1
|
He Y, Liu Y, Li X, Guo H, Zhu T, Liu Y. Polyvinyl Chloride Microplastics Facilitate Nitrous Oxide Production in Partial Nitritation Systems. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:1954-1965. [PMID: 38239129 DOI: 10.1021/acs.est.3c09280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2024]
Abstract
Partial nitritation (PN) is an important partner with anammox in the sidestream line treating high-strength wastewater and primarily contributes to nitrous oxide (N2O) emissions in such a hybrid system, which also suffers from ubiquitous microplastics because of the growing usage and disposal levels of plastics. In this study, the influences of polyvinyl chloride microplastics (PVC-MPs) on N2O-contributing pathways were experimentally revealed to fill the knowledge gap on N2O emission from the PN system under microplastics stress. The long-term results showed that the overall PN performance was hardly affected by the low-dose PVC-MPs (0.5 mg/L) while obviously deteriorated by the high dose (5 mg/L). According to the batch tests, PVC-MPs reduced biomass-specific ammonia oxidation rates (AORs) by 5.78-21.94% and stimulated aerobic N2O production by 9.22-88.36%. Further, upon increasing dissolved oxygen concentrations from 0.3 to 0.9 mg O2/L, the degree of AOR inhibition increased but that of N2O stimulation was lightened. Site preference analysis in combination with metabolic inhibitors demonstrated that the contributions of hydroxylamine oxidation and heterotrophic denitrification to N2O production at 0.3 mg O2/L were enhanced by 18.84 and 10.34%, respectively, accompanied by a corresponding decreased contribution of nitrifier denitrification. Finally, the underlying mechanisms proposed for negative influences of PVC-MPs were bisphenol A leaching and reactive oxygen species production, which led to more cell death, altered sludge properties, and reshaped microbial communities, further resulting in enhanced N2O emission. Overall, this work implied that the ubiquitous microplastics are a hidden danger that cannot be ignored in the PN system.
Collapse
Affiliation(s)
- Yanying He
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, P. R. China
| | - Yingrui Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, P. R. China
| | - Xuecheng Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, P. R. China
| | - Haixiao Guo
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, P. R. China
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, P. R. China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, P. R. China
| |
Collapse
|
2
|
Zheng X, Yan Z, Zhao C, He L, Lin Z, Liu M. Homogeneous environmental selection mainly determines the denitrifying bacterial community in intensive aquaculture water. Front Microbiol 2023; 14:1280450. [PMID: 38029183 PMCID: PMC10653326 DOI: 10.3389/fmicb.2023.1280450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 10/18/2023] [Indexed: 12/01/2023] Open
Abstract
Nitrate reduction by napA (encodes periplasmic nitrate reductase) bacteria and nitrous oxide reduction by nosZ (encodes nitrous oxide reductase) bacteria play important roles in nitrogen cycling and removal in intensive aquaculture systems. This study investigated the diversity, dynamics, drivers, and assembly mechanisms of total bacteria as well as napA and nosZ denitrifiers in intensive shrimp aquaculture ponds over a 100-day period. Alpha diversity of the total bacterial community increased significantly over time. In contrast, the alpha diversity of napA and nosZ bacteria remained relatively stable throughout the aquaculture process. The community structure changed markedly across all groups over the culture period. Total nitrogen, phosphate, total phosphorus, and silicate were identified as significant drivers of the denitrifying bacterial communities. Network analysis revealed complex co-occurrence patterns between total, napA, and nosZ bacteria which fluctuated over time. A null model approach showed that, unlike the total community dominated by stochastic factors, napA and nosZ bacteria were primarily governed by deterministic processes. The level of determinism increased with nutrient loading, suggesting the denitrifying community can be manipulated by bioaugmentation. The dominant genus Ruegeria may be a promising candidate for introducing targeted denitrifiers into aquaculture systems to improve nitrogen removal. Overall, this study provides important ecological insights into aerobic and nitrous oxide-reducing denitrifiers in intensive aquaculture, supporting strategies to optimize microbial community structure and function.
