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Yang Z, Li Z, Zhu K, Zhou J, Lin H, Zhou J. Pre-anoxic electro-stimulation enhanced simultaneous nitrification-denitrification in single-stage electrolysis-integrated sequencing batch biofilm reactor. BIORESOURCE TECHNOLOGY 2024; 412:131412. [PMID: 39226944 DOI: 10.1016/j.biortech.2024.131412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2024] [Revised: 08/18/2024] [Accepted: 08/31/2024] [Indexed: 09/05/2024]
Abstract
Simultaneous nitrification-denitrification (SND) is a promising nitrogen removal process. However, total nitrogen (TN) removal is limited due to unsatisfactory denitrification. This study demonstrated that short-time (1 h) pre-anoxic electro-stimulation significantly enhanced SND efficiency in the aerobic phase by promoting the proliferation of mixotrophic and heterotrophic denitrifiers. SND and TN removal efficiencies at the optimal electric current (EC) (0.02 A) were 85.6 % and 93.9 %, which were 39.1 % and 17.2 % higher than control. Microbial community analysis indicated that the abundance of mixotrophic and heterotrophic denitrifiers significantly increased. H2 generated in the electro-stimulation process induced the proliferation of mixotrophic denitrifiers. The weak EC (0.02 A) promoted the activity and growth of heterotrophic denitrifiers by accelerating electron transfer. They concurrently mediated heterotrophic denitrification to enhance SND efficiency. PICRUSt2 analysis revealed that the abundance of denitrifying genes dramatically surged. This study provides new insights into applying electrolysis to achieve advanced SND while minimizing electricity consumption.
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Affiliation(s)
- Zhi Yang
- College of Eco-Environmental Engineering, Guizhou Minzu University, Guiyang 550025, China
| | - Zhigang Li
- Southwest Municipal Engineering Design & Research Institute of China, Chengdu 610213, China
| | - Kun Zhu
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Jiong Zhou
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Hong Lin
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Jian Zhou
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China.
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Wu H, Xing Z, Zhan G. Dissolved oxygen drives heterotrophic microorganism succession to regulate low carbon source wastewater treatment enhanced by slurry. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 366:121804. [PMID: 38996606 DOI: 10.1016/j.jenvman.2024.121804] [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: 03/27/2024] [Revised: 07/04/2024] [Accepted: 07/07/2024] [Indexed: 07/14/2024]
Abstract
The limited availability of carbon sources in low carbon source wastewater has always hindered nitrogen removal efficiency. The residual slurry liquid after anaerobic digestion has the potential to be used as a carbon source. This study investigated the optimal parameters of dissolved oxygen (DO) for enhancing the treatment of low carbon source wastewater using slurry, and revealed the characteristics of carbon metabolism gene enrichment and carbon fixation potential driven by DO. The results indicated that treating wastewater under high DO concentrations (3-4 mg/L) conditions could meet the emission standards set by wastewater treatment plants in China. However, the lower-cost DO concentration of 3 mg/L is considered a more cost-effective parameter, effectively removing 85.68% of chemical oxygen demand and 91.56% of total nitrogen. Mechanistic analysis suggested that reducing DO concentration increased the diversity of microbial communities. Regulating DO concentration reshaped the co-metabolic network of microorganisms with different DO sensitivities by influencing Hydrogenophaga and Chlorobium. This ultimately led to the reconstruction of heterotrophic microbial communities dominated by Sphaerotilus and Acidovorax under high DO conditions, and heterotrophic-autotrophic co-enriched microbial communities dominated by Chlorobium under low DO conditions (1-2 mg/L). Additionally, under high DO conditions, high microbial mass transfer efficiency and the enrichment of functional genes were crucial for achieving high nitrogen removal performance. Further, the microbial carbon fixation potential was relatively high under the DO 3 mg/L condition, helping to reduce the consumption of additional carbon sources. This study provided innovative ideas for the sustainable and low-carbon development of wastewater treatment technology.
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Affiliation(s)
- Heng Wu
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, PR China; College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
| | - Zhilin Xing
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, PR China.
| | - Guoqiang Zhan
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, PR China.
