECHNOLOGY 2023; 387:129607. [PMID: 37544532 DOI: 10.1016/j.biortech.2023.129607] [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: 06/24/2023] [Revised: 07/29/2023] [Accepted: 08/01/2023] [Indexed: 08/08/2023]
Abstract
In mainstream partial nitritation/anammox (PN/A), suppression of nitrite oxidizing bacteria (NOB) and mitigation of N2O emissions are two essential operational goals. The N2O emissions linked to three typical NOB suppression strategies were tested in a covered rotating biological contactor (RBC) biofilm system at 21 °C: (i) low dissolved oxygen (DO) concentrations, and treatments with (ii) free ammonia (FA), and (iii) free nitrous acids (FNA). Low emerged DO levels effectively minimized NOB activity and decreased N2O emissions, but NOB adaptation appeared after 200 days of operation. Further NOB suppression was successfully achieved by periodic (3 h per week) treatments with FA (29.3 ± 2.6 mg NH3-N L-1) or FNA (3.1 ± 0.3 mg HNO2-N L-1). FA treatment, however, promoted N2O emissions, while FNA did not affect these. Hence, biofilm PN/A should be operated at relatively low DO levels with periodic FNA treatment to maximize nitrogen removal efficiency while avoiding high greenhouse gas emissions.
Collapse
Affiliation(s)
- Weiqiang Zhu
- Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium; School of Water Conservancy and Environment, University of Jinan, Jinan 250022, PR China
| | - Michiel Van Tendeloo
- Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Jolien De Paepe
- Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium
| | - Siegfried E Vlaeminck
- Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
| |
Collapse
|
17
|
Tsukamoto H, Phan HV, Suenaga T, Yasuda S, Kuroiwa M, Riya S, Ogata A, Hori T, Terada A. Microaerophilic Activated Sludge System for Ammonia Retention toward Recovery from High-Strength Nitrogenous Wastewater: Performance and Microbial Communities. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:13874-13886. [PMID: 37676844 DOI: 10.1021/acs.est.3c03002] [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] [Indexed: 09/09/2023]
Abstract
A transition to ammonia recovery from wastewater has started; however, a technology for sustainable nitrogen retention in the form of ammonia and organic carbon removal is still in development. This study validated a microaerophilic activated sludge (MAS) system to efficiently retain ammonia from high-strength nitrogenous wastewater. The MAS is based on conventional activated sludge (CAS) with aerobic and settling compartments. Low dissolved oxygen (DO) concentrations (<0.2 mg/L) and short solids retention times (SRTs) (<5 days) eliminated nitrifying bacteria. The two parallel MASs were successfully operated for 300 days and had ammonia retention of 101.7 ± 24.9% and organic carbon removal of 85.5 ± 8.9%. The MASs mitigated N2O emissions with an emission factor of <0.23%, much lower than the default value of CAS (1.6%). A short-term step-change test demonstrated that N2O indicated the initiation of nitrification and the completion of denitrification in the MAS. The parallel MASs had comparable microbial diversity, promoting organic carbon oxidation while inhibiting ammonia-oxidizing microorganisms (AOMs), as revealed by 16S rRNA gene amplicon sequencing, the quantitative polymerase chain reaction of functional genes, and fluorescence in situ hybridization of β-proteobacteria AOB. The microbial analyses also uncovered that filamentous bacteria were positively correlated with effluent turbidity. Together, controlling DO and SRT achieved organic carbon removal and successful ammonia retention, mainly by suppressing AOM activity. This process represents a new nitrogen management paradigm.
Collapse
Affiliation(s)
- Hiroki Tsukamoto
- Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-Cho, Koganei, Tokyo 184-8588, Japan
| | - Hop V Phan
- Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-Cho, Koganei, Tokyo 184-8588, Japan
| | - Toshikazu Suenaga
- Global Innovation Research Institute, Tokyo University of Agriculture and Technology, 3-8-1 Harumi-Cho, Fuchu, Tokyo 185-8538, Japan
- Department of Chemical Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi- Hiroshima, Hiroshima 739-8527, Japan
| | - Shohei Yasuda
- Global Innovation Research Institute, Tokyo University of Agriculture and Technology, 3-8-1 Harumi-Cho, Fuchu, Tokyo 185-8538, Japan
| | - Megumi Kuroiwa
- Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-Cho, Koganei, Tokyo 184-8588, Japan
| | - Shohei Riya
- Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-Cho, Koganei, Tokyo 184-8588, Japan
- Global Innovation Research Institute, Tokyo University of Agriculture and Technology, 3-8-1 Harumi-Cho, Fuchu, Tokyo 185-8538, Japan
| | - Atsushi Ogata
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan
| | - Tomoyuki Hori
- Environmental Management Research Institute, National Institute of Advanced Industrial Science and Technology, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan
| | - Akihiko Terada
- Department of Applied Physics and Chemical Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-Cho, Koganei, Tokyo 184-8588, Japan
- Global Innovation Research Institute, Tokyo University of Agriculture and Technology, 3-8-1 Harumi-Cho, Fuchu, Tokyo 185-8538, Japan
| |
Collapse
|
18
|
Wan R, Ge L, Chen B, Tang JM, Tan E, Zou W, Tian L, Li M, Liu Z, Hou L, Yin G, Kao SJ. Permeability decides the effect of antibiotics on sedimentary nitrogen removal in Jiulong River Estuary. WATER RESEARCH 2023; 243:120400. [PMID: 37523923 DOI: 10.1016/j.watres.2023.120400] [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: 05/10/2023] [Revised: 07/21/2023] [Accepted: 07/22/2023] [Indexed: 08/02/2023]
Abstract
Sedimentary denitrification takes place beneath the oxic layer at the sediment-water interface, where nitrate and antibiotics need to diffuse through the overlying water. However, the antibiotics' effect on sedimentary N removal and associated N2O production has not been adequately investigated under in situ conditions. Here, isotope pairing techniques, including slurry incubations (potential) and intact core incubations (in situ), combined with metagenomic analysis were applied to investigate the impacts of two protein-inhibiting antibiotics (oxytetracycline and thiamphenicol) on sediment nitrogen removal in a subtropical estuary. Slurry incubations showed that the two antibiotics significantly inhibited denitrification (67-98%) and anammox (49-99%), while intact core incubations presented no antibiotic effect at upstream but significant inhibition (23%-52%) at downstream. Meanwhile, N2O yields were stimulated up to 20 folds in slurry incubations yet showing insignificant response in intact cores. Such contrasting results between up- and down-stream and between slurry and intact core incubations strongly indicated that permeability, which determines diffusion of antibiotics to microbes, is the key to exert the effect of antibiotics on in situ sedimentary nitrogen removal processes regardless the existence of antibiotics resistance genes. This diffusive obstruction may mitigate the toxic effect of antibiotics on nitrogen removal related microbes in natural environments.
Collapse
Affiliation(s)
- Ru Wan
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Lianghao Ge
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Bin Chen
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Jin-Ming Tang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Ehui Tan
- State Key Laboratory of Marine Resource Utilization in South China Sea, School of Marine Science and Engineering, Hainan University, Haikou, Hainan, China.
| | - Wenbin Zou
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Li Tian
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Meng Li
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, China; Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, China
| | - Zongbao Liu
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University), Ministry of Education, Guilin, Guangxi, China
| | - Lijun Hou
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
| | - Guoyu Yin
- Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China; School of Geographic Sciences, East China Normal University, Shanghai 200241, China
| | - Shuh-Ji Kao
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China; State Key Laboratory of Marine Resource Utilization in South China Sea, School of Marine Science and Engineering, Hainan University, Haikou, Hainan, China.
| |
Collapse
|
19
|
He Y, Liu Y, Li X, Zhu T, Liu Y. Unveiling the roles of biofilm in reducing N 2O emission in a nitrifying integrated fixed-film activated sludge (IFAS) system. WATER RESEARCH 2023; 243:120326. [PMID: 37454457 DOI: 10.1016/j.watres.2023.120326] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 06/07/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023]
Abstract
Biofilm process such as integrated fixed-film activated sludge (IFAS) system has been preliminarily found to produce less nitrous oxide (N2O) than suspended sludge system. However, the N2O emission behaviors and underlying N2O mitigation mechanism in such hybrid system remain unclear. This study therefore aims to fully unveil the roles of biofilm in reducing N2O emission in a nitrifying IFAS system with the aid of some advanced technologies such as N2O microsensor and site-preference analysis. It was found that ammonia oxidation occurred mostly in the sludge flocs (˃ 86%) and biofilm could reduce N2O emission by 43.77% in a typical operating cycle. Biofilm not only reduced nitrite accumulation in nitrification process, inhibiting N2O production via nitrifier denitrification pathway, but also served as a N2O sink, promoting the reduction of N2O via endogenous denitrification. As a result, N2O emissions from the IFAS system were 50%-83% lower than those from the solo sludge flocs. Further, more N2O emission was reduced in the presence of biofilm with decreasing the dissolved oxygen level in the range of 0.5-3.0 mg O2/L. Microbial community and key enzyme analyses revealed that biofilm had relatively high microbial diversity and unique enzyme composition, providing a reasonable explanation for the changed contributions of different N2O production pathways and reduced N2O emission.