Collapse
Affiliation(s)
- Xiafei Zheng
- Ninghai Institute of Mariculture Breeding and Seed Industry, Zhejiang Wanli University, Ningbo, China
- Zhejiang Key Laboratory of Aquatic Germplasm Resource, College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, China
| | - Zhongneng Yan
- Ninghai Institute of Mariculture Breeding and Seed Industry, Zhejiang Wanli University, Ningbo, China
- Zhejiang Key Laboratory of Aquatic Germplasm Resource, College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, China
| | - Chenxi Zhao
- Ninghai Institute of Mariculture Breeding and Seed Industry, Zhejiang Wanli University, Ningbo, China
- Zhejiang Key Laboratory of Aquatic Germplasm Resource, College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, China
| | - Lin He
- Ninghai Institute of Mariculture Breeding and Seed Industry, Zhejiang Wanli University, Ningbo, China
- Zhejiang Key Laboratory of Aquatic Germplasm Resource, College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, China
| | - Zhihua Lin
- Ninghai Institute of Mariculture Breeding and Seed Industry, Zhejiang Wanli University, Ningbo, China
- Zhejiang Key Laboratory of Aquatic Germplasm Resource, College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, China
| | - Minhai Liu
- Ninghai Institute of Mariculture Breeding and Seed Industry, Zhejiang Wanli University, Ningbo, China
- Zhejiang Key Laboratory of Aquatic Germplasm Resource, College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, China
| |
Collapse
|
3
|
Zheng S, Li J, Ye C, Xian X, Feng M, Yu X. Microbiological risks increased by ammonia-oxidizing bacteria under global warming: The neglected issue in chloraminated drinking water distribution system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 874:162353. [PMID: 36822432 DOI: 10.1016/j.scitotenv.2023.162353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
A rising outbreak of waterborne diseases caused by global warming requires higher microbial stability in the drinking water distribution system (DWDS). Chloramine disinfection is gaining popularity in this context due to its good persistent stability and fewer disinfection byproducts. However, the microbiological risks may be significantly magnified by ammonia-oxidizing bacteria (AOB) in distribution systems during global warming, which is rarely noticed. Hence, this work mainly focuses on AOB to explore its impact on water quality biosafety in the context of global warming. Research indicates that global warming-induced high temperatures can directly or indirectly promote the growth of AOB, thus leading to nitrification. Further, its metabolites or cellular residues can be used as substrates for the growth of heterotrophic bacteria (e.g., waterborne pathogens). Thus, biofilm may be more persistent in the pipelines due to the presence of AOB. Breakpoint chlorination is usually applied to control such situations. However, switching between this strategy and chloramine disinfection would result in even more severe nitrification and other adverse effects. Based on the elevated microbiological risks in DWDS, the following aspects should be paid attention to in future research: (1) to understand the response of nitrifying bacteria to high temperatures and the possible association between AOB and pathogenic growth, (2) to reveal the mechanisms of AOB-mediated biofilm formation under high-temperature stress, and (3) to develop new technologies to prevent and control the occurrence of nitrification in drinking water distribution system.
Collapse
Affiliation(s)
- Shikan Zheng
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Jianguo Li
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Chengsong Ye
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Xuanxuan Xian
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Mingbao Feng
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China
| | - Xin Yu
- College of the Environment and Ecology, Xiamen University, Xiamen 361102, China.