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Jiang S, Yang J, Wu C, Du H, Zheng H, Lin Q, Pan W, Zhong C, Tan K, Lin F, Luo Z, Pan Z, Ye J, Lin P. Purification of inorganic nitrogen from the mariculture tail water by anaerobic/anoxic/oxic (A 2O) process. MARINE POLLUTION BULLETIN 2024; 203:116404. [PMID: 38718546 DOI: 10.1016/j.marpolbul.2024.116404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 04/15/2024] [Accepted: 04/19/2024] [Indexed: 06/06/2024]
Abstract
This study aims to address the suboptimal performance of conventional denitrifying strains in treating mariculture tail water (MTW) containing inorganic nitrogen (IN). The concentration of inorganic nitrogen in the mariculture tail water is about 5-20 mg·L-1. A biofilm treatment process was developed and evaluated using an anoxic-anoxic-aerobic biofilter composite system inoculated with the denitrifying strain Meyerozyma guilliermondii Y8. The removal effect of total nitrogen (TN), IN, and Chemical Oxygen Demand (CODMn) from MTW was investigated. The results indicate that the A2O composite biological filter has excellent pollutant removal efficiency within 25 days of operation, after the acclimation of the denitrifying microorganisms. The initial concentrations of TN, IN, and CODMn ranged between 10.24 and 12.89 mg·L-1, 7.84-10.49 mg·L-1, and 9.44-11.52 mg·L-1, respectively, and the removal rates of these indexes reached 38-68 %, 45-70 %, and 55-70 %, respectively. The experiments with different hydraulic retention times (HRT = 6 h, 8 h, 10 h) demonstrated that longer HRT was more conducive to the removal of inorganic nitrogen. Moreover, scanning electron microscopy observations revealed that the target strain successfully grew and attached to the filler in large quantities. The findings of this study provide practical guidance for the development of efficient biofilm processes for the treatment of MTW.
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Affiliation(s)
- Shuangcheng Jiang
- Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, Shantou University, Shantou 515063, China; Fisheries Research Institution of Fujian, Xiamen 361013, China
| | - Jinkun Yang
- College of Environment and Resources, Fujian Normal University, Fuzhou 350000, China
| | - Chunshan Wu
- College of Environment and Resources, Fujian Normal University, Fuzhou 350000, China
| | - Hong Du
- Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, Shantou University, Shantou 515063, China
| | - Huidong Zheng
- Fisheries Research Institution of Fujian, Xiamen 361013, China
| | - Qi Lin
- Fisheries Research Institution of Fujian, Xiamen 361013, China.
| | - Wentao Pan
- Fisheries Research Institution of Fujian, Xiamen 361013, China
| | - Chongming Zhong
- Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, Shantou University, Shantou 515063, China; Fisheries Research Institution of Fujian, Xiamen 361013, China
| | - Kaiwen Tan
- Third institute of oceanography, Ministry of Natural Resources, Xiamen 361005, PR China
| | - Feng Lin
- Third institute of oceanography, Ministry of Natural Resources, Xiamen 361005, PR China.
| | - Zhuhua Luo
- Third institute of oceanography, Ministry of Natural Resources, Xiamen 361005, PR China
| | - Zhong Pan
- Third institute of oceanography, Ministry of Natural Resources, Xiamen 361005, PR China
| | - Jingwen Ye
- Fisheries Research Institution of Fujian, Xiamen 361013, China
| | - Peng Lin
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, United States of America
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Zhao X, Qin X, Jing X, Wang T, Qiao Q, Li X, Yan P, Li Y. Key genes of electron transfer, the nitrogen cycle and tetracycline removal in bioelectrochemical systems. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:174. [PMID: 37974273 PMCID: PMC10652473 DOI: 10.1186/s13068-023-02430-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/08/2023] [Indexed: 11/19/2023]
Abstract
