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Timothy J Clough, Gary J Lanigan, Cecile A M de Klein, Md Sainur Samad, Sergio E Morales, David Rex, Lars R Bakken, Charlotte Johns, Leo M Condron, Jim Grant, Karl G Richards
Intensively managed agricultural pastures contribute to N2O and N2 fluxes resulting in detrimental environmental outcomes and poor N use efficiency, respectively. Besides nitrification, nitrifier-denitrification and heterotrophic denitrification, alternative pathways such as codenitrification also contribute to emissions under ruminant urine-affected soil. However, information on codenitrification is sparse. The objectives of this experiment were to assess the effects of soil moisture and soil inorganic-N dynamics on the relative contributions of codenitrification and denitrification (heterotrophic denitrification) to the N2O and N2 fluxes under a simulated ruminant urine event...
May 19, 2017: Scientific Reports
Lei Zheng, Xue Zhao, Guibing Zhu, Wei Yang, Chao Xia, Tao Xu
Using molecular biology methods (qualitative and quantitative PCR), we determined the occurrence and abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) from a dry inland soil in Basel, Switzerland, and from the riparian zone of Baiyangdian Lake, China. We also determined the contributions of these microorganisms to ammonia oxidization at different depths based on the nitrification rate. The number of archaeal amoA genes (the key functional gene in AOA) was larger than the number of bacterial amoA genes in each sample, suggesting a dominant role for the AOA amoA gene in environments with a low ammonium concentration...
May 19, 2017: MicrobiologyOpen
Natalie A Keene, Steve R Reusser, Matthew J Scarborough, Alan L Grooms, Matt Seib, Jorge Santo Domingo, Daniel R Noguera
Aeration in biological nutrient removal (BNR) processes accounts for nearly half of the total electricity costs at many wastewater treatment plants. Even though conventional BNR processes are usually operated to have aerated zones with high dissolved oxygen (DO) concentrations, recent research has shown that nitrification can be maintained using very low-DO concentrations (e.g., below 0.2 mg O2/L), and therefore, it may be possible to reduce energy use and costs in BNR facilities by decreasing aeration. However, the effect of reduced aeration on enhanced biological phosphorus removal (EBPR) is not understood...
May 13, 2017: Water Research
Alexandra Fumasoli, Helmut Buergmann, David G Weissbrodt, George F Wells, Karin Beck, Joachim Mohn, Eberhard Morgenroth, Kai M Udert
Ammonia oxidation decreases the pH in wastewaters where the alkalinity is limited relative to the total ammonia. The activity of ammonia oxidizing bacteria (AOB), however, typically decreases with pH and often ceases completely in slightly acidic wastewaters. Nevertheless, low pH nitrification has been reported in reactors treating human urine, but it is not clear which organisms are involved. In this study, we followed the population dynamics of ammonia oxidizing organisms and reactor performance in synthetic, synthetic fully hydrolysed urine as the pH decreased over time in response to a decrease in the loading rate...
May 16, 2017: Environmental Science & Technology
K Tatari, A Gülay, B Thamdrup, H-J Albrechtsen, B F Smets
Allylthiourea (ATU) and chlorate (ClO3(-)) are often used to selectively inhibit nitritation and nitratation. In this work we identified challenges with use of these compounds in inhibitory assays with filter material from a biological rapid sand filter for groundwater treatment. Inhibition was investigated in continuous-flow lab-scale columns, packed with filter material from a full-scale filter and supplied with NH4(+) or NO2(-). ATU concentrations of 0.1-0.5 mM interfered with the indophenol blue method for NH4(+) quantification leading to underestimation of the measured NH4(+) concentration...
May 3, 2017: Chemosphere
Wei Chen, Yanmei Gu, Hang Xu, Zhigang Liu, Chunhui Lu, Chenshuo Lin
This study aimed to investigate the variation of microbial communities and functional genes during the biofilm formation in raw water distribution systems without prechlorination and associated effects on the transformation of nitrogen pollutants by using a designed model pipe system. The results showed the transformation of nitrogen pollutants was obvious during the biofilm formation. The richness and diversity of the microbial communities changed significantly. The higher abundance of Nitrospirae in biofilm samples significantly contributed to biological nitrification...
May 13, 2017: Environmental Science and Pollution Research International
Tengxia He, Deti Xie, Zhenlun Li, Jiupai Ni, Quan Sun
The ability of Arthrobacter arilaitensis Y-10 for nitrogen removal from simulated wastewater was studied. Results showed that ammonium was the best inorganic nitrogen for strain Y-10's cell growth, which could also promote nitrate reduction. Approximately 100.0% of ammonium was removed in the nitrogen removal experiments. The nitrate removal efficiency was 73.3% with nitrate as sole nitrogen source, and then the nitrate efficiency was increased to 85.3% and 100.0% with ammonium and nitrate (both about 5 or 100mg/L) as the mixed nitrogen sources...
