1
|
Wang Y, Li G, Ji Q. Aquacultural source of nitrous oxide revealed by nitrogen isotopes. WATER RESEARCH X 2024; 25:100249. [PMID: 39280357 PMCID: PMC11399704 DOI: 10.1016/j.wroa.2024.100249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Revised: 08/06/2024] [Accepted: 08/19/2024] [Indexed: 09/18/2024]
Abstract
The rapid expansion of coastal aquaculture has led to an increase in the coverage of aquaculture ponds, where intense feed-derived nitrogen is causing significant emissions of nitrous oxide (N2O). Multiple N2O production pathways and the relative importance of water column vs. sedimentary production in aquaculture ponds remain uncertain. Clarifying these pathways is vital for sustainable aquaculture development. Using 15N-labeled dissolved inorganic nitrogen, the pathways and rates of N2O production in subtropical aquaculture ponds located in south China, cultivating whiteleg shrimp, Japanese seabass, and giant river prawn, were successfully characterized. Total N2O production rates ranged from 6 to 70 µmol-N m-2 d-1, with the shrimp pond exhibiting the highest total N2O production rates, followed by ponds for seabass and prawn. These differences are primarily due to varying feed amounts causing differences in dissolved nutrients in water column and sediment. Particularly, nutrient and organic matter accumulation at the surface sediment stimulated N2O production. The oxygenated sediment on a centimeter scale could produce substantially more N2O compared to the water column above on a meter scale. Partial denitrification, i.e., nitrate and nitrite reduction to N2O, was more important (> 60 %) for N2O production in aquaculture ponds. The availability of nitrite is likely a major factor driving partial denitrification for both sedimentary and water column N2O production.
Collapse
Affiliation(s)
- Yang Wang
- Earth, Ocean and Atmospheric Sciences Thrust, Function Hub, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou 511458, China
| | - Guangbo Li
- Division of Emerging Interdisciplinary Areas, Academy of Interdisciplinary Studies, The Hong Kong University of Science and Technology, Hong Kong 999077, China
| | - Qixing Ji
- Earth, Ocean and Atmospheric Sciences Thrust, Function Hub, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou 511458, China
- Center for Ocean Research in Hong Kong and Macau, The Hong Kong University of Science and Technology, Hong Kong 999077, China
| |
Collapse
|
2
|
Xiong H, Hu N, Liang Y, Wang Q, Jiang C, Yang Z, Huang L. Greenhouse gas emissions from rotating biological contactors combined with hybrid constructed wetlands treating polluted river. BIORESOURCE TECHNOLOGY 2024; 414:131550. [PMID: 39362344 DOI: 10.1016/j.biortech.2024.131550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2024] [Revised: 09/28/2024] [Accepted: 09/28/2024] [Indexed: 10/05/2024]
Abstract
The rotating biological contactors combined with hybrid constructed wetlands (R-HCWs) has promising treatment performance, however, concerns persisted regarding greenhouse gases (GHGs) emissions. In this study, GHGs in the R-HCWs was evaluated, and results revealed that R-HCWs facilitated nitrogen conversion and provided alternating oxygen environments, thereby promoting the reduction of N2O and CH4 emissions. Therefore, the comprehensive global warming potential (8.7±2.7 g CO2-eq·m-3·d-1) for handling unit volume of river water was low, thus, greater ecological benefits were achieved. The relative abundance of functional microorganisms such as Bacillus, Acinetobacter, Nitrospira and norank_f__norank_o__SBR1031, increased due to warm season, which promoted the nitrogen cycle and N2O emission reduction. Anammox and denitrifying bacteria showed significantly correlated with N2O and CH4 emissions (p < 0.01). This study provides valuable insights for the potential adoption of biological and ecological integrated treatment approach optimized for improving water and mitigating GHGs emissions.
Collapse
Affiliation(s)
- Haifeng Xiong
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, PR China
| | - Ning Hu
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, PR China
| | - Yinkun Liang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, PR China
| | - Qinghua Wang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, PR China
| | - Chunli Jiang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, PR China
| | - Zhimin Yang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, PR China
| | - Lei Huang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, PR China; Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, PR China; Chongqing Engineering Research Center of Rural Cleaner Production, Chongqing 400716, PR China.
| |
Collapse
|
3
|
Xue Y, Zhang C, Li S, Zhou Q, Zhou X, Zhang Y. Enhanced denitrification by graphene oxide-modified cathode for the secondary effluent of wastewater treatment plants in three-dimensional biofilm electrode reactors. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2024; 89:3192-3207. [PMID: 39150420 DOI: 10.2166/wst.2024.179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 05/21/2024] [Indexed: 08/17/2024]
Abstract
In this study, a novel three-dimensional biofilm electrode reactor (3D-BER) with a graphene oxide (GO)-modified cathode was developed to enhance the denitrification performance of secondary effluent from wastewater treatment plants (SEWTPs). The effects of different hydraulic retention times (HRTs) and currents on the 3D-BER were explored. The results indicated that at the optimal HRT of 4 h and current of 350 mA/m2, the 3D-BER with GO-modified cathode had a higher denitrification rate (2.40 ± 0.1 mg TN/L/h) and less accumulation of intermediate products, especially with 3.34% total nitrogen (TN) molar conversion to N2O. The GO-modified cathode offered a large biocompatible specific surface area and enhanced the conductivity, which favored microbial growth and increased electron transfer efficiency and extracellular enzyme activities. Moreover, the activity of nitrite reductase increased more than that of nitrate reductase to accelerate nitrite reduction, thus facilitating the denitrification process. The proposed 3D-BER provided an effective solution to elevate tertiary denitrification in the SEWTP.
Collapse
Affiliation(s)
- Ying Xue
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Chaojie Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China E-mail:
| | - Sibo Li
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Qi Zhou
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Xuefei Zhou
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Yalei Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| |
Collapse
|
4
|
Yang R, Yuan L, Wang R. Enzymatic regulation of N 2O production by denitrifying bacteria in the sludge of biological nitrogen removal process. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 846:157513. [PMID: 35872196 DOI: 10.1016/j.scitotenv.2022.157513] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/14/2022] [Accepted: 07/16/2022] [Indexed: 06/15/2023]
Abstract
This study analyzed the activities of all denitrifying enzymes involved in the denitrification process under different organic loads in a continuously operating sequencing batch reactor (SBR), to reveal how the denitrifying enzymes performed while the denitrifying bacteria facing changes in organic load, and leading to nitrous oxide (N2O) production by fine-tuning enzyme activities. Results show that the activities of nitrate reductase (Nar), nitrite reductase (Nir), nitric oxide reductase (Nor) and nitrous oxide reductase (N2OR) increased with the increase of organic loads, and the increase of the activity of different enzymes promoted by the organic load increase were as Nar > Nir > Nor > N2OR. Compared with the Nar and Nir, the catalytic processes of the Nor and N2OR were more susceptible to the influence of the substrate concentration and the content of internal and external carbon sources. The Nor usually maintained "excess" catalytic activity to ensure the smooth reduction of nitric oxide when the electron donor and substrate were sufficient. Otherwise, it reduced to a relatively lower catalytic activity and remained stable. The activities of the N2OR were generally weaker than that of other denitrifying enzymes. More N2O was produced in the period feeding with low organic loads (COD/NO3--N ≤ 4.9). The mechanism of the enzyme activities (Nor and N2OR) regulating the total concentrations of N2O was clarified. When the organic load was relatively low (COD/NO3--N ≤ 2.5), the N2OR activity was inhibited due to its inability to acquire enough electrons, resulting the production of N2O. When the organic load was moderate (2.5 < COD/NO3--N ≤ 4.9), the N2OR activity was lower than the Nor activity due to the different activation rates of Nor and N2OR by the substrate in bacteria, resulting the production of N2O.
Collapse
Affiliation(s)
- Rui Yang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta road, Xi'an 710055, PR China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, No.13 Yanta road, Xi'an 710055, PR China; Shaanxi Key Lab of Environmental Engineering, Xi'an 710055, PR China
| | - Linjiang Yuan
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta road, Xi'an 710055, PR China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, No.13 Yanta road, Xi'an 710055, PR China; Shaanxi Key Lab of Environmental Engineering, Xi'an 710055, PR China.
| | - Ru Wang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta road, Xi'an 710055, PR China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, No.13 Yanta road, Xi'an 710055, PR China; Shaanxi Key Lab of Environmental Engineering, Xi'an 710055, PR China
| |
Collapse
|
5
|
Yu KH, Can F, Ergenekon P. Nitric oxide and nitrite removal by partial denitrifying hollow-fiber membrane biofilm reactor coupled with nitrous oxide generation as energy recovery. ENVIRONMENTAL TECHNOLOGY 2022; 43:2934-2947. [PMID: 33779527 DOI: 10.1080/09593330.2021.1910348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 03/22/2021] [Indexed: 06/12/2023]
Abstract
Nitrogen oxide (NOx) emissions cause significant impacts on the environment and must therefore be controlled even more stringently. This requires the development of cost-effective removal strategies which simultaneously create value-added by-products or energy from the waste. This study aims to treat gaseous nitric oxide (NO) by hollow-fibre membrane biofilm reactor (HFMBfR) in the presence of nitrite (NO2-) and evaluate nitrous oxide (N2O) emissions formed as an intermediate product during the denitrification process. Accumulated N2O can be utilised in methane oxidation as an oxidant to produce energy. In the first stage of the study, the HFMBfR was operated by feeding only gaseous NO as the nitrogen source. During this period, the best performance was achieved with 92% NO removal efficiency (RE). In the second stage, both NO gas and NO2- were supplied to the system, and 91% NO and 99% NO2- reduction were achieved simultaneously with the maximum N2O generation of 386 ± 31 ppm. Lower influent carbon to nitrogen (C/N) ratios, such as 4.5 and 2.0, and higher NO2--N loading rate of 158 mg N day-1 favoured N2O generation. An improved NO removal rate and N2O accumulation were seen with the increasing amount of PO43- in the medium. The 16S rDNA sequencing analysis revealed that Alicycliphilus denitrificans and Pseudomonas putida were the dominant species. The study shows that an HFMBfR can be successfully used to eliminate both NO2- and gaseous NO and simultaneously generate N2O by adjusting the system parameters such as C/N ratio, NO2- and PO43- loading.