Collapse
Affiliation(s)
- Yanying He
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yingrui Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Xuecheng Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China.
| |
Collapse
|
20
|
Chen F, Liu Y, He Y, Chen X, Zhu T, Liu Y. Evaluation of nitrogen removal and nitrous oxide turnovers in granule-based simultaneous nitrification and denitrification system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 873:162446. [PMID: 36841401 DOI: 10.1016/j.scitotenv.2023.162446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 02/11/2023] [Accepted: 02/20/2023] [Indexed: 06/18/2023]
Abstract
Nitrous oxide (N2O) is an inevitable intermediate generated during the nitrogen removal process of granule-based simultaneous nitrification and denitrification (SND) system. In order to alleviate N2O production while maintaining a desired total nitrogen (TN) removal level in this system, a comprehensive evaluation of the contribution pathways and process parameters affecting N2O turnovers is keenly required. Therefore, mathematical models were applied to evaluate the impact of operating conditions and unravel potential mechanisms on TN removal performance and N2O production. Simulation results show that higher N2O production (11.6 %-14.2 %) occurs at higher dissolved oxygen (DO) concentrations, lower chemical oxygen demand (COD) levels, longer hydraulic retention time (HRT) and larger granule size in the granular SND system. The relative conversion rates of nitrogenous components in different regions within the granule influence N2O turnovers, with the nitrification process occurring only in the region 200 μm inward from the granule surface and denitrification working throughout the entire granule. In the inner region of the granule (0-300 μm), the heterotrophic bacteria (HB) denitrification pathway dominates N2O production as a source of N2O. While in the outer region (300-450 μm), HB denitrification acts as a sink for N2O and regulates N2O turnovers (i.e. production and reduction of N2O) together with the hydroxylamine (NH2OH) pathway that is the main contributor of N2O production. Moreover, simultaneous adjustment of multiple operating parameters within a certain range can lower the N2O production factor (<0.5 %) while achieving the desired TN removal efficiency (>80 %), resulting in a feasible N2O mitigation strategy.
Collapse
Affiliation(s)
- Feng Chen
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yingrui Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yanying He
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Xueming Chen
- Fujian Provincial Engineering Research Center of Rural Waste Recycling Technology, College of Environment and Safety Engineering, Fuzhou University, Fujian 350116, China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
| |
Collapse
|
21
|
Wang Y, Peng Y, Lv C, Xu X, Meng H, Zhou Y, Wang G, Lu Y. Quantitative discrimination of algae multi-impacts on N 2O emissions in eutrophic lakes: Implications for N 2O budgets and mitigation. WATER RESEARCH 2023; 235:119857. [PMID: 36924553 DOI: 10.1016/j.watres.2023.119857] [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: 12/21/2022] [Revised: 03/02/2023] [Accepted: 03/07/2023] [Indexed: 06/18/2023]
Abstract
It is generally accepted that eutrophic lakes significantly contribute to nitrous oxide (N2O) emissions. However, how these emissions are affected by the formation, disappearance, and mechanisms of algal blooms in these lakes has not been systematically investigated. This study examined and determined the relative contribution of spatiotemporal N2O production pathways in hypereutrophic Lake Taihu. Synchronously, the multi-impacts of algae on N2O production and release potential were measured in the field and in microcosms using isotope ratios of oxygen (δ18O) and bulk nitrogen (δ15N) to N2O and to intramolecular 15N site preference (SP). Results showed that N2O production in Lake Taihu was derived from microbial effects (nitrification and incomplete denitrification) and water air exchanges. N2O production was also affected by the N2O reduction process. The mean dissolved N2O concentrations in the water column during the pre-outbreak, outbreak, and decay stages of algae accumulation were almost the same (0.05 μmol·L-1), which was 2-10 times higher than in lake areas algae was not accumulating. However, except for the central lake area, all surveyed areas (with and without accumulated algae) displayed strong release potential and acted as the emission source because of dissolved N2O supersaturation in the water column. The mean N2O release fluxes during the pre-outbreak, outbreak, and decay stages of algae accumulation areas were 17.95, 26.36, and 79.32 μmol·m-2·d-1, respectively, which were 2.0-7.5 times higher than the values in the non-algae accumulation areas. In addition, the decay and decomposition of algae released large amounts of nutrients and changed the physiochemical properties of the water column. Additionally, the increased algae biomass promoted N2O release and improved the proportion of N2O produced via denitrification process to being 9.8-20.4% microbial-derived N2O. This proportion became higher when the N2O consumption during denitrification was considered as evidenced by isotopic data. However, when the algae biomass was excessive in hypereutrophic state, the algae decomposition also consumed a large amount of oxygen, thus limiting the N2O production due to complete denitrification as well as due to the limited substrate supply of nitrate by nitrification in hypoxic or anoxic conditions. Further, the excessive algae accumulation on the water surface reduced N2O release fluxes via hindering the migration of the dissolved N2O into the atmosphere. These findings provide a new perspective and understanding for accurately evaluating N2O release fluxes driven by algae processes in eutrophic lakes.
Collapse
Affiliation(s)
- Yiping Wang
- School of Water Resources and Hydropower Engineering, Wuhan University, Wuhan 430072, China; School of Environment, Nanjing Normal University, No.1, Wenyuan Road, Nanjing 210023, China; State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China
| | - Yu Peng
- School of Environment, Nanjing Normal University, No.1, Wenyuan Road, Nanjing 210023, China
| | - Chengxu Lv
- School of Environment, Nanjing Normal University, No.1, Wenyuan Road, Nanjing 210023, China
| | - Xiaoguang Xu
- School of Environment, Nanjing Normal University, No.1, Wenyuan Road, Nanjing 210023, China.
| | - Han Meng
- School of Environment, Nanjing Normal University, No.1, Wenyuan Road, Nanjing 210023, China
| | - Yiwen Zhou
- Department of Chemical Engineering, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan
| | - Guoxiang Wang
- School of Environment, Nanjing Normal University, No.1, Wenyuan Road, Nanjing 210023, China
| | - Yongjun Lu
- State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China
| |
Collapse
|
22
|
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).
Collapse
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
| |
Collapse
|
23
|
Lu H, Wang H, Wu Q, Luo H, Zhao Q, Liu B, Si Q, Zheng S, Guo W, Ren N. Automatic control and optimal operation for greenhouse gas mitigation in sustainable wastewater treatment plants: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 855:158849. [PMID: 36122730 DOI: 10.1016/j.scitotenv.2022.158849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/01/2022] [Accepted: 09/14/2022] [Indexed: 06/15/2023]
Abstract
In order to promote low-carbon sustainable operational management of the wastewater treatment plants (WWTPs), automatic control and optimal operation technologies, which devote to improving effluent quality, operational costs and greenhouse gas (GHG) emissions, have flourished in recent years. There is no consensus on the design procedure for optimal control/operation of sustainable WWTPs. In this review, we summarize recent researches on developing control and optimization strategies for GHG mitigation in WWTPs. Faced with the fact that direct carbon dioxide (CO2) emissions (considered biological origin) are generally not included in the carbon footprint of WWTPs, direct emissions (nitrous oxide (N2O), methane (CH4)) and indirect emissions are paid much attention. Firstly, the plant-wide models with GHG dynamic simulation, which are employed to design and evaluate the automatic control schemes as well as representative studies on identifying key factors affecting GHG emissions or comprehensive performance are outlined. Then, both traditional and advanced control methods commonly used in GHG mitigation are reviewed in detail, followed by the multi-objective optimization practices of control/operational parameters. Based on the mentioned control and (or) optimization strategies, a novel design framework for the optimal control/operation of sustainable WWTPs is proposed. The findings and design framework proposed in the paper will provide guidance for GHG mitigation and sustainable operation in WWTPs. It is foreseeable that more accurate and appropriate plant-wide models together with flexible control methods and intelligent optimization strategies will be developed to satisfy the upgrading requirements of WWTPs in the future.
