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Phyu K, Zhi S, Liang J, Chang CC, Liu J, Cao Y, Wang H, Zhang K. Microalgal-bacterial consortia for the treatment of livestock wastewater: Removal of pollutants, interaction mechanisms, influencing factors, and prospects for application. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 349:123864. [PMID: 38554837 DOI: 10.1016/j.envpol.2024.123864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 03/06/2024] [Accepted: 03/23/2024] [Indexed: 04/02/2024]
Abstract
The livestock sector is responsible for a significant amount of wastewater globally. The microalgal-bacterial consortium (MBC) treatment has gained increasing attention as it is able to eliminate pollutants to yield value-added microalgal products. This review offers a critical discussion of the source of pollutants from livestock wastewater and the environmental impact of these pollutants. It also discusses the interactions between microalgae and bacteria in treatment systems and natural habitats in detail. The effects on MBC on the removal of various pollutants (conventional and emerging) are highlighted, focusing specifically on analysis of the removal mechanisms. Notably, the various influencing factors are classified into internal, external, and operating factors, and the mutual feedback relationships between them and the target (removal efficiency and biomass) have been thoroughly analysed. Finally, a wastewater recycling treatment model based on MBC is proposed for the construction of a green livestock farm, and the application value of various microalgal products has been analysed. The overall aim was to indicate that the use of MBC can provide cost-effective and eco-friendly approaches for the treatment of livestock wastewater, thereby advancing the path toward a promising microalgal-bacterial-based technology.
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Affiliation(s)
- KhinKhin Phyu
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, PR China.
| | - Suli Zhi
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, PR China; Key Laboratory of Low-Carbon Green Agriculture, North China, Ministry of Agriculture and Rural Affairs, Beijing 100193, PR China.
| | - Junfeng Liang
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, PR China; Key Laboratory of Low-Carbon Green Agriculture, North China, Ministry of Agriculture and Rural Affairs, Beijing 100193, PR China.
| | - Chein-Chi Chang
- Washington D.C. Water and Sewer Authority, Ellicott City, MD, 21042, USA.
| | - Jiahua Liu
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, PR China.
| | - Yuang Cao
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, PR China.
| | - Han Wang
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, PR China.
| | - Keqiang Zhang
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, PR China; Key Laboratory of Low-Carbon Green Agriculture, North China, Ministry of Agriculture and Rural Affairs, Beijing 100193, PR China.
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Hu J, Su Q, Xiao C, Deng X, Liu X, Feng J, Chi R. Removal of ammonia nitrogen from residual ammonium leaching solution by heterotrophic nitrification-aerobic denitrification process. ENVIRONMENTAL TECHNOLOGY 2023; 44:3479-3490. [PMID: 35388746 DOI: 10.1080/09593330.2022.2064235] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/27/2022] [Indexed: 06/14/2023]
Abstract
The aftermath of mining weathered crust elution-deposited rare earth ore produces a large amount of residual ammonium leaching solution, which causes ammonia and nitrogen pollution to the mine site. Recently, denitrification by heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria has attracted much attention. However, limited studies exist regarding the denitrification process of HN-AD bacteria. In this study, we combined four strains of HN-AD bacteria, Pseudomonas fulva K3, Pseudomonas mosselii K17, Klebsiella oxytoca A12, and Enterobacter hormaechei A16, obtained from rare earth element leaching sites, to select the best microbial consortium for ammonia nitrogen removal. We designed an ammonia removal process applicable to HN-AD bacteria to directly remove ammonia nitrogen from acidic leaching solutions. The experimental results demonstrated that the most efficient microbial consortium for ammonia nitrogen removal to be K3 + K17 + A16, with a removal efficiency of 89.68% for 8 h. In this process, considering the influencing factors of the ammonia removal process, the larger the influent flow rate and influent ammonia nitrogen concentration, the greater the ammonia nitrogen accumulation and pH decrease in the reactor. In consecutive multi-batch experiments, the ammonia removal process was used to remove ammonia nitrogen, at concentrations of 100-600 mg/L, from the simulated leaching solution at pH 4-7, whereby the effluent ammonia nitrogen concentration was lower than 15 mg/L. The results demonstrate that the ammonia removal process is highly feasible and stable. These findings will provide new ideas for the application of HN-AD bacteria and new methods for the removal of ammonia nitrogen from acidic leaching solutions.
