Journal articles: 'Denitrification'

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Hong, Xiaohong, Liaofan Tang, Haixia Feng, Xiaolei Zhang, and Xianqiong Hu. "Agriculture Waste as Slow Carbon Releasing Source of Mixotrophic Denitrification Process for Treating Low C/N Wastewater." Separations 9, no. 10 (October 21, 2022): 323. http://dx.doi.org/10.3390/separations9100323.

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Mixotrophic denitrification has showed great potential for treating wastewater with a low C/N ratio. Mixotrophic denitrification is the process combining autotrophic denitrification and heterotrophic denitrification in one system. It can compensate the disadvantage of the both denitrifications. Instead of using sodium acetate and glucose as carbon source for the heterotrophic denitrification, agriculture solid wastes including rice straw (RS), wheat straw (WS), and corncob (CC) were employed in this study to investigate their potential as carbon source for treating low C/N wastewater. The carbon releasing pattern of the three carbon rich materials has been studied as well as their capacity in denitrification. The results showed that the highest denitrification occurred in the corncob system which was 0.34 kg N/(m3·d). Corncob was then selected to combine with sulfur beads to build the mixotrophic denitrification system. The reactor packed with sulfur bead on the top and corncob on the bottom achieved 0.34 kg N/(m3·d) denitrification efficiency, which is higher than that of the reactor packed with completely mixed sulfur bead and corncob. The autotrophic denitrification and heterotrophic denitrification were 42.2% and 57.8%, respectively. The microorganisms in the sulfur layer were Thermomonas, Ferritrophicum, Thiobacillus belonging to autotrophic denitrification bacteria. Kouleothrix and Geothrix were mostly found in the corncob layer, which have the function for fiber hydrolysis and denitrification. The study has provided an insight into agriculture solid waste application and enhancement on denitrification of wastewater treatment.

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Xie, Li, Chi Ji, Rui Wang, and Qi Zhou. "Microbial Communities in Anaerobic Acidification-Denitrification and Methanogenesis Process for Cassava Stillage Treatment." Applied Mechanics and Materials 522-524 (February 2014): 573–78. http://dx.doi.org/10.4028/www.scientific.net/amm.522-524.573.

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This study investigated operational performance and microbial communities in the integrated acidification-denitrification bioreactor and the followed methanogenesis process. Industrial wastewater, cassava stillage (CS) was used as the carbon source amended with or without nitrate. The results showed that acidification and denitrification could occur simultaneously in a single acidification-denitrification reactor, and denitrificatoin did not suppress the acidogenic activity. Both denitrification and DNRA could contribute to nitrate reduction and proportions of them were about 60% and 40% respectively at the tested condition of COD/NO3-Nof 50. The introduction of nitrate into acidogenic phase did not have any effect on the followed methanogenic process. Microbial communities sampled from two systems were analyzed by culture-independent techniques based on PCR-DGGE. The relative abundance of acid-producing bacteria (primarily Parabacteroides distasonis and Chloroflexi) in the nitrate-amended reactor further confirmed that the addition of nitrate did not suppress the activity of acid-producing bacteria. Bacteria involved in denitrification and DNRA were also detected. The archaeal communities in methanogenic reactors of two systems showed no significant differences. And Methanoculleus and Methanolobus were the dominant bacteria in the culture.

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Saeed, Waleed, Orfan Shouakar-Stash, Andrè Unger, and Warren W. Wood. "Application of Multi-Tracer Methods to Evaluate Nitrate Sources and Transformation in Sabkha Matti (Saudi Arabia)." E3S Web of Conferences 98 (2019): 12018. http://dx.doi.org/10.1051/e3sconf/20199812018.

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An unusually high concentration of nitrate (NO3) ranging between 291 and 6790 mg/L (as N) was observed during a review of solute data for brine samples from the inland Sabkha Matti. A multi-tracer approach considering water chemistry, stable nitrate isotopes (δ15N and δ18O), and the radioactive isotope of hydrogen (tritium, 3H) was utilized to evaluate the nitrate sources and transformation in this hydrogeological setting. The results suggested that the source of the high nitrate levels is related to a leakage from a manure/septic system near the proximal eastern edge of the Sabkha. Moreover, the impact of Sabkha’s characteristics on biological denitrifications was evaluated in this study. The results suggest that denitrification was not a major process in Sabkha Matti. Several factors may contribute to the limitation of denitrification on the brine samples including high dissolved oxygen contents, high salinity and chloride.

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Grgas, Dijana, Tibela Landeka Dragičević, Anita Štrkalj, Andrijana Brozinčević, Mirjana Galant, and Tea Štefanac. "Biological denitrification." Hrvatski časopis za prehrambenu tehnologiju, biotehnologiju i nutricionizam 16, no. 1-2 (June 1, 2021): 28–34. http://dx.doi.org/10.31895/hcptbn.16.1-2.4.

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Ubrzani napredak industrije, poljoprivrede i domaćinstva su pogodovali povišenim koncentracijama dušika u vodenom ekosustavu, što uzrokuje eutrofikaciju. Dušik se iz otpadne vode uklanja procesom biološke denitrifikacije. U ovom preglednom radu dan je osvrt na denitrifikaciju, s aspekta mikroorganizama, koncentracije otopljenog kisika, donora i akceptora elektrona.

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Kafkewitz, David, and Jung Jeng Su. "Aerobic denitrification." Trends in Ecology & Evolution 9, no. 4 (April 1994): 149. http://dx.doi.org/10.1016/0169-5347(94)90182-1.

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Yeomans, J. C., J. M. Bremner, and G. W. McCarty. "Denitrification capacity and denitrification potential of subsurface soils." Communications in Soil Science and Plant Analysis 23, no. 9-10 (June 1992): 919–27. http://dx.doi.org/10.1080/00103629209368639.

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Vermes, Jean-François, and David D. Myrold. "Denitrification in forest soils of Oregon." Canadian Journal of Forest Research 22, no. 4 (April 1, 1992): 504–12. http://dx.doi.org/10.1139/x92-066.

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Denitrification represents a potential loss of N from forest soils as well as a source of N oxides to the atmosphere; however, this process has not been closely examined in forest ecosystems of the Pacific Northwest. The objectives of this study were to survey insitu denitrification rates in a range of forest ecosystems and to assess the importance of selected soil properties as controlling factors of denitrification in forest soils. Soils from eight mature conifer stands, three recently clear-cut sites, and four Alnusrubra Bong, stands were sampled in spring, summer, and autumn. Denitrification potentials (anaerobic soil slurries), insitu denitrification rates, soil respiration rates, soil water contents, and soil NO3− concentrations were measured. Denitrification potentials ranged from <1 to 1900 ng N•g−1•h−1, and insitu denitrification rates varied from 0.1 to 40 g N•ha−1•day−1. Denitrification potentials were highly correlated with soil NO3− concentrations and soil water contents; these two soil variables explained more than 90% of the variation in denitrification potentials. Field denitrification rates were best correlated with soil water contents: using multiple regression, up to 79% of the variation in field denitrification rates was explained by soil water contents. Experiments on the short-term dynamics of denitrification following water addition confirmed the importance of soil water content as a regulator of denitrification and suggested that active denitrification requires formation of anaerobic microsites. Extrapolation of seasonal denitrification measurements suggests that relatively little N (<10 kg N•ha−1•year−1) is lost from Oregon forest soils as N gases.

