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1
Taylor, Anne E., Neeraja Vajrala, Andrew T. Giguere, Alix I. Gitelman, Daniel J. Arp, David D. Myrold, Luis Sayavedra-Soto e Peter J. Bottomley. "Use of Aliphaticn-Alkynes To Discriminate Soil Nitrification Activities of Ammonia-Oxidizing Thaumarchaea and Bacteria". Applied and Environmental Microbiology 79, n. 21 (16 agosto 2013): 6544–51. http://dx.doi.org/10.1128/aem.01928-13.
Testo completoAbstract (sommario):
ABSTRACTAmmonia (NH3)-oxidizing bacteria (AOB) and thaumarchaea (AOA) co-occupy most soils, yet no short-term growth-independent method exists to determine their relative contributions to nitrificationin situ. Microbial monooxygenases differ in their vulnerability to inactivation by aliphaticn-alkynes, and we found that NH3oxidation by the marine thaumarchaeonNitrosopumilus maritimuswas unaffected during a 24-h exposure to ≤20 μM concentrations of 1-alkynes C8and C9. In contrast, NH3oxidation by two AOB (Nitrosomonas europaeaandNitrosospira multiformis) was quickly and irreversibly inactivated by 1 μM C8(octyne). Evidence that nitrification carried out by soilborne AOA was also insensitive to octyne was obtained. In incubations (21 or 28 days) of two different whole soils, both acetylene and octyne effectively prevented NH4+-stimulated increases in AOB population densities, but octyne did not prevent increases in AOA population densities that were prevented by acetylene. Furthermore, octyne-resistant, NH4+-stimulated net nitrification rates of 2 and 7 μg N/g soil/day persisted throughout the incubation of the two soils. Other evidence that octyne-resistant nitrification was due to AOA included (i) a positive correlation of octyne-resistant nitrification in soil slurries of cropped and noncropped soils with allylthiourea-resistant activity (100 μM) and (ii) the finding that the fraction of octyne-resistant nitrification in soil slurries correlated with the fraction of nitrification that recovered from irreversible acetylene inactivation in the presence of bacterial protein synthesis inhibitors and with the octyne-resistant fraction of NH4+-saturated net nitrification measured in whole soils. Octyne can be useful in short-term assays to discriminate AOA and AOB contributions to soil nitrification.
2
Fiocchi, N., E. Ficara, S. Bonelli, R. Canziani, F. Ciappelloni, S. Mariani, M. Pirani, P. Ratini, D. Mazouni e J. Harmand. "Automatic set-point titration for monitoring nitrification in SBRs". Water Science and Technology 58, n. 2 (1 agosto 2008): 331–36. http://dx.doi.org/10.2166/wst.2008.387.
Testo completoAbstract (sommario):
Nitrification is usually the bottleneck of biological nitrogen removal processes. In SBRs systems, it is not often enough to monitor dissolved oxygen, pH and ORP to spot problems which may occur in nitrification processes. Therefore, automated supervision systems should be designed to include the possibility of monitoring the activity of nitrifying populations. Though the applicability of set-point titration for monitoring biological processes has been widely demonstrated in the literature, the possibility of an automated procedure is still at its early stage of industrial development. In this work, the use of an at-line automated titrator named TITAAN (TITrimetric Automated ANalyser) is presented. The completely automated sensor enables us to track nitrification rate trend with time in an SBR, detecting the causes leading to slower specific nitrification rates. It was also possible to perform early detection of toxic compounds in the influent by assessing their effect on the nitrifying biomass. Nitrifications rates were determined with average errors±10% (on 26 tests), never exceeding 20% as compared with UV-spectrophotometric determinations.
3
Yao, Chuang, Heng-Yi Lei, Qiang Yu, Shu-Ping Li, Hua-Liang Li, Kai Chen e Xing-Hong Zhang. "Application of magnetic enhanced bio-effect on nitrification: a comparative study of magnetic and non-magnetic carriers". Water Science and Technology 67, n. 6 (1 marzo 2013): 1280–87. http://dx.doi.org/10.2166/wst.2013.697.
Testo completoAbstract (sommario):
A novel magnetic carrier with surface magnetic field of 4 mT was developed for studying the magnetic enhanced bio-effect on nitrification. The bio-effect on nitrificaton induced by the magnetic carrier was studied by comparing the performance of sequencing batch biofilm reactors filled with magnetic (MC) and non-magnetic (NMC) carriers. The result showed that the bioreactor with MC had better performance for nitrification than bioreactor with NMC. During the biofilm culturing period, the time required for nitrification formation in biofilm of the MC reactor was 25% less than that for the NMC reactor. The results also showed that the ammonium oxidation rate of the MC reactor was 1.6-fold faster than that in the NMC reactor at high influent NH4-N concentration, while nitrite oxidation rate was always accelerated regardless of influent NH4-N concentration. The specific oxygen uptake rate analysis revealed that ammonia and nitrite oxidation activities in biofilm of the MC reactor were 1.65 and 1.98 times greater than those of the NMC reactor, respectively.
4
Wang, B., S. He, L. Wang e L. Shuo. "Simultaneous nitrification and de-nitrification in MBR". Water Science and Technology 52, n. 10-11 (1 novembre 2005): 435–42. http://dx.doi.org/10.2166/wst.2005.0721.
