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Huoqing Wang, Yuepeng Sun, Guangxue Wu, Yuntao Guan
Characteristics of nitrogen removal and nitrous oxide (N2O) emission in the multiple anoxic/aerobic (AO) process were examined in three sequencing batch reactors (SBRs) with different anoxic durations (50 min, SBRH; 40 min, SBRM; 30 min, SBRL) and a fixed aerobic duration of 30 min. The highest total inorganic nitrogen removal percentage of 85.8% was obtained in SBRH, while a minimum N2O emission factor of 1.9% was obtained in SBRL. During nitrification batch experiments, the N2O emission factor and emission rate were both lower in SBRH than SBRL...
January 15, 2018: Environmental Technology
Ingrid R Caton, Todd M Caton, Mark A Schneegurt
Small streams exert great influences on the retention and attenuation of nitrogen (N) within stream networks. Human land use can lead to increased transport of dissolved inorganic N compounds and downstream eutrophication. Microbial activity in streams is important for maintaining an actively functioning N cycle. Chronically high N loading in streams affects the rates of the central processes of the N cycle by increasing rates of nitrification and denitrification, with biota exhibiting decreased efficiency of N use...
January 15, 2018: Archives of Microbiology
Susan Jane Fowler, Alejandro Palomo, Arnaud Dechesne, Paul D Mines, Barth F Smets
The recent discovery of completely nitrifying Nitrospira demands a re-examination of nitrifying environments to evaluate their contribution to nitrogen cycling. To approach this challenge, tools are needed to detect and quantify comammox Nitrospira. We present primers for the simultaneous quantification and diversity assessement of both comammox Nitrospira clades. The primers cover a wide range of comammox diversity, spanning all available high quality sequences. We applied these primers to 12 groundwater-fed rapid sand filters, and found comammox Nitrospira to be abundant in all filters...
December 21, 2017: Environmental Microbiology
Yuting He, Lian Peng, Yumei Hua, Jianwei Zhao, Naidong Xiao
A hybrid constructed wetland (CW) system was operated at pilot scale to evaluate the treatment of domestic wastewater from university dorms in Hubei province, China. The hybrid system consisted of an integrated vertical flow constructed wetland (IVF CW) (a down-flow VF CW and an up-flow VF CW) and a horizontal subsurface flow constructed wetland (HSF CW). The influent for the hybrid CW containing chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), and ammonium nitrogen (NH4+-N) with mean concentrations of 152, 0...
January 8, 2018: Environmental Science and Pollution Research International
Yu Zhang, Rui Sun, Aijuan Zhou, Jiaguang Zhang, Yunbo Luan, Jianna Jia, Xiuping Yue, Jie Zhang
Most studies have employed aeration-biofiltration process for the simultaneous removal of iron, manganese and ammonia in groundwater. However, what's inside the "black box", i.e., the potential contribution of functional microorganisms behavior and interactions have seldom been investigated. Moreover, little attention has been paid to the correlations between environmental variables and functional microorganisms. In this study, the performance of industrial-scale biofilters for the contaminated groundwater treatment was studied...
January 8, 2018: AMB Express
M Caschetto, W Robertson, M Petitta, R Aravena
Natural attenuation of nitrogen (N) was investigated in a well characterized septic system plume at a campground in Ontario, Canada. Total inorganic N (TIN) concentrations in deeper portions of the plume were about one third of the septic tank value of 40.7mgL-1. NH4+ and NO3- isotopic characterization were used to provide insight into potential attenuation processes. Concentrations of NH4+ and NO3- were highly variable in the plume, but approached the septic tank TIN value in some shallow zones and exhibited δ15N values like the tank value of +6‰...
January 3, 2018: Science of the Total Environment
Florian B Wagner, Peter Borch Nielsen, Rasmus Boe-Hansen, Hans-Jørgen Albrechtsen
Drinking water treatment plants based on groundwater may suffer from incomplete ammonium removal, which deteriorates drinking water quality and constrains water utilities in the operation of their plants. Ammonium is normally removed through nitrification in biological granular media filters, and recent studies have demonstrated that dosing of copper can stimulate the removal of ammonium. Here, we investigated if copper dosing could generically improve ammonium removal of biofilters, at treatment plants with different characteristics...