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Isokpehi, Raphael D., Yungkul Kim, Sarah E. Krejci, and Vishwa D. Trivedi. "Ecological Trait-Based Digital Categorization of Microbial Genomes for Denitrification Potential." Microorganisms 12, no. 4 (April 13, 2024): 791. http://dx.doi.org/10.3390/microorganisms12040791.

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Microorganisms encode proteins that function in the transformations of useful and harmful nitrogenous compounds in the global nitrogen cycle. The major transformations in the nitrogen cycle are nitrogen fixation, nitrification, denitrification, anaerobic ammonium oxidation, and ammonification. The focus of this report is the complex biogeochemical process of denitrification, which, in the complete form, consists of a series of four enzyme-catalyzed reduction reactions that transforms nitrate to nitrogen gas. Denitrification is a microbial strain-level ecological trait (characteristic), and denitrification potential (functional performance) can be inferred from trait rules that rely on the presence or absence of genes for denitrifying enzymes in microbial genomes. Despite the global significance of denitrification and associated large-scale genomic and scholarly data sources, there is lack of datasets and interactive computational tools for investigating microbial genomes according to denitrification trait rules. Therefore, our goal is to categorize archaeal and bacterial genomes by denitrification potential based on denitrification traits defined by rules of enzyme involvement in the denitrification reduction steps. We report the integration of datasets on genome, taxonomic lineage, ecosystem, and denitrifying enzymes to provide data investigations context for the denitrification potential of microbial strains. We constructed an ecosystem and taxonomic annotated denitrification potential dataset of 62,624 microbial genomes (866 archaea and 61,758 bacteria) that encode at least one of the twelve denitrifying enzymes in the four-step canonical denitrification pathway. Our four-digit binary-coding scheme categorized the microbial genomes to one of sixteen denitrification traits including complete denitrification traits assigned to 3280 genomes from 260 bacteria genera. The bacterial strains with complete denitrification potential pattern included Arcobacteraceae strains isolated or detected in diverse ecosystems including aquatic, human, plant, and Mollusca (shellfish). The dataset on microbial denitrification potential and associated interactive data investigations tools can serve as research resources for understanding the biochemical, molecular, and physiological aspects of microbial denitrification, among others. The microbial denitrification data resources produced in our research can also be useful for identifying microbial strains for synthetic denitrifying communities.

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Pániková, Kristína, Zuzana Bílková, and Jitka Malá. "The Behavior of Terbuthylazine, Tebuconazole, and Alachlor during Denitrification Process." Journal of Xenobiotics 13, no. 4 (October 1, 2023): 560–71. http://dx.doi.org/10.3390/jox13040036.

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Pesticide compounds can influence denitrification processes in groundwater in many ways. This study observed behavior of three selected pesticides under denitrifying conditions. Alachlor, terbuthylazine, and tebuconazole, in a concentration of 0.1 mL L−1, were examined using two laboratory denitrifications assays: a “short” 7-day and a “long” 28-day test. During these tests, removal of pesticides via adsorption and biotic decomposition, as well as the efficiency of nitrate removal in the presence of the pesticides, were measured. No considerable inhibition of the denitrification process was observed for any of the pesticides. On the contrary, significant stimulation was observed after 21 days for alachlor (49%) and after seven days for terbuthylazine (40%) and tebuconazole (36%). Adsorption was in progress only during the first seven days in the case of all tested pesticides and increased only negligibly afterwards. Immediate adsorption of terbuthylazine was probably influenced by the mercuric chloride inhibitor. A biotic loss of 4% was measured only in the case of alachlor.

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Machefert, S. E., and N. B. Dise. "Hydrological controls on denitrification in riparian ecosystems." Hydrology and Earth System Sciences 8, no. 4 (August 31, 2004): 686–94. http://dx.doi.org/10.5194/hess-8-686-2004.

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Abstract. Nitrous oxide fluxes and denitrification rates were measured in situ over a year at a riparian site in the UK. An exponential relationship was found between denitrification rates and soil moisture, with a sharp increase in denitrification rate at a water-filled pore space of 60–80%. Similar relationships were found in other studies compiled for comparison. The present study is unique in measuring denitrification in an "intact" ecosystem in the field, rather than in cores in the field or the lab. The exponential relationship between denitrification rate and soil moisture, with a "threshold" at 60–80% water-filled pore space (20–40% gravimetric moisture), has proven to be comparable across a wide range of ecosystems, treatments and study conditions. Whereas moisture content determines the potential for denitrification, the absolute rate of denitrification is determined by available nitrate (NO3-), dissolved organic carbon and temperature. As a first approximation, denitrification rates can be simply modelled by using a general exponential relationship between denitrification potential and water-filled pore space (or volumetric/gravimetric water content) multiplied by a constant value determined by the nitrogen status of the site. As such, it is recommended that the current relationship used in INCA to relate denitrification to soil moisture be amended to an exponential form, with a threshold of approximately 70% for the onset of denitrification. Keywords: nitrous oxide, denitrification, soil moisture, nitrogen, eutrophication, riparian

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Zhang, Xue Ying, and Xue Feng Dong. "Adjustment Analysis of AIG Spray Ammonia Denitration System Optimization in Coal-Fired Power Plant." Advanced Materials Research 1073-1076 (December 2014): 929–32. http://dx.doi.org/10.4028/www.scientific.net/amr.1073-1076.929.

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Aiming at power plants denitrification system existing chimney entrance NOx concentration than denitrification system outlet NOx concentration of "upside down" phenomenon, adjust and optimize the test denitrification system, denitrification system NOx concentration distribution uniformity can be obviously improved after the adjustment, improve economy of denitration system operation. At the same time, the denitrification system operation suggestion.

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Gan, Yanling, Wenjing Dai, Pingli Huang, Boge Zhang, and Suping Cui. "Preparation of Denitrification Materials with Nickel Slag for Nitric Oxide Decomposition in Cement Kilns." Materials 16, no. 17 (August 27, 2023): 5859. http://dx.doi.org/10.3390/ma16175859.

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NOx emission from the cement industry have received much attention. In order to reduce the NOx emission in cement kilns, nickel slag was used to prepare the non-ammonia denitrification material, and a denitrification mechanism was proposed in this study. The results showed that the denitrification material prepared at pH 7 exhibited the best denitrification performance. At low temperature, the highest denitrification performance was achieved between 200 and 300 °C with a NO decomposition rate of approximately 40%. Then, the NO decomposition rate increased as the temperature increased, reaching over 95% above 700 °C. The physicochemical characteristics showed that the material had the highest specific surface area and the highest relative Fe content, which benefited the denitrification performance. The divalent iron of the denitrification material was considered the active site for the reaction, and trivalent iron was not conducive to denitrification performance at a low temperature range. After the denitrification reaction, the Fe3+/Fe2+ increased from 0.89 to 1.31. The proposed denitrification mechanism was the redox process between divalent iron and trivalent iron. This study not only recycles industrial waste to reduce solid waste pollution but also efficiently removes nitrogen oxides from cement kilns without ammonia.

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Bergstrom, D. W., and E. G. Beauchamp. "Relationships between denitrification rate and determinant soil properties under barley." Canadian Journal of Soil Science 73, no. 4 (November 1, 1993): 567–78. http://dx.doi.org/10.4141/cjss93-056.