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Affiliation(s)
- Jingang Hu
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, People's Republic of China
| | - Qi Su
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, People's Republic of China
| | - Chunqiao Xiao
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, People's Republic of China
- Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, Wuhan Institute of Technology, Wuhan, People's Republic of China
| | - Xiangyi Deng
- School of Resources and Safety Engineering, Wuhan Institute of Technology, Wuhan, People's Republic of China
| | - Xuemei Liu
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, People's Republic of China
- School of Resources and Safety Engineering, Wuhan Institute of Technology, Wuhan, People's Republic of China
| | - Jian Feng
- Key Laboratory for Green Chemical Process of Ministry of Education, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, People's Republic of China
- School of Resources and Safety Engineering, Wuhan Institute of Technology, Wuhan, People's Republic of China
| | - Ruan Chi
- Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, Wuhan Institute of Technology, Wuhan, People's Republic of China
- School of Resources and Safety Engineering, Wuhan Institute of Technology, Wuhan, People's Republic of China
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Zhou Y, Chen L, Wang J, Lu L, Liu F, Chen C, Qin X. Solution, exchangeable and fixed ammonium in natural diatomite as a simulated PRB material: effects of adsorption and bioregeneration processes. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:52433-52445. [PMID: 36840872 DOI: 10.1007/s11356-023-26058-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
Ammonia nitrogen (NH4+-N) is widely found in aquifers with strong reducibility or poor adsorptivity as a dissolved inorganic nitrogen pollutant. The application of adsorbents with effective long-term in situ bioregeneration as permeable reactive barrier (PRB) media for nitrogen removal has raised concern. In this study, the advantage of natural diatomite as a PRB material was investigated by exploring its NH4+-N adsorption and desorption characteristics, and the ability of diatomite and zeolite to be loaded nitrifying bacteria was also compared. The results showed that the exchangeable ammonium from chemical-monolayer adsorption was the main form of NH4+-N and was adsorbed by diatomite. Moreover, the adsorption process was limited with a maximum adsorption capacity of 0.677 mg g-1. However, diatomite demonstrated an excellent loading of aerobic-heterotrophic microorganisms, even stronger than zeolite. Compared with zeolite reactors, a higher OD600 value of nitrifiers, a faster NH4+-N degradation rate and more abundant functional genes were observed during the bioregeneration process of diatomite. Both the solution and exchangeable ammonium forms were bioavailable, and the regeneration of diatomite was more than 80.0% after two days. Moreover, desorption-biodegradation was systematically analysed to determine the bioregeneration mechanism of diatomite. Diatomite with good regeneration ability can be used as a competitive alternative to address sudden nitrogen pollution.
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Affiliation(s)
- Yang Zhou
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, People's Republic of China
- Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, People's Republic of China
| | - Linpeng Chen
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, People's Republic of China
- Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, People's Republic of China
| | - Jialin Wang
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, People's Republic of China
- Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, People's Republic of China
| | - Li Lu
- Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, Guangxi, China
- Guangxi Karst Resources and Environment Research Center of Engineering Technology, Guilin, 541004, Guangxi, China
| | - Fei Liu
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, People's Republic of China
- Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, People's Republic of China
| | - Cuibai Chen
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing, 100083, People's Republic of China.
- Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences (Beijing), Beijing, 100083, People's Republic of China.
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China.
| | - Xiaopeng Qin
- Technical Centre for Soil, Agricultural and Rural Ecology and Environment, Ministry of Ecology and Environment, Beijing, 100012, People's Republic of China.