Testo completoAbstract (sommario):
Experiments have been carried out to get an understanding of the effect of DO, C/N ratio and pH on the performance of a bench scale membrane bioreactor (MBR) in simultaneous nitrification and de-nitrification. It was found that under the conditions of MLSS in the range of 8000–9000mg/L and temperature of water in the MBR of 24°C, influent COD and NH3-N in the range of 523–700mg/L and 17.24–24mg/L respectively, the removals of COD, NH3-N and TN were 98%,99% and 60%; 96.5%,98% and 75%; 96%,95% and 92%; 90%,70% and 60% respectively at DO of 6, 3, 1 and 0.5mg/L. It was also found that the changes in C/N ratio and pH in a certain range have a slight effect on COD removal but have significant influence on the removal of NH3-N and TN. The results showed that only under the conditions that each ecological factor was maintained relatively steadily, simultaneous nitrification and de-nitrification proceeded smoothly. It was found that when C/N ratio was 30, the influent pH 7.2, the temperature of water in MBR 24°C and DO 1mg/L, as optimum conditions, the removals of COD, NH3-N and TN were 96%, 95% and 92% respectively. In addition, mechanism research on simultaneous nitrification and de-nitrification in MBR has been conducted as well.
5
Li, Pengzhang, Yongzhen Peng, Shuying Wang e Yue Liu. "N2O Emission from Partial Nitrification and Full Nitrification in Domestic Wastewater Treatment Process". Water 14, n. 20 (11 ottobre 2022): 3195. http://dx.doi.org/10.3390/w14203195.
Testo completoAbstract (sommario):
Using actual domestic wastewater as the research object, nitrogen compounds and their combinations were added to different nitrification (partial nitrification, full nitrification) processes to investigate nitrous oxide (N2O) emission and its nitrification mechanisms. The presence of influent NH4+ was the driving force of N2O emission during nitrification. Compared with full nitrification, NO2− in partial nitrification more readily generated N2O by denitrification. Under the proportional gradient of NH4+-N:NO2−-N/NO3−-N, 30:0, 20:10, 10:20, and 0:30, total N2O emissions during partial nitrification were 2.81, 11.30, 65.20, and 11.67 times greater than the total N2O emissions during full nitrification. Full nitrification was more beneficial to N2O emission reduction. This provides a control strategy for N2O emission reduction in wastewater treatment processes under the background of reducing the production of greenhouse gases.
6
Guo, Changqing, Hongmei Wang, Dianbo Zou, Yue Wang e Xiaori Han. "A novel amended nitrification inhibitor confers an enhanced suppression role in the nitrification of ammonium in soil". Journal of Soils and Sediments 22, n. 3 (2 gennaio 2022): 831–43. http://dx.doi.org/10.1007/s11368-021-03118-3.
Testo completoAbstract (sommario):
Abstract Purpose Nitrification inhibitor plays an important regulatory role in inhibiting the nitrification of ammonium in soils. However, most of nitrification inhibitors lack the sustainable effects in suppressing the nitrification of ammonium. In this study, a novel DMS nitrification inhibitor was prepared and tested to explore its lasting effect of nitrification suppression in black soil. Materials and methods Both culture experiments and field trial were performed in black soils. Three kinds of nitrification inhibitors (NIs), dicyandiamide (DCD) with low bioactivity, 3,4-dimethylpyrazole phosphate (DMPP) with high bioactivity, and a novel 3,4-dimethylpyrazole sulfate zinc (DMS) with long half-life, were applied into soils, respectively, and the abundance changes of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were investigated; then, the accumulation changes of inorganic nitrogen, nitrogen use efficiency, and crop yields were furtherly evaluated. Results and discussions A novel DMS nitrification inhibitor with high activity and long half-life maintained a persistent effect of nitrification suppression, and remarkably increased the accumulation of ammonium nitrogen in soil, thus improving nitrogen use efficiency and crop yields. This study implies that lowering the nitrogen loss of nitrification-triggered in soil is of great importance for improving nitrogen use efficiency. Conclusions This study provided an insight into the sustainable nitrification suppression of a novel DMS nitrification inhibitor under excessive application of nitrogen fertilizer in black soils. Compared with improving the activity, reasonably prolonging the validity of nitrification inhibitors in soil is a more important strategy increasing the sustainable effects of nitrification inhibition, and the survival period of nitrification inhibitors in soil should be a crucial factor improving nitrogen use efficiency.
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Schrantz, Karen A., Jonathan G. Pressman e David G. Wahman. "Simulated distribution nitrification: Nitrification Index evaluation and viable AOB". Journal - American Water Works Association 105, n. 5 (maggio 2013): E242—E254. http://dx.doi.org/10.5942/jawwa.2013.105.0046.
Testo completo
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Fleming, Kala K., Gregory W. Harrington e Daniel R. Noguera. "Nitrification potential curves: a new strategy for nitrification prevention". Journal - American Water Works Association 97, n. 8 (agosto 2005): 90–99. http://dx.doi.org/10.1002/j.1551-8833.2005.tb07453.x.
Testo completo
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Purwanto, Supriyadi e Aniek Hindrayani. "Effectiveness of Nitrification Inhibition on Various Species of Brachiaria Grass Rhizosphere". E3S Web of Conferences 31 (2018): 03007. http://dx.doi.org/10.1051/e3sconf/20183103007.
Testo completoAbstract (sommario):
Nitrification has the potential to decrease the efficiency of nitrogen utilization by plants. The use of nitrifying inhibitory chemicals proved to be effective in controlling nitrification, but also affects beneficial soil microbes. Another attempt to inhibit the more environmentally-friendly nitrification is to use plants that have allelochemical nitrification inhibiting compounds such as the grasses of Brachiaria. The aim of this research is to know the effectivity of B.mutica, B.decumbens, and B.humidicola as inhibitors of nitrification rate in soil. The experiment was carried out by pot experimental method based on nondestructive sampling and Complete Randomized Design, consisting of Brachiaria plant types and various doses of N fertilizer, 100 kg/ha, 150 kg/ha, 200 kg/ha. The results of this study show that 1) B.mutica, B.decumbens, and B.humidicola, highly significant to the soil potential nitrification, but the treatment of various doses of N fertilizer is not significant to the soil potential nitrification. 2) the highest soil potential nitrification in B.mutica rhizosphere was 5.160 mg NO2-/g of soil/5h, while the lowest soil potential nitrification in the rhizosphere of B.humidicola plant was 0.414 mg NO2-/g/5h. 3) From the four treatment of Brachiaria plants can be concluded B.humidicola plant more effective in inhibition of nitrification.