| |
Collapse
|
4
|
Chen Y, Qin H, Lu Y, Liu H, Zhang J. A novel method to measure air-immobile regions of the composting pile by inverse calculation combined with gas tracer test. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 150:131-140. [PMID: 35830767 DOI: 10.1016/j.wasman.2022.06.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 06/27/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
Air-immobile regions in composting piles obstruct O2 mass transport and exacerbate the formation and emission of harmful off-gases. However, effective methods for measuring the parameters of these air-immobile regions are lacking. With quartz sand piles, this study first adjusted the circumstances of a gas tracer test (gas tracer, its injection volume, and chamber type) using the two-region model (TRM). The effects of β (proportional coefficient of gas in the air-mobile region) and ω (mass exchange coefficient) on the breakthrough curves (BTCs) of the gases were then explored. Finally, an inverse calculation method was used to measure the feature parameters of air-immobile regions in two composting piles (temperature-increasing and thermophilic phases) and estimate the O2 concentrations in different composting piles (50, 100, 200 cm whole height; layers of 50, 100, 200 cm height in a 200-cm high pile). The results showed that the optimal conditions were achieved when 100 mL helium (He) as the gas tracer and a cylinder with a height/diameter ratio of 3 as the chamber were used. With the simulating composting piles, increasing β or ω slowed breakthrough and decreased peak concentration in BTCs of a gas tracer. Tracer-inverse calculation protocol can be used to efficiently estimate the volume ratios of air-immobile regions (φ) and first-order mass transfer coefficient (α), with the values of 39%/46% and 0.001/0.006 min-1 in the composting piles during temperature-increasing /thermophilic phase. The TRM also predicted the O2 concentration in the off-gas or air-mobile/immobile regions of the temperature-increasing-phase composting piles.
Collapse
Affiliation(s)
- Yixiao Chen
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China
| | - Haiguang Qin
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China
| | - Yulan Lu
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China
| | - Hongtao Liu
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
| | - Jun Zhang
- Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China.
| |
Collapse
|
5
|
Lin Z, Ma K, Yang Y. Nitrous Oxide Emission from Full-Scale Anammox-Driven Wastewater Treatment Systems. LIFE (BASEL, SWITZERLAND) 2022; 12:life12070971. [PMID: 35888061 PMCID: PMC9317218 DOI: 10.3390/life12070971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/16/2022] [Accepted: 06/27/2022] [Indexed: 11/23/2022]
Abstract
Wastewater treatment plants (WWTPs) are important contributors to global greenhouse gas (GHG) emissions, partly due to their huge emission of nitrous oxide (N2O), which has a global warming potential of 298 CO2 equivalents. Anaerobic ammonium-oxidizing (anammox) bacteria provide a shortcut in the nitrogen removal pathway by directly transforming ammonium and nitrite to nitrogen gas (N2). Due to its energy efficiency, the anammox-driven treatment has been applied worldwide for the removal of inorganic nitrogen from ammonium-rich wastewater. Although direct evidence of the metabolic production of N2O by anammox bacteria is lacking, the microorganisms coexisting in anammox-driven WWTPs could produce a considerable amount of N2O and hence affect the sustainability of wastewater treatment. Thus, N2O emission is still one of the downsides of anammox-driven wastewater treatment, and efforts are required to understand the mechanisms of N2O emission from anammox-driven WWTPs using different nitrogen removal strategies and develop effective mitigation strategies. Here, three main N2O production processes, namely, hydroxylamine oxidation, nitrifier denitrification, and heterotrophic denitrification, and the unique N2O consumption process termed nosZ-dominated N2O degradation, occurring in anammox-driven wastewater treatment systems, are summarized and discussed. The key factors influencing N2O emission and mitigation strategies are discussed in detail, and areas in which further research is urgently required are identified.
Collapse
|
6
|
Li Z, Yang X, Chen H, Du M, Ok YS. Modeling nitrous oxide emissions in membrane bioreactors: Advancements, challenges and perspectives. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:151394. [PMID: 34740645 DOI: 10.1016/j.scitotenv.2021.151394] [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: 09/03/2021] [Revised: 10/21/2021] [Accepted: 10/30/2021] [Indexed: 06/13/2023]
Abstract
Membrane bioreactors (MBRs) have become a well-established wastewater treatment technology owing to their extraordinary efficiency and low space advantage over conventional activated sludge processes. Although the extended activated sludge models can predict the general trend of nitrous oxide (N2O) emissions in MBRs, the simulation results usually deviate from the actual values. This review critically evaluates the recent advances in the modeling of N2O emissions in MBRs, and proposes future directions for the development and improvement of models that better match the MBR characteristics. The quantitative impact of MBR characteristics on N2O emissions is identified as a key knowledge gap demanding urgent attention. Accurately clarification of the N2O emission pathways governed by MBR characteristics is essential to improve the reliability and practicability of existing models. This article lays a momentous foundation for the optimization of N2O models in MBRs, and proposes new demands for the next-generation model. The contents will assist academics and engineers in developing N2O production models for accurate prediction.