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Zidan K, Sbahi S, Hejjaj A, Ouazzani N, Assabbane A, Mandi L. Removal of bacterial indicators in on-site two-stage multi-soil-layering plant under arid climate (Morocco): prediction of total coliform content using K-nearest neighbor algorithm. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:75716-75729. [PMID: 35661304 DOI: 10.1007/s11356-022-21194-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
This study aims to evaluate and monitor the efficacy of a full-scale two-stage multi-soil-layering (TS-MSL) plant in removing fecal contamination from domestic wastewater. The TS-MSL plant under investigation consisted of two units in series, one with a vertical flow regime (VF-MSL) and the other with a horizontal flow regime (HF-MSL). Furthermore, this study attempts to see whether linear model (LM) and K-nearest neighbor (KNN) model can be used to predict total coliform (TC) removal in the TS-MSL system. For 24 months, the TS-MSL system was monitored, with bimonthly measurements recorded at the inlet and outlet of each compartment. Obtained results show removal of 85% of COD, 67% of TP, 27% of TN, and 3 log units of coliforms with good system stability. Thus, the effluent meets the Moroccan water quality code for reuse in the irrigation of green spaces. In addition, as compared to LM, the KNN model (R2 = 0.988) may be considered as an effective method for predicting TC removal in the TS-MSL system. Finally, sensitivity analysis has shown that TC and dissolved oxygen level in the influent were the most influential parameters for predicting TC removal in the TS-MSL system.
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Affiliation(s)
- Khadija Zidan
- National Center for Studies and Research on Water and Energy (CNEREE), Cadi Ayyad University, Marrakech, Morocco
- Laboratory of Water, Biodiversity and Climate Change, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco
- Laboratory of Physical Chemistry (Photocatalysis and Environment), Faculty of Sciences Agadir, University Ibn Zohr, Agadir, Morocco
| | - Sofyan Sbahi
- National Center for Studies and Research on Water and Energy (CNEREE), Cadi Ayyad University, Marrakech, Morocco
- Laboratory of Water, Biodiversity and Climate Change, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco
| | - Abdessamed Hejjaj
- National Center for Studies and Research on Water and Energy (CNEREE), Cadi Ayyad University, Marrakech, Morocco
| | - Naaila Ouazzani
- National Center for Studies and Research on Water and Energy (CNEREE), Cadi Ayyad University, Marrakech, Morocco
- Laboratory of Water, Biodiversity and Climate Change, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco
| | - Ali Assabbane
- Laboratory of Physical Chemistry (Photocatalysis and Environment), Faculty of Sciences Agadir, University Ibn Zohr, Agadir, Morocco
| | - Laila Mandi
- National Center for Studies and Research on Water and Energy (CNEREE), Cadi Ayyad University, Marrakech, Morocco.
- Laboratory of Water, Biodiversity and Climate Change, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco.
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Nitrate Water Contamination from Industrial Activities and Complete Denitrification as a Remediation Option. WATER 2022. [DOI: 10.3390/w14050799] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Freshwater is a scarce resource that continues to be at high risk of pollution from anthropogenic activities, requiring remediation in such cases for its continuous use. The agricultural and mining industries extensively use water and nitrogen (N)-dependent products, mainly in fertilizers and explosives, respectively, with their excess accumulating in different water bodies. Although removal of NO3 from water and soil through the application of chemical, physical, and biological methods has been studied globally, these methods seldom yield N2 gas as a desired byproduct for nitrogen cycling. These methods predominantly cause secondary contamination with deposits of chemical waste such as slurry brine, nitrite (NO2), ammonia (NH3), and nitrous oxide (N2O), which are also harmful and fastidious to remove. This review focuses on complete denitrification facilitated by bacteria as a remedial option aimed at producing nitrogen gas as a terminal byproduct. Synergistic interaction of different nitrogen metabolisms from different bacteria is highlighted, with detailed attention to the optimization of their enzymatic activities. A biotechnological approach to mitigating industrial NO3 contamination using indigenous bacteria from wastewater is proposed, holding the prospect of optimizing to the point of complete denitrification. The approach was reviewed and found to be durable, sustainable, cost effective, and environmentally friendly, as opposed to current chemical and physical water remediation technologies.
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Biological Treatment of Organic Waste in Wastewater—Towards a Circular and Bio-Based Economy. WATER 2022. [DOI: 10.3390/w14030360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Due to population growth, accelerated urbanization, and economic development, the quantity of both industrial and urban wastewater generated, and its overall pollution load are increasing globally [...]
