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Rui Zuo, Shuhe Jin, Minhua Chen, Xin Guan, Jinsheng Wang, Yuanzheng Zhai, Yanguo Teng, Xueru Guo
The objective of this study was to explore the controlling factors on the migration and transformation of nitrogenous wastes in groundwater using long-term observations from a contaminated site on the southwestern edge of the Tengger Desert in northwestern China. Contamination was caused by wastewater discharge rich in ammonia. Two long-term groundwater monitoring wells (Wells 1# and 2#) were constructed, and 24 water samples were collected. Five key indicators were tested: ammonia, nitrate, nitrite, dissolved oxygen, and manganese...
March 5, 2018: Journal of Contaminant Hydrology
He-Shan Zheng, Wan-Qian Guo, Qu-Li Wu, Nan-Qi Ren, Jo-Shu Chang
Hospital wastewater is one of the possible sources responsible for antibiotic resistant bacteria spread into the environment. This study proposed a promising strategy, electro-peroxone (E-peroxone) pretreatment followed by a sequencing batch reactor (SBR) for simulated hospital wastewater treatment, aiming to enhance the wastewater treatment performance and to reduce antibiotic resistance genes production simultaneously. The highest chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiency of 94...
March 15, 2018: Environment International
Xue-Yan Liu, Keisuke Koba, Lina A Koyama, Sarah E Hobbie, Marissa S Weiss, Yoshiyuki Inagaki, Gaius R Shaver, Anne E Giblin, Satoru Hobara, Knute J Nadelhoffer, Martin Sommerkorn, Edward B Rastetter, George W Kling, James A Laundre, Yuriko Yano, Akiko Makabe, Midori Yano, Cong-Qiang Liu
Plant nitrogen (N) use is a key component of the N cycle in terrestrial ecosystems. The supply of N to plants affects community species composition and ecosystem processes such as photosynthesis and carbon (C) accumulation. However, the availabilities and relative importance of different N forms to plants are not well understood. While nitrate (NO3 - ) is a major N form used by plants worldwide, it is discounted as a N source for Arctic tundra plants because of extremely low NO3 - concentrations in Arctic tundra soils, undetectable soil nitrification, and plant-tissue NO3 - that is typically below detection limits...
March 14, 2018: Proceedings of the National Academy of Sciences of the United States of America
Alejandro Gonzalez-Martinez, Alejandro Margareto, Alejandro Rodriguez-Sanchez, Chiara Pesciaroli, Silvia Diaz-Cruz, Damia Barcelo, Riku Vahala
The emergence and spread of antibiotics resistance in wastewater treatment systems have been pointed as a major environmental health problem. Nevertheless, research about adaptation and antibiotics resistance gain in wastewater treatment systems subjected to antibiotics has not been successfully developed considering bioreactor performance, microbial community dynamics and microbial activity dynamics at the same time. To observe this in autotrophic nitrogen removal systems, a partial-nitritation biofilter was subjected to a continuous loading of antibiotics mix of azithromycin, norfloxacin, trimethoprim, and sulfamethoxazole...
2018: Frontiers in Microbiology
Mingwei Cai, Siu-Kin Ng, Chee Kent Lim, Hongyuan Lu, Yangyang Jia, Patrick K H Lee
Nitrification plays a crucial role in global nitrogen cycling and treatment processes. However, the relationships between the nitrifier guilds of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) are still poorly understood, especially in freshwater habitats. This study examined the physiological interactions between the AOB and NOB present in a freshwater aquarium biofilter by culturing them, either together or separately, in a synthetic medium. Metagenomic and 16S rRNA gene sequencing revealed the presence and the draft genomes of Nitrosomonas -like AOB as well as Nitrobacter -like NOB in the cultures, including the first draft genome of Nitrobacter vulgaris ...
2018: Frontiers in Microbiology
Liang Li, Yihua Dong, Guangsheng Qian, Xiaomin Hu, Linlin Ye
A pair of Fe-C electrodes was installed in a traditional submerged membrane bioreactor (MBR, Rc), and a novel asynchronous periodic reversal bio-electrocoagulation system (Re) was developed. The simultaneous nitrification and denitrification (SND) performance was discussed under limited dissolved oxygen (DO). Results showed that electrocoagulation enhanced total nitrogen (TN) removal from 59.48% to 75.09% at 1.2 mg/L DO. Additionally, Fe electrode could increase sludge concentration, particle size, and enzyme activities related to nitrogen removal...
February 28, 2018: Bioresource Technology
Katharina M Keiblinger, Franz Zehetner, Axel Mentler, Sophie Zechmeister-Boltenstern
Biochar (BC) application to soils is of growing interest as a strategy to improve soil fertility and mitigate climate change. However, BC-induced alterations in the soil N cycle are currently under debate. BC has recently been shown to accelerate the emissions of N2 O via the biotic ammonium oxidation pathway, which results in lower nitrogen use efficiency and environmentally harmful losses of NO3 and/ or N2 O. To avoid these potential losses, the use of nitrification inhibitor (NI) could provide a useful mitigation strategy for BC-amended agricultural fields...