Collapse
Affiliation(s)
- Zeyu Li
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Xiao Yang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Hongbo Chen
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China.
| | - Mingyang Du
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Yong Sik Ok
- Korea Biochar Research Center, O-Jeong Eco-Resilience Institute (OJERI), Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea.
| |
Collapse
|
7
|
Yan X, Yang J, Guo D, Ma J, Su X, Sun J. Effect of carbon source on nitrous oxide emission characteristics and sludge properties during anoxic/aerobic wastewater treatment process. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:57557-57568. [PMID: 34091848 DOI: 10.1007/s11356-021-14713-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 05/31/2021] [Indexed: 06/12/2023]
Abstract
Carbon sources are an important parameter in wastewater treatment processes and are closely related to treatment efficiency and nitrous oxide (N2O) emissions. In this study, three parallel sequencing batch reactors (SBRs) were processed with acetic acid, propionic acid, and a 1:1 mixture of both acids (calculated in COD) to study the effect of carbon sources on N2O generation and sludge properties (including intracellular polymer content, extracellular polymeric substance (EPS) composition, particle size distribution, settleability, and microbial community structure). The results showed that the highest COD, NH4+-N, and TP removal efficiencies (92.2%, 100%, and 82.3%, respectively) were achieved by the reactor with mixed acid as the carbon source, whereas the reactor using acetic acid had the highest TN removal rate (82.6%) and the lowest N2O-N conversion rate (1.4%, based on TN removal). The reactor with the carbon source of mixed acid produced the highest polyhydroxyalkanoate (PHA) content, which led to an increase in N2O generation from the aerobic denitrification pathway. The SBR with mixed acid carbon source also had the highest concentration of EPS, which resulted in the largest particle size and the lowest settleability of sludge flocs among the SBRs. Microbial analysis results revealed that the difference in carbon sources resulted in a variation in the microbial community as well as in the relative abundances of functional microbes involved in biological nitrogen removal processes. The mixed acid promoted the development of ammonia-oxidizing bacteria (AOB), which conducted the primary N2O generation pathway of aerobic denitrification bioreactions. The carbon source of acetic acid promoted the growth of denitrifying bacteria (DNB), which led to the highest TN removal rate. This study provides a comprehensive understanding of the effects of carbon sources on N2O generation and sludge properties for WWTPs.
Collapse
Affiliation(s)
- Xu Yan
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China.
| | - Jie Yang
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Dongli Guo
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jiahui Ma
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Xianfa Su
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jianhui Sun
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| |
Collapse
|
8
|
Ji J, Peng L, Redina MM, Gao T, Khan A, Liu P, Li X. Perfluorooctane sulfonate decreases the performance of a sequencing batch reactor system and changes the sludge microbial community. CHEMOSPHERE 2021; 279:130596. [PMID: 33887592 DOI: 10.1016/j.chemosphere.2021.130596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 04/08/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
The existence of perfluorooctane sulfonate (PFOS) in large quantities threatens environment biosafety. However, the fate of PFOS in a sequencing batch reactor (SBR) system and its influence in system has not yet been revealed. In this study, the fate and behavior of PFOS in an SBR processing system were investigated. Mass balance analyses revealed that PFOS removal was mainly through adsorption. After the reactors were run for 20 days, the PFOS (100 mg/L) removal rate was only 28%. Under the influence of PFOS, the removal rates of chemical oxygen demand (COD) and ammonia nitrogen dropped rapidly from 92, 98% to 23, 35% in the 20th day of system operation, respectively, while, accumulation of nitrite and nitrate was reduced. Compared with the control group, PFOS stimulates microorganisms to secrete more soluble microbial products (SMP) and extracellular polymeric substances (EPS). The adsorption of PFOS and EPS causes sludge bulking and decreases settling. The richness and diversity of microorganisms decreased significantly, affecting the system's removal of COD and ammonia nitrogen. Therefore, the SBR system is not suitable for treating wastewater containing PFOS. It is necessary to remove PFOS through pretreatment to reduce its impact on the SBR system.