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To better understand environmental regulation of denitrification, we examined relationships between denitrification rate and six determinant soil properties: moisture content, air-filled porosity, NO3− content, respiration rate, mineralizable-C concentration and denitrifying enzyme activity (DEA). Soil cores were collected on 27 sampling dates over a growing season at a site seeded to barley (Hordeum vulgare). Denitrification rate was measured using a static core technique and acetylene blockage. Moisture content and air-filled porosity and, to a lesser extent, mineralizable-C concentration and respiration rate were more strongly related to denitrification rate than was DEA. Denitrification rate was unrelated to NO3− content. On most sampling dates, mean denitrification rate increased substantially only below an air-filled porosity of 0.3. Moreover, the distribution of individual measurements of denitrification rate was less skewed at lower air-filled porosities. Approximately 60% of variation in mean values of denitrification rate for each sampling date could be accounted for by measurements of bulk soil properties, of which moisture content and air-filled porosity were most important. Measurements of bulk soil properties did not account for nil values of denitrification rate at low air-filled porosities or for small-scale spatial variability. Such measurements were better indicators of temporal variation — that is, when denitrification occurred — than of actual rates. Key words: Denitrification, air-filled porosity, denitrifying enzyme activity

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Davies, S., G. W. Mann, K. S. Carslaw, M. P. Chipperfield, J. J. Remedios, G. Allen, A. M. Waterfall, R. Spang, and G. C. Toon. "Testing our understanding of Arctic denitrification using MIPAS-E satellite measurements in winter 2002/3." Atmospheric Chemistry and Physics Discussions 5, no. 6 (November 1, 2005): 10997–1028. http://dx.doi.org/10.5194/acpd-5-10997-2005.

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Abstract. Observations of gas-phase HNO3 and N2O in the polar stratosphere from the Michelson Interferometer for Passive Atmospheric Sounding aboard the ENVISAT satellite (MIPAS-E) were made during the cold Arctic winter of 2002/3. Vortex temperatures were unusually low in early winter and remained favourable for polar stratospheric cloud formation and denitrification until mid-January. MIPAS-E observations provide the first dataset with sufficient coverage of the polar vortex in mid-winter which enables a reasonable estimate of the timing of onset and spatial distribution of denitrification of the Arctic lower stratosphere to be performed. We use the observations from MIPAS-E to test the evolution of denitrification in the DLAPSE (Denitrification by Lagrangian Particle Sedimentation) microphysical denitrification model coupled to the SLIMCAT chemical transport model. In addition, the predicted denitrification from a simple equilibrium nitric acid trihydrate-based scheme is also compared with MIPAS-E. Modelled denitrification is compared with in-vortex NOy and N2O observations from the balloon-borne MarkIV interferometer in mid-December. Denitrification was clearly observed by MIPAS-E in mid-December 2002 and reached 80% in the core of the vortex by early January 2003. The DLAPSE model is broadly able to capture both the timing of onset and the spatial distribution of the observed denitrification. A simple thermodynamic equilibrium scheme is able to reproduce the observed denitrification in the core of the vortex but overestimates denitrification closer to the vortex edge. This study also suggests that the onset of denitrification in simple thermodynamic schemes may be earlier than in the MIPAS-E observations.

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Davies, S., G. W. Mann, K. S. Carslaw, M. P. Chipperfield, J. J. Remedios, G. Allen, A. M. Waterfall, R. Spang, and G. C. Toon. "Testing our understanding of Arctic denitrification using MIPAS-E satellite measurements in winter 2002/2003." Atmospheric Chemistry and Physics 6, no. 10 (July 31, 2006): 3149–61. http://dx.doi.org/10.5194/acp-6-3149-2006.

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Abstract. Observations of gas-phase HNO3 and N2O in the polar stratosphere from the Michelson Interferometer for Passive Atmospheric Sounding aboard the ENVISAT satellite (MIPAS-E) were made during the cold Arctic winter of 2002/2003. Vortex temperatures were unusually low in early winter and remained favourable for polar stratospheric cloud formation and denitrification until mid-January. MIPAS-E observations provide the first dataset with sufficient coverage of the polar vortex in mid-winter which enables a reasonable estimate of the timing of onset and spatial distribution of denitrification of the Arctic lower stratosphere to be performed. We use the observations from MIPAS-E to test the evolution of denitrification in the DLAPSE (Denitrification by Lagrangian Particle Sedimentation) microphysical denitrification model coupled to the SLIMCAT chemical transport model. In addition, the predicted denitrification from a simple equilibrium nitric acid trihydrate-based scheme is also compared with MIPAS-E. Modelled denitrification is compared with in-vortex NOy and N2O observations from the balloon-borne MarkIV interferometer in mid-December. Denitrification was clearly observed by MIPAS-E in mid-December 2002 and reached 80% in the core of the vortex by early January 2003. The DLAPSE model is broadly able to capture both the timing of onset and the spatial distribution of the observed denitrification. A simple thermodynamic equilibrium scheme is able to reproduce the observed denitrification in the core of the vortex but overestimates denitrification closer to the vortex edge. This study also suggests that the onset of denitrification in simple thermodynamic schemes may be earlier than in the MIPAS-E observations.

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Liang, B. C., and A. F. MacKenzie. "Seasonal denitrification rates under corn (Zea mays L.) in two Quebec soils." Canadian Journal of Soil Science 77, no. 1 (February 1, 1997): 21–25. http://dx.doi.org/10.4141/s96-018.

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Nitrogen losses in soil through denitrification are important due to reduced agronomic effectiveness and environmental concerns with nitrous oxide emissions. Knowledge of denitrification may allow for management procedures to reduce these losses. Field experiments were conducted in 1991 and 1992 to investigate N fertilizer effects on denitrification under corn (Zea mays L.) on two soils of contrasting texture in southwestern Quebec. Soil core incubation with C2H2 was used to assess denitrification rates. Total calculated denitrification rate from April to November in 1991 and 1992 varied from 4 to 41 kg N ha−1 on a Chicot sandy clay loam and from 29 to 53 kg N ha−1 on a Ste. Rosalie clay. Denitrification rates increased linearly with increasing fertilizer N rates only in the Ste. Rosalie clay in 1991. Denitrification in the Ste. Rosalie soil was positively related to temperature and NO3− levels in April and May, moisture content from August to November, and temperature in October and November. Denitrification in the Chicot soil was positively related to soil moisture content and NO3− levels in April and May, and soil moisture content in June. Reducing soil NO3− concentrations in April and May could decrease denitrification rate in both Chicot and Ste. Rosalie soils. Key words: Denitrification, fertilizer N, temperature, moisture content

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De Roach, Robert J., Andrew W. Rate, Brenton Knott, and Peter M. Davies. "Denitrification activity in sediment surrounding polychaete (Ceratonereis aequisetis) burrows." Marine and Freshwater Research 53, no. 1 (2002): 35. http://dx.doi.org/10.1071/mf00059.

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The effect of burrow-dwelling fauna on sediment denitrification within the Swan River Estuary, Western Australia, was assessed by determining the spatial profile of potential denitrification activity surrounding individual burrows of a polychaete. This activity was described for Ceratonereis aequisetis and compared with uninhabited sediment. Potential porewater denitrification activity was measured as N’2O production in the presence of acetylene (which blocks N2O reduction and NH4+ oxidation) and supplementary NO3-(provided as a substrate for denitrification). Snap-freezing of sediment cores in liquid nitrogen allowed easy sectioning in both the vertical (perpendicular depth from surface sediment) and radial (depth from burrow wall) planes. Overall, potential denitrification activity was significantly greater in inhabited sediment than in uninhabited sediment, although uninhabited sediment had higher surficial (0–10 mm) potential denitrification activity. Potential denitrification activity was also greater closer to the burrow wall (0–9 mm) rather than further into the sediment (9–13 mm). Greater sampling resolution would be required to determine whether a thin oxygenated surface layer (of either the vertical or radial plane) exists in which denitrification is inhibited. Although this study accurately demonstrates the spatial effect of C. aequisetis on sediment potential denitrification, the reported denitrification intensity may not reflect the rate in situ.

