Article
Ecology
C. A. Arias, D. Istenic, O. Stein, X. Zhai, R. Kilian, I. Vera-Puerto, H. Brix
Summary: This study assessed the impact of recycling water from VFCW effluent on a decentralized wastewater system and recommended an appropriate bed depth based on the changes in water quality. The results showed that the system performed well and the dimensions given in the Danish guidelines may be overdesigned.
ECOLOGICAL ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Zhaolei Li, Zhaoqi Zeng, Zhaopeng Song, Dashuan Tian, Xingzhao Huang, Sheng Nie, Jun Wang, Lifen Jiang, Yiqi Luo, Jun Cui, Shuli Niu
Summary: This study provides insights into the geographical variations and primary controlling factors of global soil N2O emissions based on a new dataset of soil N2O emission rates compiled from field observations. It highlights the critical roles of soil N substrates on N2O emissions, contributing to the optimization of process-models for soil N2O emissions.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Environmental Sciences
Manping Zhang, Jung-Chen Huang, Shanshan Sun, Muhammad Muneeb Ur Rehman, Shengbing He, Weili Zhou
Summary: Constructed wetlands are effective in removing nitrogen from water, with potential activities of DNRA, anammox, denitrification, and nitrification contributing to nitrogen removal. Planted mesocosms showed better performance in nitrogen removal compared to unplanted mesocosms, with higher values of potential activities of nitrogen-cycling pathways observed in the planted mesocosms.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Environmental Sciences
Shuiping Cheng, Jing Huai, Fei Zhong, Juan Wu, Shaole Yu
Summary: The study found that adding algae to constructed wetlands can strengthen the anoxic environment, increase volatile fatty acid concentrations, and improve the ratios of various nitrite reductase and nitrate reductase genes, thus expanding the active space for denitrification. Therefore, algae addition could potentially enhance denitrification in wastewater treatment with low COD/N ratios.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Environmental Sciences
Yuhui Wang, Panpan Zhou, Xinshan Song, Zhongshuo Xu
Summary: Considerable advances have been made in the substrate design and operation strategies of constructed wetlands to facilitate nitrogen elimination. This study developed a new technology for constructed wetlands, which achieved efficient nitrogen removal under limited aeration conditions by using gradient distribution of inorganic and solid organic substrates, and confirmed the occurrence of simultaneous nitrification and denitrification process.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Engineering, Environmental
Li-Li Han, Helin Wang, Lianghao Ge, Min Nina Xu, Jin-Ming Tang, Li Luo, Ping Li, Shuh-Ji Kao
Summary: Ammonium (NH4+) retention/removal processes in groundwater are important due to human activities increasing nitrogenous compound loading. However, the transformation processes determining NH4+ fate in groundwater under different redox conditions have not been well studied. In a high nitrogen groundwater system in China, NH4+ source and sink processes were identified and quantified, revealing the dominance of mineralization and nitrification in oxidizing zones, and anammox in reducing zones. The NH4+ production/consumption ratio increased downstream, indicating NH4+ accumulation in strongly reducing groundwater where aerobic conditions are lacking. These findings provide insights for understanding NH4+ dynamics and suggest mitigation techniques for groundwater NH4+.
Article
Environmental Sciences
Thi Thu Hang Pham, Vincent Cochevelou, Hoang Dang Khoa Dinh, Florian Breider, Pierre Rossi
Summary: The project describes the implementation of a laboratory-based continuous closed recirculation aquaculture system in the Mekong delta region. The system utilizes a constructed wetland as a water treatment filter, operating under high loading rate conditions and significantly improving shrimp culture water quality.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2021)
Article
Environmental Sciences
A. Pascual, J. A. Alvarez, D. de la Varga, C. A. Arias, D. Van Oirschot, R. Kilian, M. Soto
Summary: The influence of bed depth on the performance of aerated horizontal constructed wetlands was investigated at the pilot plant scale. The results showed that a larger bed depth and artificial aeration can improve the loading rate and the removal efficiency of organic matter and nitrogen in the horizontal constructed wetlands.