BACKGROUND Soil microbial fuel cells (MFCs) can remove antibiotics and antibiotic resistance genes (ARGs) simultaneously, but their removal mechanism is unclear. In this study, metagenomic analysis was employed to reveal the functional genes involved in degradation, electron transfer and the nitrogen cycle in the soil MFC. RESULTS The results showed that the soil MFC effectively removed tetracycline in the overlapping area of the cathode and anode, which was 64% higher than that of the control. The ARGs abundance increased by 14% after tetracycline was added (54% of the amplified ARGs belonged to efflux pump genes), while the abundance decreased by 17% in the soil MFC. Five potential degraders of tetracycline were identified, especially the species Phenylobacterium zucineum, which could secrete the 4-hydroxyacetophenone monooxygenase encoded by EC 1.14.13.84 to catalyse deacylation or decarboxylation. Bacillus, Geobacter, Anaerolinea, Gemmatirosa kalamazoonesis and Steroidobacter denitrificans since ubiquinone reductase (encoded by EC 1.6.5.3), succinate dehydrogenase (EC 1.3.5.1), Coenzyme Q-cytochrome c reductase (EC 1.10.2.2), cytochrome-c oxidase (EC 1.9.3.1) and electron transfer flavoprotein-ubiquinone oxidoreductase (EC 1.5.5.1) served as complexes I, II, III, IV and ubiquinone, respectively, to accelerate electron transfer. Additionally, nitrogen metabolism-related gene abundance increased by 16% to support the microbial efficacy in the soil MFC, and especially EC 1.7.5.1, and coding the mutual conversion between nitrite and nitrate was obviously improved. CONCLUSIONS The soil MFC promoted functional bacterial growth, increased functional gene abundance (including nitrogen cycling, electron transfer, and biodegradation), and facilitated antibiotic and ARG removal. Therefore, soil MFCs have expansive prospects in the remediation of antibiotic-contaminated soil. This study provides insight into the biodegradation mechanism at the gene level in soil bioelectrochemical remediation.
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Affiliation(s)
- Xiaodong Zhao
- College of Biological Sciences and Technology, Taiyuan Normal University, Yuci, 030619, People's Republic of China
| | - Xiaorui Qin
- College of Biological Sciences and Technology, Taiyuan Normal University, Yuci, 030619, People's Republic of China
| | - Xiuqing Jing
- College of Biological Sciences and Technology, Taiyuan Normal University, Yuci, 030619, People's Republic of China
| | - Teng Wang
- Department of Life Science, Changzhi University, Changzhi, 046011, People's Republic of China
| | - Qingqing Qiao
- College of Biological Sciences and Technology, Taiyuan Normal University, Yuci, 030619, People's Republic of China
| | - Xiaojing Li
- Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, MARA, Tianjin Key Laboratory of Agro-Environment and Agro-Product Safety, Tianjin, 300191, People's Republic of China.
| | - Pingmei Yan
- College of Biological Sciences and Technology, Taiyuan Normal University, Yuci, 030619, People's Republic of China
| | - Yongtao Li
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, People's Republic of China
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Pyo M, Kim D, Lee EJ, Kim H, Lee KH. Effects of air blower and pump failures on the performance of A 2O processes for wastewater treatment. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 344:118380. [PMID: 37329585 DOI: 10.1016/j.jenvman.2023.118380] [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: 03/29/2023] [Revised: 06/05/2023] [Accepted: 06/10/2023] [Indexed: 06/19/2023]
Abstract
The unexpected failure of equipment such as pumps and fans in wastewater treatment plants can reduce wastewater treatment efficiency, leading to direct leakage of untreated wastewater into the environment. It is hence important to predict the possible consequences of equipment failure to minimize the leakage of harmful substances. This study examines the impacts of equipment shutdown on the performance and recovery time of a laboratory-scale anaerobic/anoxic/aerobic system with regard to reactor conditions and water quality. Two days after the air blowers are stopped, the concentrations of the soluble chemical oxygen demand, NH4-N, and PO4-P in the effluent of the settling tank increase to 122 mg/L, 23.8 mg/L, and 46.6 mg/L, respectively. These concentrations return to their initial values after 12, 24, and 48 h of restarting the air blowers. The concentrations of PO4-P and NO3-N in the effluent increase to 58 mg/L and 20 mg/L, respectively, about 24 h after stopping the return activated sludge and mixed liquor recirculation pumps, owing to the release of phosphates in the settling tank and inhibition of denitrification.