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Barton, L., C. D. A. McLay, L. A. Schipper, and C. T. Smith. "Annual denitrification rates in agricultural and forest soils: a review." Soil Research 37, no. 6 (1999): 1073. http://dx.doi.org/10.1071/sr99009.

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Denitrification is an important soil process for assessing nitrogen cycling and controlling nitrogen pollution in the environment. Numerous studies of denitrification rates in soils have been reported over the last decade, many with sampling protocols that are more reliable than in the past. In this paper, we review denitrification rates for agricultural and forest soils that have been reported in the literature, discuss factors that appear to be important in controlling the amount of denitrification that occurs in these soils, and summarise modelling approaches that have been used to predict annual denitrification rates. Most studies of in situ denitrification in upland soils have been conducted in agricultural grassland and forest ecosystems, with a paucity of studies reported from other ecosystems. A large range of annual, in situ, denitrification rates have been reported (0–239 kg N/ha.year), with the highest rates typically occurring in irrigated, nitrogen-fertilised soils. However, most annual denitrification rates reported in the literature appear to be fairly low, with over half of the rates in forest soils being <1 kg N/ha.year (mean of 1.9 kg N/ha.year). Rates of denitrification in agricultural soils tend to be higher than in forest soils, with 85% of rates reported being >1 kg N/ha.year, and a mean rate of 13 kg N/ha.year. Numerous soil, site, and management factors have been reported to affect the denitrification process in situ. The literature indicates that the highest rates of denitrification can be expected in nitrogen-fertilised soils, or where site management increases soil nitrate availability. Where nitrate is non-limiting, denitrification rates appear to be highest in irrigated loam soils. The review suggests that it is difficult to predict denitrification rates based on our current understanding, and that pilot studies should still be conducted if soil nitrogen balances are required.

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Yamamoto-Ikemoto, R., T. Komori, M. Nomuri, Y. Ide, and T. Matsukami. "Nitrogen removal from hydroponic culture wastewater by autotrophic denitrification using thiosulfate." Water Science and Technology 42, no. 3-4 (August 1, 2000): 369–76. http://dx.doi.org/10.2166/wst.2000.0405.

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Using the upflow biological filter reactor, sulfur denitrification using thiosulfate of hydroponic culture wastewater was examined. Start-up periods of the reactor were one to two weeks. About 90% of nitrogen removal ratio were achieved over 80 days, at 6.3 kg/m3·days of nitrogen loading. Shock loading among 0.56-2.8 kgN/m3· day did not affect the reactor performance. However, when temperature went below 15°C, the effluent characteristics became poor. Suitable S/N and IC/N ratios were calculated as 3.3 and 0.15, respectively. The activities of sulfur denitrification, heterotrophic denitrification and sulfur reduction were examined by the bath experiments under several conditions using biomass grown in the reactor. In the anoxic conditions, denitrification using thiosulfate was occurred stoichiometrically in the presence of thiosulfate. The denitrification activity was highest (17 mgN/gBiomass·hr). When the electron donor was not added to the substrate, denitrification occurred using sulfur granules accumulated in the biomass. Seventy mg of sulfur granule were accumulated in one g of biomass. The denitrification activity using sulfur granules was 2.9-5.0 mgN/gBiomass·hr. Heterotrophic denitrification occurred in the presence of organic matter. The activities were 1.4-5.4 mgN/gBiomass·hr. In the anaerobic conditions, the accumulated sulfur was reduced to sulfide at a rate of 1.4 mgS/gBiomass·hr. These results suggested that sulfur denitrification, heterotrophic denitrification and sulfur reduction bacteria coexisted in the biofilm and sulfur cycle was established in the reactor. Accumulated sulfur plays an important role in the sulfur denitrification.

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Dorias, Bernd, and Peter Baumann. "Denitrification in trickling filters." Water Science and Technology 30, no. 6 (September 1, 1994): 181–84. http://dx.doi.org/10.2166/wst.1994.0267.

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National and international regulations require a minimum nitrogen removal efficiency of 70% in most public sewage treatment plants. Unlike in activated sludge plants, selective denitrification in trickling filters was not possible until now. Therefore the aim was to employ trickling filter plants for selective denitrification, using innovative technology that involved minimum capital expenditure. For selective denitrification, it is necessary to prevent as much as possible the transfer of oxygen into the trickling filter while feeding the nitrate to be removed, a process similar to upstream denitrification in the activated sludge process. In a test operation conducted in several sewage treatment plants for over a year, the new process with selective denitrification in a covered trickling filter has given successful results. The denitrification efficiency of this system is comparable to that of upstream denitrification in the activated sludge process. Thus, selective denitrification in the trickling filter is a practical alternative to other nitrogen removal processes, while maintaining the established advantages offered by the trickling filter process.

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Xie, Yixuan, Ajun Wan, Xingmin Wang, Hengjie Dong, and Yunpeng Wu. "An iron-carbon-activated carbon and zeolite composite filter, anaerobic-aerobic integrated denitrification device for nitrogen removal in low C/N ratio sewage." Water Science and Technology 80, no. 2 (July 15, 2019): 223–31. http://dx.doi.org/10.2166/wst.2019.261.

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Abstract In this study, we use an anaerobic-aerobic integrated denitrification (Fe/C-ZACID) device with an iron-carbon-activated carbon and zeolite composite filter to remove nitrogen from simulated low carbon-nitrogen ratio (C/N) sewage. The impacts of dissolved oxygen (DO) level, hydraulic retention time (HRT), C/N and nitrate recirculation ratio on denitrification performance were studied. The results show that when HRT was 6 h, DO was 3 ± 0.1 mg/L, influent C/N was 3, and nitrate recirculation ratio was 100%, and removal rates of 95% for ammonia and 85% for total nitrogen (TN) were achieved. A beaker comparison test demonstrated that this synergistic denitrification system included heterotrophic denitrification, physicochemical denitrification, iron autotrophic denitrification and hydrogen autotrophic denitrification, etc. The Fe/C-ZACID device has a high-efficiency nitrogen removal effect for low C/N ratio sewage and strong shock resistance, which provides technical support and a theoretical basis for advanced denitrification of rural domestic sewage.

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Peng, Yong-zhen, Wang Shao-po, Wang Shu-ying, Hu Jian-ge, and Qiao Hai-Bing. "Effect of denitrification type on pH profiles in the sequencing batch reactor process." Water Science and Technology 53, no. 9 (April 1, 2006): 87–93. http://dx.doi.org/10.2166/wst.2006.279.