SCIENCE OF THE TOTAL ENVIRONMENT
(2024)
Article
Environmental Sciences
Young-Jae Jeong, Bo-Seong Seo, Nuri Baek, Jin-Hyeob Kwak, Sang-Mo Lee, Hyun-Jin Park, Woo-Jung Choi
Summary: This study proposed methods for determining the δN-15 of multiple nitrogen species. The methods included traditional distillation, direct evaporation, and isotope mass balance equation. The accuracy and precision of the methods were evaluated through a series of experiments, and the influences of different conditions on the analysis results were assessed.
FRONTIERS IN ENVIRONMENTAL SCIENCE
(2022)
Article
Engineering, Environmental
Naveen Chand, Kapil Kumar, Surindra Suthar
Summary: The study demonstrated that intermittent aeration in VFCWs significantly improved the removal efficiency of COD, NH4+-N, NO3-N, and TP compared to non-aerated setups, while setups with biochar (BC) addition and plantation were more advantageous in nutrient removal than those without BC. Moreover, the COD/N ratio of wastewater did not have a significant impact on VFCWs with BC and intermittent aeration, indicating the effectiveness of slow adsorption and fast aerobic degradation processes.
JOURNAL OF WATER PROCESS ENGINEERING
(2021)
Article
Environmental Sciences
Zhouying Xu, Chen Wu, Yihui Ban, Shiyang Zhang
Summary: In this study, a hybrid constructed wetland system was used to treat synthetic domestic wastewater, with the optimal shunt rate identified as 40%. Denitrifying bacteria were found to be the dominant microorganisms, with nitrification and denitrification being the main nitrogen removal pathways, and anammox was also discovered in the HFCW.
WATER AIR AND SOIL POLLUTION
(2021)
Article
Environmental Sciences
Wenbo Liu, Md Hasibur Rahaman, Jun Zhai, Jacek Makinia
Summary: The study investigated the coupling transformation of carbon, nitrogen, and sulfur compounds in a full-scale horizontal subsurface flow wetland. Results showed that heterotrophic denitrification and sulfide-based autotrophic denitrification were the main pathways. Increasing TOC or NO3- concentrations promoted heterotrophic denitrification, while increasing S2- concentrations enhanced sulfide-based autotrophic denitrification.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Biotechnology & Applied Microbiology
Songsong Chen, Limin Ma, Guodong Yao, Yuncai Wang
Summary: This study demonstrated the effectiveness of using a mixed culture of atrazine-degrading bacteria to improve atrazine removal in constructed wetlands. The results showed that atrazine was primarily degraded through a hydrolysis pathway mediated by microorganisms. Stable isotope analysis supported the findings, showing that 90% of atrazine was removed biologically.
INTERNATIONAL BIODETERIORATION & BIODEGRADATION
(2023)
Article
Green & Sustainable Science & Technology
Rongzhen Wang, Xinwen Zhang, Shuya Yang, Zhenghe Xu, Chengye Feng, Fangxing Zhao
Summary: This study designed a novel hybrid constructed wetland with sulfur-siderite filler and drop aeration to enhance nitrogen removal. The results showed that the TN removal rate increased significantly, with sulfur autotrophic denitrification as the dominant pathway. Compounds generated during nitrogen removal acted as trace elements, promoting the growth of wetland plants.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Engineering, Environmental
Hai Wang, Renrong Liu, Qian Chen, Haixin Xia, Yaohong Zhang
Summary: In this study, the composite of Chitosan-FeS @ peanut shell biochar (CFP) was applied in constructed wetlands (CWs) to treat N and Pb co-existing wastewater. The results showed that adding CFP enhanced the nitrification and denitrification intensity and increased the removal rates of NO3-, NH4+ and TN. CFP not only acted as an electron donor to drive denitrification, but also increased the abundance of Thiobacillus, Sulfurimonas and Geobacter, thus promoting N removal. Furthermore, CFP alleviated Pb stress on Acorus calamus L.
JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Rachel Murray, Dirk Erler, Judith Rosentreter, Naomi S. Wells, Bradley D. Eyre
Article
Geochemistry & Geophysics
Naomi S. Wells, Jian-Jhih Chen, Damien T. Maher, Peisheng Huang, Dirk Erler, Matthew Hipsey, Bradley D. Eyre
GEOCHIMICA ET COSMOCHIMICA ACTA
(2020)
Article
Limnology
Jian-Jhih Chen, Dirk V. Erler, Naomi S. Wells, Jianyin Huang, David T. Welsh, Bradley D. Eyre
Summary: Estuaries function as key modulators of nitrogen flow to marine ecosystems, with the dominant pathway for N-2 production being coupled nitrification-denitrification, especially in vegetated habitats. Macroalgae habitats play a significant role in N removal and retention, contributing to a large portion of N-2 production and DNRA despite their smaller surface area compared to other habitats. The presence of seagrass and macroalgae is strongly correlated with N-2 production, indicating a potential decrease in the capacity of estuaries to mitigate reactive N loads with the loss of these vegetated habitats.
LIMNOLOGY AND OCEANOGRAPHY
(2021)
Article
Environmental Sciences
Roisin McCallum, Bradley Eyre, Glenn Hyndes, Kathryn McMahon, Joanne M. Oakes, Naomi S. Wells
Summary: Estuaries and their catchments play a crucial role in the cycling of dissolved organic matter and nutrients, with ICOLLs impacting the biogeochemical processes and release of nitrogen and carbon into coastal environments. Despite low inorganic nitrogen concentrations, the eutrophic ICOLL studied in southwest Australia experiences issues such as algal blooms and low dissolved oxygen, highlighting the importance of considering dissolved organic nitrogen in nitrogen studies. Including dissolved organic nitrogen in nitrogen studies may have a significant impact on the current understanding of the global nitrogen budget.
Article
Geochemistry & Geophysics
Naomi S. Wells, Bradley Eyre
Summary: This study focuses on the role of streams in regulating N cycling and greenhouse gas emissions. The research found that as stream discharge dropped, concentrations of NO3- and N2O in surface water increased significantly due to within-stream production rather than increased groundwater inputs. This highlights the importance of hydrological dynamics in directly influencing biological cycling of nitrogen and nitrous oxide in streams.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Environmental Sciences
Judith A. Rosentreter, Naomi S. Wells, Amber J. Ulseth, Bradley D. Eyre
Summary: Spatial and temporal variability, as well as poor predictability of gas transfer velocity (k(600)), contribute to high global uncertainties in water-air CO2, CH4, and N2O fluxes from estuaries. The study in the Maroochy estuary found that temporal variability of k(600) was greater than spatial variability, with the highest variability of k(600) between gas species observed in the lower estuary. Additionally, k(600)CO(2) was mostly higher than k(600)CH(4) and k(600)N(2)O, likely due to chemical and enzymatic enhancements and/or microbial activity in the surface microlayer.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2021)
Article
Environmental Sciences
Peisheng Huang, Eduardo R. De Sousa, Naomi S. Wells, Bradley D. Eyre, Badin Gibbes, Matthew R. Hipsey
Summary: Estuaries play a significant role in the global greenhouse gas budget, but there are uncertainties in modeling predictions of CO2 and CH4 emissions. This study presents a modeling framework to assess the sensitivity and uncertainty of CO2 and CH4 concentrations and emissions, applied to the Brisbane River in Australia. The findings demonstrate that riverine inputs are the main factor influencing estuarine CO2 concentrations, while sediment production and pelagic oxidation are the main factors influencing estuarine CH4 concentrations.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2022)
Article
Multidisciplinary Sciences
E. Harris, L. Yu, Y-P. Wang, J. Mohn, S. Henne, E. Bai, M. Barthel, M. Bauters, P. Boeckx, C. Dorich, M. Farrell, P. B. Krummel, Z. M. Loh, M. Reichstein, J. Six, M. Steinbacher, N. S. Wells, M. Bahn, P. Rayner
Summary: Anthropogenic nitrogen inputs have significant negative impacts on the environment, especially through the emission of the important greenhouse gas N2O. The shifts in terrestrial nitrogen loss pathways driven by global change are highly uncertain. This study presents a model that quantifies terrestrial nitrogen losses and N2O emission factors, revealing that atmospheric deposition inputs are the main cause of anthropogenic N2O emissions from soils. The predicted increase in fertilizer use in emerging economies will further accelerate N2O-driven climate warming, unless targeted mitigation measures are implemented.