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Xi H, Zhou X, Arslan M, Luo Z, Wei J, Wu Z, Gamal El-Din M. Heterotrophic nitrification and aerobic denitrification process: Promising but a long way to go in the wastewater treatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 805:150212. [PMID: 34536867 DOI: 10.1016/j.scitotenv.2021.150212] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 09/03/2021] [Accepted: 09/03/2021] [Indexed: 05/27/2023]
Abstract
The traditional biological nitrogen removal (BNR) follows the conventional scheme of sequential nitrification and denitrification. In recent years, novel processes such as anaerobic ammonia oxidation (anammox), complete oxidation of ammonia to nitrate in one organism (comammox), heterotrophic nitrification and aerobic denitrification (HN-AD), and dissimilatory nitrate reduction to ammonium (DNRA) are gaining tremendous attention after the discovery of metabolically versatile bacteria. Among them, HN-AD offers several advantages because individual bacteria could achieve one-stage nitrogen removal under aerobic conditions in the presence of organic carbon. In this review, besides classical BNR processes, we summarized the existing literature on HN-AD bacteria which have been isolated from diverse habitats. A particular focus was given on the diversity and physiology of HN-AD bacteria, influences of physiological and biochemical factors on their growth, nitrogen removal performances, as well as limitations and strategies in unraveling HN-AD metabolic pathways. We also presented case studies of HN-AD application in wastewater treatment facilities, pointed out forthcoming challenges of HN-AD in these systems, and presented modulation strategies for HN-AD application in engineering. This review may help improve the existing design of wastewater treatment plants by harnessing HN-AD bacteria for effective nitrogen removal.
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Affiliation(s)
- Haipeng Xi
- Institute of Environmental Health and Ecological Safety, Jiangsu University, Zhenjiang 212013, China
| | - Xiangtong Zhou
- Institute of Environmental Health and Ecological Safety, Jiangsu University, Zhenjiang 212013, China.
| | - Muhammad Arslan
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Zhijun Luo
- Institute of Environmental Health and Ecological Safety, Jiangsu University, Zhenjiang 212013, China
| | - Jing Wei
- Institute of Environmental Health and Ecological Safety, Jiangsu University, Zhenjiang 212013, China
| | - Zhiren Wu
- Institute of Environmental Health and Ecological Safety, Jiangsu University, Zhenjiang 212013, China
| | - Mohamed Gamal El-Din
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
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Tang VT, Li Q, Rene ER, Behera SK, Maleki A, Da CT, Phong NT. Immobilization of microorganisms in activated zeolite beads and alkaline pretreated straws for ammonium-nitrogen removal from urban river water. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 85:63-76. [PMID: 35050866 DOI: 10.2166/wst.2021.496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The non-treated wastewater from residential areas contains high concentrations of ammonium-nitrogen (NH4+-N). When discharged into the drainage water system, it deteriorates the water quality in urban rivers. This study used two types of materials to form eco-bags, using activated zeolite bead (AZB) and alkaline pretreated straw (APS), in geotextile bags for easy recovery and reuse. The AZB and APS provided the breeding habitat for the microorganisms that promoted biofilm formation on their surface. The immobilization of engineered denitrification microorganisms facilitated the removal of NH4+-N from the urban river water. The NH4+-N removal in the AZB and APS bags were in the range of 64-73%, and 56-61%, respectively, while the chemical oxygen demand (COD) removal in the AZB and APS bags ranged from 33-36%, and 30-31%, respectively. In addition, as evident from DNA and microbial community analysis, the microorganisms demonstrated a greater proclivity to grow and proliferate on the surface of AZB and APS and improved the water quality of urban rivers.