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Laboratory batch experiments were conducted to investigate pH profiles during partial and complete denitrification with sufficient organic carbon source. Five stirred tank-type glass vessels, with a 7 L working volume for each, were used as SBR reactors that were all operated in denitrification mode. Five levels of initial proportion of nitrogen substances, i.e. nitrate and nitrite, were used in five reactors, respectively. Results showed that, at given temperature and mixed liquor suspended solids (MLSS), partial denitrification could attain a higher pH value than complete denitrification at the end of denitrification with the same initial NOx− concentration. The larger proportion the nitrite took in initial NOx− concentration, the higher pH peak would be obtained on pH profiles during denitrification despite the same total alkalinity produced. It was found that different types of alkalinity were produced during biological denitrification with different nitrogen substances. Partial denitrification could more carbonate alkalinity produce than complete denitrification. Furthermore, some characteristic points were identified on pH profiles which could indicate the disappearance of not only nitrate, but also nitrite in system. When computers are used to detect these features, they can provide rapid, real-time information, regarding the biological state of the system.

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Buday, J., L. Halász, M. Drtil, I. Bodík, P. Németh, and M. Buday. "Nitrogen removal from wastewater of the chemical company Duslo." Water Science and Technology 41, no. 9 (May 1, 2000): 259–64. http://dx.doi.org/10.2166/wst.2000.0220.

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The results of laboratory scale modelling and real scale performance of the pre- and post-denitrification of a wastewater from the production of industrial fertilizers, pesticides and rubber additives are presented. As a substrate for the pre-denitrification, the biologically degradable organic compounds present in the influent were used. Selected wastewaters from chemical industry were used as a substrate for the post-denitrification. The results of the laboratory scale research of the pre-denitrification were successfully verified in real scale, an efficiency of 97% and 88% was reached for the removal of NO2––N and NO3––N respectively. The efficiency of the post-denitrification in real scale was 15% from the entering amount of NOx––N (NO2––NO3––N). Pre-denitrification removed about 190 kg NOx––N and post-denitrification about 85 kg NOx––N daily.

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Kim, E. W., and J. H. Bae. "Alkalinity requirements and the possibility of simultaneous heterotrophic denitrification during sulfur-utilizing autotrophic denitrification." Water Science and Technology 42, no. 3-4 (August 1, 2000): 233–38. http://dx.doi.org/10.2166/wst.2000.0385.

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Alkalinity requirement and the possibility of simultaneous heterotrophic denitrification during sulfur-utilizing autotrophic denitrification were evaluated with sulfur packed bed reactors (SPBRs). SPBR showed >99% NO3--N removal efficiency at influent NO3--N concentration of 1,500 mg/L, although 25-40% of the added NO3--N was recovered as N2O. Complete denitrification without N2O production was achieved when the influent NO3--N concentration decreased to 750 mg/L. When nitrified landfill leachate containing 602–687 mg/L of NO3--N was fed to SPBR, denitrification efficiency was greater than 98%. During leachate treatment, alkalinity consumption was 3.25–3.76 g CaCO3/g NO3--N removed. Most of denitrification activity occurred within bottom 11.5 cm of sulfur layer, meaning that effective HRT of 2.34 hours was enough for the complete denitrification at the loading rate of 2.2 kg NO3--N/m3-day. Complete denitrification was also achieved when methanol was added to nitrified leachate without alkalinity addition. In this case, alkalinity produced by heterotrophs was used for sulfur-utilizing denitrification.

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25

Jiang, Feng, Zhen-Sheng Liang, Guo-Liang Peng, Jin Qian, and Guang-Hao Chen. "Nitrogen removal capacity of simultaneously autotrophic and heterotrophic denitrification in a sewer receiving nitrified source-separated urine." Water Practice and Technology 8, no. 1 (March 1, 2013): 33–40. http://dx.doi.org/10.2166/wpt.2013.005.

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Discharging source-separated and nitrified urine into sewer helps to save cost and space in biological nitrogen treatment as in-sewer denitrification is induced. This unique denitrification process may become complicated in sewers with sulfide contamination as simultaneously autotrophic and heterotrophic denitrification possibly occur but may compete each other for nitrate in oxidation of sulfide and organics. The objective of this study is to estimate the mixed denitrification rate in a sulfide-contaminated sewer when nitrified urine (mainly nitrite and nitrate) is discharged. In this study two investigations were conducted: (1) determination of the autotrophic, heterotrophic and mixed denitrification rates via lab batch tests and (2) determination of the total nitrogen removal rate in a 6.5-km long force main sewer via field study with calcium nitrate dosed at an average influent rate of 15.6 mg N/L. The lab tests determined the rates of autotrophic, heterotrophic and mixed denitrification at 0.36 ± 0.06, 6.54 ± 0.04 and 1.99 ± 0.1 mg N/L/h, respectively, while the field study estimated the total in-sewer denitrification rate at 2.32 mg N/L/h in the sewer when sulfide was present. Simultaneously autotrophic and heterotrophic denitrification was found when sewage was contaminated with sulfide. However, nitrogen removal rate of heterotrophic denitrification was 3.3 times higher that of the mixed denitrification process. The results indicate that discharging source-separated and nitrified urine into sewer is meaningful to decentralized sewage treatment, especially when sulfide is absent in the sewer.

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Zhang, Song, Zhou, Cao, and Zhou. "Coupling between Nitrification and Denitrification as well as Its Effect on Phosphorus Release in Sediments of Chinese Shallow Lakes." Water 11, no. 9 (August 30, 2019): 1809. http://dx.doi.org/10.3390/w11091809.

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The coupling of nitrification and denitrification has attracted wide attention since it plays an important role in mitigating eutrophication in aquatic ecosystems. However, the underlying mechanism is largely unknown. In order to study the coupling relationship between nitrification and denitrification, as well as its effect on phosphorus release, nutrient levels, functional gene abundance and potential rates involved in nitrification and denitrification were analyzed in three shallow urban lakes with different nutrient status. Trophic level was found positively related to not only copy numbers of functional genes of nitrosomonas and denitrifiers, but also the potential nitrification and denitrification rates. In addition, the concentrations of different forms of phosphorus showed a positive correlation with the number of nitrosomonas and denitrifiers, as well as potential nitrification and denitrification rates. Furthermore, the number of functional genes of nitrosomonas exhibited positive linear correlations with functional genes and rate of denitrification. These facts suggested that an increase in phosphorus concentration might have promoted the coupling of nitrification and denitrification by increasing their functional genes. Strong nitrification–denitrification fueled the nitrogen removal from the system, and accelerated the phosphorus release due to the anaerobic state caused by organic matter decomposition and nitrification. Moreover, dissolved organic nitrogen was also released into the water column during this process, which was favorable for balancing the nitrogen and phosphorus ratio. In conclusion, the close coupling between nitrification and denitrification mediated by nitrifier denitrification had an important effect on the cycling mode of nitrogen and phosphorus.

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27

Yamashita, Takahiro, and Ryoko Yamamoto-Ikemoto. "Phosphate removal and sulfate reduction in a denitrification reactor packed with iron and wood as electron donors." Water Science and Technology 58, no. 7 (October 1, 2008): 1405–13. http://dx.doi.org/10.2166/wst.2008.728.

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Phosphorus removal and denitrification using iron and wood as electron donors were examined in a laboratory-scale biological filter reactor. Phosphorus removal and denitrification using iron and wood continued for 1,200 days of operation. Wood degradation by heterotrophic denitrification and iron oxidation by hydrogenotrophic denitrification occurred simultaneously. In the biofilm inside the wood, not only heterotrophic denitrification activity but also sulfate reduction and sulfur denitrification activities were recognized inside the wood, indicating that a sulfur oxidation-reduction cycle was established. Sulfate reduction and denitrification were accelerated with the addition of cellulose. Microbial communities of sulfate-reducing bacteria by PCR primer sets could be amplified in the biofilm in the reactors. The dissimilatory sulfite reductase gene and the 16S rRNA gene of six phylogenetic groups of SRB in the reactors were analyzed. Some SRB group-specific primers-amplification products were obtained inside the wood and around iron.