Collapse
Affiliation(s)
- Jing Ji
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu, 730000, PR China
| | - Liang Peng
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu, 730000, PR China
| | - M M Redina
- Peoples' Friendship University of Russia, 117198, Moscow, Miklukho-Maklaya str., 6, Russia
| | - Tianpeng Gao
- School of Biological and Environmental Engineering, Xi'an University, Xi'an, 710065, PR China
| | - Aman Khan
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu, 730000, PR China
| | - Pu Liu
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu, 730000, PR China
| | - Xiangkai Li
- Gansu Key Laboratory of Biomonitoring and Bioremediation for Environment Pollution, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu, 730000, PR China; Key Laboratory for Resources Utilization Technology of Unconventional Water of Gansu Province, Gansu Academy of Membrane Science and Technology, Duanjiatanlu #1272, Lanzhou, 730020, PR China.
| |
Collapse
|
9
|
Dai H, Han T, Sun T, Zhu H, Wang X, Lu X. Nitrous oxide emission during denitrifying phosphorus removal process: A review on the mechanisms and influencing factors. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 278:111561. [PMID: 33126199 DOI: 10.1016/j.jenvman.2020.111561] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 08/17/2020] [Accepted: 10/21/2020] [Indexed: 06/11/2023]
Abstract
Excessive emissions of nitrogen (N) and phosphorus (P) pollutants are leading to increased eutrophication of water bodies. Biological N and P removal processes have become a research priority in the field of sewage treatment with the aim of improving sewage discharge standards in countries worldwide. Denitrifying P removal processes are more efficient for solving problems related to carbon source competition, sludge age conflict, and high aeration energy consumption compared to traditional biological N and P removal processes, but they are easy to produce nitrous oxide (N2O) in the process of sewage treatment. N2O is a greenhouse gas with a global warming potential approximately 190-270 times that of CO2 and 4-21 times that of CH4, which was produced and released into the environmental in denitrifying P removal systems under conditions of a low C/N ratio, high dissolved oxygen, and low activity of denitrifying phosphorus accumulating organisms (DPAOs). This paper reviews the emission characteristics and influencing factors of N2O during denitrifying P removal processes and proposes appropriate strategies for controlling the emission of N2O. This work serves as a basis for the development of new sewage treatment processes and the reduction of greenhouse gas emissions in future wastewater treatment plants.
Collapse
Affiliation(s)
- Hongliang Dai
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212003, China; School of Environmental and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China; School of Energy and Environment, Southeast University, Nanjing, 210096, China.
| | - Ting Han
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212003, China
| | - Tongshuai Sun
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212003, China
| | - Hui Zhu
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212003, China
| | - Xingang Wang
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212003, China.
| | - Xiwu Lu
- School of Energy and Environment, Southeast University, Nanjing, 210096, China
| |
Collapse
|
10
|
Chen H, Zou M, Zhou Y, Zeng L, Yang X. Monitoring the nitrous oxide emissions and biological nutrient removal from wastewater treatment: Impact of perfluorooctanoic acid. JOURNAL OF HAZARDOUS MATERIALS 2021; 402:123469. [PMID: 32702618 DOI: 10.1016/j.jhazmat.2020.123469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/08/2020] [Accepted: 07/13/2020] [Indexed: 06/11/2023]
Abstract
The impacts of perfluorooctanoic acid (PFOA) on biological nutrient removal and nitrous oxide (N2O) emissions have been specifically studied. The experimental results show that PFOA inhibited nitrification, but promoted denitrification and reduced N2O emissions without significantly affecting phosphorus removal. The existence of 20 mg/L of PFOA increased total nitrogen removal efficiency from 78.7 ± 6.89 % to 86.8 ± 6.39 % and reduced N2O emission factor from 6.02 ± 0.24 % to 4.43 ± 0.10 %. The mechanism studies reveal that microorganisms released extracellular polymeric substances (EPS) under PFOA exposure to protect sludge cells against PFOA toxicity. The generated PFOA-EPS conjugates reduced the nitrification rate, but increased the denitrification rate by regulating the activity of oxidoreductases. In addition, PFOA reduced the activity of polyphosphate accumulating organisms and glycogen accumulating organisms to save carbon source for denitrification, which reduced the electronic competition between reductases, thereby achieving complete denitrification and N2O mitigation. The promotion of PFOA for denitrification and N2O mitigation can gain a more comprehensive cognition of the role of PFOA in wastewater treatment. The release mechanism of EPS can afford new insights for the development of effective methods to enhance nitrogen removal and reduce N2O emissions.