December 27, 2017: Water Research
Chitoshi Mizota, Takahiro Hosono, Midori Matsunaga, Azusa Okumura
Dual (oxygen and nitrogen) isotopic composition of the museum archived nitrates from the United States of America, South Africa and Australia was studied. The analyzed specimens were collected in middle 19th to early 20th centuries, and represent world-wide acquisition of the Smithsonian Institution Natural Museum of Natural History (Washington, D. C., USA) and the Natural History Museum (London, UK). The samples consist of transparent to semi-transparent aggregates of minute nitrate, euhedral crystallites which imply precipitation from percolating fluids under ample space and dry regimes...
January 2, 2018: Science of the Total Environment
Jiao Chen, Yixin Lu, Jun Cheng, Jianqiang Zhang
Three constructed rapid infiltration (CRI) systems (C1, C2 and C3) were operated under 7, 14 and 21 days of continuous starvation, respectively. The effect of starvation on the ammonia removal efficiency (ARE), nitrite accumulation rate (NAR), bioactivity of nitrifiers and content of extracellular polymeric substances (EPS) was investigated. The results showed that the activity of nitrite-oxidizing bacteria (NOB) was higher than that of ammonia-oxidizing bacteria (AOB) in stabilization periods, leading to a complete nitrification in CRI systems...
January 4, 2018: Environmental Technology
Hong Chen, Xuhao Zhao, Yuying Cheng, Mingji Jiang, Xiang Li, Gang Xue
Simultaneous nitrification and denitrification (SND) is a promising single-reactor biological nitrogen-removal method. Activated sludge with and without iron scrap supplementation (Sludge-Fe and Sludge-C, respectively) was acclimated under aerobic condition. The total nitrogen (TN) content of Sludge-Fe substantially decreased from 25.0±1.0 to 11.2±0.4 mg/L, but Sludge-C did not show the TN-removal capacity. Further investigations excluded a chemical reduction of NO3--N by iron and a decrease of NH4+-N by microbial assimilation, and the contribution of SND was verified...
January 3, 2018: Environmental Science & Technology
Daisuke Hira, Nobuyuki Aiko, Yoshinori Yabuki, Takao Fujii
Nitrogenous pollution of water is regarded as a global environmental problem, and nitrogen removal has become an important issue in wastewater treatment processes. Landfill leachate is a typical large source of nitrogenous wastewater. Although the characteristics of leachate vary according to the age of the landfill, leachates of mature landfill have high concentrations of nitrogenous compounds. Most nitrogen in these leachates is in the form of ammonium nitrogen. In this study, we investigated the bacterial community of sludge from a landfill leachate lagoon by pyrosequencing of the bacterial 16S rRNA gene...
December 29, 2017: Journal of Environmental Management
Maoxia Chen, Yangwu Chen, Shiyang Dong, Shuhuan Lan, Houzhen Zhou, Zhouliang Tan, Xudong Li
In this study, the nitrification performance, metabolic activity, antioxidant enzyme activity as well as bacterial community of mixed nitrifying bacteria culture under different temperature dropping strategies [(#1) growth temperature kept at 20 °C; (#2) sharp1 decreased from 20 °C to 10 °C; (#3) growth at 20 °C for 6 days followed by sharp decrease to 10 °C; and (#4) gradual decreased from 20 °C to 10 °C] were evaluated. It was shown that acclimation at 20 °C for 6 days allowed to maintain better nitrification activity at 10 °C...
December 28, 2017: Chemosphere
Nannan Zhao, Xiaohu Li, Xiangdan Jin, Irini Angelidaki, Yifeng Zhang
Ammonia monitoring is important to control anaerobic digestion (AD) process due to inhibition effect. Here, an electrolysis cell (EC) was integrated with a complete nitrification reactor as an alternative approach for online monitoring of ammonia during AD processes. The AD effluent was pumped into nitrification reactor to convert ammonia to nitrate, followed by the introduction of nitrate-rich effluent to EC cathode. It was first evaluated with synthetic ammonia-rich digesters and was observed that the current at 5 min were linearly corresponding to the ammonia levels (from 0 to 7...
December 26, 2017: Chemosphere
Bryce A Figdore, H David Stensel, Mari-Karoliina H Winkler
Three types of nitrifying granules were grown on media simulating anaerobic digestion dewatering reject water and compared for their potential to increase nitrification capacity when added to mainstream flocculent activated sludge treatment. An advantage of nitrification bioaugmentation with sidestream granules instead of flocculent biomass is that the granules can be selectively maintained at longer retention times than flocs and thus provide higher nitrification capacity from bioaugmentation. The three granule types and feeding conditions were: nitrifying granules with aerobic feeding, nitrifying-denitrifying granules with anoxic feeding, and nitrifying-denitrifying/phosphate-accumulating (NDN-PAO) granules with anaerobic feeding...