Collapse
Affiliation(s)
- Hao Lu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Huazhe Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qinglian Wu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Haichao Luo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qi Zhao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Banghai Liu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qishi Si
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shanshan Zheng
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Wanqian Guo
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| |
Collapse
|
24
|
Gao J, Wang R, Li Y, Huang H, Su X, An Z, Yin W, Yang L, Rong L, Sun F. Effect of aeration modes on nitrogen removal and N 2O emission in the partial nitrification and denitrification process for landfill leachate treatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 853:158424. [PMID: 36067854 DOI: 10.1016/j.scitotenv.2022.158424] [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: 07/06/2022] [Revised: 08/26/2022] [Accepted: 08/26/2022] [Indexed: 06/15/2023]
Abstract
The anoxic/multi-aerobic process is widely applied for treating landfill leachate with low carbon to nitrogen ratio. In this study, the effect of two aeration modes in the aerobic phase, i.e. decreasing dissolved oxygen (DO) and increasing DO, on nitrogen removal and N2O emission in the process were systematically compared. The results demonstrate that the aerobic phase with increasing DO mode has a positive effect on improved total nitrogen removal (78 %) under the COD/N ratio as low as 3.45 and minimized N2O emission. DO concentration higher than 1.5 mg/L in the aerobic phase reduced nitrogen removal and led to a significant high N2O emission in the process. Complete nitrite denitrification in the anoxic phase correlated with minimized N2O emission. Under efficient nitrogen removal stage, N2O emission factor was 2.4 ± 1.0 % of the total incoming nitrogen. Microbial analysis revealed that increasing DO mode increased the abundance of ammonia oxidizing bacteria and denitrifiers.
Collapse
Affiliation(s)
- Junliang Gao
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China; Key Laboratory of Environmental Pollution Control Technology Research of Zhejiang Province, Eco-environmental Science Research & Design Institute of Zhejiang Province, Hangzhou 310007, China
| | - Rui Wang
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China
| | - Yilin Li
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China
| | - Huimin Huang
- Zhejiang Huanke Certification Center for Environment Co. Ltd., Hangzhou 310007, China
| | - Xiaomei Su
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China.
| | - Zijing An
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China
| | - Wenjun Yin
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China
| | - Lizhen Yang
- China Wuzhou Engineering Group Co. Ltd., Beijing 100053, China
| | - Liang Rong
- China Wuzhou Engineering Group Co. Ltd., Beijing 100053, China
| | - Faqian Sun
- College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China.
| |
Collapse
|
25
|
Solís B, Guisasola A, Pijuan M, Baeza JA. Exploring GHG emissions in the mainstream SCEPPHAR configuration during wastewater resource recovery. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 849:157626. [PMID: 35901871 DOI: 10.1016/j.scitotenv.2022.157626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
The wastewater sector paradigm is shifting from wastewater treatment to resource recovery. In addition, concerns regarding sustainability during the operation have increased. In this sense, many water utilities have become aware of the potential GHG emissions during the operation of wastewater treatment. This study assesses the nitrous oxide and methane emissions during the long-term operation of a novel wastewater resource recovery facility (WRRF) configuration: the mainstream SCEPPHAR. The long-term N2O and CH4 emission factors calculated were in the low range of the literature, 1 % and 0.1 %, respectively, even with high nitrite accumulation in the case of N2O. The dynamics and possible sources of production of these emissions are discussed. Finally, different aeration strategies were implemented to study the impact on the N2O emissions in the nitrifying reactor. Results showed that operating the pilot-plant under different dissolved oxygen concentrations (between 1 and 3 g O2 m-3) did not have an effect on the N2O emission factor. Intermittent aeration was the aeration strategy that most mitigated the N2O emissions in the nitrifying reactor, obtaining a reduction of 40 % compared to the normal operation of the pilot plant.
Collapse
Affiliation(s)
- Borja Solís
- GENOCOV, Departament d'Enginyeria Química, Biològica i Ambiental, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
| | - Albert Guisasola
- GENOCOV, Departament d'Enginyeria Química, Biològica i Ambiental, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
| | - Maite Pijuan
- Catalan Institute for Water Research (ICRA), Emili Grahit 101, 17003 Girona, Spain; University of Girona, Girona, Spain.
| | - Juan Antonio Baeza
- GENOCOV, Departament d'Enginyeria Química, Biològica i Ambiental, Escola d'Enginyeria, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
| |
Collapse
|
26
|
Ni H, Arslan M, Liang Z, Wang C, Luo Z, Qian J, Wu Z, Gamal El-Din M. Mixotrophic denitrification processes in basalt fiber bio-carriers drive effective treatment of low carbon/nitrogen lithium slurry wastewater. BIORESOURCE TECHNOLOGY 2022; 364:128036. [PMID: 36174892 DOI: 10.1016/j.biortech.2022.128036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/19/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Lithium battery slurry wastewater was successfully treatedby using basalt fiber (BF) bio-carriers in a biological contact oxidation reactor. This resulted in a significant reduction of COD (93.3 ± 0.5 %) and total nitrogen (77.4 ± 1.0 %) at 12 h of HRT and dissolved oxygen (DO) of 0-1 mg/L. The modified Stover-Kincannon model indicated that the total nitrogen removal rate was 4.462 kg/m3/d in R-BF while the substrate maximum specific reaction rate (qmax) in the Monod model was 0.323 mg-N/mgVSS/d. A stable internal environment was established within the bio-nest. Metataxonomic analysis revealed the presence of denitrification and decarbonization bacteria, combined heterotrophic nitrification-aerobic denitrification bacteria, nitrite-oxidizing bacteria, and ammonia-oxidizing bacteria. Functional analysis displayed changes related to (aerobic)chemoheterotrophy, nitrogen respiration, nitrate reduction, respiration/denitrification of nitrite, and nitrate in R-BF. The study proposes a novel approach to achieve denitrification for the treatment of lithium slurry wastewater at low C/N conditions.
Collapse
Affiliation(s)
- Huicheng Ni
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, Jiangsu Province, PR China
| | - Muhammad Arslan
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Zhishui Liang
- School of Civil Engineering, Southeast University, Nanjing 211189, Jiangsu Province, PR China
| | - Chencheng Wang
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu Province, PR China
| | - Zhijun Luo
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu Province, PR China
| | - Junchao Qian
- Jiangsu Key Laboratory for Environment Functional Materials, Suzhou University of Science and Technology, SuZhou 215009, Jiangsu Province, PR China
| | - Zhiren Wu
- School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu Province, PR China
| | - Mohamed Gamal El-Din
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada; School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu Province, PR China.
| |
Collapse
|
27
|
He Y, Liu Y, Yan M, Zhao T, Liu Y, Zhu T, Ni BJ. Insights into N 2O turnovers under polyethylene terephthalate microplastics stress in mainstream biological nitrogen removal process. WATER RESEARCH 2022; 224:119037. [PMID: 36088769 DOI: 10.1016/j.watres.2022.119037] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 08/24/2022] [Accepted: 08/28/2022] [Indexed: 06/15/2023]
Abstract
The ubiquitous microplastics in wastewater have raised growing concerns due to their unintended effects on microbial activities. However, whether and how microplastics affect nitrous oxide (N2O) (a potent greenhouse gas) turnovers in mainstream biological nitrogen removal (BNR) process remain unclear. This work therefore aimed to fill such knowledge gap by conducting both long-term and batch tests. After over 100 days of feeding with wastewater containing polyethylene terephthalate (PET) microplastics (0-500 μg/L), the long-term results showed that both production and reduction of N2O during denitrification were reduced, as well as the N2O production during nitrification. Accordingly, 60% reduction in N2O accumulation and 70% reduction in N2O production were observed in the denitrification and nitrification batch tests, respectively. Nevertheless, the long-term N2O emission factors under PET microplastics stress were comparable to that in the control reactor, mainly because PET microplastics led to more nitrite accumulation in anoxic period. With the aid of online N2O sensors and site-preference analysis, it was demonstrated that the heterotrophic bacteria pathway and ammonia oxidizing bacteria denitrification pathway for N2O production were negatively affected by PET microplastics, whereas a clear increase in the contribution of hydroxylamine pathway (+ 22.9%) was observed. Further investigation revealed that PET microplastics even at environmental level (i.e. 10 μg/L) significantly reshaped the BNR sludge characteristics (e.g. much larger particle size) and microbial communities (e.g. Thauera, Rhodobacte and Nitrospira) as well as the nitrogen metabolism pathways, which were chiefly responsible for the changes of N2O turnovers and N2O production pathways under the PET microplastics stress.
Collapse
Affiliation(s)
- Yanying He
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yingrui Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Min Yan
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Tianhang Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China.