March 8, 2018: Environmental Science and Pollution Research International
Perry L Mccarty
Many different aerobic and anaerobic biological processes and treatment schemes are available for transforming organics and/or removing nitrogen from domestic wastewaters. Significant reductions in oxygen requirements and absence of a need for organics for nitrogen reduction are often indicated as advantageous for using the newer anammox organism approach for nitrogen removal rather than the traditional nitrification/denitrification method, the most common one in use today. However, treatment schemes differ, and there are some in which such suggested advantages may not hold...
March 6, 2018: Environmental Science & Technology
Ahmed S Abouhend, Adam McNair, Wenye Camilla Kuo-Dahab, Christopher Watt, Caitlyn S Butler, Kim Milferstedt, Jerome Hamelin, Jeongmi Seo, Gitau J Gikonyo, Khalid M El-Moselhy, Chul Park
This study presents the oxygenic photogranule (OPG) process, a light-driven process for wastewater treatment, developed based on photogranulation of filamentous cyanobacteria, non-phototrophic bacteria, and microalgae. Unlike other biogranular processes requiring airlift or upflow-based mixing, the OPG process was operated in stirred-tank reactors without aeration. Reactors were seeded with hydrostatically-grown photogranules and operated in a sequencing-batch mode for five months to treat wastewater. New reactor biomass propagated with progression of photogranulation under periodic light/dark cycles...
March 5, 2018: Environmental Science & Technology
Veronica E Aponte-Morales, Karl A Payne, Jeffrey A Cunningham, Sarina J Ergas
Nitrification of high total ammonia nitrogen-strength wastewaters is challenging due to free ammonia (FA) inhibition of nitrification. FA inhibition can potentially be alleviated by temporarily adsorbing ammonium (NH4+) to natural zeolite, such as chabazite, followed by direct zeolite bioregeneration via nitrification. In this research, the effectiveness of chabazite addition for reducing nitrification inhibition during treatment of centrate from anaerobic digestion of swine waste was quantified. A mathematical model was developed that accounts for ion exchange of NH4+ and sodium at the chabazite surface, surface diffusion of adsorbed NH4+ within the chabazite grains, sequential nitrification of aqueous NH4+ to nitrite and nitrate, and inhibition of nitritation and nitratation rates by NH4+...
March 5, 2018: Environmental Science & Technology
Chuan Wang, Shuangyuan Liu, Yi Zhang, Biyun Liu, Feng He, Dong Xu, Qiaohong Zhou, Zhenbin Wu
Submerged vegetation biomass fluctuation usually occurs during the preliminary stage of vegetation restoration in shallow lakes, which impacts the final status and duration for achieving a macrophyte-dominant state. This study uncovered the sediment N characteristics and the sediment bacterial community and their predicted functions during the preliminary stage of vegetation recovery in the West Lake, a typical subtropical degenerated shallow lake in China. Results showed increased amounts of sediment TN and NH4 -N, reaching 3425...
March 3, 2018: Microbial Ecology
Holger Daims, Michael Wagner
In this infographic, the key metabolic functions of Nitrospira and the role that these bacteria play in nitrification and other processes in the environment is shown. Nitrospira plays pivotal roles in nitrification as an aerobic chemolithoautotrophic nitrite-oxidizing bacterium. These bacteria often occur in close association with ammonia-oxidizing bacteria or archaea that convert ammonia to nitrite, which is further oxidized to nitrate by Nitrospira. However, in 'reciprocal feeding' interactions, Nitrospira can also provide ammonia oxidizers with ammonia released from urea or cyanate, which is further nitrified as described above...
February 28, 2018: Trends in Microbiology
Xianhui Sean Wan, Hua-Xia Sheng, Minhan Dai, Yao Zhang, Dalin Shi, Thomas W Trull, Yifan Zhu, Michael W Lomas, Shuh-Ji Kao
Phytoplankton assimilation and microbial oxidation of ammonium are two critical conversion pathways in the marine nitrogen cycle. The underlying regulatory mechanisms of these two competing processes remain unclear. Here we show that ambient nitrate acts as a key variable to bifurcate ammonium flow through assimilation or oxidation, and the depth of the nitracline represents a robust spatial boundary between ammonium assimilators and oxidizers in the stratified ocean. Profiles of ammonium utilization show that phytoplankton assemblages in nitrate-depleted regimes have higher ammonium affinity than nitrifiers...