Collapse
Affiliation(s)
- Khin Hnin Yu
- Department of Environmental Engineering, Gebze Technical University, Kocaeli, Turkey
| | - Faruk Can
- Department of Environmental Engineering, Gebze Technical University, Kocaeli, Turkey
- Faculty of Engineering and Natural Sciences, Sabancı University, Istanbul, Turkey
| | - Pınar Ergenekon
- Department of Environmental Engineering, Gebze Technical University, Kocaeli, Turkey
| |
Collapse
|
6
|
Yang Q, Cui B, Zhou Y, Li J, Liu Z, Liu X. Impact of gas-water ratios on N 2O emissions in biological aerated filters and analysis of N 2O emissions pathways. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 723:137984. [PMID: 32213406 DOI: 10.1016/j.scitotenv.2020.137984] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/12/2020] [Accepted: 03/15/2020] [Indexed: 06/10/2023]
Abstract
Biological aerated filter (BAF) is a widely applied biofilm process for wastewater treatment. However, characteristics of nitrous oxide (N2O) production in BAF are rarely reported. In this study, two tandem BAFs treating domestic wastewater were built up, and different gas-water ratios were controlled to explore N2O production pathway. Results showed that N2O production increased with increasing gas-water ratio in both BAFs; higher gas-water ratio promoted more N2O releasing from hydroxylamine oxidation process. To improve nitrogen removal performance and reduce N2O emission, the optimal gas-water ratios for BAF1 and BAF2 were 5:1 and 1.5:1, respectively. Most of N2O was produced from ammonia oxidizing bacteria (AOB) denitrification and hydroxylamine oxidation in BAF1, and heterotrophic denitrification contributed to relieve N2O emission. In BAF2, N2O was emitted from AOB denitrification and hydroxylamine oxidation by 87.8% and 12.2%, respectively. Heterotrophic denitrification is a N2O sink in BAF, causing BAF1 produced less N2O than BAF2 with the same gas-water ratio. Enhancing heterotrophic denitrification and anaerobic ammonium oxidation (Anammox) activity could reduce the release of N2O in BAFs.
Collapse
Affiliation(s)
- Qing Yang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, PR China.
| | - Bin Cui
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, PR China
| | - Yao Zhou
- Beijing Drainage Group Water Design & Research Institute Co., Ltd, Beijing 100022, PR China
| | - Jianmin Li
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, PR China
| | - Zhibin Liu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, PR China
| | - Xiuhong Liu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, PR China
| |
Collapse
|
7
|
Shao X, Zhao L, Sheng X, Wu M. Effects of influent salinity on water purification and greenhouse gas emissions in lab-scale constructed wetlands. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:21487-21496. [PMID: 32274697 DOI: 10.1007/s11356-020-08497-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 03/17/2020] [Indexed: 06/11/2023]
Abstract
Salinity has a significant impact on the sewage treatment efficiency of constructed wetlands (CWs), as well as affecting the greenhouse gas emissions of CWs. A lab-scale CW simulation system was constructed to observe the treatment efficiency and greenhouse gas flux occurring in CWs at different influent salinities (0%, 0.5%, 1.0%, 1.5%, and 2.0%). The results show that (1) the removal rates of COD, TN, NH4+-N, NO3--N, and TP reach the highest at salinity of 0 or 0.5%. And the lowest removal rates are all at a salinity of 2.0%. (2) The emission flux of CO2, CH4, and N2O in CWs varies with an increase in salinity. The trends of CO2 and CH4 emission flux were consistent with those of COD reduction rate. However, it was opposite for N2O flux to that of TN, NH4+-N, and NO3--N removal rate. Affected by salinity, the greenhouse gas emission flux in this study is generally lower than what was reported in literature. (3) Correlation analysis showed that CO2 and CH4 emission fluxes were positively correlated with the COD reduction rate. N2O emission flux was negatively correlated with the removal rates of TN, NH4+-N, and NO3--N. The results suggest that different pollutants are inhibited by salinity to different degrees. COD is more affected by salinity than nitrogen and phosphorus, while nitrogen is more easily inhibited by salinity than phosphorus. CWs can have a high removal rate of pollutants in treating low-salinity wastewater. Although increased salinity reduces treatment efficiency of wastewater to some extent, it also inhibits the emission of CO2 and CH4.
Collapse
Affiliation(s)
- Xuexin Shao
- Wetland Ecosystem Research Station of Hangzhou Bay, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, Zhejiang, China
| | - Linli Zhao
- Wetland Ecosystem Research Station of Hangzhou Bay, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, Zhejiang, China
| | - Xuancai Sheng
- East China Forest Inventory and Planning Institute, State Forestry Administration, Hangzhou, 310019, Zhejiang, China
| | - Ming Wu
- Wetland Ecosystem Research Station of Hangzhou Bay, Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou, 311400, Zhejiang, China.
| |
Collapse
|
8
|
Chen M, Zhou X, Chen X, Cai Q, Zeng RJ, Zhou S. Mechanisms of nitrous oxide emission during photoelectrotrophic denitrification by self-photosensitized Thiobacillus denitrificans. WATER RESEARCH 2020; 172:115501. [PMID: 31954933 DOI: 10.1016/j.watres.2020.115501] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/31/2019] [Accepted: 01/10/2020] [Indexed: 06/10/2023]
Abstract
Photoelectrotrophic denitrification (PEDeN) using bio-hybrids has the potential to remove nitrate (NO3-) from wastewater in an economical and sustainable way. As a gas of global concern, the mechanisms of nitrous oxide (N2O) emissions during this novel process remain unclear. Herein, a self-photosensitized bio-hybrid, i. e., Thiobacillus denitrificans-cadmium sulfide, was constructed and the factors affecting N2O emissions during PEDeN by the bio-hybrids were investigated. The system was sensitive to the input NO3--N and NO2--N, resulting in changes in the N2O/(N2+N2O) ratio from 1% to 95%. In addition to free nitrous acid (FNA), reactive oxidative species (ROS) were a unique factor affecting N2O emission during PEDeN. Importantly, the N2O reduction step exhibited greater susceptibility to the ROS than nitrate reduction step. The contributions of hydrogen peroxide (H2O2), superoxides (O2-•), hydroxyl radicals (•OH) and FNA to the inhibition of N2O reduction were >15.0%, >5.4%, 1.3%, and <70.2%, respectively for a reduction of 13.5 mg/L NO3--N. A significant down-regulation of the relative transcription of the gene nosZ demonstrated that the inhibition of N2O reductase occurred at the gene level. This finding has important implications not only for mitigating N2O emissions during the PEDeN process but also for encouraging a reexamination process of N2O emissions in nature, particularly in systems in which ROS are present during the denitrification process.
Collapse
Affiliation(s)
- Man Chen
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Xiaofang Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Xiangyu Chen
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Quanhua Cai
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Raymond Jianxiong Zeng
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Shungui Zhou
- Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.