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW, 2007, Australia.
| |
Collapse
|
28
|
Zhao J, Zhao J, Yang W, Hu B, Huang T, Xie S, Lei S, Hou W. Mechanisms of NO and N 2O production by enriched nitrifying sludge in a sequencing batch reactor: Effects of hydroxylamine. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 316:115237. [PMID: 35568014 DOI: 10.1016/j.jenvman.2022.115237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 03/09/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
NO and N2O as important greenhouse gases andtheir production mechanisms during nitrification are not completely understood. This study aimed to analyze the effect of hydroxylamine (NH2OH) on NO and N2O produced by nitrifying bacteria from activated sludge in a sequencing batch reactor (SBR). Experimental results showed that when nitrite (NO2-) accumulated during aerobic ammonia (NH4+) oxidation, N2O was the main product. The total amount of NO and N2O produced by NH2OH oxidation was positively correlated with dissolved oxygen (DO) levels. The imbalance of NH4+ oxidation caused by NH2OH addition was more conducive to the generation of NO and N2O under high DO conditions. When NH2OH was added into the reactor with NO2- as the substrate, the production of NO and N2O under high DO levels was mainly related to NH2OH oxidation. Under low DO conditions, NO and N2O from the biotic/abiotic hybrid pathways were more significant in the reactor of the coexistence of NO2- and NH2OH, which could be mainly caused by the pathways of nitrifier denitrification and abiotic reaction. Besides, limited amount of NO and N2O was generated by heterotrophic denitrification pathway during autotrophic nitrification. The implications for the above results are important for understanding the production of NO and N2O under NH2OH stress in nitrifying sludge reactor.
Collapse
Affiliation(s)
- Junkai Zhao
- School of Water and Environment, Chang'an University, Xi'an, 710064, Shaanxi, China; Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region (Chang'an University), Ministry of Education, Xi'an, 710064, Shaanxi, China
| | - Jianqiang Zhao
- School of Water and Environment, Chang'an University, Xi'an, 710064, Shaanxi, China; Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region (Chang'an University), Ministry of Education, Xi'an, 710064, Shaanxi, China.
| | - Wenjuan Yang
- School of Water and Environment, Chang'an University, Xi'an, 710064, Shaanxi, China.
| | - Bo Hu
- School of Civil Engineering, Chang'an University, Xi'an, 710061, Shaanxi, China
| | - Ting Huang
- School of Civil Engineering, Chang'an University, Xi'an, 710061, Shaanxi, China
| | - Shuting Xie
- School of Water and Environment, Chang'an University, Xi'an, 710064, Shaanxi, China
| | - Shuhan Lei
- School of Water and Environment, Chang'an University, Xi'an, 710064, Shaanxi, China
| | - Wei Hou
- Petro China ChangQing Oilfield Company, Xi'an, 710021, Shaanxi, China
| |
Collapse
|
29
|
Enhancing algal growth and nutrient removal from nitrified anaerobic digestion piggery effluent through process optimization. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
30
|
Boiocchi R, Bertanza G. Evaluating the potential impact of energy-efficient ammonia control on the carbon footprint of a full-scale wastewater treatment plant. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 85:1673-1687. [PMID: 35290239 DOI: 10.2166/wst.2022.052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
An assessment was performed for elucidating the possible impact of different aeration strategies on the carbon footprint of a full-scale wastewater treatment plant. Using a calibrated model, the impact of different aeration strategies was simulated. The ammonia controller tested showed its ability in ensuring effluent ammonia concentrations compliant with regulation along with significant savings on aeration energy, compared to fixed oxygen set point (DOsp) control strategies. At the same time, nitrous oxide emissions increased due to accumulation of nitrification intermediates. Nevertheless, when coupled with the carbon dioxide emissions due to electrical energy consumption for aeration, the overall carbon footprint was only marginally affected. Using the local average CO2 emission factor, ammonia control slightly reduced the carbon footprint with respect to the scenario where DOsp was fixed at 2 mg·L-1. Conversely, no significant change could be detected when compared against the scenarios where the DOsp was fixed. Overall, the actual impact of ammonia control on the carbon footprint compared to other aeration strategies was found to be strictly connected to the sources of energy employed, where the larger amount of low CO2-emitting energy is, the higher the relative increase in the carbon footprint will be.
Collapse
Affiliation(s)
- Riccardo Boiocchi
- DICATAM - Department of Civil, Environmental, Architectural Engineering and Mathematics, Universita degli Studi di Brescia, via Branze 43, 25123, Brescia, Italy E-mail:
| | - Giorgio Bertanza
- DICATAM - Department of Civil, Environmental, Architectural Engineering and Mathematics, Universita degli Studi di Brescia, via Branze 43, 25123, Brescia, Italy E-mail:
| |
Collapse
|
31
|
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.
Collapse
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
| |
Collapse
|
32
|
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.
Collapse
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
| |
Collapse
|
33
|
Bae WB, Park Y, Chandran K, Shin J, Kang SB, Wang J, Kim YM. Temporal triggers of N 2O emissions during cyclical and seasonal variations of a full-scale sequencing batch reactor treating municipal wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 797:149093. [PMID: 34303238 DOI: 10.1016/j.scitotenv.2021.149093] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 07/11/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
To investigate the major triggers of nitrous oxide (N2O) production in a full-scale wastewater treatment plant, N2O emissions and wastewater characteristics (ammonia, nitrite, nitrate, total nitrogen, dissolved inorganic carbon, dissolved organic carbon, pH, temperature, dissolved oxygen and specific oxygen uptake rate), the results of variations in the cycling of a sequential batch reactor (SBR, where only full nitrification was performed), were monitored seasonally for 16 months. Major triggers of N2O production were investigated based on a seasonal measured database using a random forest (RF) model and sensitivity analysis, which was applied to identify important input variables. As the result of seasonal monitoring in the full-scale SBR, the N2O emission factor relative to daily total nitrogen removal ranged from 0.05 to 2.68%, corresponding to a range of N2O production rate from 0.02 to 0.70 kg-N/day. Results from the RF model and sensitivity analysis revealed that emissions during nitrification were directly or indirectly related to nitrite accumulation, temperature, ammonia loading rate and the specific oxygen uptake rate ratio between ammonia oxidizing bacteria and nitrite oxidizing bacteria (sOUR-ratio). However, changes in the microbial community did not significantly impact N2O emissions. Based on these results, the sOUR-ratio could represent the major trigger for N2O emission in a full-scale BNR system: a higher sOUR-ratio value with an average of 3.13 ± 0.23 was linked to a higher N2O production rate with an average value of 1.27 ± 0.12 kg-N/day (corresponding to 3.96 ± 1.20% of N2O emission factor relative to daily TN removal), while a lower sOUR-ratio with an average value of 2.39 ± 0.27 was correlated with a lower N2O production average rate of 0.17 ± 0.11 kg-N/day (corresponding to 0.74 ± 0.69% of N2O emission factor) (p-value = 0.00001, Mann-Whitney test).
Collapse
Affiliation(s)
- Wo Bin Bae
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-Gwagiro, Gwangju 61005, Republic of Korea
| | - Yongeun Park
- School of Civil and Environmental Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Kartik Chandran
- Department of Earth and Environmental Engineering, Columbia University in the City of New York, New York, NY 10027, USA
| | - Jingyeong Shin
- Department of Civil and Environmental Engineering, Hanyang University, Seongdong-gu, Seoul 04763, Republic of Korea
| | - Sung Bong Kang
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdan-Gwagiro, Gwangju 61005, Republic of Korea
| | - Jinhua Wang
- College of Resources and Environment, Shandong Agricultural University, Tai'an 271018, China
| | - Young Mo Kim
- Department of Civil and Environmental Engineering, Hanyang University, Seongdong-gu, Seoul 04763, Republic of Korea.
| |
Collapse
|
34
|
Wan X, Laureni M, Jia M, Volcke EIP. Impact of organics, aeration and flocs on N 2O emissions during granular-based partial nitritation-anammox. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 797:149092. [PMID: 34303231 PMCID: PMC7612980 DOI: 10.1016/j.scitotenv.2021.149092] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 07/11/2021] [Accepted: 07/13/2021] [Indexed: 05/21/2023]
Abstract
Partial nitration-anammox is a resource-efficient technology for nitrogen removal from wastewater. However, the advantages of this nitrogen removal technology are challenged by the emission of N2O, a potent greenhouse gas. In this study, a granular sludge one-stage partial nitritation-anammox reactor comprising granules and flocs was run for 337 days in the presence of influent organics to investigate its effect on N removal and N2O emissions. Besides, the effect of aeration control strategies and flocs removal was investigated as well. The interpretation of the experimental results was complemented with modelling and simulation. The presence of influent organics (1 g COD g-1 N) helped to suppress NOB and significantly reduced the overall N2O emissions while having no significant effect on anammox activity. Besides, long-term monitoring of the reactor indicated that constant airflow rate control resulted in more stable effluent quality and less N2O emissions than DO control. Still, floc removal reduced N2O emissions at DO control but increased N2O emissions at constant airflow rate. Furthermore, anammox bacteria could significantly reduce N2O production during heterotrophic denitrification, likely via competition for NO with heterotrophs. Overall, this study demonstrated that the presence of influent organics together with proper aeration control strategies and floc management could significantly reduce the N2O emissions without compromising nitrogen removal efficiency during one-stage partial nitritation-anammox processes.