May 4, 2017: Bioresource Technology
Kento Ishii, Hirotsugu Fujitani, Kentaro Soh, Tatsunori Nakagawa, Reiji Takahashi, Satoshi Tsuneda
Nitrite-oxidizing bacteria (NOB) are responsible for the second step of nitrification in natural and engineered ecosystems. The recently discovered genus Nitrotoga belongs to the Betaproteobacteria and has potentially high environmental importance. Although environmental clones affiliated with Nitrotoga are widely distributed, the limited number of cultivated Nitrotoga results in poor understanding of their ecophysiological features. In this study, we successfully enriched the non-marine cold-adapted Nitrotoga sp...
May 12, 2017: Applied and Environmental Microbiology
Qian Dong, Yanchen Liu, Hanchang Shi, Xia Huang
Graphite nanoparticles (GNPs) might result in unexpected effects during their transportation and transformation in wastewater treatment systems, including strong thermo-catalytic and catalytic effects and microbial cytotoxicity. In particular, the effects of GNPs on the nitrification process in activated sludge systems should be addressed. This study aimed to estimate the influence of GNPs on the nitrification process in a short-term nitrification reactor with exposure to different light sources. The results indicated that GNPs could only improve the efficiency of photothermal transformation slightly in the activated sludge system because of its photothermal effects under the standard illuminant (imitating 1 × sun)...
May 8, 2017: Chemosphere
Mathieu Nsenga Kumwimba, Bo Zhu, Diana Kavidia Muyembe
Three different types of ditches, each 300 m in length, were employed in this study. One vegetated constructed ditch (VCD), three natural vegetated soil ditches (NVSD), and three constructed ditches left unvegetated (UCD) as controls were investigated using simple in/out mass balances and uptake by plant species with a potential for phytoremediation and their mechanisms. Significant differences in the ditches were observed, suggesting the importance of plant species in nutrient mitigation. The removal rates of TN (total nitrogen) and TP (total phosphorus) were 64...
June 2017: Environmental Monitoring and Assessment
Huma Ilyas, Ilyas Masih
The effects of different aeration strategies including tidal flow (TF), effluent recirculation (ER) and artificial aeration (AA) on performance of vertical flow constructed wetland (VFCW), horizontal flow constructed wetland (HFCW) and hybrid constructed wetland (HCW) are comprehensively and critically reviewed in this paper. The removal efficiencies of nine types of intensified constructed wetlands (CWs) were examined in detail and their mean and standard deviation were estimated at 89 ± 11%, 84 ± 12%, 81 ± 17% and 63 ± 20% for total suspended solids (TSS), chemical oxygen demand (COD), ammonium-nitrogen (NH4(+)N) and total nitrogen (TN), respectively...
May 8, 2017: Journal of Environmental Management
D M González-Pérez, J I Pérez, M A Gómez
The behaviour and removal efficiency of ibuprofen (IBU), diclofenac (DCF), ketoprofen (KPF), and naproxen (NPX) during the real urban wastewater treatment by an experimental full-scale MBR working at high sludge and hydraulic retention time (SRT, HRT) were determined. The MBR worked in denitrification/nitrification conformation at 35.4h of HRT (Q=0.45m(3)/h), 37 d of SRT and a recirculation flow rate of 4Q. The experiments were made under steady-state conditions, reaching a biodegradable organic matter removal higher than 99...
April 26, 2017: Journal of Hazardous Materials
Zhibin Wang, Xiaolin Liu, Shou-Qing Ni, Jian Zhang, Xu Zhang, Hafiz Adeel Ahmad, Baoyu Gao
Partial nitrification (PN) combined with anaerobic ammonium oxidation process has been recognized as a promising technology for the removal of nitrogenous contaminants from wastewater. This research aimed to investigate the potential of external magnetic field for enhancing the PN process in short and long term laboratory-scale experiments. Different strength magnetic fields (0, 5, 10, 15, 20 and 25 mT) were evaluated in short-term batch tests and 5 mT magnetic field was found to have better ability to increase the activities of aerobic ammonium oxidizing bacteria (AOB) of PN consortium...