| |
Collapse
|
9
|
You QG, Wang JH, Qi GX, Zhou YM, Guo ZW, Shen Y, Gao X. Anammox and partial denitrification coupling: a review. RSC Adv 2020; 10:12554-12572. [PMID: 35497592 PMCID: PMC9051081 DOI: 10.1039/d0ra00001a] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 03/12/2020] [Indexed: 12/02/2022] Open
Abstract
As a new wastewater biological nitrogen removal process, anammox and partial denitrification coupling not only plays a significant role in the nitrogen cycle, but also holds high engineering application value. Because anammox and some denitrifying bacteria are coupled under harsh living conditions, certain operating conditions and mechanisms of the coupling process are not clear; thus, it is more difficult to control the process, which is why the process has not been widely applied. This paper analyzes the research focusing on the coupling process in recent years, including anammox and partial denitrification coupling process inhibitors such as nitrogen (NH4+, NO2−), organics (toxic and non-toxic organics), and salts. The mechanism of substrate removal in anammox and partial denitrification coupling nitrogen removal is described in detail. Due to the differences in process methods, experimental conditions, and sludge choices between the rapid start-up and stable operation stages of the reactor, there are significant differences in substrate inhibition. Multiple process parameters (such as pH, temperature, dissolved oxygen, redox potential, carbon-to-nitrogen ratio, and sludge) can be adjusted to improve the coupling of anammox and partial denitrification to modify nitrogen removal performance. As a new wastewater biological nitrogen removal process, anammox and partial denitrification coupling not only plays a significant role in the nitrogen cycle, but also holds high engineering application value.![]()
Collapse
Affiliation(s)
- Qing-Guo You
- National Research Base of Intelligent Manufacturing Service
- Chongqing Technology and Business University
- Chongqing 400067
- China
- Chongqing South-to-Thais Environmental Protection Technology Research Institute Co., Ltd
| | - Jian-Hui Wang
- National Research Base of Intelligent Manufacturing Service
- Chongqing Technology and Business University
- Chongqing 400067
- China
- Chongqing South-to-Thais Environmental Protection Technology Research Institute Co., Ltd
| | - Gao-Xiang Qi
- National Research Base of Intelligent Manufacturing Service
- Chongqing Technology and Business University
- Chongqing 400067
- China
- Chongqing South-to-Thais Environmental Protection Technology Research Institute Co., Ltd
| | - Yue-Ming Zhou
- National Research Base of Intelligent Manufacturing Service
- Chongqing Technology and Business University
- Chongqing 400067
- China
- Chongqing South-to-Thais Environmental Protection Technology Research Institute Co., Ltd
| | - Zhi-Wei Guo
- National Research Base of Intelligent Manufacturing Service
- Chongqing Technology and Business University
- Chongqing 400067
- China
- Chongqing South-to-Thais Environmental Protection Technology Research Institute Co., Ltd
| | - Yu Shen
- National Research Base of Intelligent Manufacturing Service
- Chongqing Technology and Business University
- Chongqing 400067
- China
- Chongqing South-to-Thais Environmental Protection Technology Research Institute Co., Ltd
| | - Xu Gao
- National Research Base of Intelligent Manufacturing Service
- Chongqing Technology and Business University
- Chongqing 400067
- China
- Chongqing South-to-Thais Environmental Protection Technology Research Institute Co., Ltd
| |
Collapse
|
10
|
Peng B, Liang H, Wang S, Gao D. Effects of DO on N 2O emission during biological nitrogen removal using aerobic granular sludge via shortcut simultaneous nitrification and denitrification. ENVIRONMENTAL TECHNOLOGY 2020; 41:251-259. [PMID: 29962291 DOI: 10.1080/09593330.2018.1494757] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 06/23/2018] [Indexed: 06/08/2023]
Abstract
Dissolved oxygen (DO) is an important factor influencing biological nitrogen removal. This study investigated the effects of different DO concentrations (4, 2, 1 mg/L) on nitrous oxide (N2O) production and nitrogen removal via shortcut simultaneous nitrification and denitrification by aerobic granular sludge (SNDAG) using a sequencing bath reactor. The results showed that N2O production was highest (127.6 mg/m3) at a DO concentration of 2 mg/L; this was 24.17 and 2.90 times the production at DO concentrations of 4 and 12 mg/L, respectively. The removal efficiency of total nitrogen also was the highest (61.68%) when the DO concentration was 2 mg/L, compared to 35.22% and 50.65% at DO concentrations of 4 and 1 mg/L, respectively. The efficiency of the SNDAG process reached 53.86% at a DO concentration of 2 mg/L, which was 1.33 and 1.67 times the efficiencies at DO concentrations of 4 and 1 mg/L, respectively. Therefore, reducing the DO concentration benefited the SNDAG process, but increased the emission of N2O.
Collapse
Affiliation(s)
- Bo Peng
- Center for Ecological Research, Northeast Forestry University, Harbin, People's Republic of China
| | - Hong Liang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, People's Republic of China
| | - Shanshan Wang
- Center for Ecological Research, Northeast Forestry University, Harbin, People's Republic of China
| | - Dawen Gao
- Center for Ecological Research, Northeast Forestry University, Harbin, People's Republic of China
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, People's Republic of China
| |
Collapse
|
11
|
Wang S, Zhao J, Huang T. High NO and N 2O accumulation during nitrite denitrification in lab-scale sequencing batch reactor: influencing factors and mechanism. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:34377-34387. [PMID: 31637614 DOI: 10.1007/s11356-019-06391-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/30/2019] [Indexed: 06/10/2023]
Abstract
Nitrous oxide (N2O) accumulation in biological nitrogen removal has drawn much attention in recent years; however, nitric oxide (NO) accumulation in denitrification was rarely studied. In this study, NO and N2O accumulation during nitrite denitrification in a lab-scale sequencing batch reactor (SBR) were investigated. Results showed that low pH (< 7) and high influent loading (> 360:90) (COD:NO2--N) caused serious NO and N2O accumulation. The maximal NO accumulation of 4.96 mg L-1 was observed at influent loading of 720:180 and the maximal N2O accumulation of 46.29 mg L-1 was found at pH of 6. The NO accumulation was far higher than the values reported in previous studies. In addition, the high NO accumulation could completely inhibit the activities of reductases involved in denitrification. High NO and N2O accumulation were mainly caused by significant free nitrous acid (FNA) and NO inhibition at low pH and high influent loading. There were significant differences on NO and N2O accumulation at different carbon to nitrogen (COD/N). Low COD/N (≤ 4) could mitigate NO accumulation, but led to high N2O accumulation. It is speculated that NO accumulation is related to the rapid denitrification with accumulated electron in anaerobic stage at high COD/N. N2O accumulation is attributed to intense electron competition at low COD/N. High dissolved oxygen (DO) of 4.04 mg L-1 was detected during NO detoxification in this experiment, which is speculated to be partly caused by NO dismutation.
Collapse
Affiliation(s)
- Sha Wang
- School of Environmental Science and Engineering, Chang'an University, Xi'an, 710064, Shaanxi, China
| | - Jianqiang Zhao
- School of Environmental Science and Engineering, Chang'an University, Xi'an, 710064, Shaanxi, China.
- Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of Ministry of Education, Xi'an, 710064, Shaanxi, China.
| | - Ting Huang
- School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an, 710054, Shaanxi, China
| |
Collapse
|
12
|
Zhou N, Dang C, Zhao Z, He S, Zheng M, Liu W, Wang X. Role of sludge retention time in mitigation of nitrous oxide emission from a pilot-scale oxidation ditch. BIORESOURCE TECHNOLOGY 2019; 292:121961. [PMID: 31419708 DOI: 10.1016/j.biortech.2019.121961] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/01/2019] [Accepted: 08/04/2019] [Indexed: 06/10/2023]
Abstract
Nitrous oxide (N2O) emission from wastewater treatment plants (WWTPs) has become a focus of attention due to its significant greenhouse effect. In this study, the role of sludge retention time (SRT) in mitigation of N2O emission from a pilot-scale oxidation ditch was systematically investigated. The activated sludge system that operated at SRT of 25 days demonstrated significantly lower N2O emission factor, higher resistance to ammonia overload and aeration failure shock than those obtained at SRT of 15 days no matter which hydraulic retention time (HRT) was adopted. Batch experiments revealed that nitrifier denitrification (ND) was the primary mechanism of N2O generation. However, more microbes affiliated with Nitrospira genera were harbored in the system at SRT 25 d, which could effectively avoid nitrite accumulation, a key factor promoting N2O generation by ND. PICRUSt results further suggested the system at SRT 25 d possessed higher genetic potential for N2O reduction reflected by the more abundant nitrous-oxide reductase.
Collapse
Affiliation(s)
- Nan Zhou
- MOE Key Laboratory of Regional Energy Systems Optimization, Environmental Research Academy, North China Electric Power University, Beijing 102206, China
| | - Chenyuan Dang
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Zhirong Zhao
- MOE Key Laboratory of Regional Energy Systems Optimization, Environmental Research Academy, North China Electric Power University, Beijing 102206, China
| | - Shishi He
- MOE Key Laboratory of Regional Energy Systems Optimization, Environmental Research Academy, North China Electric Power University, Beijing 102206, China
| | - Maosheng Zheng
- MOE Key Laboratory of Regional Energy Systems Optimization, Environmental Research Academy, North China Electric Power University, Beijing 102206, China.
| | - Wen Liu
- Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Xiangke Wang
- MOE Key Laboratory of Regional Energy Systems Optimization, Environmental Research Academy, North China Electric Power University, Beijing 102206, China
| |
Collapse
|
13
|
Wisniewski K, Kowalski M, Makinia J. Modeling nitrous oxide production by a denitrifying-enhanced biologically phosphorus removing (EBPR) activated sludge in the presence of different carbon sources and electron acceptors. WATER RESEARCH 2018; 142:55-64. [PMID: 29859392 DOI: 10.1016/j.watres.2018.05.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/04/2018] [Accepted: 05/23/2018] [Indexed: 06/08/2023]
Abstract
In this study, the IWA Activated Sludge Model No. 2d (ASM2d) was expanded to identify the most important mechanisms leading to the anoxic nitrous oxide (N2O) production in the combined nitrogen (N) and phosphorus (P) removal activated sludge systems. The new model adopted a three-stage denitrification concept and was evaluated against the measured data from one/two-phase batch experiments carried out with activated sludge withdrawn from a local, large-scale biological nutrient removal wastewater treatment plant. The experiments were focused on investigating the effects of different external carbon sources (acetate, ethanol) and electron acceptors (nitrite, nitrate) on the mechanisms of N2O production in enhanced biological P removal by polyphosphate accumulating organisms (PAOs) and external carbon-based denitrification by ordinary heterotrophic organisms (OHOs). The experimental results explicitly showed that N2O production was predominantly governed by the presence of nitrite in the reactor regardless of the examined carbon source and the ratio COD/N in the reactor. The model was capable of accurately predicting (with R2 > 0.9) the behavior of not only N2O-N, but also NO3-N, NO2-N, soluble COD, and PO4-P. The simulation results revealed that only OHOs were responsible for N2O production, whereas the present denitrifying PAOs reduced only nitrate to nitrite.