Collapse
Affiliation(s)
- Xinyu Wan
- BioCo Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000, Ghent, Belgium
| | - Michele Laureni
- BioCo Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000, Ghent, Belgium; Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, Delft 2629 HZ, the Netherlands
| | - Mingsheng Jia
- BioCo Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000, Ghent, Belgium
| | - Eveline I P Volcke
- BioCo Research Group, Department of Green Chemistry and Technology, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000, Ghent, Belgium.
| |
Collapse
|
35
|
Yan X, Yang J, Guo D, Ma J, Su X, Sun J. Effect of carbon source on nitrous oxide emission characteristics and sludge properties during anoxic/aerobic wastewater treatment process. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:57557-57568. [PMID: 34091848 DOI: 10.1007/s11356-021-14713-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 05/31/2021] [Indexed: 06/12/2023]
Abstract
Carbon sources are an important parameter in wastewater treatment processes and are closely related to treatment efficiency and nitrous oxide (N2O) emissions. In this study, three parallel sequencing batch reactors (SBRs) were processed with acetic acid, propionic acid, and a 1:1 mixture of both acids (calculated in COD) to study the effect of carbon sources on N2O generation and sludge properties (including intracellular polymer content, extracellular polymeric substance (EPS) composition, particle size distribution, settleability, and microbial community structure). The results showed that the highest COD, NH4+-N, and TP removal efficiencies (92.2%, 100%, and 82.3%, respectively) were achieved by the reactor with mixed acid as the carbon source, whereas the reactor using acetic acid had the highest TN removal rate (82.6%) and the lowest N2O-N conversion rate (1.4%, based on TN removal). The reactor with the carbon source of mixed acid produced the highest polyhydroxyalkanoate (PHA) content, which led to an increase in N2O generation from the aerobic denitrification pathway. The SBR with mixed acid carbon source also had the highest concentration of EPS, which resulted in the largest particle size and the lowest settleability of sludge flocs among the SBRs. Microbial analysis results revealed that the difference in carbon sources resulted in a variation in the microbial community as well as in the relative abundances of functional microbes involved in biological nitrogen removal processes. The mixed acid promoted the development of ammonia-oxidizing bacteria (AOB), which conducted the primary N2O generation pathway of aerobic denitrification bioreactions. The carbon source of acetic acid promoted the growth of denitrifying bacteria (DNB), which led to the highest TN removal rate. This study provides a comprehensive understanding of the effects of carbon sources on N2O generation and sludge properties for WWTPs.
Collapse
Affiliation(s)
- Xu Yan
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China.
| | - Jie Yang
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Dongli Guo
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jiahui Ma
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Xianfa Su
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jianhui Sun
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| |
Collapse
|
36
|
Liu X, Zhang Y, Li Z, Li P, Xu G, Cheng Y, Zhang T. Response of water quality to land use in hydrologic response unit and riparian buffer along the Dan River, China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:28251-28262. [PMID: 33532999 DOI: 10.1007/s11356-021-12636-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 01/20/2021] [Indexed: 06/12/2023]
Abstract
Land uses determine water quality within riparian environments to a certain extent and directly affect human health via drinking water. The main objective of this paper is to investigate the influences of land use, both in hydrologic response units (HRUs) and 200-m-wide buffer areas, on surface water quality. The variations and interrelationships between water physicochemical properties and land uses were assessed for better management of water environment. Nitrogen was the dominant nutrient and was significantly correlated with other water quality parameters. In the HRUs and buffer areas, the dominant landscape was grassland and farmland, respectively. Total organic carbon (TOC) and dissolved oxygen (DO) had negative correlation with land use factors; nitrate nitrogen, total nitrogen, total phosphorus, electrical conductivity, and temperature, in contrast, were positively correlated with them. Industrial and residential land was the critical land use for the aquatic environment in the Dan River, indicating that point pollution should receive more attention. Vegetation area had strong regression relationships with TOC and DO. Furthermore, more specific types of land use (subcategory classification) had a greater role in water quality. The land use in buffers can act on the water body more directly and effectively.
Collapse
Affiliation(s)
- Xiaojun Liu
- Key Laboratory of Silviculture, College of Forestry, Jiangxi Agricultural University, Nanchang, 330045, Jiangxi, China
| | - Yi Zhang
- State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area at XAUT, Xi'an, 710048, Shaanxi, China
| | - Zhanbin Li
- State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area at XAUT, Xi'an, 710048, Shaanxi, China
| | - Peng Li
- State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area at XAUT, Xi'an, 710048, Shaanxi, China.
- Xi'an University of Technology, No. 5, South Jinhua Road, Xi'an, 710048, Shaanxi, China.
| | - Guoce Xu
- State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area at XAUT, Xi'an, 710048, Shaanxi, China
| | - Yuting Cheng
- State Key Laboratory Base of Eco-Hydraulic Engineering in Arid Area at XAUT, Xi'an, 710048, Shaanxi, China
| | - Tiegang Zhang
- Institute of Water Resources for Pastoral Area, MWR, Huhhot, 010020, Inner Mongolia Autonomous Region, China
| |
Collapse
|
37
|
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.
Collapse
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
| |
Collapse
|
38
|
Liu G, Wu X, Li D, Jiang L, Huang J, Zhuang L. Long-Term Low Dissolved Oxygen Operation Decreases N 2O Emissions in the Activated Sludge Process. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:6975-6983. [PMID: 33904707 DOI: 10.1021/acs.est.0c07279] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nitrous oxide (N2O) is an important greenhouse gas and a dominant ozone-depleting substance. Nitrification in the activated sludge process (ASP) is an important N2O emission source. This study demonstrated that a short-term low dissolved oxygen (DO) increased the N2O emissions by six times, while long-term low DO operation decreased the N2O emissions by 54% (P < 0.01). Under long-term low DO, the ammonia oxidizer abundance in the ASP increased significantly, and thus, complete nitrification was recovered and no NH3 or nitrite accumulated. Moreover, long-term low DO decreased the abundance of ammonia-oxidizing bacteria (AOB) by 28%, while increased the abundance of ammonia-oxidizing archaea (AOA) by 507%, mainly due to their higher oxygen affinity. As a result, AOA outnumbered AOB with the AOA/AOB amoA gene ratio increasing to 19.5 under long-term low DO. The efficient nitrification and decreased AOB abundance might not increase N2O production via AOB under long-term low DO conditions. The enriched AOA could decrease the N2O emissions because they were reported to lack canonical nitric oxide (NO) reductase genes that convert NO to N2O. Probably because of AOA enrichment, the positive and significant (P = 0.02) correlation of N2O emission and nitrite concentration became insignificant (P = 0.332) after 80 days of low DO operation. Therefore, ASPs can be operated with low DO and extended sludge age to synchronously reduce N2O production and carbon dioxide emissions owing to lower aeration energy without compromising the nitrification efficiency.