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Strauss, Eric A., Nicole L. Mitchell e Gary A. Lamberti. "Factors regulating nitrification in aquatic sediments: effects of organic carbon, nitrogen availability, and pH". Canadian Journal of Fisheries and Aquatic Sciences 59, n. 3 (1 marzo 2002): 554–63. http://dx.doi.org/10.1139/f02-032.
Testo completoAbstract (sommario):
We investigated the response in nitrification to organic carbon (C) availability, the interactive effects of the C: nitrogen (N) ratio and organic N availability, and differing pH in sediments from several streams in the upper midwestern United States. In addition, we surveyed 36 streams to assess variability in sediment nitrification rates. Labile dissolved organic carbon (DOC) additions of 30 mg C·L1 (as acetate) to stream sediments reduced nitrification rates (P < 0.003), but lower concentration additions or dilution of ambient DOC concentration had no effect on nitrification. C:N and organic N availability strongly interacted to affect nitrification (P < 0.0001), with N availability increasing nitrification most at lower C:N. Nitrification was also strongly influenced by pH (P < 0.002), with maximum rates occurring at pH 7.5. A multiple regression model developed from the stream survey consisted of five variables (stream temperature, pH, conductivity, DOC concentration, and total extractable NH4+) and explained 60% of the variation observed in nitrification. Our results suggest that nitrification is regulated by several variables, with NH4+ availability and pH being the most important. Organic C is likely important at regulating nitrification only under high environmental C:N conditions and if most available C is relatively labile.
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Tijhuis, L., M. C. M. van Loosdrecht e J. J. Heijnen. "Nitrification with Biofilms on Small Suspended Particles in Airlift Reactors". Water Science and Technology 26, n. 9-11 (1 novembre 1992): 2207–11. http://dx.doi.org/10.2166/wst.1992.0698.
Testo completoAbstract (sommario):
The development of nitrifying biofilms and short and long term influences on the nitrification process were studied in a Biofilm-Airlift-Suspension-reactor. The studied changes are (i) startup of nitrification reactor at different dilution rates, (ii) the effect of temperature on N-oxidation capacity, (iii) the short term effect of N-loading rate on conversion to determine the nitrification overcapacity and (iv) long term effect of N-loading rate on conversion to determine the maximum nitrification capacity in this reactor system. It is shown that the specific nitrification capacity during start-up is constant, 1 g N/(gorg.mat. d), which is high compared to the activated sludge process. The influence of the temperature on the nitrification rate is much less than can be expected from pure culture experiments. On a short term there is only a small nitrification overcapacity in the reactor. The maximum nitrification rate during these experiments was 6 kg N/(m3 d), which is very high compared to the activated sludge process.
12
Zhang, Jie, Jia Liu, Guilong Li e Meng Wu. "Screening Potential Nitrification Inhibitors through a Structure–Activity Relationship Study—The Case of Cinnamic Acid Derivatives". Sustainability 16, n. 13 (8 luglio 2024): 5791. http://dx.doi.org/10.3390/su16135791.
Testo completoAbstract (sommario):
Using a nitrification inhibitor to decrease nitrification rates in soil represents a promising strategy to improve nitrogen fertilizer use efficiency. Nonetheless, rapid screening of nitrification inhibitors remains challenging. In this study, we propose a strategy to screen potential nitrification inhibitors through a structure–activity relationship (SAR) study based on a rapid determination of nitrification inhibition. To demonstrate this, the nitrification inhibition potentials of cinnamic acid derivatives against Nitrosomonas europaea growth were evaluated in a liquid culture. The SAR study showed that hydroxyl and fluoride groups were the favorable substituents on the benzene ring, and the ester group and double bond in the side chain were essential for maintaining high inhibition efficacy. Three compounds with notable inhibitory efficacy (EC50 = 8–25 μM) were further assessed in agricultural soil, and they displayed a noteworthy reduction in nitrification rate and bacterial amoA gene numbers. Based on the results, we identified methyl cinnamate, methyl 4-hydroxycinnamate, and methyl 4-fluorocinnamate as promising candidates for nitrification inhibition.
13
Peng, Y. Z., J. F. Gao, S. Y. Wang e M. H. Sui. "Use of pH as fuzzy control parameter for nitrification under different alkalinity in SBR process". Water Science and Technology 47, n. 11 (1 giugno 2003): 77–84. http://dx.doi.org/10.2166/wst.2003.0589.
Testo completoAbstract (sommario):
In order to achieve fuzzy control of nitrification in a Sequencing Batch Reactor (SBR) brewery wastewater was used as the substrate. The effect of alkalinity on pH variation during nitrification was systematically studied, at the same time the variations of DO and ORP were investigated. Alkalinity and pH of the wastewater were adjusted by adding sodium bicarbonate at five levels and sodium hydroxide at two levels. Unadjusted wastewater was also studied. According to the results, variation of pH could be divided into rising type and descending type. When bicarbonate alkalinity was deficient or sufficient, the descending type happened. If alkalinity was deficient, the pH decreasing rate got slower when nitrification nearly stopped; if alkalinity was sufficient, at the end of nitrification pH turned from decrease to increase. This was the most common situation and pH could be used to control the end of nitrification. When alkalinity was excessive, the rising type happened, pH was increasing at nearly a constant rate during and after nitrification and could not be used to control the nitrification time, but if the aeration rate was moderate DO could be used to control the nitrification time. This situation seldom happened. Therefore the variation of pH could not only be used to control the nitrification time but also to judge whether the alkalinity was enough or not. On the basis of this, the fuzzy controller of nitrification in SBR was constructed. When discussing the influence of pH on nitrification rate the composition and concentration of alkalinity must be considered or else the results may be incomprehensive. And to some extent the influence of alkalinity on nitrification rate was more important than pH.