Collapse
Affiliation(s)
- K Wisniewski
- Faculty of Civil and Environmental Engineering, Gdansk University of Technology, ul. Narutowicza 11/12, 80-233, Gdansk, Poland.
| | - M Kowalski
- Deptartment of Civil Engineering, University of Manitoba, 15 Gillson Road, R3T 5V6, Winnipeg, Canada
| | - J Makinia
- Faculty of Civil and Environmental Engineering, Gdansk University of Technology, ul. Narutowicza 11/12, 80-233, Gdansk, Poland
| |
Collapse
|
14
|
Sabba F, Terada A, Wells G, Smets BF, Nerenberg R. Nitrous oxide emissions from biofilm processes for wastewater treatment. Appl Microbiol Biotechnol 2018; 102:9815-9829. [DOI: 10.1007/s00253-018-9332-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 08/13/2018] [Accepted: 08/15/2018] [Indexed: 01/21/2023]
|
15
|
Mannina G, Chandran K, Capodici M, Cosenza A, Di Trapani D, van Loosdrecht MCM. Greenhouse gas emissions from membrane bioreactors: analysis of a two-year survey on different MBR configurations. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2018; 78:896-903. [PMID: 30252667 DOI: 10.2166/wst.2018.366] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This study aimed at evaluating the nitrous oxide (N2O) emissions from membrane bioreactors (MBRs) for wastewater treatment. The study investigated the N2O emissions considering multiple influential factors over a two-year period: (i) different MBR based process configurations; (ii) wastewater composition (municipal or industrial); (iii) operational conditions (i.e. sludge retention time, carbon-to-nitrogen ratio, C/N, hydraulic retention time); (iv) membrane modules. Among the overall analysed configurations, the highest N2O emission occurred from the aerated reactors. The treatment of industrial wastewater, contaminated with salt and hydrocarbons, provided the highest N2O emission factor (EF): 16% of the influent nitrogen for the denitrification/nitrification-MBR plant. The lowest N2O emission (EF = 0.5% of the influent nitrogen) was obtained in the biological phosphorus removal-moving bed-MBR plant likely due to an improvement in biological performances exerted by the co-presence of both suspended and attached biomass. The influent C/N ratio has been identified as a key factor affecting the N2O production. Indeed, a decrease of the C/N ratio (from 10 to 2) promoted the increase of N2O emissions in both gaseous and dissolved phases, mainly related to a decreased efficiency of the denitrification processes.
Collapse
Affiliation(s)
- Giorgio Mannina
- Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università degli Studi di Palermo, Viale delle Scienze, Ed. 8, 90128, Palermo, Italy E-mail: ; Department of Earth and Environmental Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA
| | - Kartik Chandran
- Department of Earth and Environmental Engineering, Columbia University, 500 West 120th Street, New York, NY 10027, USA
| | - Marco Capodici
- Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università degli Studi di Palermo, Viale delle Scienze, Ed. 8, 90128, Palermo, Italy E-mail:
| | - Alida Cosenza
- Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università degli Studi di Palermo, Viale delle Scienze, Ed. 8, 90128, Palermo, Italy E-mail:
| | - Daniele Di Trapani
- Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università degli Studi di Palermo, Viale delle Scienze, Ed. 8, 90128, Palermo, Italy E-mail:
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| |
Collapse
|
16
|
Bian R, Sun Y, Li W, Ma Q, Chai X. Co-composting of municipal solid waste mixed with matured sewage sludge: The relationship between N 2O emissions and denitrifying gene abundance. CHEMOSPHERE 2017; 189:581-589. [PMID: 28963975 DOI: 10.1016/j.chemosphere.2017.09.070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 08/27/2017] [Accepted: 09/15/2017] [Indexed: 06/07/2023]
Abstract
Aerobic composting is an alternative measure to the disposal of municipal solid waste (MSW). However, it produces nitrous oxide (N2O), a highly potent greenhouse via microbial nitrification and denitrification. In this study, the effects of matured sewage sludge (MSS) amendment on N2O emissions and the inter-relationships between N2O emissions and the abundance of denitrifying bacteria were investigated during aerobic composting of MSW. The results demonstrated that MSW composting with MSS amendments (C1, and C2, with a MSW to MSS ratio of 2:1 and 4:1, (v/v), respectively) significantly increased N2O emissions during the initial stage, yet contributed to the mitigation of N2O emissions during the cooling and maturation stage. MSS amended composting emitted a total of 18.4%-25.7% less N2O than the control treatment without MSS amendment (CK). Matured sewage sludge amendment also significantly altered the abundance of denitrifying bacteria. The quantification of denitrifying functional genes revealed that the N2O emission rate had a significant positive correlation with the abundance of the nirS, nirK genes in both treatments with MSS amendment. The nosZ/(nirS + nirK) ratio could be a good indicator for predicting N2O emissions. The higher N2O emission rate during the initial stage of composting mixed with MSS was characterized by lower nosZ/(nirS + nirK) ratios, compared to CK treatment. Higher ratios of nosZ/(nirS + nirK) were measured during the cooling and maturation stage in treatments with MSS which resulted in a reduction of the N2O emissions. These results demonstrated that MSS amendment could be a valid strategy for mitigating N2O emissions during MSW composting.
Collapse
Affiliation(s)
- Rongxing Bian
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China
| | - Yingjie Sun
- Department of Environment and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, China.
| | - Weihua Li
- Department of Environment and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, China
| | - Qiang Ma
- Department of Environment and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, China
| | - Xiaoli Chai
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China
| |
Collapse
|
17
|
Li W, Sun Y, Bian R, Wang H, Zhang D. N 2O emissions from an intermittently aerated semi-aerobic aged refuse bioreactor: Combined effect of COD and NH 4+-N in influent leachate. WASTE MANAGEMENT (NEW YORK, N.Y.) 2017; 69:242-249. [PMID: 28811146 DOI: 10.1016/j.wasman.2017.08.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 06/30/2017] [Accepted: 08/09/2017] [Indexed: 06/07/2023]
Abstract
The carbon-nitrogen ratio (COD/NH4+-N) is an important factor affecting nitrification and denitrification in wastewater treatment; this factor also influences nitrous oxide (N2O) emissions. This study investigated two simulated intermittently aerated semi-aerobic aged refuse bioreactors (SAARB) filled with 8-year old aged refuse (AR). The research analyzed how differences in and the combination of influent COD and NH4+-N impact N2O emissions in leachate treatment. Experimental results showed that N2O emissions increased as the influent COD/NH4+-N decreased. The influent COD had a greater effect on N2O emissions than NH4+-N at the same influent ratios of COD/NH4+-N (2.7 and 8.0, respectively). The maximum N2O emission accounted for 8.82±2.65% of the total nitrogen removed from the influent leachate; the maximum level occurred when the COD was 2000mg/L. An analysis of differences in influent carbon sources at the same COD/NH4+-N ratios concluded that the availability of biodegradable carbon substrates (i.e. glucose) is an important factor affecting N2O emissions. At a low influent COD/NH4+-N ratio (2.7), the N2O conversion rate was greater when there were more biodegradable carbon substrates. Although the SAARB included the N2O generation and reduction processes, N2O reduction mainly occurred later in the process, after leachate recirculation. The maximum N2O emission rate occurred in the first hour of single-period (24h) experiments, as leachate contacted the surface AR. In practical SAARB applications, N2O emissions may be reduced by measures such as reducing the initial recirculation loading of NH4+-N substrates, adding a later supplement of biodegradable carbon substrates, and/or prolonging hydraulic retention time (HRT) of influent leachate.
Collapse
Affiliation(s)
- Weihua Li
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China
| | - Yingjie Sun
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China.
| | - Rongxing Bian
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China
| | - Huawei Wang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China
| | - Dalei Zhang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China
| |
Collapse
|
18
|
Du R, Cao S, Li B, Niu M, Wang S, Peng Y. Performance and microbial community analysis of a novel DEAMOX based on partial-denitrification and anammox treating ammonia and nitrate wastewaters. WATER RESEARCH 2017; 108:46-56. [PMID: 27817892 DOI: 10.1016/j.watres.2016.10.051] [Citation(s) in RCA: 278] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 10/19/2016] [Accepted: 10/20/2016] [Indexed: 06/06/2023]
Abstract
In this study, a novel DEAMOX (DEnitrifying AMmonium OXidation) process coupling anammox with partial-denitrification generated nitrite (NO2--N) from nitrate (NO3--N) was developed for simultaneously treating ammonia (NH4+-N) and NO3--N containing wastewaters. The performance was evaluated in sequencing batch reactors (SBRs) with different carbon sources for partial-denitrification: acetate (R1) and ethanol (R2). Long-term operation (180 days) suggested that desirable nitrogen removal was achieved in both reactors. The performance maintained stably in R1 despite the seasonal decrease of temperature (29.2 °C-12.7 °C), and high nitrogen removal efficiency (NRE) of 93.6% on average was obtained with influent NO3--N to NH4+-N ratio (NO3--N/NH4+-N) of 1.0. The anammox process contributed above 95% to total nitrogen (TN) removal in R1 with the nitrate-to-nitrite transformation ratio (NTR) of 95.8% in partial-denitrification. A little lower NRE was observed in R2 with temperature dropped from 90.0% at 22.7 °C to 85.2% at 16.6 °C due to the reduced NTR (87.0%-67.0%). High-throughput sequencing analysis revealed that Thauera genera were dominant in both SBRs (accounted for 61.53% in R1 and 45.17% in R2) and possibly played a key role for partial-denitrification with high NO2--N accumulation. The Denitratisoma capable of complete denitrification (NO3--N→N2) was found in R2 that might lead to lower NTR. Furthermore, different anammox species was detected with Candidatus Brocadia and Candidatus Kuenenia in R1, and only Candidatus Kuenenia in R2.