April 26, 2017: Water Research
Ugo Barry, Jean-Marc Choubert, Jean-Pierre Canler, Olivier Pétrimaux, Alain Héduit, Paul Lessard
This work presents a one-dimensional model of a moving bed bioreactor (MBBR) process designed for the removal of nitrogen from raw wastewaters. A comprehensive experimental strategy was deployed at a semi-industrial pilot-scale plant fed with a municipal wastewater operated at 10-12 °C, and surface loading rates of 1-2 g filtered COD/m(2) d and 0.4-0.55 g NH4-N/m(2) d. Data were collected on influent/effluent composition, and on measurement of key variables or parameters (biofilm mass and maximal thickness, thickness of the limit liquid layer, maximal nitrification rate, oxygen mass transfer coefficient)...
May 8, 2017: Bioprocess and Biosystems Engineering
Dibyendu Kamilya, Mitila Debbarma, Prasenjit Pal, Biswanath Kheti, Sudipto Sarkar, Sukham Tushiba Singh
The present study was undertaken to investigate the effect of biofloc-based aquaculture system on inorganic nitrogen control, and growth and immunological responses of rohu (Labeo rohita). Fingerlings of rohu were cultured in indoor biofloc tanks in light-limited condition for 16 weeks with daily addition of molasses as carbon source to maintain the C/N ratio at 15. Different water quality parameters were measured at weekly interval. Growth, survival and welfare indices including stress and immunological status were measured after the end of the experimental period...
May 3, 2017: Chemosphere
Tao Liu, Yongchao Liang, Guixin Chu
Nitrification inhibitors (NIs) have been used extensively to reduce nitrogen losses and increase crop nitrogen nutrition. However, information is still scant regarding the influence of NIs on nitrogen transformation, nitrous oxide (N2O) emission and nitrogen utilization in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition. Therefore, a field trial was conducted to evaluate the effect of nitrapyrin (2-chloro-6-(trichloromethyl)-pyridine) on soil mineral nitrogen (N) transformation, N2O emission and nitrogen use efficiency (NUE) in a drip-fertigated cotton-growing calcareous field...
2017: PloS One
Qian Yao, Dangcong Peng, Bo Wang, Yuanyuan Chen, Jiaqi Li, Qiaodi Zhao, Binbin Wang
Successful partial nitrification not only guarantees the inhibition of nitrite oxidation, but also does not excessively retard the ammonia oxidation rate. Therefore, the performance of ammonium oxidizing bacteria (AOB) during partial nitrification is fundamental to this process. In this study, two lab-scale partial nitrification bioreactors containing different inhibition conditions-one with free ammonium (FA) inhibition, the other with free nitrous acid (FNA) inhibition-were used to compare the differences between activity, quantity, aggregation morphology and extracellular polymeric substance (EPS) distribution of AOB...
May 2, 2017: Journal of Bioscience and Bioengineering
Signe Høgslund, Tomas Cedhagen, Samuel S Bowser, Nils Risgaard-Petersen
A substantial nitrate pool is stored within living cells in various benthic marine environments. The fate of this bioavailable nitrogen differs according to the organisms managing the intracellular nitrate (ICN). While some light has been shed on the nitrate carried by diatoms and foraminiferans, no study has so far followed the nitrate kept by gromiids. Gromiids are large protists and their ICN concentration can exceed 1000x the ambient nitrate concentration. In the present study we investigated gromiids from diverse habitats and showed that they contained nitrate at concentrations ranging from 1 to 370 mM...
2017: Frontiers in Microbiology
Xuan Hong, Zhongwei Chen, Chungui Zhao, Suping Yang
Marichromatium gracile: YL28 (M. gracile YL28) is an anoxygenic phototrophic bacterial strain that utilizes ammonia, nitrate, or nitrite as its sole nitrogen source during growth. In this study, we investigated the removal and transformation of ammonium, nitrate, and nitrite by M. gracile YL28 grown in a combinatorial culture system of sodium acetate-ammonium, sodium acetate-nitrate and sodium acetate-nitrite in response to different initial dissolved oxygen (DO) levels. In the sodium acetate-ammonium system under aerobic conditions (initial DO = 7...
June 2017: World Journal of Microbiology & Biotechnology
S Descloux, V Chanudet, D Serça, F Guérin
Two greenhouse gases -methane (CH4) and nitrous oxide (N2O) - were monitored monthly during one year (2011) at the Eguzon Reservoir in France. The objective of the study was to quantify for the first time in a temperate area the total emissions of these gases through the main emission pathways (diffusion and bubbling from the reservoir, degassing and downstream diffusion). The reservoir was impounded in 1926 and had, in 2011, a eutrophic status promoting high organic matter degradation and nitrification-denitrification, all favouring CH4 and N2O production...
April 28, 2017: Science of the Total Environment
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