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Lorenzen, Jan, Lars Hauer Larsen, Thomas Kjær e Niels-Peter Revsbech. "Biosensor Determination of the Microscale Distribution of Nitrate, Nitrate Assimilation, Nitrification, and Denitrification in a Diatom-Inhabited Freshwater Sediment". Applied and Environmental Microbiology 64, n. 9 (1 settembre 1998): 3264–69. http://dx.doi.org/10.1128/aem.64.9.3264-3269.1998.
Testo completoAbstract (sommario):
ABSTRACT High-resolution NO3 − profiles in freshwater sediment covered with benthic diatoms were obtained with a new microscale NO3 − biosensor characterized by absence of interference from chemical species other than NO2 − and N2O. Analysis of the microprofiles obtained indicated no nitrification during darkness, high rates of nitrification and a tight coupling between nitrification and denitrification during illumination, and substantial rates of NO3 − assimilation during illumination. Nitrification during darkness could be induced by purging the bulk water with O2 gas, indicating that the stimulatory effect on nitrification by illumination was caused by algal production of O2. NH4 + addition did not stimulate nitrification during darkness when O2 was restricted to the upper 1-mm layer, and there was thus a low nitrification potential in the permanently oxic top 1 mm of the sediment.
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How, S. W., S. Y. Lim, P. B. Lim, A. M. Aris, G. C. Ngoh, T. P. Curtis e A. S. M. Chua. "Low-dissolved-oxygen nitrification in tropical sewage: an investigation on potential, performance and functional microbial community". Water Science and Technology 77, n. 9 (28 marzo 2018): 2274–83. http://dx.doi.org/10.2166/wst.2018.143.
Testo completoAbstract (sommario):
Abstract Intensive aeration for nitrification is a major energy consumer in sewage treatment plants (STPs). Low-dissolved-oxygen (low-DO) nitrification has the potential to lower the aeration demand. However, the applicability of low-DO nitrification in the tropical climate is not well-understood. In this study, the potential of low-DO nitrification in tropical setting was first examined using batch kinetic experiments. Subsequently, the performance of low-DO nitrification was investigated in a laboratory-scale sequential batch reactor (SBR) for 42 days using real tropical sewage. The batch kinetic experiments showed that the seed sludge has a relatively high oxygen affinity. Thus, the rate of nitrification was not significantly reduced at low DO concentrations (0.5 mg/L). During the operation of the low-DO nitrification SBR, 90% of NH4-N was removed. The active low-DO nitrification was mainly attributed to the limited biodegradable organics in the sewage. Fluorescence in-situ hybridisation and 16S rRNA amplicon sequencing revealed the nitrifiers were related to Nitrospira genus and Nitrosomonadaceae family. Phylogenetic analysis suggests 47% of the operational taxonomic units in Nitrospira genus are closely related to a comammox bacteria. This study has demonstrated active low-DO nitrification in tropical setting, which is a more sustainable process that could significantly reduce the energy footprint of STPs.
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Christensson, M., e T. Welander. "Treatment of municipal wastewater in a hybrid process using a new suspended carrier with large surface area". Water Science and Technology 49, n. 11-12 (1 giugno 2004): 207–14. http://dx.doi.org/10.2166/wst.2004.0843.
Testo completoAbstract (sommario):
An activated sludge/biofilm hybrid process treating municipal wastewater was studied in pilot plant trials. A new type of suspended carrier, with large effective surface area, was employed in the process with the aim of enhancing nitrification. The pilot plant was operated for 1.5 years in five different configurations including pre-denitrification in all five and enhanced biological phosphorus removal in the final two. The wastewater temperature ranged between 11°C and 20°C, and the nominal dissolved oxygen (DO) level was 5-6 mg/L. The nitrification rate obtained on the new carrier within the hybrid stage was in the range of 0.9-1.2 g NH4-N/m2/d corresponding to a volumetric rate of 19-23 g NH4-N/m3/h (total nitrification including nitrification in the suspended solids). More than 80% of the total nitrification took place on the carrier (and the remainder in the suspended solids). The nitrification rate was shown to correlate with DO, decreasing when the DO was decreased. The results supported the idea of using the new carrier as a tool to upgrade plants not having nitrification today or improve nitrification in activated sludge processes not reaching necessary discharge levels. The large surface area present for nitrification makes it possible to obtain high nitrification rates within limited volumes. The possibility to keep the total suspended solid content low (<3 g/L) and avoiding problems with the filament Microthrix parvicella, are other beneficial properties of the hybrid process.
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Chuchvaga, I. G., e V. V. Volkogon. "NITRIFICATION IN THE ROOT ZONE OF WINTER RYE UNDER THE INFLUENCE OF MINERAL NITROGEN AND PRESOWING SEED BACTERIZATION". Agriciltural microbiology 17 (1 ottobre 2013): 79–88. http://dx.doi.org/10.35868/1997-3004.17.79-88.
Testo completoAbstract (sommario):
The paper studies the influence of mineral nitrogen and presowing seeds bakterization on the activity of autotrophic and heterotrophic nitrification in rhizosphere soil of winter rye plants. Increasing doses of mineral nitrogen enhance nitrification activity. Application of microbial preparation Diazobakteryn has a prolonged influence and improves nitrification process, mainly due to the increase of heterotrophic nitrification activity.
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Vabolienė, Giedrė, e Algirdas Bronislovas Matuzevičius. "ASSESMENT OF NITRIFICATION AND DENITRIFICATION RATE IN BIOLOGICAL NITROGEN REMOVAL FROM WASTEWATER". JOURNAL OF ENVIRONMENTAL ENGINEERING AND LANDSCAPE MANAGEMENT 15, n. 2 (30 giugno 2007): 77–84. http://dx.doi.org/10.3846/16486897.2007.9636912.