Collapse
Affiliation(s)
- Rui Du
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovory Engineering, Beijing University of Technology, Beijing 100124, China
| | - Shenbin Cao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Baikun Li
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovory Engineering, Beijing University of Technology, Beijing 100124, China
| | - Meng Niu
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovory Engineering, Beijing University of Technology, Beijing 100124, China
| | - Shuying Wang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovory Engineering, Beijing University of Technology, Beijing 100124, China
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovory Engineering, Beijing University of Technology, Beijing 100124, China.
| |
Collapse
|
19
|
Ribera-Guardia A, Marques R, Arangio C, Carvalheira M, Oehmen A, Pijuan M. Distinctive denitrifying capabilities lead to differences in N2O production by denitrifying polyphosphate accumulating organisms and denitrifying glycogen accumulating organisms. BIORESOURCE TECHNOLOGY 2016; 219:106-113. [PMID: 27479801 DOI: 10.1016/j.biortech.2016.07.092] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/20/2016] [Accepted: 07/22/2016] [Indexed: 06/06/2023]
Abstract
This study aims at investigating the denitrification kinetics in two separate enriched cultures of denitrifying polyphosphate accumulating organisms (dPAO) and denitrifying glycogen accumulating organisms (dGAO) and compare their N2O accumulation potential under different conditions. Two sequencing batch reactors were inoculated to develop dPAO and dGAO enriched microbial communities separately. Seven batch tests with different combinations of electron acceptors (nitrate, nitrite and/or nitrous oxide) were carried out with the enriched biomass from both reactors. Results indicate that in almost all batch tests, N2O accumulated for both cultures, however dPAOs showed a higher denitrification capacity compared to dGAOs due to their higher nitrogen oxides reduction rates. Additionally, the effect of the simultaneous presence of several electron acceptors in the reduction rates of the different nitrogen oxides was also assessed in dPAOs and dGAOs.
Collapse
Affiliation(s)
- Anna Ribera-Guardia
- Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, 17003 Girona, Spain
| | - Ricardo Marques
- UCIBIO, REQUIMTE, Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Corrado Arangio
- Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, 17003 Girona, Spain; Dipartimento di ingegneria civile e architettura (DICAR), Università di Catania, 95100 Catania, Sicily, Italy
| | - Monica Carvalheira
- UCIBIO, REQUIMTE, Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Adrian Oehmen
- UCIBIO, REQUIMTE, Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Maite Pijuan
- Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, 17003 Girona, Spain.
| |
Collapse
|
20
|
Lv Y, Ju K, Wang L, Chen X, Miao R, Zhang X. Effect of pH on nitrous oxide production and emissions from a partial nitritation reactor under oxygen-limited conditions. Process Biochem 2016. [DOI: 10.1016/j.procbio.2016.02.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
21
|
Du R, Peng Y, Cao S, Wang S, Niu M. Characteristic of nitrous oxide production in partial denitrification process with high nitrite accumulation. BIORESOURCE TECHNOLOGY 2016; 203:341-347. [PMID: 26760756 DOI: 10.1016/j.biortech.2015.12.044] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/07/2015] [Accepted: 12/15/2015] [Indexed: 06/05/2023]
Abstract
Nitrous oxide (N2O) production during the partial denitrification process with nitrate (NO3(-)-N) to nitrite (NO2(-)-N) transformation ratio of 80% was investigated in this study. Results showed that N2O was seldom observed before complete depletion of NO3(-)-N, but it was closely related to the reduction of NO2(-)-N rather than NO3(-)-N. High COD/NO3(-)-N was in favor of N2O production in partial denitrification with high NO2(-)-N accumulation. It was seriously enhanced at constant acidic pH due to the free nitrous acid (FNA) inhibition. However, the N2O production was much lower at initial pH of 5.5 and 6.5 due to the pH increase during denitrification process. Significantly, the pH turning point could be chosen as a controlled parameter to denote the end of NO3(-)-N reduction, which could not only achieve high NO2(-)-N accumulation but also decrease the N2O production significantly for practical application.
Collapse
Affiliation(s)
- Rui Du
- Engineering Research Center of Beijing, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China
| | - Yongzhen Peng
- Engineering Research Center of Beijing, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China.
| | - Shenbin Cao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shuying Wang
- Engineering Research Center of Beijing, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China
| | - Meng Niu
- Engineering Research Center of Beijing, Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China
| |
Collapse
|
22
|
Wu C, Shimaoka T, Nakayama H, Komiya T. Kinetics of nitrous oxide production by denitrification in municipal solid waste. CHEMOSPHERE 2015; 125:64-69. [PMID: 25697806 DOI: 10.1016/j.chemosphere.2015.01.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 01/05/2015] [Accepted: 01/16/2015] [Indexed: 06/04/2023]
Abstract
As one of the Nitrous Oxide (N2O) production pathways, denitrification plays an important role in regulating the emission of N2O into the atmosphere. In this study, the influences of different substrate concentrations and transient conditions on the denitrification rate and N2O-reducing activities were investigated. Results revealed that N2O production rates (i.e. denitrification rates) were stimulated by increased total organic carbon (TOC) concentration, while it was restrained under high oxygen concentrations. Moreover, the impact of nitrate concentrations on N2O production rates depended on the TOC/NO3--N ratios. All the N2O production rate data fitted well to a multiplicative Monod equation, with terms describing the influence of TOC and nitrate concentrations, and an Arrhenius-type equation. Furthermore, results demonstrated that high temperatures minimized the N2O-reducing activities in aged municipal solid waste, resulting in an accumulation of N2O. On the other hand, a transient condition caused by changing O2 concentrations may strongly influence the N2O production rates and N2O-reducing activities in solid waste. Finally, based on the results, we believe that a landfill aeration strategy properly designed to prevent rising temperatures and to cycle air injection is the key to reducing emissions of N2O during remediation of old landfills by means of in situ aeration.
Collapse
Affiliation(s)
- Chuanfu Wu
- Department of Environmental Engineering, School of Civil and Environmental Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China; Graduate School of Engineering, Kyushu University, Japan.
| | - Takayuki Shimaoka
- Department of Urban and Environmental Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Hirofumi Nakayama
- Department of Urban and Environmental Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Teppei Komiya
- Department of Urban and Environmental Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| |
Collapse
|
23
|
Rodriguez-Caballero A, Aymerich I, Marques R, Poch M, Pijuan M. Minimizing N2O emissions and carbon footprint on a full-scale activated sludge sequencing batch reactor. WATER RESEARCH 2015; 71:1-10. [PMID: 25577689 DOI: 10.1016/j.watres.2014.12.032] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/26/2014] [Accepted: 12/18/2014] [Indexed: 06/04/2023]
Abstract
A continuous, on-line quantification of the nitrous oxide (N2O) emissions from a full-scale sequencing batch reactor (SBR) placed in a municipal wastewater treatment plant (WWTP) was performed in this study. In general, N2O emissions from the biological wastewater treatment system were 97.1 ± 6.9 g N2O-N/Kg [Formula: see text] consumed or 6.8% of the influent [Formula: see text] load. In the WWTP of this study, N2O emissions accounted for over 60% of the total carbon footprint of the facility, on average. Different cycle configurations were implemented in the SBR aiming at reaching acceptable effluent values. Each cycle configuration consisted of sequences of aerated and non-aerated phases of different time length being controlled by the ammonium set-point fixed. Cycles with long aerated phases showed the largest N2O emissions, with the consequent increase in carbon footprint. Cycle configurations with intermittent aeration (aerated phases up to 20-30 min followed by short anoxic phases) were proven to effectively reduce N2O emissions, without compromising nitrification performance or increasing electricity consumption. This is the first study in which a successful operational strategy for N2O mitigation is identified at full-scale.
Collapse
Affiliation(s)
- A Rodriguez-Caballero
- Catalan Institute for Water Research (ICRA), Emili Grahit Street, 101, H(2)O Building, Scientific and Technological Park of the University of Girona, 17003 Girona, Spain
| | - I Aymerich
- Catalan Institute for Water Research (ICRA), Emili Grahit Street, 101, H(2)O Building, Scientific and Technological Park of the University of Girona, 17003 Girona, Spain
| | - Ricardo Marques
- Catalan Institute for Water Research (ICRA), Emili Grahit Street, 101, H(2)O Building, Scientific and Technological Park of the University of Girona, 17003 Girona, Spain; REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal
| | - M Poch
- Laboratory of Chemical and Environmental Engineering (LEQUIA-UdG), Institute of the Environment, University of Girona, Campus Montilivi s/n, E-17071 Girona, Spain
| | - M Pijuan
- Catalan Institute for Water Research (ICRA), Emili Grahit Street, 101, H(2)O Building, Scientific and Technological Park of the University of Girona, 17003 Girona, Spain.
| |
Collapse
|
24
|
N2O and NO emissions during wastewater denitrification step: Influence of temperature on the biological process. CR CHIM 2015. [DOI: 10.1016/j.crci.2014.11.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
25
|
Ribera-Guardia A, Kassotaki E, Gutierrez O, Pijuan M. Effect of carbon source and competition for electrons on nitrous oxide reduction in a mixed denitrifying microbial community. Process Biochem 2014. [DOI: 10.1016/j.procbio.2014.09.020] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
26
|
Saucedo-Lucero JO, Marcos R, Salvador M, Arriaga S, Muñoz R, Quijano G. Treatment of O₂-free toluene emissions by anoxic biotrickling filtration. CHEMOSPHERE 2014; 117:774-780. [PMID: 25461947 DOI: 10.1016/j.chemosphere.2014.10.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 10/09/2014] [Accepted: 10/11/2014] [Indexed: 06/04/2023]
Abstract
Toluene biotrickling filtration under anoxic denitrifying conditions was evaluated in two identical bioreactors (R1 and R2) operated at liquid recycling rates of 1.3, 2.7 and 5.3 m h−1 and liquid renewal rates of 0 and 0.17 d−1. R1 and R2 achieved a similar maximum elimination capacity (EC ∼30 g m−3 h−1) at the same toluene inlet load (∼50 g m−3 h−1), which was approximately 7 times higher compared with available literature on continuous toluene removal under anoxic conditions. Nevertheless, higher metabolite accumulation was observed in the bioreactor operated without periodical liquid phase renewal (R2), leading to intermittent drops in its toluene removal performance. This is the first work operating an anoxic biotrickling filter at empty bed residence time of 3 min, which is comparable with those employed in conventional aerobic systems. A characterization of the metabolites accumulated in the liquid phase revealed a dynamic metabolite production and degradation.