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Han, Hong Jun, Yu Fei Li, Hong Bo Hu, and Bing Wang. "Effect of External Carbon Source on Denitrification in Biofilter at Low Temperature." Advanced Materials Research 113-116 (June 2010): 1358–62. http://dx.doi.org/10.4028/www.scientific.net/amr.113-116.1358.

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The aim of this study is to investigate the denitrification efficiency enhancement and to evaluate the denitrification potential at the condition of lower temperature. Three identical biofilter were operated in parallel at batch tests. Results showed that the denitrification potential can be substantially increased by addition of ethanol and hydrolysate of sludge as external carbon sources compared with raw sewage. The mean denitrification rates of ethanol and hydrolysate reached up to 0.058 and 0.08 mgN/(g MLVSS•h), respectively, while that of raw sewage was only 0.041 mgN/(g MLVSS•h). The denitrification potential increased respectively from 0.76 to 1.54 and 5.3 mg NO3-N/L owing to ethanol and hydrolysate addition. By comparison, hydrolysate of sludge was found to be the better carbon source for denitrification considering strengthening denitrification performance and price. This study provides evidence for external carbon sources choice of sewage plant and surplus sludge reutilization.

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Wang, Yan, Weiyi Xu, Xue Yang, Zhengming Ren, Kaiwen Huang, Feiyue Qian, and Ji Li. "Long-Term Operation of a Pilot-Scale Sulfur-Based Autotrophic Denitrification System for Deep Nitrogen Removal." Water 15, no. 3 (January 20, 2023): 428. http://dx.doi.org/10.3390/w15030428.

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Sulfur-based autotrophic denitrification is a novel biological denitrification process characterized by the absence of an organic carbon source, a short reaction time, a high denitrification rate, a low treatment cost, and a small footprint. However, the technique is facing challenges with respect to engineering applications. In this study, a pilot-scale sulfur-based autotrophic denitrification system was established with an optimal hydraulic retention time (HRT) of 0.21 h, which achieved the highest denitrification load of 1158 mg/(L·d) and a denitrification rate of 164 gNO3−-N/(m3·h). Effective backwashing is the basis for the long-term stable and efficient nitrogen removal performance, which recovered its normal nitrogen removal performance within 0.5 h. In addition, the operation cost is merely 0.013 $/t, indicating that the sulfur-based autotrophic denitrification process presents good economic applicability, and the relatively low operation cost will lay a foundation for practical application.

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30

Toyofuku, Masanori, Nobuhiko Nomura, Eriko Kuno, Yosuke Tashiro, Toshiaki Nakajima, and Hiroo Uchiyama. "Influence of the Pseudomonas Quinolone Signal on Denitrification in Pseudomonas aeruginosa." Journal of Bacteriology 190, no. 24 (October 17, 2008): 7947–56. http://dx.doi.org/10.1128/jb.00968-08.

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ABSTRACT Denitrification is a well-studied respiratory system that is also important in the biogeochemical nitrogen cycle. Environmental signals such as oxygen and N-oxides have been demonstrated to regulate denitrification, though how denitrification is regulated in a bacterial community remains obscure. Pseudomonas aeruginosa is a ubiquitous bacterium that controls numerous genes through cell-to-cell signals. The bacterium possesses at least two N-acyl-l-homoserine lactone (AHL) signals. In our previous study, these quorum-sensing signals controlled denitrification in P. aeruginosa. In addition to the AHL signals, a third cell-to-cell communication signal, 2-heptyl-3-hydroxy-4-quinolone, referred to as the Pseudomonas quinolone signal (PQS), has been characterized. In this study, we examined the effect of PQS on denitrification to obtain more insight into the respiratory regulation in a bacterial community. Denitrification in P. aeruginosa was repressed by PQS, which was partially mediated by PqsR and PqsE. Measuring the denitrifying enzyme activities indicated that nitrite reductase activity was increased by PQS, whereas PQS inhibited nitric oxide reductase and the nitrate-respiratory chain activities. This is the first report to demonstrate that PQS influences enzyme activities, suggesting this effect is not specific to P. aeruginosa. Furthermore, when iron was supplied to the PQS-added medium, denitrifying activity was almost restored, indicating that the iron chelating property of PQS affected denitrification. Thus, our data indicate that PQS regulates denitrification primarily through iron chelation. The PQS effect on denitrification was relevant in a condition where oxygen was limited and denitrification was induced, suggesting its role in controlling denitrification where oxygen is present.

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31

Simonne, Eric H., Guodong Liu, and Benjamin Morgant. "Denitrification in Seepage-Irrigated Vegetable Fields in South Florida." EDIS 2019 (September 11, 2019): 11. http://dx.doi.org/10.32473/edis-hs248-2019.

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The objectives of this article are to: describe denitrification and the factors known to affect its rate, present current methods available for the measurement of denitrification rate, summarize available estimates of denitrification rate, and attempt to provide guidelines on how to account for potential denitrification losses in fertilizer programs. This 11-page fact sheet is a minor revision written by Eric H. Simonne, Guodong Liu, and Benjamin Morgant, and published by the Horticultural Sciences Department, August 2019. HS1004/HS248: Denitrification in Seepage-Irrigated Vegetable Fields in South Florida (ufl.edu)

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32

Tang, Xinhua, Yu Huang, Shenyu Tan, and Heng Yang. "Vertical spatial denitrification performance and microbial community composition in denitrification biofilters coupled with water electrolysis." RSC Advances 14, no. 22 (2024): 15431–40. http://dx.doi.org/10.1039/d4ra02260b.

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Vertical spatial denitrification performance, microbial community and key denitrification genes in a biofilter coupled with water electrolysis were studied to explain the mechanisms of heterotrophic–hydrogen autotrophic denitrification.

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33

Liang, Baorui, Tong Zhu, Fei Kang, Yao Wang, and Sai Yao. "Denitrification performance and microbial communities of solid-phase denitrifying reactors using novel composite." Advances in Engineering Technology Research 1, no. 1 (May 13, 2022): 42. http://dx.doi.org/10.56028/aetr.1.1.42.

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This study explored the denitrification performance of solid-phase denitrification reactors packed with elemental sulfur/wheat straw/shell powder composites to treat nitrate-contaminated wastewater under different conditions. The sulfur-based autotrophic denitrification integrated natural-carbon-source (NCS)-based heterotrophic denitrification system was formed (SND). The fast start-up and intensified nitrogen removal performance were obtained in SND systems. The optimum denitrification performance was achieved by the SND15 reactor, with a maximum denitrification rate of 530 mg N·L-1·d-1 over 180 days operation. The co-existence of autotrophs and heterotrophs were observed in all reactors, this may contribute to better control of nitrogen in SND system. The outcomes provide a potential strategy of cost reduction to improve nitrogen removal of wastewater treatment plants (WWTPs) effluent.

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34

Yin, Lian Qin, Shu Dong Mao, Hai Hong Ji, and Shan Shan Zhang. "Study on Denitrification Technology Improvement of a Coal-Fired Power Plant." Advanced Materials Research 726-731 (August 2013): 1945–49. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.1945.