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Affiliation(s)
- Minsu Pyo
- Department of Environmental Engineering, Daegu University, 201 Daegudae-ro, Jillyang, Gyeongsan-si, Gyeongbuk, 38453, Republic of Korea; Graduate School of Water Resources, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 440746, Republic of Korea
| | - Dongyeon Kim
- Department of Environmental Engineering, Daegu University, 201 Daegudae-ro, Jillyang, Gyeongsan-si, Gyeongbuk, 38453, Republic of Korea
| | - Eui-Jong Lee
- Department of Environmental Engineering, Daegu University, 201 Daegudae-ro, Jillyang, Gyeongsan-si, Gyeongbuk, 38453, Republic of Korea.
| | - Hyungsoo Kim
- Graduate School of Water Resources, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do, 440746, Republic of Korea
| | - Kang Hoon Lee
- Department of Energy and Environmental Engineering, Catholic University, 43 Jibong-ro, Bucheon-si, 14662, Republic of Korea
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Li X, Li Y, Wu J. Different in root exudates and rhizosphere microorganisms effect on nitrogen removal between three emergent aquatic plants in surface flow constructed wetlands. CHEMOSPHERE 2023; 337:139422. [PMID: 37422212 DOI: 10.1016/j.chemosphere.2023.139422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/05/2023] [Accepted: 07/04/2023] [Indexed: 07/10/2023]
Abstract
Swine wastewater contains high concentration of nitrogen (N), causing pollution of surrounding water bodies. Constructed wetlands (CWs) are considered as an effective ecological treatment measure to remove nitrogen. Some emergent aquatic plants could tolerate high ammonia, and play a crucial part in CWs to treat high concentration N wastewater. However, the mechanism of root exudates and rhizosphere microorganisms of emergent plants on nitrogen removal is still unclear. Effects of organic and amino acids on rhizosphere N cycle microorganisms and environmental factors across three emergent plants were investigated in this study. The highest TN removal efficiency were 81.20% in surface flow constructed wetlands (SFCWs) plant with Pontederia cordata. The root exudation rates results showed that organic and amino acids were higher in 56 d than that in 0 d in SFCWs plants with Iris pseudacorus and P. cordata. The highest ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) gene copy numbers were found in I. pseudacorus rhizosphere soil, while the highest nirS, nirK, hzsB and 16S rRNA gene copy numbers were detected in P. cordata rhizosphere soil. Regression analysis results demonstrated that organic and amino acids exudation rates were positive related to rhizosphere microorganisms. These results indicated that organic and amino acids secretion could stimulate growth of emergent plants rhizosphere microorganisms in SFCWs for swine wastewater treatment. In addition, the EC, TN, NH4+-N and NO3--N were negatively correlated with organic and amino acids exudation rates, and abundances of rhizosphere microorganisms via Pearson correlation analysis. These results imply that organic and amino acids, and rhizosphere microorganisms synergically affected on the nitrogen removal in SFCWs.
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Affiliation(s)
- Xi Li
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, China; Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, China
| | - Yuyuan Li
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, China; Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, China.
| | - Jinshui Wu
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, China; Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Hunan, 410125, China; University of Chinese Academy of Sciences, Beijing 100049, China
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James SN, Vijayanandan A. Recent advances in simultaneous nitrification and denitrification for nitrogen and micropollutant removal: a review. Biodegradation 2023; 34:103-123. [PMID: 36899211 DOI: 10.1007/s10532-023-10015-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 02/06/2023] [Indexed: 03/12/2023]
Abstract
Simultaneous Nitrification and Denitrification (SND) is a promising process for biological nitrogen removal. Compared to conventional nitrogen removal processes, SND is cost-effective due to the decreased structural footprint and low oxygen and energy requirements. This critical review summarizes the current knowledge on SND related to fundamentals, mechanisms, and influence factors. The creation of stable aerobic and anoxic conditions within the flocs, as well as the optimization of dissolved oxygen (DO), are the most significant challenges in SND. Innovative reactor configurations coupled with diversified microbial communities have achieved significant carbon and nitrogen reduction from wastewater. In addition, the review also presents the recent advances in SND for removing micropollutants. The micropollutants are exposed to various enzymes due to the microaerobic and diverse redox conditions present in the SND system, which would eventually enhance biotransformation. This review presents SND as a potential biological treatment process for carbon, nitrogen, and micropollutant removal from wastewater.
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Affiliation(s)
- Susan N James
- Department of Civil Engineering, Indian Institute of Technology, Delhi, 110016, India
| | - Arya Vijayanandan
- Department of Civil Engineering, Indian Institute of Technology, Delhi, 110016, India.
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