Collapse
Affiliation(s)
- J Octavio Saucedo-Lucero
- Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain
| | | | | | | | | | | |
Collapse
|
27
|
Zamouche-Zerdazi R, Bencheikh Lehocine M, Meniai AH. Influence of Endogenous OUR Determination on the KLa$${K_L}a$$, Exogenous OUR, Total Oxygen Consumption and Heterotrophic Yield in a Completely Mixed Batch Reactor. INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING 2014. [DOI: 10.1515/ijcre-2014-0069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In wastewater treatment, waste removal and biomass activity are important processes which need to be monitored for a good process control. The difficulties in the interpretation of the total COD, BOD and VSS measurements encouraged the development of respirometric methods for assessing the kinetic constants. Respirometry is an important technique in assessing biological reaction in wastewater treatment.
K
L
a
$${K_L}a$$
, depends on endogenous oxygen uptake rate (OURend), is a key constant in evaluating respirogram-specific parameters. Generally, OURend is assumed constant in the dissolved oxygen equations. However, it is not the case. Consequently, this paper deals with the influence of OURend calculations region on
K
L
a
$${K_L}a$$
determination, exogenous oxygen uptake rate (OURexo), total oxygen consumption and heterotrophic yield (Y
H). It was shown that the value of OURend and
K
L
a
$${K_L}a$$
varied considerably, a maximum of 56%, depending on where to consider C
fin, on the oxygen concentration variation curve. Even though, the variation on OURend and
K
L
a
$${K_L}a$$
is important its influence on Yo/x and Y
H is attenuated to 7.5% and 6%, respectively. This may be due to the local nature of the first parameters (OURend and
K
L
a
$${K_L}a$$
) and the global nature of the later ones. Moreover, this can be seen through the variation of the calculated amount of oxygen consumed (QThete) which is of the order 7.6%.
Collapse
Affiliation(s)
- R. Zamouche-Zerdazi
- Laboratoire de l’Ingénierie des Procédés d’Environnement “LIPE”, Faculté de Génie de Procédés Pharmaceutiques, Université Constantine 3, 25000 Algérie
| | - M. Bencheikh Lehocine
- Laboratoire de l’Ingénierie des Procédés d’Environnement “LIPE”, Faculté de Génie de Procédés Pharmaceutiques, Université Constantine 3, 25000 Algérie
| | - A.-H. Meniai
- Laboratoire de l’Ingénierie des Procédés d’Environnement “LIPE”, Faculté de Génie de Procédés Pharmaceutiques, Université Constantine 3, 25000 Algérie
| |
Collapse
|
28
|
Wang YN, Sun YJ, Wang L, Sun XJ, Wu H, Bian RX, Li JJ. N₂O emission from a combined ex-situ nitrification and in-situ denitrification bioreactor landfill. WASTE MANAGEMENT (NEW YORK, N.Y.) 2014; 34:2209-2217. [PMID: 25062936 DOI: 10.1016/j.wasman.2014.06.023] [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: 03/19/2014] [Revised: 06/09/2014] [Accepted: 06/21/2014] [Indexed: 06/03/2023]
Abstract
A combined process comprised of ex-situ nitrification in an aged refuse bioreactor (designated as A bioreactor) and in-situ denitrification in a fresh refuse bioreactor (designated as F bioreactor) was constructed for investigating N2O emission during the stabilization of municipal solid waste (MSW). The results showed that N2O concentration in the F bioreactor varied from undetectable to about 130 ppm, while it was much higher in the A bioreactor with the concentration varying from undetectable to about 900 ppm. The greatly differences of continuous monitoring of N2O emission after leachate cross recirculation in each period were primarily attributed to the stabilization degree of MSW. Moreover, the variation of N2O concentration was closely related to the leachate quality in both bioreactors and it was mainly affected by the COD and COD/TN ratio of leachate from the F bioreactor, as well as the DO, ORP, and NO3(-)-N of leachate from the A bioreactor.
Collapse
Affiliation(s)
- Ya-nan Wang
- School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; School of Environmental and Municipal Engineering, Qingdao Technological University, Qingdao 266033, China
| | - Ying-jie Sun
- School of Environmental and Municipal Engineering, Qingdao Technological University, Qingdao 266033, China.
| | - Lei Wang
- School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Xiao-jie Sun
- College of Environmental Science and Engineering, Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China
| | - Hao Wu
- Sanlihe Subdistrict Office, Jiaozhou, Qingdao 266033, China
| | - Rong-xing Bian
- School of Environmental and Municipal Engineering, Qingdao Technological University, Qingdao 266033, China
| | - Jing-jing Li
- School of Environmental and Municipal Engineering, Qingdao Technological University, Qingdao 266033, China
| |
Collapse
|
29
|
Nitritation and N2O Emission in a Denitrification and Nitrification Two-Sludge System Treating High Ammonium Containing Wastewater. WATER 2014. [DOI: 10.3390/w6102978] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
30
|
Zheng M, He D, Ma T, Chen Q, Liu S, Ahmad M, Gui M, Ni J. Reducing NO and N₂O emission during aerobic denitrification by newly isolated Pseudomonas stutzeri PCN-1. BIORESOURCE TECHNOLOGY 2014; 162:80-88. [PMID: 24747385 DOI: 10.1016/j.biortech.2014.03.125] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 03/21/2014] [Accepted: 03/23/2014] [Indexed: 06/03/2023]
Abstract
As two obligatory intermediates of denitrification, both NO and N2O had harmful environmental and biological impacts. An aerobic denitrifying bacterial strain PCN-1 was newly isolated and identified as Pseudomonas stutzeri, which was capable of high efficient nitrogen removal under aerobic condition with maximal NO and N2O accumulation as low as 0.003% and 0.33% of removed NO3(-)-N, respectively. Further experiment taking nitrite as denitrifying substrate indicated similar low NO and N2O emission of 0.006% and 0.29% of reduced NO2(-)-N, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that the coordinate expression of denitrification gene nirS (for cytochrome cd1 nitrite reductase), cnorB (for NO reductase) and nosZ (for N2O reductase) was the fundamental reason of low NO and N2O accumulation. Activated sludge system bioaugmented by strain PCN-1 demonstrated a significant reduction of NO and N2O emission from wastewater during aerobic denitrification, implied great potential of PCN-1 in practical applications.
Collapse
Affiliation(s)
- Maosheng Zheng
- Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Da He
- Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Tao Ma
- Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Qian Chen
- Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Sitong Liu
- Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Muhammad Ahmad
- Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Mengyao Gui
- Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China
| | - Jinren Ni
- Department of Environmental Engineering, Peking University, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China.
| |
Collapse
|
31
|
Pan M, Wen X, Wu G, Zhang M, Zhan X. Characteristics of nitrous oxide (N2O) emission from intermittently aerated sequencing batch reactors (IASBRs) treating slaughterhouse wastewater at low temperature. Biochem Eng J 2014. [DOI: 10.1016/j.bej.2014.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
32
|
Liang H, Yang J, Gao D. N2O emission from nitrogen removal via nitrite in oxic-anoxic granular sludge sequencing batch reactor. J Environ Sci (China) 2014; 26:537-541. [PMID: 25079265 DOI: 10.1016/s1001-0742(13)60449-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 07/03/2013] [Accepted: 07/04/2013] [Indexed: 06/03/2023]
Abstract
Bionitrification is considered to be a potential source of nitrous oxide (N2O) emissions, which are produced as a by-product during the nitrogen removal process. To investigate the production of N2O during the process of nitrogen removal via nitrite, a granular sludge was studied using a lab-scale sequence batch reactor operated with real-time control. The total production of N2O generated during the nitrification and denitrification processes were 1.724 mg/L and 0.125 mg/L, respectively, demonstrating that N2O is produced during both processes, with the nitrification phase generating larger amount. In addition, due to the N2O-N mass/oxidized ammonia mass ratio, it can be concluded that nitrite accumulation has a positive influence on N2O emissions. Results obtained from PCR-DGGE analysis demonstrate that a specific Nitrosomonas microorganism is related to N2O emission.
Collapse
Affiliation(s)
- Hong Liang
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Jiaoling Yang
- School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Dawen Gao
- School of Forestry, Northeast Forestry University, Harbin 150040, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| |
Collapse
|
33
|
Wu G, Zhai X, Li B, Jiang C, Guan Y. Endogenous Nitrous Oxide Emission for Denitrifiers Acclimated with Different Organic Carbons. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.proenv.2014.09.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
34
|
Sun Y, Wang YN, Sun X, Wu H, Zhang H. Production characteristics of N2O during stabilization of municipal solid waste in an intermittent aerated semi-aerobic bioreactor landfill. WASTE MANAGEMENT (NEW YORK, N.Y.) 2013; 33:2729-2736. [PMID: 24011970 DOI: 10.1016/j.wasman.2013.08.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Revised: 08/01/2013] [Accepted: 08/13/2013] [Indexed: 06/02/2023]
Abstract
An intermittent aerated semi-aerobic bioreactor landfill has the advantages such as accelerating stabilization of municipal solid waste (MSW), reducing methane, and in situ nitrogen removal. However, the introduction of air into a nutrient rich environment induces nitrification and denitrification processes, as well as the potential to generate N species at intermediate oxidation states, including nitrous oxide (N2O). In this study, a simulated intermittent aerated semi-aerobic bioreactor landfill was designed and operated for 262 d in order to establish the production characteristics of N2O. The N2O concentration changed significantly with the degree of MSW stabilization, a low concentration level ranged from undetectable to 100 ppm in the initial stabilization period, then one or two orders of magnitude higher in the later stabilization period compared with the initial period. It is clear that N2O production is relevant to the biodegradable organics in leachate and refuse. Once the biodegradable carbon sources were insufficient, which limited the activity of denitrifying organisms, higher N2O production began.