Collapse
Affiliation(s)
- Guoqiang Liu
- School of Environment, Guangdong Engineering Research Center of Water Treatment Processes and Materials and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China
| | - Xianwei Wu
- School of Environment, Guangdong Engineering Research Center of Water Treatment Processes and Materials and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China
| | - Deyong Li
- School of Environment, Guangdong Engineering Research Center of Water Treatment Processes and Materials and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China
| | - Lugao Jiang
- School of Environment, Guangdong Engineering Research Center of Water Treatment Processes and Materials and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China
| | - Ju Huang
- School of Environment, Guangdong Engineering Research Center of Water Treatment Processes and Materials and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China
| | - Li Zhuang
- School of Environment, Guangdong Engineering Research Center of Water Treatment Processes and Materials and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China
| |
Collapse
|
39
|
Li D, Fang F, Liu G. Efficient Nitrification and Low-Level N 2O Emission in a Weakly Acidic Bioreactor at Low Dissolved-Oxygen Levels Are Due to Comammox. Appl Environ Microbiol 2021; 87:e00154-21. [PMID: 33975896 PMCID: PMC8208134 DOI: 10.1128/aem.00154-21r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/13/2021] [Indexed: 01/31/2023] Open
Abstract
Nitrification is an essential process for nutrient removal from wastewater and an important emission source of nitrous oxide (N2O), which is a powerful greenhouse gas and a dominant ozone-depleting substance. In this study, nitrification and N2O emissions were tested in two weakly acidic (pH 6.3 to 6.8) reactors: one with dissolved oxygen (DO) at over 2.0 mg/liter and the other with DO at approximately 0.5 mg/liter. Efficient nitrification was achieved in both reactors. Compared to that in the high-DO reactor, N2O emission in the low-DO reactor decreased slightly, by 20%, and had insignificant correlation with the fluctuations of DO (P = 0.935) and nitrite (P = 0.713), indicating that N2O might not be produced mainly via nitrifier denitrification. Based on quantitative PCR (qPCR), quantitative fluorescent in situ hybridization (qFISH), and functional gene amplicon and metagenome sequencing, it was found that complete ammonia oxidizers (comammox), i.e., Nitrospira organisms, significantly outnumbered canonical ammonia-oxidizing bacteria (AOB) in both weakly acidic reactors, especially in the low-DO reactor with the comammox/AOB amoA gene ratio increasing from 6.6 to 17.1. Therefore, it was speculated that the enriched comammox was the primary cause for the slightly decreased N2O emission under long-term low DO in the weakly acidic reactor. This study demonstrated that the comammox Nitrospira can survive well under the weakly acidic and low-DO conditions, implying that achieving efficient nitrification with low N2O emission as well as low energy and alkalinity consumption is feasible for wastewater treatment.IMPORTANCE Nitrification in wastewater treatment is an important process for eutrophication control and an emission source for the greenhouse gas N2O. The nitrifying process is usually operated at a slightly alkaline pH and high DO (>2 mg/liter) to ensure efficient nitrification. However, it consumes a large amount of energy and chemicals, especially for wastewater without sufficient alkalinity. This paper demonstrates that comammox can adapt well to the weakly acidic and low-DO bioreactors, with a result of efficient nitrification and low N2O emission. These findings indicate that comammox organisms are significant for sustainable wastewater treatment, which provides an opportunity to achieve efficient nitrification with low N2O production as well as low energy and chemical consumption simultaneously.
Collapse
Affiliation(s)
- Deyong Li
- School of the Environment, Guangdong Engineering Research Center of Water Treatment Processes and Materials, Jinan University, Guangzhou, China
- School of the Environment, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, China
| | - Fang Fang
- College of the Environment and Ecology, Chongqing University, Chongqing, China
| | - Guoqiang Liu
- School of the Environment, Guangdong Engineering Research Center of Water Treatment Processes and Materials, Jinan University, Guangzhou, China
- School of the Environment, Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, China
| |
Collapse
|
40
|
Efficient nitrification and low N 2O emission in a weakly acidic bioreactor at low dissolved oxygen levels are due to comammox. Appl Environ Microbiol 2021; 87:AEM.00154-21. [PMID: 33741624 DOI: 10.1128/aem.00154-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Nitrification is an essential process for nutrient removal from wastewater and an important emission source of nitrous-oxide (N2O), which is a powerful greenhouse gas and a dominant ozone-depleting substance. In this study, nitrification and N2O emissions were tested in two weakly acidic (pH = 6.3-6.8) reactors: one with dissolved oxygen (DO) over 2.0 mg/L and the other with DO approximately 0.5 mg/L. Efficient nitrification was achieved in both reactors. Compared to the high-DO reactor, N2O emission in the low-DO reactor decreased slightly by 20% and had insignificant correlation with the fluctuations of DO (P = 0.935) and nitrite (P = 0.713), indicating that N2O might not be mainly produced via nitrifier denitrification. Based on qPCR, qFISH, functional gene amplicon and metagenome sequencing, it was found that complete ammonia oxidizer (comammox) Nitrospira significantly outnumbered canonical ammonia-oxidizing bacteria (AOB) in both weakly acidic reactors, especially in the low DO reactor with the comammox/AOB amoA gene ratio increasing from 6.6 to 17.1. Therefore, it was speculated that the enriched comammox was the primary cause for the slightly decreased N2O emission under long-term low DO in weakly acidic reactor. This study demonstrated that comammox Nitrospira can survive well under the weakly acidic and low-DO conditions, implying that achieving efficient nitrification with low N2O emission as well as low energy and alkalinity consumption is feasible for wastewater treatment.ImportanceNitrification in wastewater treatment is an important process for eutrophication control and an emission source for greenhouse gas of N2O. The nitrifying process is usually operated at a slightly alkaline pH and high DO (>2 mg/L) to ensure efficient nitrification. However, it consumes a large amount of energy and chemicals especially for wastewater without sufficient alkalinity. This manuscript demonstrated that comammox can adapt well to the weakly acidic and low-DO bioreactors, with a result of efficient nitrification and low N2O emission. These findings indicate that comammox are significant for sustainable wastewater treatment, which provides an opportunity to achieve efficient nitrification with low N2O production as well as low energy and chemical consumption simultaneously.
Collapse
|
41
|
A review of partial nitrification in biological nitrogen removal processes: from development to application. Biodegradation 2021; 32:229-249. [PMID: 33825095 DOI: 10.1007/s10532-021-09938-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/24/2021] [Indexed: 10/21/2022]
Abstract
To further reduce the energy consumption in the wastewater biological nitrogen removal process, partial nitrification and its integrated processes have attracted increasing attentions owing to their economy and efficiency. Shortening the steps of ammonia oxidation to nitrate saves a large amount of aeration, and the accumulated nitrite could be reduced by denitritation or anammox, which requires less electron donors compared with denitrification. Therefore, the strategies through mainstream suppression and sidestream inhibition for the achievement of partial nitrification in recent years are reviewed. Specifically, the enrichment strategies of functional microorganisms are obtained on the basis of their growth and metabolic characteristics under different selective pressures. Furthermore, the promising developments, current application bottlenecks and possible future trends of some biological nitrogen removal processes integrating partial nitrification are discussed. The obtained knowledge would provide a new idea for the fast realization of economic, efficient and long-term stable partial nitrification and biological nitrogen removal process.
Collapse
|
42
|
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.
Collapse
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
| |
Collapse
|
43
|
Xiao P, Ai S, Zhou J, Luo X, Kang B, Feng L, Zhao T. N 2O profiles in the enhanced CANON process via long-term N 2H 4 addition: minimized N 2O production and the influence of exogenous N 2H 4 on N 2O sources. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:37188-37198. [PMID: 31748991 DOI: 10.1007/s11356-019-06508-w] [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: 07/14/2019] [Accepted: 09/10/2019] [Indexed: 06/10/2023]
Abstract
Production of the greenhouse gas nitrous oxide (N2O) from the completely autotrophic nitrogen removal over nitrite (CANON) process is of growing concern. In this study, the effect of added hydrazine (N2H4) on N2O production during the CANON process was investigated. Long-term trace N2H4 addition minimized N2O production (0.018% ± 0.013% per unit total nitrogen removed) and maintaining high nitrogen removal capacity of CANON process (nitrogen removal rate and TN removal efficiency was 450 ± 60 mg N/L/day and 71 ± 8%, respectively). Ammonium oxidizing bacteria (AOB) was the main N2O producer. AOB activity inhibition by N2H4 decreased N2O production during aeration, and the N2H4 concentration was negatively correlated with N2O production rate in NH4+ oxidation via AOB, whereas N2O production was facilitated under anaerobic conditions because hydroxylamine (NH2OH) production was accelerated due to anammox bacteria (AnAOB) activity strengthen via N2H4. Added N2H4 completely degraded in the initial aeration phases of the CANON SBR, during which some N2H4 intensified anammox for total nitrogen removal to eliminate N2O production from nitrifier denitrification (ND) by anammox-associated, while the remaining N2H4 competed with NH2OH for hydroxylamine oxidoreductase (HAO) in AOB to inhibit intermediates formation that result in N2O production via NH2OH oxidation (HO) pathway, consequently decreasing total N2O production.