NATURE COMMUNICATIONS
(2022)
Article
Environmental Sciences
Jian-Jhih Chen, Naomi S. Wells, Dirk Erler, Bradley D. Eyre
Summary: Land-use changes in catchments have an impact on benthic N2O cycling in estuaries, with benthic habitats acting as either a sink or source of N2O. Benthic N2O fluxes are significantly correlated with benthic NO3- fluxes, indicating the importance of NO3- availability in controlling benthic N2O fluxes.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2022)
Article
Environmental Sciences
Naomi S. Wells, Daren C. Gooddy, Mustefa Yasin Reshid, Peter J. Williams, Andrew C. Smith, Bradley D. Eyre
Summary: Accurately tracing the sources and fate of excess PO43- in waterways is crucial for sustainable catchment management. The natural abundance isotopic composition of O in PO43- (δO-18(P)) shows promise as a tracer for point source pollution, but its ability to track diffuse agricultural pollution is still uncertain.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2022)
Article
Ecology
S. Cronin-O'Reilly, N. S. Wells, R. McCallum, C. S. Hallett, J. R. Tweedley, F. J. Valesini, B. D. Eyre
Summary: Anthropogenic alterations to coastal sediments and their benthic macroinvertebrate communities impair ecosystem function. Sediment condition has a greater influence on benthic metabolism, while the macroinvertebrate community has a greater impact on nutrient exchange. Denitrification is driven by both sediment condition and the community. Overall, benthic macroinvertebrates have limited effects on ecosystem processes, indicating their limited functional role in this estuary. There is also a functional decoupling between sediment condition and the community. Community biomass is the most frequently selected predictor for significant macroinvertebrate effects.
MARINE ECOLOGY PROGRESS SERIES
(2022)
Article
Ecology
S. Cronin-O'Reilly, N. S. Wells, R. McCallum, C. S. Hallett, J. R. Tweedley, F. J. Valesini, B. D. Eyre
Summary: The ability of deoxygenation treatment to remove macroinvertebrates from sediment cores is limited, and the remaining biomass has significant effects on environmental fluxes. Different communities have divergent responses to hypoxia.
MARINE ECOLOGY PROGRESS SERIES
(2022)
Article
Chemistry, Multidisciplinary
Xin Wang, Naomi S. Wells, Wei Xiao, Jessica L. Hamilton, Adele M. Jones, Richard N. Collins
Summary: This study evaluated the influence of low to nearly neutral pH on FeS in NO3- chemodenitrification, finding optimal reduction at pH 3.5 and no contribution to N2O(g) formation. Additionally, the first step of NO3- reduction by FeS does not affect stable isotope analysis of the residual NO3- pool significantly.
ACS EARTH AND SPACE CHEMISTRY
(2022)
Article
Geochemistry & Geophysics
Xin Wang, Naomi S. Wells, Wei Xiao, Jessica L. Hamilton, Adele M. Jones, Richard N. Collins
Summary: The kinetics and stable isotopic fractionation of nitrate (NO3-) reduction in Fe(II)/Fe(III) homogeneous/heterogeneous systems were investigated. The reduction of NO3- was only significant in the presence of layered double hydroxide green rust (GR) minerals. The study provides insight into the importance of GR minerals in NO3- reduction and the potential use of stable isotopic fractionation analyses in distinguishing abiotic anoxic reactions from anaerobic bacterial NO3- reduction processes.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Chemistry, Inorganic & Nuclear
Germain Esquivel-Hernandez, Ioannis Matiatos, Ricardo Sanchez-Murillo, Yuliya Vystavna, Raffaella Balestrini, Naomi S. Wells, Lucilena R. Monteiro, Somporn Chantara, Wendell Walters, Leonard I. Wassenaar
Summary: Stable isotope ratios of nitrogen and oxygen in nitrate (NO3-) can be used as effective tracers to understand the sources, conversions, and deposition of reactive atmospheric nitrogen (N-r) in the environment. This study proposes best-practice guidelines for accurate and precise sampling and analysis of NO3- isotopes in precipitation based on an international research project coordinated by the International Atomic Energy Agency (IAEA). The results showed good agreement between the concentrations of NO3- measured at different laboratories, confirming the accuracy of the Ti(III) reduction method for isotope analysis. This work highlights the capability of NO3- isotopes to assess the origin and atmospheric oxidation of N-r and suggests incorporating other isotopes like O-17 in future studies.
ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES
(2023)