Testo completoAbstract (sommario):
Biological nitrogen removal from wastewater is based on nitrification and denitrification processes in biological treatment plants with activated sludge. Slowed growth of nitrification bacteria is one of basic problems in biological nitrogen removal from wasterwater. Using biological nitrogen removal technologies at changing nitrification and denitrification rate, it is very important to evaluate properly aeration and reduced aeration duration and to estimate nitrification and denitrification rate. To this purpose an investigation was carried out at Utena Wastewater Treatment Plant. Nitrification and denitrification rate was estimated during five experiments in aeration tanks when the duration of aeration and reduced aeration was from 120 to 180 min. Nitrification and denitrification rate at a different aeration regime and impact of aeration regime on biological nitrogen removal was estimated in the work.
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Tijhuis, L., E. Rekswinkel, M. C. M. van Loosdrecht e J. J. Heijnen. "Dynamics of population and biofilm structure in the biofilm airlift suspension reactor for carbon and nitrogen removal". Water Science and Technology 29, n. 10-11 (1 ottobre 1994): 377–84. http://dx.doi.org/10.2166/wst.1994.0782.
Testo completoAbstract (sommario):
The dynamics of population and biofilm structure of nitrifying and heterotrophic biomass in biofilms on small suspended particles in an airlift reactor were measured during shifts from purely nitrification to a heterotrophic medium and back to nitrification. Biofilms from a full scale reactor with predominantly heterotrophic activity were used as start material. In the first twenty days of the nitrification period ammonia was oxidized to nitrite. Hereafter the oxidation was mainly to nitrate. A conversion of nearly 5 kgN/(m3 d) was reached in fifty days. Following the change to heterotrophic medium the nitrifying biofilm served as carrier for the development of a heterotrophic biofilm layer. The nitrification capacity of the biofilms dropped to 1 kgN/(m3 d) due to oxygen diffusion limitation in the heterotrophic layer. After the switch back to nitrification the heterotrophic biofilm layer was sheared off very rapidly, while the nitrification activity increased very fast to the level at the end of the first nitrification period due to decreased diffusion limitation.
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Montagnini, F., B. L. Haines, W. T. Swank e J. B. Waide. "Nitrification in undisturbed mixed hardwoods and manipulated forests in the southern Appalachian Mountains of North Carolina, U.S.A." Canadian Journal of Forest Research 19, n. 10 (1 ottobre 1989): 1226–34. http://dx.doi.org/10.1139/x89-187.
Testo completoAbstract (sommario):
This paper summarizes data on nitrification at the Coweeta Hydrologic Laboratory, in the southern Appalachian Mountains of North Carolina, U.S.A., focusing on effects of watershed treatment and vegetation type. At Coweeta, as at other United States sites, oak–hickory forests gave the lowest nitrification potentials. Nitrification potentials and nitrifier numbers were lower in oak–hickory forests of undisturbed watersheds than in disturbed watersheds. Nitrification potentials were also low in a white pine plantation, although higher than in other pine forests in the United States. In a regenerating clear-cut and in a 17-year-old successional forest at Coweeta, nitrification potential was higher in dense stands of black locust (Robiniapseudoacacia L.) than in areas where black locust was absent. In the undisturbed forests at Coweeta, low nutrient availability probably limits the size of nitrifier populations; the influence of soil pH on nitrification was unclear. In the disturbed forests, nitrification is apparently controlled by the availability of ammonium nitrogen and other nutrients.
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Hanson, Eric J., Philip A. Throop, Sedat Serce, John Ravenscroft e Eldor A. Paul. "Comparison of Nitrification Rates in Blueberry and Forest Soils". Journal of the American Society for Horticultural Science 127, n. 1 (gennaio 2002): 136–42. http://dx.doi.org/10.21273/jashs.127.1.136.
Testo completoAbstract (sommario):
Highbush blueberries (Vaccinium corymbosum L.) are long lived perennial plants that are grown on acidic soils. The goal of this study was to determine how blueberry cultivation might influence the nitrification capacity of acidic soils by comparing the nitrification potential of blueberry soils to adjacent noncultivated forest soils. The net nitrification potential of blueberry and forest soils was compared by treating soils with 15N enriched (NH4)2SO4, and monitoring nitrate (NO3--N) production during a 34-day incubation period in plastic bags at 18 °C. Net nitrification was also compared by an aerobic slurry method. Autotrophic nitrifiers were quantified by the most probable number method. Nitrate production from labeled ammonium (15NH4+) indicated that nitrification was more rapid in blueberry soils than in forest soils from six of the seven study sites. Slurry nitrification assays provided similar results. Blueberry soils also contained higher numbers of nitrifying bacteria compared to forest soils. Nitrification in forest soils did not appear to be limited by availability of NH4+ substrate. Results suggest that blueberry production practices lead to greater numbers of autotrophic nitrifying bacteria and increased nitrification capacity, possibly resulting from annual application of ammonium containing fertilizers.
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Wu, C. Y., S. Ushiwaka, H. Horii e K. Yamagiwa. "Boosting nitrification by membrane-attached biofilm". Water Science and Technology 54, n. 9 (1 novembre 2006): 121–28. http://dx.doi.org/10.2166/wst.2006.864.