Collapse
Affiliation(s)
- Pengying Xiao
- College of Chemistry and Chemical Engineering, Chongqing University of Technology, No. 69 Hongguang Avenue, Chongqing, 400054, Banan District, People's Republic of China.
| | - Shuo Ai
- College of Chemistry and Chemical Engineering, Chongqing University of Technology, No. 69 Hongguang Avenue, Chongqing, 400054, Banan District, People's Republic of China
| | - Jing Zhou
- College of Chemistry and Chemical Engineering, Chongqing University of Technology, No. 69 Hongguang Avenue, Chongqing, 400054, Banan District, People's Republic of China
| | - Xiaojing Luo
- College of Chemistry and Chemical Engineering, Chongqing University of Technology, No. 69 Hongguang Avenue, Chongqing, 400054, Banan District, People's Republic of China
| | - Baowen Kang
- College of Chemistry and Chemical Engineering, Chongqing University of Technology, No. 69 Hongguang Avenue, Chongqing, 400054, Banan District, People's Republic of China
| | - Li Feng
- Chongqing Academy of Environmental Science, Chongqing, 400054, People's Republic of China
| | - Tiantao Zhao
- College of Chemistry and Chemical Engineering, Chongqing University of Technology, No. 69 Hongguang Avenue, Chongqing, 400054, Banan District, People's Republic of China.
| |
Collapse
|
44
|
Song MJ, Choi S, Bae WB, Lee J, Han H, Kim DD, Kwon M, Myung J, Kim YM, Yoon S. Identification of primary effecters of N 2O emissions from full-scale biological nitrogen removal systems using random forest approach. WATER RESEARCH 2020; 184:116144. [PMID: 32731040 DOI: 10.1016/j.watres.2020.116144] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/30/2020] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
Wastewater treatment plants (WWTPs) have long been recognized as point sources of N2O, a potent greenhouse gas and ozone-depleting agent. Multiple mechanisms, both biotic and abiotic, have been suggested to be responsible for N2O production from WWTPs, with basis on extrapolation from laboratory results and statistical analyses of metadata collected from operational full-scale plants. In this study, random forest (RF) analysis, a machine-learning approach for feature selection from highly multivariate datasets, was adopted to investigate N2O production mechanism in activated sludge tanks of WWTPs from a novel perspective. Standardized measurements of N2O effluxes coupled with exhaustive metadata collection were performed at activated sludge tanks of three biological nitrogen removal WWTPs at different times of the year. The multivariate datasets were used as inputs for RF analyses. Computation of the permutation variable importance measures returned biomass-normalized dissolved inorganic carbon concentration (DIC·VSS-1) and specific ammonia oxidation activity (sOURAOB) as the most influential parameters determining N2O emissions from the aerated zones (or phases) of activated sludge bioreactors. For the anoxic tanks, dissolved-organic-carbon-to-NO2-/NO3- ratio (DOC·(NO2--N + NO3--N)-1) was singled out as the most influential. These data analysis results clearly indicate disparate mechanisms for N2O generation in the oxic and anoxic activated sludge bioreactors, and provide evidences against significant contributions of N2O carryover across different zones or phases or niche-specific microbial reactions, with aerobic NH3/NH4+ oxidation to NO2- and anoxic denitrification predominantly responsible from aerated and anoxic zones or phases of activated sludge bioreactors, respectively.
Collapse
Affiliation(s)
- Min Joon Song
- Department of Civil and Environmental Engineering, KAIST, Daejeon, 34141, Republic of Korea
| | - Sangki Choi
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea
| | - Wo Bin Bae
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea
| | - Jaejin Lee
- Department of Agricultural and Biosystems Engineering, Iowa State University, Ames, IA, 50011, United states
| | - Heejoo Han
- Department of Civil and Environmental Engineering, KAIST, Daejeon, 34141, Republic of Korea
| | - Daehyun D Kim
- Department of Civil and Environmental Engineering, KAIST, Daejeon, 34141, Republic of Korea
| | - Miye Kwon
- Department of Civil and Environmental Engineering, KAIST, Daejeon, 34141, Republic of Korea
| | - Jaewook Myung
- Department of Civil and Environmental Engineering, KAIST, Daejeon, 34141, Republic of Korea
| | - Young Mo Kim
- Department of Civil and Environmental Engineering, Hanyang University, Seongdong-gu, Seoul, 04763, Republic of Korea
| | - Sukhwan Yoon
- Department of Civil and Environmental Engineering, KAIST, Daejeon, 34141, Republic of Korea.
| |
Collapse
|
45
|
Xiang Y, Shao Z, Chai H, Ji F, He Q. Functional microorganisms and enzymes related nitrogen cycle in the biofilm performing simultaneous nitrification and denitrification. BIORESOURCE TECHNOLOGY 2020; 314:123697. [PMID: 32593105 DOI: 10.1016/j.biortech.2020.123697] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/11/2020] [Accepted: 06/13/2020] [Indexed: 06/11/2023]
Abstract
Simultaneous nitrification and denitrification (SND) is a potential energy-saving process in wastewater treatment while the nitrogen removal mechanism is still unclear due to the lack of information about the functional microbes and enzymes. Sequencing batch biofilm reactors were implemented to achieve efficient SND. Eight nitrogen removal related microorganisms out of the top abundant 20 microbial community and reference species were used to construct a phylogenetic tree. Functional enzymes and modules analysis were investigated to reveal the SND pathway: in the aerobic part of the biofilm, ammonia oxidation was catalyzed by complete ammonia oxidizers while in the inner anoxic part, denitrification, dissimilatory nitrate reduction (DNRA) and nitrogen fixation (NF) cooperated to stimulate nitrate removal. These results provide a practical aeration control strategy to achieve SND and indicate that DNRA and NF are important nitrogen removal pathways that should not be ignored in the SND mechanism.
Collapse
Affiliation(s)
- Yu Xiang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China
| | - Zhiyu Shao
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China
| | - Hongxiang Chai
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China.
| | - Fangying Ji
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China
| | - Qiang He
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China
| |
Collapse
|
46
|
Chen H, Zeng L, Wang D, Zhou Y, Yang X. Recent advances in nitrous oxide production and mitigation in wastewater treatment. WATER RESEARCH 2020; 184:116168. [PMID: 32683143 DOI: 10.1016/j.watres.2020.116168] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/17/2020] [Accepted: 07/10/2020] [Indexed: 05/21/2023]
Abstract
Nitrous oxide (N2O) emitted from wastewater treatment plants has caused widespread concern. Over the past decade, people have made tremendous efforts to discover the microorganisms responsible for N2O production, elucidate metabolic pathways, establish production models and formulate mitigation strategies. The ultimate goal of all these efforts is to shed new light on how N2O is produced and how to reduce it, and one of the best ways is to find key opportunities by integrating the information obtained. This review article critically evaluates the knowledge gained in the field within a decade, especially in N2O production microbiology, biochemistry, models and mitigation strategies, with a focus on denitrification. Previous research has greatly deepened the understanding of the N2O generation mechanism, but further efforts are still needed due to the lack of standardized methodology for establishing N2O mitigation strategies in full-scale systems. One of the challenges seems to be to convert the denitrification process from a net N2O source into an effective sink, which is recommended as a key opportunity to reduce N2O production in this review.
Collapse
Affiliation(s)
- Hongbo Chen
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China.
| | - Long Zeng
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Dongbo Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China.
| | - Yaoyu Zhou
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Xiao Yang
- Korea Biochar Research Center, O-Jeong Eco-Resilience Institute & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, South Korea
| |
Collapse
|
47
|
Liu Y, Zhao T, Su Z, Zhu T, Ni BJ. Evaluating the roles of coexistence of sludge flocs on nitrogen removal and nitrous oxide production in a granule-based autotrophic nitrogen removal system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 730:139018. [PMID: 32413601 DOI: 10.1016/j.scitotenv.2020.139018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/24/2020] [Accepted: 04/24/2020] [Indexed: 06/11/2023]
Abstract
Certain levels of sludge flocs would always coexist in granule-based reactors due to the biomass detachment from granules. Such inevitable coexistence could affect both total nitrogen (TN) removal and nitrous oxide (N2O) production in autotrophic nitrogen removal systems. This work utilized a mathematical approach to systematically study the influence of the coexisting sludge flocs on TN removal and N2O production in a granular nitritation-anaerobic ammonium oxidation (Anammox) process for the first time, based on a 2-pathway N2O production model concept. The modelling results reveal that the highest TN removal efficiency decreases from ca. 87-88% to ca. 41-49% as the fraction of sludge flocs in the system increases from 10% to 40%, while the N2O production rate gradually increases with such increase. Meanwhile, both bulk dissolved oxygen (DO, 0.05-0.3 mg/L) and the size of granule (200-400 μm) could also influence the TN removal efficiency and N2O production. As the fraction of sludge flocs increases from 10% to 40%, the contribution of granular biomass to total N2O production is reduced due to increase of N2O-producing ammonia-oxidizing bacteria (AOB) in the sludge flocs, and the increase of granule size could intensify such decrease. In addition, the hydroxylamine oxidation pathway dominates the nitrifier denitrification pathway in both granules and sludge flocs under various testing conditions, whereas the increasing contribution of the latter would occur at a certain DO range, higher fraction of sludge flocs and smaller granule size. These results disclose an important influence of the coexisting sludge flocs on the performance of granular nitritation-Anammox systems.