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Affiliation(s)
- Van Tai Tang
- Safety, Health and Environment Research Institute, Ho Chi Minh City, Vietnam
| | - Qiuhong Li
- NARI Technology Development Company Limited, Nanjing, Jiangsu 210012, China
| | - Eldon R Rene
- Department of Water Supply, Sanitation and Environmental Engineering, IHE Delft Institute for Water Education, Delft 2601DA, The Netherlands
| | - Shishir Kumar Behera
- Industrial Ecology Research Group, School of Chemical Engineering, Vellore Institute of Technology, Vellore, Tamilnadu 632014, India
| | - Afshin Maleki
- Environmental Health Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Kurdistan Province 72M2 + MHQ, Iran
| | - Chau Thi Da
- Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam
| | - Nguyen Tan Phong
- Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, 700000, Vietnam E-mail:
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Shah SB, McKettrick W, Najafian A, Grimes J. Impact of microbial waste additives and glucose on ammonia emissions from broiler litter in the lab. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2021; 56:454-459. [PMID: 33632065 DOI: 10.1080/10934529.2021.1886776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 01/30/2021] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
Ammonia (NH3) produced inside livestock houses can adversely affect animal welfare and performance and degrade the environment. In broiler houses, NH3 levels are mitigated by applying acidifiers to the litter but acidifiers provide short-term NH3 suppression requiring heavy or repeated applications. Microbial additives may provide longer-term NH3 control through nitrogen (N) immobilization and nitrification. The objective of this 50-d lab study was to evaluate the impact of two microbial additives (Environoc 301 and Environoc 501), 2% glucose, and distilled water (control) treatments applied to broiler litter on NH3 emissions and litter properties. During the first 34 d, glucose significantly but modestly reduced NH3 emissions vs. the other treatments which were not significantly different from one-another. For the entire study, when glucose was excluded (due to lost replicates), the three treatments were not significantly different. The unreplicated glucose treatment had higher final litter nitrate concentration than the other treatments. Litter properties were unaffected by the two microbial additive and control treatments. The effectiveness of glucose in reducing NH3 emission could have been due to greater N immobilization and nitrification vs. the other treatments. More research on cost-effective labile carbon sources and higher application rates to achieve greater NH3 reduction is required.
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Affiliation(s)
- Sanjay B Shah
- Biological and Agricultural Department, NC State University, Raleigh, NC, USA
| | - Will McKettrick
- Biological and Agricultural Department, NC State University, Raleigh, NC, USA
| | | | - Jesse Grimes
- Prestage Department of Poultry Science, NC State University, Raleigh, NC, USA
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Rampuria A, Kulshreshtha NM, Gupta A, Brighu U. Novel microbial nitrogen transformation processes in constructed wetlands treating municipal sewage: a mini-review. World J Microbiol Biotechnol 2021; 37:40. [PMID: 33544217 DOI: 10.1007/s11274-021-03001-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/08/2021] [Indexed: 01/18/2023]
Abstract
Traditionally nitrogen transformation in constructed wetlands (CWs) has been attributed to the activities of aerobic autotrophic nitrifiers followed by anoxic heterotrophic denitrifiers. However, the nitrogen balances in such systems are far from being explained as a large fraction of the losses remain unaccounted for. The classical nitrification-denitrification theory has been successfully employed in certain unit processes by culturing fast-growing bacteria, but the CWs offer an ideal environment for slow-growing bacteria that may be beneficially exploited to achieve enhanced nitrogen removal by manipulating the environmental conditions in their favor. In the last three decades, many novel microorganisms have been isolated from CWs that have led to the discovery of some other routes that have made researchers believe could play a significant role in nitrogen transformation processes. The increased understanding of novel discerned pathways like anaerobic ammonium oxidation (ANAMMOX), heterotrophic nitrification and aerobic denitrification, which are mediated by specialized bacteria has indicated that these microorganisms could be enriched by applying selection pressures within CWs for achieving high rates of nitrogen removal. Understanding these novel nitrogen transformation processes along with the associated microbial population can provide new dimensions to the design of CWs for enhanced nitrogen removal.
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Affiliation(s)
- Aakanksha Rampuria
- Department of Civil Engineering, Malaviya National Institute of Technology, Jaipur, India
| | | | | | - Urmila Brighu
- Department of Civil Engineering, Malaviya National Institute of Technology, Jaipur, India
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