Collapse
Affiliation(s)
- Hongbo Chen
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Mei Zou
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Yaoyu Zhou
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Long Zeng
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Xiao Yang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
| |
Collapse
|
11
|
Yan X, Zheng S, Yang J, Ma J, Han Y, Feng J, Su X, Sun J. Effects of hydrodynamic shear stress on sludge properties, N 2O generation, and microbial community structure during activated sludge process. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 274:111215. [PMID: 32814212 DOI: 10.1016/j.jenvman.2020.111215] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/06/2020] [Accepted: 08/07/2020] [Indexed: 06/11/2023]
Abstract
Sludge properties are critical to the treatment performance and potentially correlate with nitrous oxide (N2O) generation during activated sludge processes. The hydrodynamic shear stress induced by aeration has a significant influence on sludge properties and is inevitable for wastewater treatment plants (WWTPs). In this study, the effects of aerobic induced hydrodynamic shear stress on sludge properties, N2O generation, and microbial community structure were investigated using three parallel sequencing batch reactors (SBRs) with identical dissolved oxygen (DO) concentrations. Results showed that with a shear stress increase from 1.5 × 10-2 N/m2 to 5.0 × 10-2 N/m2, the COD and NH4+-N removal rates were enhanced from 89.4% to 94.0% and from 93.9% to 98.0%, respectively, while the TN removal rate decreased from 66.0% to 56.5%. Settleability of the activated sludge flocs (ASFs) also increased with the enhancement of shear stress, due to variation in sludge properties including particle size, regularity, compactibility, and EPS (extracellular polymeric substances) composition. The increase in shear stress promoted oxygen diffusion within the ASFs and mitigated NO2--N accumulation, leading to a decrease in the N2O-N conversion rate from (4.8 ± 0.3)% to (2.2 ± 0.6)% (based on TN removal). Microbial analysis results showed that the functional bacteria involved in the biological nitrogen removal was closely related with shear stress. The increase in shear stress favored the enrichment of nitrite oxidizing bacteria (NOB) while suppressed the accumulation of ammonia-oxidizing bacteria (AOB) and denitrifying bacteria (DNB).
Collapse
Affiliation(s)
- Xu Yan
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China.
| | - Shikan Zheng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jie Yang
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jiahui Ma
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Yunping Han
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Jinglan Feng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Xianfa Su
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jianhui Sun
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| |
Collapse
|
12
|
Chen H, Du M, Wang D, Zhou Y, Zeng L, Yang X. Influence of chlortetracycline as an antibiotic residue on nitrous oxide emissions from wastewater treatment. BIORESOURCE TECHNOLOGY 2020; 313:123696. [PMID: 32570074 DOI: 10.1016/j.biortech.2020.123696] [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: 04/28/2020] [Revised: 06/10/2020] [Accepted: 06/13/2020] [Indexed: 06/11/2023]
Abstract
Strengthening the removal of antibiotics in wastewater treatment plants is a research focus, but whether antibiotics affect nitrous oxide (N2O) emissions from wastewater treatment remains to be determined. In this study, the effect of chlortetracycline (CTC) on N2O emissions in anaerobic/oxic/anoxic sequential batch reactors was investigated. Experimental results show that CTC promotes N2O emissions during biological nutrient removal. The addition of 0.1 mg/L CTC increased the N2O emission factor by 41.4% compared to the control. Mechanism exploration shows that CTC stimulates the release of extracellular polymeric substance (EPS) and binds to it, the generated EPS-CTC conjugates hinder or expand the mass transfer channel, which intensifies the electronic competition between oxidoreductases and the substrate competition between microorganisms, resulting in incomplete denitrification and nitrite accumulation, thereby increasing N2O emissions.