Testo completoAbstract (sommario):
Nitrification is a key step for reliable biological nitrogen removal. In order to enhance nitrification in the activated sludge (AS) process, membrane-attached biofilm (MAB) was incorporated in a conventional activated sludge tank. Simultaneous organic carbon removal and nitrification of the MAB incorporated activated sludge (AS+MAB) process was investigated with continuous wastewater treatment. The effluent TOC concentration of AS and the AS+MAB processes were about 6.3 mg/L and 7.9 mg/L, respectively. The TOC removal efficiency of both AS and AS+MAB were above 95% during the wastewater treatment, indicating excellent organic carbon removal performance in both processes. Little nitrification occurred in the AS process. On the contrary, successful nitrification was obtained with the AS+MAB process with nitrification efficiency of about 90%. The volumetric and surface nitrification rates were about 0.14 g/Ld and 6.5 g/m2d, respectively. The results clearly demonstrated that nitrification in the conventional AS process was boosted by MAB. Furthermore, the microfaunal population in the AS+MAB process was different from that in the AS process. The high concentration of rotifers in the AS+MAB process was expected to decrease the generation of excess sludge in the process.
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Egenolf, Konrad, Philipp Schad, Ashly Arevalo, Daniel Villegas, Jacobo Arango, Hannes Karwat, Georg Cadisch e Frank Rasche. "Inter-microbial competition for N and plant NO3− uptake rather than BNI determines soil net nitrification under intensively managed Brachiaria humidicola". Biology and Fertility of Soils 58, n. 3 (13 novembre 2021): 307–19. http://dx.doi.org/10.1007/s00374-021-01606-9.
Testo completoAbstract (sommario):
AbstractBrachiaria humidicola (syn. Urochloa humidicola) has been acknowledged to control soil nitrification through release of nitrification inhibitors (NI), a phenomenon conceptualized as biological nitrification inhibition (BNI). Liming and N fertilization as features of agricultural intensification may suppress BNI performance, due to a decrease in NI exudation, increased NH3 availability and promotion of ammonia oxidizing bacteria (AOB) over archaea (AOA). A 2-year three-factorial pot trial was conducted to investigate the influence of soil pH and soil microbial background (ratio of archaea to bacteria) on BNI performance of B. humidicola. The study verified the capacity of B. humidicola to reduce net nitrification rates by 50 to 85% compared to the non-planted control, irrespective of soil pH and microbial background. The reduction of net nitrification, however, was largely dependent on microbial N immobilization and efficient plant N uptake. A reduction of gross nitrification could not be confirmed for the AOA dominated soil, but possibly contributed to reduced net nitrification rates in the AOB-dominated soil. However, this putative reduction of gross nitrification was attributed to plant-facilitated inter-microbial competition between bacterial heterotrophs and nitrifiers rather than BNI. It was concluded that BNI may play a dominant role in extensive B. humidicola pasture systems, while N immobilization and efficient plant N uptake may display the dominant factors controlling net nitrification rates under intensively managed B. humidicola.
24
Okey, Robert W., H. David Stensel e Mary C. Martis. "Modeling nitrification inhibition". Water Science and Technology 33, n. 6 (1 marzo 1996): 101–7. http://dx.doi.org/10.2166/wst.1996.0086.
Testo completoAbstract (sommario):
A quantitative structure-activity relationship (QSAR)-type model using groups and molecular connectivity has been developed on nitrification inhibition data derived from soil. The model has been tested against data derived from the inhibition of nitrification by specific nitrogen-containing pesticides. A second QSAR-type model developed from acclimated biodegradation data has been applied to the pesticides tested for nitrification inhibition. Data on the impact of specific compounds on activated sludge nitrification have been included and the soil model applied to these activated sludge data. In general, the agreement between predicted and observed values for nitrification inhibition was satisfactory. The agreement was only marginal with respect to the biological system data. The biodegradation model indicated that most of the strong inhibitors also would have prolonged existence in the open environment. The models are included in the paper as well as the specific methodology.
25
Shi, Xiuzhen, Hang-Wei Hu, Christoph Müller, Ji-Zheng He, Deli Chen e Helen Charlotte Suter. "Effects of the Nitrification Inhibitor 3,4-Dimethylpyrazole Phosphate on Nitrification and Nitrifiers in Two Contrasting Agricultural Soils". Applied and Environmental Microbiology 82, n. 17 (17 giugno 2016): 5236–48. http://dx.doi.org/10.1128/aem.01031-16.
Testo completoAbstract (sommario):
ABSTRACTThe nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) is a powerful tool that can be used to promote nitrogen (N) use efficiency and reduce N losses from agricultural systems by slowing nitrification. Mounting evidence has confirmed the functional importance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in nitrification and N2O production; however, their responses to DMPP amendment and the microbial mechanisms underlying the variable efficiencies of DMPP across different soils remain largely unknown. Here we compared the impacts of DMPP on nitrification and the dynamics of ammonia oxidizers between an acidic pasture soil and an alkaline vegetable soil using a15N tracing and13CO2-DNA–stable-isotope probing (SIP) technique. The results showed that DMPP significantly inhibited nitrification and N2O production in the vegetable soil only, and the transient inhibition was coupled with a significant decrease in AOB abundance. No significant effects on the community structure of ammonia oxidizers or the abundances of total bacteria and denitrifiers were observed in either soil. The15N tracing experiment revealed that autotrophic nitrification was the predominant form of nitrification in both soils. The13CO2-DNA–SIP results indicated the involvement of AOB in active nitrification in both soils, but DMPP inhibited the assimilation of13CO2into AOB only in the vegetable soil. Our findings provide evidence that DMPP could effectively inhibit nitrification through impeding the abundance and metabolic activity of AOB in the alkaline vegetable soil but not in the acidic pasture soil, possibly due to the low AOB abundance or the adsorption of DMPP by organic matter.IMPORTANCEThe combination of the15N tracing model and13CO2-DNA–SIP technique provides important evidence that the nitrification inhibitor DMPP could effectively inhibit nitrification and nitrous oxide emission in an alkaline soil through influencing the abundance and metabolic activity of AOB. In contrast, DMPP amendment has no significant effect on nitrification or nitrifiers in an acidic soil, potentially owing to the low abundance of AOB and the possible adsorption of DMPP by organic matter. Our findings have direct implications for improved agricultural practices through utilizing the nitrification inhibitor DMPP in appropriate situations, and they emphasize the importance of microbial communities to the efficacy of DMPP.