Collapse
Affiliation(s)
- Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; Academy of Environment and Ecology, Tianjin University, Tianjin 300072, China
| | - Tianhang Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Zhongxian Su
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Bing-Jie Ni
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| |
Collapse
|
48
|
Nonfodji OM, Fatombi JK, Ahoyo TA, Boya B, Baba-Moussa LS, Aminou T. Effects of KMnO4 amounts on antibacterial properties of activated carbon for efficient treatment of northern Benin hospital wastewater in a fixed bed column system. Int J Hyg Environ Health 2020; 229:113581. [PMID: 32771934 DOI: 10.1016/j.ijheh.2020.113581] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 05/21/2020] [Accepted: 05/26/2020] [Indexed: 11/27/2022]
Abstract
In this study, the wastewater from the Departmental Hospital Center of Atacora in Benin was characterized and then treated with activated carbon/potassium permanganate (AC/KMnO4) composite in a fixed bed column system. The AC/KMnO4 composites with impregnation ratios range 0.025-0.100 were prepared from peanut shell activated carbon and potassium permanganate. The wastewater characteristics revealed that 75% of Escherichia coli strains identified were extended-spectrum lactamases (ESBL) with CTX-M dominance, while 25% of Staphylococcus aureus strains produced Panton and Valentine leucocidin and 77.80% of Salmonella typhi strains were resistant to Trimethoprim/Sulfamethoxazole. The fixed bed column system results showed removal efficiency of 72.18 ± 4.98% turbidity, 63.12 ± 4.11% COD, 0.70 ± 0.04 log10 against E. coli and 3.82 ± 0.01 log10 against S. typhi strains using activated carbon as adsorbent with 0.7 cm bed depth after 3 h of treatment. The composite adsorbent AC/KMnO4 significantly increased the effectiveness of treatment due to the strong oxidant power of KMnO4 in the composite material. The results depicted a removal rate of 83.88 ± 5.00%, 89 ± 1.95%, 90 ± 0.65% turbidity, 66.47 ± 1.62%, 69.82 ± 2.00%, 78.20 ± 2.82% COD, 2.0 ± 0.08 log10, 5.0 ± 0.07 log10 against E. coli and 3.82 ± 0.01 log10 against S. typhi strains using AC/KMnO4 with 0.025, 0.050 and 0.100 ratios respectively at 0.7 cm bed depth. Finally, AC/KMnO4 revealed more adsorption potential and antibacterial property than AC, hence, the composite material could be used as a cost-effective adsorbent for efficient removing of multi-resistant bacteria from hospital wastewater.
Collapse
Affiliation(s)
- Odilon M Nonfodji
- Laboratoire de Chimie de l'Eau et de l'Environnement (LCEE), Ecole Normale Supérieure de Natitingou, UNSTIM, Benin; Laboratoire de Génie de Biologie Humaine, Ecole Polytechnique d'Abomey-Calavi, UAC, Benin
| | - Jacques K Fatombi
- Laboratoire de Chimie de l'Eau et de l'Environnement (LCEE), Ecole Normale Supérieure de Natitingou, UNSTIM, Benin; Laboratoire d'Expertise et de Recherche en Chimie de l'Eau et de l'Environnement (LERCEE), Faculté des Sciences et Techniques, UAC, Benin.
| | - Théodora A Ahoyo
- Laboratoire de Génie de Biologie Humaine, Ecole Polytechnique d'Abomey-Calavi, UAC, Benin
| | - Bawa Boya
- Laboratoire de Biologie et de Typage Moléculaire en Microbiologie, Faculté des Sciences et Techniques, UAC, Benin
| | - Lamine S Baba-Moussa
- Laboratoire de Biologie et de Typage Moléculaire en Microbiologie, Faculté des Sciences et Techniques, UAC, Benin
| | - Taofiki Aminou
- Laboratoire d'Expertise et de Recherche en Chimie de l'Eau et de l'Environnement (LERCEE), Faculté des Sciences et Techniques, UAC, Benin
| |
Collapse
|
49
|
Fang F, Li H, Jiang X, Deng X, Yan P, Guo J, Chen Y, Yang J. Significant N 2O emission from a high rate granular reactor for completely autotrophic nitrogen removal over nitrite. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 266:110586. [PMID: 32392139 DOI: 10.1016/j.jenvman.2020.110586] [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: 01/20/2020] [Revised: 03/29/2020] [Accepted: 04/07/2020] [Indexed: 06/11/2023]
Abstract
Expanded granular sludge bed (EGSB) reactors were rarely applied for complete ammonium removal over nitrite. In this study, a high ammonium loading rate of 3677 mg N/L/d was achieved in an EGSB reactor. Approximately 5.5-8.5% of influent ammonium was converted to nitrous oxide (N2O) that is a potent greenhouse gas. Moreover, the percentage increased linearly with the increase in ammonium load. A model well matched the reactor dynamics. The model indicated that hydroxylamine (NH2OH) oxidation contributed to over 40% of produced N2O, and denitrification by ammonium oxidizing bacteria contributed to N2O emission significantly. Furthermore, the model suggests that a low oxygen concentration can result in a low N2O emission at the cost of a slightly low ammonium removal rate while influent organic matter play a minor role in reducing N2O emission. This study shows that EGSB reactors are effective in ammonium removal. In addition, the emission of N2O is significant.
Collapse
Affiliation(s)
- Fang Fang
- College of Environment and Ecology, Chongqing University, Chongqing, China.
| | - Hanxiang Li
- College of Environment and Ecology, Chongqing University, Chongqing, China
| | - Xin Jiang
- College of Environment and Ecology, Chongqing University, Chongqing, China
| | - Xiongwen Deng
- College of Environment and Ecology, Chongqing University, Chongqing, China
| | - Peng Yan
- College of Environment and Ecology, Chongqing University, Chongqing, China
| | - Jinsong Guo
- College of Environment and Ecology, Chongqing University, Chongqing, China
| | - Youpeng Chen
- College of Environment and Ecology, Chongqing University, Chongqing, China
| | - Jixiang Yang
- College of Environment and Ecology, Chongqing University, Chongqing, China; Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China.
| |
Collapse
|
50
|
Fang F, Li K, Guo JS, Wang H, Zhang P, Yan P. New insights into nitrous oxide emissions in a single-stage CANON process coupled with denitrification: thermodynamics and nitrogen transformation. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2020; 82:157-169. [PMID: 32910800 DOI: 10.2166/wst.2020.344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The dynamic characteristics of N2O emissions and nitrogen transformation in a sequencing batch biofilm reactor (SBBR) using the completely autotrophic nitrogen removal over nitrite (CANON) process coupled with denitrification were investigated via 15N isotope tracing and thermodynamic analysis. The results indicate that the Gibbs free energy (ΔG) values of N2O production by the nitrifier denitrification and heterotrophic denitrification reactions were greater than that of NH2OH oxidation, indicating that N2O was easier to produce via either nitrifier and heterotrophic denitrification than via NH2OH oxidation. Ammonia-oxidizing bacteria (AOB) denitrification exhibited a higher fs 0 (the fraction of electron-donor electrons utilized for cell synthesis) than NH2OH oxidation. Therefore, AOB preferred the denitrification pathway because of its growth advantage when N2O was produced by the AOB. The N2O emissions by hydroxylamine oxidation, AOB denitrification and heterotrophic denitrification in the SBBRs using different C/N ratios account for 5.4-7.6%, 45.2-60.8% and 33.8-47.2% of the N2O produced, respectively. The total N2O emission with C/N ratios of 0, 0.67 and 1 was 228.04, 205.57 and 190.4 μg N2O-N·g-1VSS, respectively. The certain carbon sources aid in the reduction of N2O emissions in the process.
Collapse
Affiliation(s)
- Fang Fang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, No.174, Shazhen Street, Chongqing 400045, China E-mail:
| | - Kai Li
- College of Eco-environment Engineering, Guizhou Minzu University, Huaxi District, Guiyang City, Guizhou 550025, China
| | - Jin-Song Guo
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, No.174, Shazhen Street, Chongqing 400045, China E-mail:
| | - Han Wang
- College of Eco-environment Engineering, Guizhou Minzu University, Huaxi District, Guiyang City, Guizhou 550025, China
| | - Ping Zhang
- College of Eco-environment Engineering, Guizhou Minzu University, Huaxi District, Guiyang City, Guizhou 550025, China
| | - Peng Yan
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, No.174, Shazhen Street, Chongqing 400045, China E-mail:
| |
Collapse
|