Collapse
Affiliation(s)
- Hongbo Chen
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China.
| | - Mingyang Du
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Dongbo Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China
| | - Yaoyu Zhou
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Long Zeng
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Xiao Yang
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| |
Collapse
|
13
|
Yan X, Zheng S, Huo Z, Shi B, Huang J, Yang J, Ma J, Han Y, Wang Y, Cheng K, Feng J, Sun J. Effects of exogenous N-acyl-homoserine lactones on nutrient removal, sludge properties and microbial community structures during activated sludge process. CHEMOSPHERE 2020; 255:126945. [PMID: 32388260 DOI: 10.1016/j.chemosphere.2020.126945] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
This study investigated the effects of exogenous N-acyl-homoserine lactone (AHL) signal molecules, N-hexanoyl-l-homoserine lactone (C6-HSL) and N-octanoyl-l-homoserine lactone (C8-HSL), on treatment performance, sludge properties and microbial community structures in activated sludge systems. Results showed that the nitrification and denitrification efficiencies were enhanced with the addition of signal molecules. The particle size, irregularity, and internal mass transfer resistance of activated sludge flocs (ASFs) increased, primarily because dosing AHLs led to a content increase and chemical composition variation of extracellular polymeric substances (EPS) in sludge. Microbial analysis indicated an increase in both the bacterial richness and diversity of the systems. The relative abundances of the key functional groups, including bacteria related to C and N removal and EPS production, varied correspondingly. This study presents an insight into the comprehensive understanding of the effects of AHL-based quorum sensing on activated sludge treatment process.
Collapse
Affiliation(s)
- Xu Yan
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China.
| | - Shikan Zheng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Zhaoman Huo
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Bowen Shi
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jiajun Huang
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jie Yang
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jiahui Ma
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Yunping Han
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Yan Wang
- School of Public Health, Xinxiang Medical University, Xinxiang, 453003, China
| | - Ke Cheng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jinglan Feng
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| | - Jianhui Sun
- School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Henan Normal University, Xinxiang, 453007, Henan, China
| |
Collapse
|
14
|
Chen H, Zeng L, Wang D, Zhou Y, Yang X. Exploring the linkage between free nitrous acid accumulation and nitrous oxide emissions in a novel static/oxic/anoxic process. BIORESOURCE TECHNOLOGY 2020; 304:123011. [PMID: 32088627 DOI: 10.1016/j.biortech.2020.123011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/08/2020] [Accepted: 02/11/2020] [Indexed: 06/10/2023]
Abstract
In this work, four batch tests were conducted to comprehensively explore the effects of free nitrous acid (FNA) accumulation on nitrous oxide (N2O) emissions in a novel energy-saving and N2O-reducing static/oxic/anoxic (SOA) process. With the accumulation of FNA, the N2O emission factor increased from 1.51% to 4.32%, and the N2O emission ratio contributed by ammonia-oxidizing bacteria (AOB) increased from 74.0% to 78.6%, accordingly. Mechanism studies show that produced FNA and weakened aerobic metabolism bring synergy to competition between reductases. Aeration conditions and FNA cytotoxicity exert a greater impact on nitrite-oxidizing bacteria than on AOB, thus enhancing the potential for nitrite accumulation. Considering the removal of nitrogen and phosphorus and the reduction of N2O emissions in the SOA process, it is feasible to keep the average dissolved oxygen above 2.0 mg/L under the premise of nitrite accumulation.
Collapse
Affiliation(s)
- Hongbo Chen
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Long Zeng
- College of Environment and Resources, Xiangtan University, Xiangtan 411105, China
| | - Dongbo Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China
| | - Yaoyu Zhou
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Xiao Yang
- Korea Biochar Research Center, O-Jeong Eco-Resilience Institute (OJERI) & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea.
| |
Collapse
|