26
Gilmour, J. T. "The Effects of Soil Properties on Nitrification and Nitrification Inhibition". Soil Science Society of America Journal 49, n. 2 (marzo 1985): 519. http://dx.doi.org/10.2136/sssaj1985.03615995004900020051x.
Testo completo
27
Korotka, I. G., e V. V. Volkogon. "THE FEATURES THE AUTOTROPHIC AND HETEROTROPHIC NITRIFICATION IN THE ROOT ZONE OF WINTER RYE PLANTS UNDER THE USE OF MINERAL FERTILIZERS AND DIAZOBAKTERYN". Agriciltural microbiology 21 (6 agosto 2015): 44–51. http://dx.doi.org/10.35868/1997-3004.21.44-51.
Testo completoAbstract (sommario):
The paper depicts the study of mineral nitrogen and pre-sowing seeds bacteryzation on the development of nitrogen fixing bacteria and the activity of autotrophic and heterotrophic nitrification. It was revealed that nitrification activity in the root zone of winter rye plants rises together with the increase of mineral nitrogen doses. Heterotrophic nitrification plays a significant role in the formation of nitrate pool in the root zone, especially during the early stages of plants organogenesis. Application of the microbial preparation Diazobakteryn had enhanced the activity autotrophic and heterotrophic nitrification processes in the rhizosphere soil of plants in the spring, during the early stages of their development while during the next organogenesis phases the reduction of nitrification processes was observed. In plants-free soil the contribution of heterotrophic nitrification to biological transformation of nitrogen was negligible.
28
Zhang, Xiumin, e Huayong Zhang. "Modelling Microbial Nitrification and Exploring Nonlinear Mechanism by Dynamical Complexity". Chiang Mai Journal of Science 51, n. 1 (31 gennaio 2024): 1–19. http://dx.doi.org/10.12982/cmjs.2024.001.
Testo completoAbstract (sommario):
Nitrification, a crucial step in nitrogen cycle of ecosystems, is an important issue that attracts many attentions. In this research, the nitrification process is investigated by developing a new dynamical model which couples the kinetics of ammonia oxidation process and nitrite oxidation process. With the application of literature-based parameter values, the dynamical characteristics of nitrification process in aquatic and soil environments are studied. Stable coexistent equilibrium, periodic oscillations, as well as more complex nitrification dynamics, such as quasiperiodic and chaotic oscillations, are predicted in both environments under seasonal variations. The projected levels of ammonia and nitrite ions are similarly aligned with previously reported observations in natural ecosystems. By uncovering the dynamical complexity of nitrification process, this research can advance our comprehension of the nonlinear mechanisms underlying microbial nitrification in ecosystems.
29
Zhang, Song, Zhou, Cao e Zhou. "Coupling between Nitrification and Denitrification as well as Its Effect on Phosphorus Release in Sediments of Chinese Shallow Lakes". Water 11, n. 9 (30 agosto 2019): 1809. http://dx.doi.org/10.3390/w11091809.
Testo completoAbstract (sommario):
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.
30
Albizuri, J., P. Grau, M. Christensson e L. Larrea. "Validating the Colloid model to optimise the design and operation of both moving-bed biofilm reactor and integrated fixed-film activated sludge systems". Water Science and Technology 69, n. 7 (3 febbraio 2014): 1552–57. http://dx.doi.org/10.2166/wst.2014.058.
Testo completoAbstract (sommario):
The paper presents a systematic study of simulations, using a previously calibrated Colloid model, from which it was found that: (i) for pure moving-bed biofilm reactor (MBBR) processes with tertiary nitrification conditions (no influent chemical oxygen demand (COD)), dissolved oxygen = 5 mg/L and residual NH4-N > 4 mgN/L, a nitrification rate of 1.2 gN/(m2d) was obtained at 10 °C. This rate decreases sharply when residual NH4-N is lower than 2 mgN/L, (ii) for MBBR systems with predenitrification–nitrification zones and COD in the influent (soluble and particulate), the nitrification rate (0.6 gN/(m2d)) is half of that in tertiary nitrification due to the effect of influent colloidal XS (particulate slowly biodegradable COD) and (iii) for integrated fixed-film activated sludge (IFAS) processes the nitrification rate in the biofilm (0.72 gN/(m2d)) is 20% higher than for the pure MBBR due to the lower effect of influent XS since it is adsorbed onto flocs. However, it is still 40% lower than the tertiary nitrification rate. In the IFAS, the fraction of the nitrification rate in suspension ranges from 10 to 70% when the aerobic solids retention time varies from 1.4 to 6 days.
31
Fenn, Mark E., Mark A. Poth, Joseph D. Terry e Timothy J. Blubaugh. "Nitrogen mineralization and nitrification in a mixed-conifer forest in southern California: controlling factors, fluxes, and nitrogen fertilization response at a high and low nitrogen deposition site". Canadian Journal of Forest Research 35, n. 6 (1 giugno 2005): 1464–86. http://dx.doi.org/10.1139/x05-068.
Testo completoAbstract (sommario):
Net fluxes of nitrogen (N) mineralization and nitrification were measured in situ on a monthly basis for 3 years at a high (HN) and low (LN) N deposition site in the San Bernardino Mountains, California. Mean N mineralization fluxes in the forest floor and top 10 cm of mineral soil were 19.0 and 59.8 kg N·ha–1·year–1 at LN and HN, respectively. Mean net nitrification fluxes were 11.2 and 55.9 kg N·ha–1·year–1 at LN and HN, respectively. Relative nitrification (the percent N mineralized that was nitrified) was generally lower under Pinus ponderosa Dougl. ex P. & C. Laws. (or Pinus jeffreyi Grev. & Balf.) canopies than under Quercus kelloggii Newb. or open canopies. The rate of net N mineralization was the key factor for predicting the rate of net nitrification. Fertilization with 50 and 150 kg N·ha–1 at LN significantly increased the rates of net mineralization and net nitrification. At HN fertilization had no significant effect on net nitrification. We conclude that at low-deposition sites increased nitrification occurs in the short term in response to added N, but that sustained elevated net nitrification is driven by the accumulation of N-enriched litter and soil organic matter in conjunction with chronic throughfall N deposition inputs.