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The nitrogen oxides emission concentration of a coal-fired units exceeded national standards. This paper analyzed the problem of the denitrification equipment, the denitrification process was transformed with low NOX combustion and hybrid SNCR&SCR denitrification technique, according to the existing denitrification technology. The nitrogen emission concentration of the coal-fired units reach the current national emission standards after transformation.

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35

Puznava, N., M. Payraudeau, and D. Thornberg. "Simultaneous nitrification and denitrification in biofilters with real time aeration control." Water Science and Technology 43, no. 1 (January 1, 2001): 269–76. http://dx.doi.org/10.2166/wst.2001.0057.

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The aim of this article is to present a new biological aerated filter (BAF) for nitrogen removal based on simultaneous nitrification and denitrification. Contrary to the systems which integrate both an aerated and a non-aerated zone to allow complete nitrogen removal in one compact or two different units (pre-denitrification and nitrification), this upflow BAF system is based on the principle of simultaneous nitrification and denitrification since the filter is completely aerated. The denitrification process is possible due to the diffusion effect which dominates biofilm processes. The real time aeration control allows us to maintain a low dissolved oxygen value (0.5 to 3 mg O2/l). In this case, the biofilm will not be fully (or less) penetrated with oxygen and denitrification will be carried out in a large part of the biofilm. Therefore, nitrification and denitrification is running simultaneously in different depths of the biofilm. By using 50% less air this BAF gave the same results (less than 20mg TN/l) on pilot plant as a classical nitrification and denitrification BAF (Toettrup et al., 1994). Less recirculation was necessary to achieve the same denitrification.

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36

Ruan, Yunjie, Lei Cai, Huifeng Lu, Meng Zhang, Xiangyang Xu, and Wenbing Li. "Performance of Aerobic Denitrification by the Strain Pseudomonas balearica RAD-17 in the Presence of Antibiotics." Microorganisms 9, no. 8 (July 26, 2021): 1584. http://dx.doi.org/10.3390/microorganisms9081584.

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Aerobic denitrification, one of the important nitrate metabolic pathways in biological denitrification, has been attracting increasing interest recently due to its functional advantages. In order to evaluate the effect of antibiotics on aerobic denitrification and guide practical engineering application of aerobic denitrification techniques, we evaluated the performance of aerobic denitrification by the strain Pseudomonas balearica RAD-17 in the presence of ciprofloxacin (CFX) and oxytetracycline (OTC). No significant negative impact on the performance of aerobic denitrification in the presence of CFX or OTC within the range of 50 to 300 μg L−1 was found. Significant degradation of OTC was found within the range of 50 μg L−1 to 300 μg L−1 under aerobic denitrification conditions, while no degradation was found for CFX. Stimulation of cell growth occurred within the investigated range of antibiotics. Under anoxic or aerobic conditions, the addition of CFX or OTC changed the N2O production trend. The results in the present study may play an important role in informing the use of aerobic denitrification techniques in the presence of antibiotics within environmentally relevant concentrations (<1 mg/L).

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37

Kozub, D. D., and S. K. Liehr. "Assessing Denitrification Rate Limiting Factors in a Constructed Wetland Receiving Landfill Leachate." Water Science and Technology 40, no. 3 (August 1, 1999): 75–82. http://dx.doi.org/10.2166/wst.1999.0140.

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The focus of this research was to investigate denitrification in constructed wetlands to improve the nitrogen treatment capabilities of these systems. A free water surface flow constructed wetland located at the New Hanover County Solid Waste Management Facility, near Wilmington, North Carolina, USA, was used for this research. Field water sampling in conjunction with a laboratory acetylene block method was used to quantify nitrogen removals in the wetland. Background denitrification rates as well as potential denitrification rates using sodium acetate and sodium phosphate were measured in the laboratory. According to field measurements, average nitrate nitrogen loading and removal rates in the constructed wetland during 1997 were 11.1 ± 3.4 g N/m3/d and 4.5 ± 2.2 g N/m3/d, respectively. Denitrification rates measured in the laboratory with the addition of sodium acetate were higher than background denitrification rates while the addition of sodium phosphate had no effect on the denitrification rates. Results suggested denitrification in the wetland was limited by the availability of easily degradable sources of organic carbon. Background denitrification rates measured using the laboratory method were comparable to the nitrate nitrogen removal rates measured by field water sampling.

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38

Tong, Shuang, Laura C. Rodriguez-Gonzalez, Chuanping Feng, and Sarina J. Ergas. "Comparison of particulate pyrite autotrophic denitrification (PPAD) and sulfur oxidizing denitrification (SOD) for treatment of nitrified wastewater." Water Science and Technology 75, no. 1 (November 8, 2016): 239–46. http://dx.doi.org/10.2166/wst.2016.502.

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The use of reduced sulfur compounds as electron donors for biological denitrification has the potential to reduce chemical and sludge disposal costs as well as carry-over of organic carbon to the effluent that often occurs with heterotrophic denitrification. Although a number of prior studies have evaluated sulfur oxidizing denitrification (SOD), no prior studies have evaluated particulate pyrite autotrophic denitrification (PPAD) in continuous flow systems. Bench-scale upflow packed bed reactors (PBRs) were set up to compare denitrification rates, by-product production and alkalinity consumption of PPAD and SOD. At an empty bed contact time of 2.9 h, average NO3−-N removal efficiencies were 39.7% and 99.9% for PPAD and SOD, respectively. Although lower denitrification rates were observed with PPAD than SOD, lower alkalinity consumption and reduced sulfur by-product formation (SO42−, S2− and SO32− plus S2O32−) were observed with PPAD. Furthermore, higher denitrification rates and lower by-product production was observed for SOD than in prior studies, possibly due to the media composition, which included sand and oyster shells. The results show that both pyrite and elemental sulfur can be used as electron donors for wastewater denitrification in PBRs.

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39

Adame, M. F., H. Franklin, N. J. Waltham, S. Rodriguez, E. Kavehei, M. P. Turschwell, S. R. Balcombe, P. Kaniewska, M. A. Burford, and M. Ronan. "Nitrogen removal by tropical floodplain wetlands through denitrification." Marine and Freshwater Research 70, no. 11 (2019): 1513. http://dx.doi.org/10.1071/mf18490.

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Excess nitrogen (N) leading to the eutrophication of water and impacts on ecosystems is a serious environmental challenge. Wetlands can remove significant amounts of N from the water, primarily through the process of denitrification. Most of our knowledge on wetland denitrification is from temperate climates; studies in natural tropical wetlands are very scarce. We measured denitrification rates during a dry and a wet season in five floodplain forests dominated by Melaleuca spp., a coastal freshwater wetland of tropical Australia. We hypothesised that the denitrification potential of these wetlands would be high throughout the year and would be limited by N and carbon (C) availability. Mean potential denitrification rates (Dt) were 5.0±1.7mgm2h–1, and were within the reported ranges for other tropical and temperate wetlands. The rates of Dt were similar between the dry and the wet seasons. From the total unamended denitrification rates (Dw, 3.1±1.7mgm2h–1), 64% was derived from NO3– of the water column and the rest from coupled nitrification–denitrification. The factor most closely associated with denitrification was background water NO3–-N concentrations. Improved management and protection of wetlands could play an important role in improving water quality in tropical catchments.

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40

Heffernan, J. B., A. R. Albertin, M. L. Fork, B. G. Katz, and M. J. Cohen. "Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer." Biogeosciences Discussions 8, no. 5 (October 20, 2011): 10247–94. http://dx.doi.org/10.5194/bgd-8-10247-2011.