Collapse
Affiliation(s)
- Yingjie Sun
- School of Environment and Municipal Engineering, Qingdao Technological University, Qingdao 266033, China
| | | | | | | | | |
Collapse
|
35
|
Van Doan T, Lee TK, Shukla SK, Tiedje JM, Park J. Increased nitrous oxide accumulation by bioelectrochemical denitrification under autotrophic conditions: kinetics and expression of denitrification pathway genes. WATER RESEARCH 2013; 47:7087-7097. [PMID: 24210359 DOI: 10.1016/j.watres.2013.08.041] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 08/07/2013] [Accepted: 08/27/2013] [Indexed: 06/02/2023]
Abstract
Under autotrophic conditions, we investigated the effects of different current densities on bioelectrochemical denitrification (BED). In this study, nitrate consumption and nitrous oxide (N2O) production, microbial diversity and population dynamics, and denitrification pathway gene expressions were explored in continuous flow BED reactors at different current densities (0.2, 1, 5, 10 and 20 A/m(2)). We found that, under the autotrophic conditions, N2O accumulation was increased with increase in current density. The maximum rate of denitrification was 1.65 NO3(-)-N (g/NCCm(3).h), and approximately 70% of the reduced N was accumulated as N2O. After each current density was applied, pyrosequencing of the expressed 16S rRNA genes amplified from the cathodic biofilms revealed that that 16 genera were active and in common at all currents, and that eight of those showed a statistically significant correlation with particular current densities. The relative expression of napA and narG was highest, whereas nosZ was low relative to its level in the inoculum suggesting that this could have contributed the high N2O accumulation. Kinetic analysis of nitrate reduction and N2O accumulation followed Michaelis-Menten kinetics. The Vmax for nitrate consumption and N2O accumulation were similar, however the Km values determined as A/m(2) were not. This study provides better understanding of the community and kinetics of a current-fed, autotrophic, cathodic biofilm for evaluating its potential for scale-up and for N2O recovery.
Collapse
Affiliation(s)
- Tuan Van Doan
- School of Civil and Environmental Engineering, Yonsei University, Seoul 120-749, Republic of Korea
| | | | | | | | | |
Collapse
|
36
|
Pan Y, Ye L, Yuan Z. Effect of H2S on N2O reduction and accumulation during denitrification by methanol utilizing denitrifiers. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:8408-8415. [PMID: 23802609 DOI: 10.1021/es401632r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Sulfide is produced in sewer networks, and previous studies suggest that sulfide in sewage could alter the activity of heterotrophic denitrification and lead to N2O accumulation during biological wastewater treatment. However, the details of this phenomenon are poorly understood. In this study, the potential inhibitory effects of sulfide on nitrate, nitrite, and N2O reduction were assessed with a methanol-utilizing denitrifying culture both prior to and after its exposure and adaptation to sulfide. Hydrogen sulfide was found to be strongly inhibitory to N2O reduction, with 50% inhibition observed at H2S concentrations of 0.04 mg H2S-S/L and 0.1 mg H2S-S/L for the unadapted and adapted cultures, respectively. In comparison, both nitrate and nitrite reduction was more tolerant to H2S. A 50% inhibition of nitrite reduction was observed at approximately 2.0 mg H2S-S/L for both unadapted and adapted cultures, while no inhibition of nitrate reduction occurred at the highest H2S concentrations applied (2.0 mg H2S-S/L) to either culture. N2O accumulation was observed during nitrate and nitrite reduction by the adapted culture when H2S concentrations were above 0.5 and 0.2 mg H2S-S/L, respectively. Additionally, we reveal that hydrogen sulfide (H2S), rather than sulfide, was likely the true inhibitor of N2O reduction, and the inhibitory effect was reversible. These findings suggest that sulfide management in sewers could potentially have a significant impact on N2O emission from wastewater treatment plants.
Collapse
Affiliation(s)
- Yuting Pan
- Advanced Water Management Centre (AWMC), The University of Queensland , St. Lucia, Brisbane, Queensland 4072, Australia
| | | | | |
Collapse
|
37
|
Quan X, Zhang M, Lawlor PG, Yang Z, Zhan X. Nitrous oxide emission and nutrient removal in aerobic granular sludge sequencing batch reactors. WATER RESEARCH 2012; 46:4981-4990. [PMID: 22835837 DOI: 10.1016/j.watres.2012.06.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 05/29/2012] [Accepted: 06/19/2012] [Indexed: 06/01/2023]
Abstract
Application of aerobic granular sludge into wastewater treatment is promising due to its excellent settling ability and high microbial concentrations. However, its spatial structure could induce incomplete denitrification, leading to generation of nitrous oxide (N(2)O) - a potent greenhouse gas. Under the temperature of 14 ± 4 °C, three identical laboratory-scale aerobic granular sludge sequencing batch reactors (SBRs) were established to treat synthetic wastewater simulating a mixture of liquid pig manure digestate and municipal wastewater at three aeration rates (0.2, 0.6 and 1.0 L air/min) and three COD:N ratios (1:0.22, 1:0.15 and 1:0.11). The studies show the proportions of N(2)O emission to the influent nitrogen loading rate at the aeration rates of 0.2, 0.6 and 1.0 L air/min were 8.2%, 6.1% and 3.8% at a COD:N ratio of 1:0.22; 7.0%, 5.1% and 3.5% at a COD:N ratio of 1:0.15; and 4.4%, 2.9% and 2.2% at a COD:N ratio of 1:0.11, respectively. With NO(2)(-) as the only nitrogen source in the liquid phase, the specific N(2)O generation rates via denitrification were 1.7, 1.6 and 1.3 μg N(2)O/(g SS· min) at the aeration rates of 0.2, 0.6 and 1.0 L air/min, respectively, which were 40.9%, 44.8%, 39.9% higher than those with NO(3)(-) as the only nitrogen source, respectively. N(2)O generation by aerobic granular sludge due to NH(4)(+)-N nitrification was not sensitive to the aeration rate, and the average specific N(2)O generation rate was 0.8 ± 0.02 μg N(2)O/(g SS· min).
Collapse
Affiliation(s)
- Xiangchun Quan
- Key Laboratory of Water and Sediment Sciences of Ministry of Education, State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China
| | | | | | | | | |
Collapse
|
38
|
Gong YK, Peng YZ, Yang Q, Wu WM, Wang SY. Formation of nitrous oxide in a gradient of oxygenation and nitrogen loading rate during denitrification of nitrite and nitrate. JOURNAL OF HAZARDOUS MATERIALS 2012; 227-228:453-460. [PMID: 22703734 DOI: 10.1016/j.jhazmat.2012.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 04/28/2012] [Accepted: 05/01/2012] [Indexed: 06/01/2023]
Abstract
Nitrous oxide (N(2)O) emission has been observed during denitrification of nitrate via nitrite as intermediate. With a laboratory-scale reactor (2.4 L), the N(2)O emission was characterized under a gradient of DO concentration from 0 to 0.7 mg/L, different ratio of nitrite versus nitrate and different nitrite feed mode. The N(2)O emission was influenced by the level of dissolved oxygen (DO) and nitrite accumulation. The higher DO level and the higher ratio of nitrite versus nitrate resulted in the higher N(2)O emission. Using nitrite as sole electron acceptor at the same loading rate, the sequence of N(2)O emission with three different feed modes was: pulse>step-wise>continuous feed. The N(2)O emitted in pulse feed reactors was 3.1-4.2 and 8.2-11.7 folds of that in the step-wise feed and continuous feed reactors, respectively. With continuous feed mode, the impact of DO concentration on the mass of N(2)O emitted was limited while the higher N(2)O emission occurred at the higher nitrite loading rate.
Collapse
Affiliation(s)
- You-Kui Gong
- School of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100022, China
| | | | | | | | | |
Collapse
|
39
|
Belmonte M, Vázquez-Padín J, Figueroa M, Campos J, Méndez R, Vidal G, Mosquera-Corral A. Denitrifying activity via nitrite and N2O production using acetate and swine wastewater. Process Biochem 2012. [DOI: 10.1016/j.procbio.2012.04.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
40
|
Schneider Y, Beier M, Rosenwinkel KH. Effect of substrate availability on nitrous oxide production by deammonification processes under anoxic conditions. Microb Biotechnol 2012; 5:415-24. [PMID: 22296600 PMCID: PMC3821684 DOI: 10.1111/j.1751-7915.2011.00328.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Due to its high global warming potential, nitrous oxide (N2O) emissions from wastewater treatment processes have recently received a high degree of attention. Nevertheless, there is still a lack of information regarding the microbiological processes leading to N2O production. In this study, two lab‐scale sequencing batch reactors were operated with deammonification biomass to investigate the role of denitrification and the influence of substrate availability regarding N2O formation during the anoxic phase of deammonification. Three different operational phases were established: within the first phase conversion by anammox was favoured and after a transition phase, denitrification activity was promoted. Low nitrous oxide production was observed during stable operation aiming for anammox conversion. Pulsed inflow of the wastewater containing ammonium (NH4+) and nitrite (NO2‐) led to increased N2O production rates. Within the period of denitrification as dominating nitrogen conversion process, the nitrous oxide concentration level was higher during continuous inflow conditions, but the reaction to pulsed inflow was less pronounced. The results indicated that denitrification was responsible for N2O formation from the deammonification biomass. Operational settings to achieve suppression of denitrification processes to a large extend were deducted from the results of the experiments.