March 2, 2018: Nature Communications
Jie Hou, Xin Wang, Jie Wang, Ling Xia, Yiqing Zhang, Dapeng Li, Xufa Ma
This study aimed at assessing the influence of aeration mode and influent COD/N ratio on nitrogen removal in constructed wetlands (CWs). The results showed that a simultaneous partial nitrification, anammox and denitrification (SNAD) process was established in the intermittent aerated V1. While nitrogen removal pathway gradually changed from partial nitrification-denitrification to complete nitrification-denitrification along with reducing COD/N ratio in the continuous limited aerated V2. Effective inhibition of NOBs under intermittent aeration conditions, good retention of anammox bacteria biomass and much faster depletion of COD prior to substantial NH4 + -N conversion jointly led to the successful achievement of stable SNDA process with elevated influent COD/N ratios in V1...
February 10, 2018: Bioresource Technology
Chenyuan Dang, Wen Liu, Yaxuan Lin, Maosheng Zheng, Huan Jiang, Qian Chen, Jinren Ni
Surface sediments are the inner source of contaminations in aquatic systems and usually maintain aerobic conditions. As the key participators of nitrification process, little is known about the activities and contributions of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in the surface sediments. In this study, we determined the net and potential nitrification rates and used 1-octyne as an AOB specific inhibitor to detect the contributions of AOA and AOB to nitrification in surface sediments of Danjiangkou reservoir, which is the water source area of the middle route of South-to-North Water Diversion Project in China...
March 1, 2018: Applied Microbiology and Biotechnology
Junjie Liu, Zhenhua Yu, Qin Yao, Yueyu Sui, Yu Shi, Haiyan Chu, Caixian Tang, Ashley E Franks, Jian Jin, Xiaobing Liu, Guanghua Wang
Black soils (Mollisols) of northeast China are highly productive and agriculturally important for food production. Ammonia-oxidizing microbes play an important role in N cycling in the black soils. However, the information related to the composition and distribution of ammonia-oxidizing microbes in the black soils has not yet been addressed. In this study, we used the amoA gene to quantify the abundance and community composition of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) across the black soil zone...
2018: Frontiers in Microbiology
Katherine E Greenstein, Julia Lew, Eric R V Dickenson, Eric C Wert
The evolving demands of drinking water treatment necessitate processes capable of removing a diverse suite of contaminants. Biofiltration can employ biotransformation and sorption to remove various classes of chemicals from water. Here, pilot-scale virgin anthracite-sand and previously used biological activated carbon (BAC)-sand dual media filters were operated for ∼250 days to assess removals of 0.4 mg/L ammonia as nitrogen, 50-140 μg/L manganese, and ∼100 ng/L each of trace organic compounds (TOrCs) spiked into pre-ozonated Colorado River water...
February 19, 2018: Chemosphere
Markus T Müller
The Chemistry Cube Game invites students at secondary school level 1 and 2 to explore basic concepts of chemistry in a playful way, either as individuals or in teams. It consists of 15 different cubes, 9 cubes for different acids, their corresponding bases and precursors, and 6 cubes for different reducing and oxidising agents. The cubes can be rotated in those directions indicated. Each 'allowed' vertical or horizontal rotation of 90° stands for a chemical reaction or a physical transition. Two different games and playing modes are presented here: First, redox chemistry is introduced for the formation of salts from elementary metals and non-metals...
February 1, 2018: Chimia
Yushu Zhang, Hong Ding, Xiangzhou Zheng, Xiangyun Ren, Laura Cardenas, Alison Carswell, Tom Misselbrook
The change in land-use from woodland to crop production leads to increased nitrous oxide (N2 O) emissions. An understanding of the main N2 O sources in soils under a particular land can be a useful tool in developing mitigation strategies. To better understand the effect of land-use on N2 O emissions, soils were collected from 5 different land-uses in southeast China: shrub land (SB), eucalyptus plantation (ET), sweet potato farmland (SP), citrus orchard (CO) and vegetable growing farmland (VE). A stable isotope experiment was conducted incubating soils from the different land use types at 60% water holding capacity (WHC), using15 NH4 NO3 and NH4 15 NO3 to determine the dominant N2 O production pathway for the different land-uses...
February 24, 2018: Environmental Pollution
Noriko A Cassman, Késia S Lourenço, Janaína B do Carmo, Heitor Cantarella, Eiko E Kuramae
Background: The production of 1 L of ethanol from sugarcane generates up to 12 L of vinasse, which is a liquid waste containing an as-yet uncharacterized microbial assemblage. Most vinasse is destined for use as a fertilizer on the sugarcane fields because of the high organic and K content; however, increased N2 O emissions have been observed when vinasse is co-applied with inorganic N fertilizers. Here we aimed to characterize the microbial assemblage of vinasse to determine the gene potential of vinasse microbes for contributing to negative environmental effects during fertirrigation and/or to the obstruction of bioethanol fermentation...
2018: Biotechnology for Biofuels
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