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Abstract. Aquifer denitrification is among the most poorly constrained fluxes in global and regional nitrogen budgets. The few direct measurements of denitrification in groundwaters provide limited information about its spatial and temporal variability, particularly at the scale of whole aquifers. Uncertainty in estimates of denitrification may also lead to underestimates of its effect on isotopic signatures of inorganic N, and thereby confound the inference of N source from these data. In this study, our objectives are to quantify the magnitude and variability of denitrification in the Upper Floridan Aquifer (UFA) and evaluate its effect on N isotopic signatures at the regional scale. Using dual noble gas tracers (Ne, Ar) to generate physical predictions of N2 gas concentrations for 112 observations from 61 UFA springs, we show that excess (i.e. denitrification-derived) N2 is highly variable in space and inversely correlated with dissolved oxygen (O2). Negative relationship between O2 and δ15NNO3 across a larger dataset of 113 springs, well-constrained isotopic fractionation coefficients, and strong 15N : 18O covariation further support inferences of denitrification in this uniquely organic-matter-poor system. Despite relatively low average rates, denitrification accounted for 32% of estimated aquifer N inputs across all sampled UFA springs. Back-calculations of source δ15NNO3 based on denitrification progression suggest that isotopically-enriched nitrate (NO3−) in many springs of the UFA reflects groundwater denitrification rather than urban- or animal-derived inputs.

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41

Wang, Te, Zhao Xia Liu, Mei Juan Wu, Fu Hui Kang, Qing Chen, Yao Jun Song, and Ling Hua Zhang. "Screening and Characterization of a Bacterium Capable of Simultaneous Heterotrophic Nitrification and Aerobic Denitrification at High Concentrations of Ammonia-Nitrogen." Applied Mechanics and Materials 665 (October 2014): 487–90. http://dx.doi.org/10.4028/www.scientific.net/amm.665.487.

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A bacterium capable of simultaneous heterotrophic nitrification and aerobic denitrification at high concentrations of ammonia-nitrogen was screened and identified and the denitrification property was investigated in this paper. The strain was isolated from aeration tank of wastewater disposed by activated sludge and analyzed and identified by 16S rDNA. The effects of different carbon sources and carbon and nitrogen mass ratios on denitrification rate were studied. The changes of various forms of ammonia-nitrogens during the simultaneous heterotrophic nitrification and aerobic denitrification process were characterized. A strain capable of simultaneous heterotrophic nitrification and aerobic denitrification at 600 mg/L nitrogen concentration has been isolated and screened. Comparison of its 16S rDNA sequence showed 100% similarity to Bacillus licheniformis strain Lr124/6. The strain was named as Bacillus sp. A22. The optimal conditions for degradation of ammonia-nitrogen by Bacillus sp. A22 were trisodium citrate as carbon source and carbon and nitrogen mass ratios of 10. The denitrification rate was 98.2% after 96 h of culture under the optimal conditions and there was hardly any intermediates accumulation in the denitrification process. It has practical applications that the denitrification can be performed efficiently at high concentrations of ammonia-nitrogen by method of simultaneous heterotrophic nitrification and aerobic denitrification by Bacillus sp. A22 in nitrogen purification treatment of wastewater with high concentrations of ammonia-nitrogen.

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42

Heffernan, J. B., A. R. Albertin, M. L. Fork, B. G. Katz, and M. J. Cohen. "Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer." Biogeosciences 9, no. 5 (May 11, 2012): 1671–90. http://dx.doi.org/10.5194/bg-9-1671-2012.

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Abstract. Aquifer denitrification is among the most poorly constrained fluxes in global and regional nitrogen budgets. The few direct measurements of denitrification in groundwaters provide limited information about its spatial and temporal variability, particularly at the scale of whole aquifers. Uncertainty in estimates of denitrification may also lead to underestimates of its effect on isotopic signatures of inorganic N, and thereby confound the inference of N source from these data. In this study, our objectives are to quantify the magnitude and variability of denitrification in the Upper Floridan Aquifer (UFA) and evaluate its effect on N isotopic signatures at the regional scale. Using dual noble gas tracers (Ne, Ar) to generate physical predictions of N2 gas concentrations for 112 observations from 61 UFA springs, we show that excess (i.e. denitrification-derived) N2 is highly variable in space and inversely correlated with dissolved oxygen (O2). Negative relationships between O2 and δ15NNO3 across a larger dataset of 113 springs, well-constrained isotopic fractionation coefficients, and strong 15N:18O covariation further support inferences of denitrification in this uniquely organic-matter-poor system. Despite relatively low average rates, denitrification accounted for 32 % of estimated aquifer N inputs across all sampled UFA springs. Back-calculations of source δ15NNO3 based on denitrification progression suggest that isotopically-enriched nitrate (NO3–) in many springs of the UFA reflects groundwater denitrification rather than urban- or animal-derived inputs.

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43

Shoun, Hirofumi, Du-Hyun Kim, Hiroo Uchiyama, and Junta Sugiyama. "Denitrification by fungi." FEMS Microbiology Letters 94, no. 3 (July 1992): 277–81. http://dx.doi.org/10.1111/j.1574-6968.1992.tb05331.x.

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44

Spalding, Roy F., and Jack D. Parrott. "Shallow groundwater denitrification." Science of The Total Environment 141, no. 1-3 (January 1994): 17–25. http://dx.doi.org/10.1016/0048-9697(94)90014-0.

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45

MATSUI, Saburo, and Masahiro TATEWAKI. "Sulfur denitrification bacteria." Journal of Environmental Conservation Engineering 18, no. 6 (1989): 373–77. http://dx.doi.org/10.5956/jriet.18.373.

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46

Hynes, R. K., A. L. Ding, and L. M. Nelson. "Denitrification byRhizobium fredii." FEMS Microbiology Letters 30, no. 1-2 (October 1985): 183–86. http://dx.doi.org/10.1111/j.1574-6968.1985.tb01008.x.

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47

Grabínska-Łoniewska, A. "Denitrification unit biocenosis." Water Research 25, no. 12 (December 1991): 1565–73. http://dx.doi.org/10.1016/0043-1354(91)90189-w.

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48

Hunt, Patrick G., Terry A. Matheny, Kyoung S. Ro, Kenneth C. Stone, and Matias B. Vanotti. "Denitrification of agricultural drainage line water via immobilized denitrification sludge." Journal of Environmental Science and Health, Part A 43, no. 9 (June 11, 2008): 1077–84. http://dx.doi.org/10.1080/10934520802060084.

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49

Wang, Yue, Charles Bott, and Robert Nerenberg. "Sulfur-based denitrification: Effect of biofilm development on denitrification fluxes." Water Research 100 (September 2016): 184–93. http://dx.doi.org/10.1016/j.watres.2016.05.020.

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Wang, Shu-Sen, Hao-Yi Cheng, Hao Zhang, Shi-Gang Su, Yi-Lu Sun, Hong-Cheng Wang, Jing-Long Han, Ai-Jie Wang, and Awoke Guadie. "Sulfur autotrophic denitrification filter and heterotrophic denitrification filter: Comparison on denitrification performance, hydrodynamic characteristics and operating cost." Environmental Research 197 (June 2021): 111029. http://dx.doi.org/10.1016/j.envres.2021.111029.

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Journal articles on the topic 'Denitrification'

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