Collapse
Affiliation(s)
- Yvonne Schneider
- Institute for Sanitary Engineering and Waste Management, Leibniz Universitaet Hannover, Welfengarten 1, 30167 Hannover, Germany.
| | | | | |
Collapse
|
41
|
Dotro G, Jefferson B, Jones M, Vale P, Cartmell E, Stephenson T. A review of the impact and potential of intermittent aeration on continuous flow nitrifying activated sludge. ENVIRONMENTAL TECHNOLOGY 2011; 33:1685-1697. [PMID: 22439554 DOI: 10.1080/09593330.2011.597783] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Intermittent aeration of activated sludge plants (ASPs) is a potential strategy that may help deliver reduced operational costs while providing an adequate effluent quality. This review paper critically assesses the implications of temporary turning aeration offin continuous flow nitrifying ASPs, including impact on dissolved oxygen concentrations, process biology and operational parameters. The potential savings and pitfalls of the approach are further illustrated through an example scenario. Findings from this review indicate rapid dissolved oxygen depletion times of 1-60 minutes and a significant reduction of nitrification rates from 0.12 to less than 0.04 g NH4-N/g VSS/d. Further negative impacts include a potential increase in nitrous oxide emissions from 0.07% to 27% N2O-N per mole of NH4-N oxidized; enhanced filamentous bacteria growth; a noticeable increase in effluent turbidity developing within one hour of air supply interruption; and, if no mechanical mixing is in place, risk of mixed liquor suspended solids settling in the bioreactor within short times (23-53 min). However, the potential savings in terms of aeration costs could amount to 33%-45% if instrumentation adequacy and impact on process biology and carbon equivalent emissions are excluded from the economic analysis. Further research on the areas of nitrous oxide emissions and the use of hybrid systems to provide resilience and robustness to the intermittent operation of continuous flow nitrifying ASPs is recommended.
Collapse
Affiliation(s)
- Gabriela Dotro
- School of Applied Sciences, Cranfield University, Cranfield, UK.
| | | | | | | | | | | |
Collapse
|
42
|
Rajagopal R, Béline F. Nitrogen removal via nitrite pathway and the related nitrous oxide emission during piggery wastewater treatment. BIORESOURCE TECHNOLOGY 2011; 102:4042-4046. [PMID: 21237639 DOI: 10.1016/j.biortech.2010.12.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 12/01/2010] [Accepted: 12/02/2010] [Indexed: 05/30/2023]
Abstract
Performance of partial nitrification (PN) via nitrite (NO(2)(-)) pathway and the related nitrous oxide (N(2)O) emission during piggery wastewater treatment was investigated. Dissolved oxygen (DO) concentration and aeration pattern were selected as operational parameters to investigate the possibility of NO(2)(-) accumulation without affecting the overall N removal. To obtain PN, aeration was done for a maximum of 3h with a stopover of oxygenation, whenever DO concentration exceeds the threshold value of 2 mg O(2)L(-1). Ammonium (NH(4)(+)) consumption ended within 2h of reaction, and at the end of NH(4)(+) oxidation, about 70-80% of N was accumulated as NO(2)(-). Using PN, an average N removal of 74-75% was observed, which is comparable to that of complete nitrification-denitrification process. Regulating the aeration pattern not only benefit to the N removal in piggery wastewater, but also favoured reduction of oxygen and organic matter requirements for nitrification and denitrification. N(2)O emission was not encouraged even with 70-80% of NO(2)(-) accumulation.
Collapse
|
43
|
Modeling nitrogen removal for a denitrification biofilter. Bioprocess Biosyst Eng 2011; 34:747-55. [DOI: 10.1007/s00449-011-0524-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 02/06/2011] [Indexed: 11/25/2022]
|
44
|
Fernandes SO, Bharathi PAL, Bonin PC, Michotey VD. Denitrification: an important pathway for nitrous oxide production in tropical mangrove sediments (Goa, India). JOURNAL OF ENVIRONMENTAL QUALITY 2010; 39:1507-1516. [PMID: 20830937 DOI: 10.2134/jeq2009.0477] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Net nitrous oxide production and denitrification activity were measured in two mangrove ecosystems of Goa, India. The relatively pristine site Tuvem was compared to Divar, which is prone to high nutrient input. Stratified sampling at 2-cm intervals within the 0- to 10-cm depth range showed that N2O production at both the locations decreased with depth. Elevated denitrification activity at Divar resulted in maximum production of up to 1.95 nmol N2O-N g(-1) h(-1) at 2 to 4 cm, which was three times higher than at Tuvem. Detailed investigations to understand the major pathway contributing to N2O production performed at Tuvem showed that incomplete denitrification was responsible for up to 43 to 93% of N2O production. Nitrous oxide production rates closely correlated to nitrite concentration (n = 15; r = -0.47; p < 0.05) and denitrifier abundance (r = 0.55; p < 0.05), suggesting that nitrite utilization by microbial activity leads to N2O production. Nitrous oxide production through nitrification was below detection, affirming that denitrification is the major pathway responsible for production of the greenhouse gas. Net N2O production in these mangrove systems are comparatively higher than those reported from other natural estuarine sediments and therefore warrant mitigation measures.
Collapse
|
45
|
Potential of aerobic denitrification by Pseudomonas stutzeri TR2 to reduce nitrous oxide emissions from wastewater treatment plants. Appl Environ Microbiol 2010; 76:4619-25. [PMID: 20495048 DOI: 10.1128/aem.01983-09] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In contrast to most denitrifiers studied so far, Pseudomonas stutzeri TR2 produces low levels of nitrous oxide (N(2)O) even under aerobic conditions. We compared the denitrification activity of strain TR2 with those of various denitrifiers in an artificial medium that was derived from piggery wastewater. Strain TR2 exhibited strong denitrification activity and produced little N(2)O under all conditions tested. Its growth rate under denitrifying conditions was near comparable to that under aerobic conditions, showing a sharp contrast to the lower growth rates of other denitrifiers under denitrifying conditions. Strain TR2 was tolerant to toxic nitrite, even utilizing it as a good denitrification substrate. When both nitrite and N(2)O were present, strain TR2 reduced N(2)O in preference to nitrite as the denitrification substrate. This bacterial strain was readily able to adapt to denitrifying conditions by expressing the denitrification genes for cytochrome cd(1) nitrite reductase (NiR) (nirS) and nitrous oxide reductase (NoS) (nosZ). Interestingly, nosZ was constitutively expressed even under nondenitrifying, aerobic conditions, consistent with our finding that strain TR2 preferred N(2)O to nitrite. These properties of strain TR2 concerning denitrification are in sharp contrast to those of well-characterized denitrifiers. These results demonstrate that some bacterial species, such as strain TR2, have adopted a strategy for survival by preferring denitrification to oxygen respiration. The bacterium was also shown to contain the potential to reduce N(2)O emissions when applied to sewage disposal fields.
Collapse
|
46
|
Senbayram M, Chen R, Mühling KH, Dittert K. Contribution of nitrification and denitrification to nitrous oxide emissions from soils after application of biogas waste and other fertilizers. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2009; 23:2489-2498. [PMID: 19603466 DOI: 10.1002/rcm.4067] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The attribution of nitrous oxide (N(2)O) emission to organic and inorganic N fertilizers requires understanding of how these inputs affect the two biological processes, i.e. denitrification and nitrification. Contradictory findings have been reported when the effects of organic and inorganic fertilizers on nitrous oxide emission were compared. Here we aimed to contribute to the understanding of such variation using (15)N-labelling techniques. We determined the processes producing N(2)O, and tested the effects of soil moisture, N rates, and the availability of organic matter. In a pot experiment, we compared soil treated with biogas waste (BGW) and mineral ammonium sulphate (Min-N) applied at four rates under two soil moisture regimes. We also tested biogas waste, conventional cattle slurry and mineral N fertilizer in a grassland field experiment. During the first 37 days after application we observed N(2)O emissions of 5.6 kg N(2)O-N ha(-1) from soils supplied with biogas waste at a rate of 360 kg N ha(-1). Fluxes were ca. 5-fold higher at 85% than at 65% water holding capacity (WHC). The effects of fertilizer types and N rates on N(2)O emission were significant only when the soil moisture was high. Organic fertilizer treated soils showed much higher N(2)O emissions than those receiving mineral fertilizer in both, pot and field experiment. Over all the treatments the percentage of the applied N emitted as N(2)O was 2.56% in BGW but only 0.68% in Min-N. In the pot experiment isotope labelling indicated that 65-95% of the N(2)O was derived from denitrification for all fertilizer types. However, the ratio of denitrification/nitrification derived N(2)O was lower at 65% than at 85% WHC. We speculate that the application of organic matter in conjunction with ammonium nitrogen first leads to a decrease in denitrification-derived N(2)O emission compared with soil receiving mineral fertilizer. However, at later stages when denitrification becomes C-limited, higher N(2)O emissions are induced when the soil moisture is high.
Collapse
Affiliation(s)
- Mehmet Senbayram
- Institute of Plant Nutrition and Soil Science, Hermann Rodewald Str. 2, 24118 Kiel, Germany
| | | | | | | |
Collapse
|