November 6, 2017: Bioresource Technology
M Z Majeed, E Miambi, I Barois, M Bernoux, A Brauman
Tropical rainforest soils harbor a considerable diversity of soil fauna that contributes to emissions of N2O. Despite their ecological dominance, there is limited information available about the contribution of epigeal ant mounds to N2O emissions in these tropical soils. This study aimed to determine whether ant mounds contribute to local soil N emissions in the tropical humid rainforest. N2O emission was determined in vitro from individual live ants, ant-processed mound soils, and surrounding reference soils for two trophically distinct and abundant ant species: the leaf-cutting Atta mexicana and omnivorous Solenopsis geminata...
December 19, 2017: Folia Microbiologica
Shanghua Wu, Guoqiang Zhuang, Zhihui Bai, Yu Cen, Shengjun Xu, Haishu Sun, Xingguo Han, Xuliang Zhuang
Nitrous oxide (N2 O) is a long-lived greenhouse gas that can result in the alteration of atmospheric chemistry and cause accompanying changes in global climate. To date, many techniques have been used to mitigate the emissions of N2 O from agricultural fields, which represent one of the most important sources of N2 O. In this study, we designed a greenhouse pot experiment and a microcosmic serum bottle incubation experiment using acidic soil from a vegetable farm to study the effects of Bacillus amyloliquefaciens (BA) on plant growth and N2 O emission rates...
December 18, 2017: Global Change Biology
Min-Ji Kim, Daegeun Ko, Kwanyoung Ko, Dawon Kim, Ji-Yeon Lee, Sang Myeong Woo, Woong Kim, Haegeun Chung
Due to the application of silver-graphene oxide (Ag-GO) in diverse fields, it is important to investigate its potential impacts on the environment including soils. In this study, the response of microbial communities in soils treated with Ag-GO synthesized by glucose reduction was determined by analyzing enzyme activities, biomass, and inorganic N concentrations and by pyrosequencing. In soils treated with 0.1-1 mg Ag-GO g-1 soil, the activities of β-glucosidase, cellobiohydrolase, and xylosidase decreased up to 80% and NO3- concentration decreased up to 82% indicating inhibited nitrification...
November 21, 2017: Journal of Hazardous Materials
Yonggang Yang, Zhilong Meng, Wentao Jiao
The hydrological and pollution processes are an important science problem for aquatic ecosystem. In this study, the samples of river water, reservoir water, shallow groundwater, deep groundwater, and precipitation in mining area are collected and analyzed. δD and δ18O are used to identify hydrological process. δ15N-NO3- and δ18O-NO3- are used to identify the sources and pollution process of NO3-. The results show that the various water bodies in Fenhe River Basin are slightly alkaline water. The ions in the water mainly come from rock weathering...
December 12, 2017: Environmental Pollution
Ming Zeng, Jie Hu, Denghui Wang, Hongting Wang, Yaochen Wang, Nan Wu, Zongpeng Zhang, Chang Wang
Purifying tank as a compact biofilm reactor has been widely used to remove organic matter in rural sewage, but its potential for nitrogen removal is rare to be discussed. This study developed a lab-scale compact biofilm reactor to realize an efficient nitrogen removal performance by step-feed, intermittent aeration, and immobilization technique. The results show that an efficient simultaneous nitrification and denitrification (SND) process took place by feeding with synthetic wastewater under high C/N ratio of 2 and with real sewage as well, mainly due to the step-feed...
December 14, 2017: Environmental Science and Pollution Research International
Huijun Jia, Qiuyan Yuan
In this study, the effects of ammonium nitrogen concentration, algae biomass concentration, and light conditions (wavelength and intensity) on the ammonium removal efficiency of algae-bacteria consortia from wastewater were investigated. The results indicated that ammonium concentration and light intensity had a significant impact on nitrification. It was found that the highest ammonia concentration (430 mg N/L) in the influent resulted in the highest ammonia removal rate of 108 ± 3.6 mg N/L/days, which was two times higher than the influent with low ammonia concentration (40 mg N/L)...
December 13, 2017: Biodegradation
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