32
Tschui, M., M. Boller, W. Gujer, J. Eugster, C. Mäder e C. Stengel. "Tertiary nitrification in aerated pilot biofilters". Water Science and Technology 29, n. 10-11 (1 ottobre 1994): 53–60. http://dx.doi.org/10.2166/wst.1994.0745.
Testo completoAbstract (sommario):
Three different types of internally aerated pilot scale biofilters were operated as tertiary nitrification systems. Long-term performance of the three aerated biofilters was tested under various operating conditions. The maximum volumetric nitrification rates under non NH4-limiting conditions for the three aerated biofilter systems were investigated. Based on measured temperature dependencies, an exponential relationship was established enabling the prediction of the nitrification rates at desired temperatures. Based on a temperature of 10°C, the results allow a comparison between the surface and volume specific nitrification rates in the tested biofilters as a function of the NH4 effluent concentration. As shown by experiments, nitrification performance depends on water as well as air velocities in the filter. Higher velocities of both air and water increase the nitrification rate. However, they also increase the head loss and thus decrease the filter run time. Therefore, the optimal operating conditions depend also on the filter media and the required effluent quality. Compared to fully O2-limiting operating conditions, nitrification performance during a period under partially NH4-limiting conditions clearly decreased in all tested biofilters.
33
Jönsson, Karin, Peter Magnusson, Lars-Erik Jönsson, Bengt Göran Hellström e Jes la Cour Jansen. "Identifying and fighting inhibition of nitrification at Öresundsverket". Water Science and Technology 33, n. 12 (1 giugno 1996): 29–38. http://dx.doi.org/10.2166/wst.1996.0296.
Testo completoAbstract (sommario):
After extension of Öresundsverket in Helsingborg severe nitrification problems have occurred. Complete inhibition of nitrification has been recognized once and a general reduction of nitrification capacity has been found compared to design, to other Swedish treatment plants and to internationally accepted design criteria. A comprehensive examination of inhibition of nitrification has identified industrial sources as the dominating contributors. Some industries have been identified as important sources but fighting inhibition of nitrification requires more than tracking down a few dominating industries, since examination shows that discharges of inhibitory substances are widespread among the industries in the catchment area. Naturally, fighting inhibition of nitrification requires the elimination of contributions from industries with identified discharge. Furthermore information campaigns directed towards the industries in general are required and finally it is necessary to include requirements for inhibitory substances in the industrial discharge permits.
34
Yang, Mengfan, Dongmei Xue, Fanqiao Meng e Zhong-Liang Wang. "The effects of salinity on coupled nitrification and aerobic denitrification in an estuarine system". Water Science and Technology 71, n. 11 (1 aprile 2015): 1718–26. http://dx.doi.org/10.2166/wst.2015.159.
Testo completoAbstract (sommario):
Salinity has significant effects on nitrification and denitrification processes, particularly in estuarine systems. A dissolved oxygen-enriched river and its estuary in northern China were selected to investigate the impact of salinity gradients (0.6, 4, 7.6, 11.4 and 14.7‰) obtained from the mixing of river samples and estuarine samples with different proportions on coupled nitrification and aerobic denitrification via incubation experiments (35 and 10 °C). Results indicated that: (a) nitrification and coupled nitrification-aerobic denitrification occurred for all treatments, which resulted in NO3− being either accumulated or removed at the end of the incubation; (b) a suitable range of salinity is 4.0–11.4‰ for nitrification and 4.0–7.6‰ for coupled nitrification-aerobic denitrification; and (c) the relatively higher temperature (35 °C) can effectively stimulate N transformation processes compared to the lower temperature (10 °C) in the incubation experiment.
35
Shan, Mingjun, Yan Zhang e Lihong Kou. "Nitrogen balance and transformation in the nitrification process of coking wastewater and the influence on nitrification kinetics". Water Science and Technology 69, n. 7 (3 febbraio 2014): 1541–45. http://dx.doi.org/10.2166/wst.2014.054.
Testo completoAbstract (sommario):
This paper describes the total nitrogen balance, and the direction and degree of nitrogen transformation during the nitrification process of coking wastewater. According to the actual nitrification process, the conventional nitrification kinetic equation was amended. After 48 h of nitrification, the total nitrogen content remained almost the same with error less than 0.6%. The total removal efficiency of NH4+-N was 91.1%, in which blow-off, producing cells and transforming to nitrate nitrogen accounted for 1.1, 17.8 and 72.2% respectively. Considering the influences of NH4+-N blow-off and conversion from cyanide, thiocyanide and organic nitrogen, the nitrification kinetic equation was amended as μ′=0.82·S/(0.48+S).
36
Veuger, B., A. Pitcher, S. Schouten, J. S. Sinninghe Damsté e J. J. Middelburg. "Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea". Biogeosciences Discussions 9, n. 11 (28 novembre 2012): 16877–906. http://dx.doi.org/10.5194/bgd-9-16877-2012.
Testo completoAbstract (sommario):
Abstract. Nitrification and the associated growth of autotrophic nitrifiers, as well as the contributions of bacteria and Thaumarchaeota to total autotrophic C-fixation by nitrifiers were investigated in the Dutch coastal North Sea from October 2007 to March 2008. Rates of nitrification were determined by incubation of water samples with 15N-ammonium and growth of autotrophic nitrifiers was measured by incubation with 13C-DIC in the presence and absence of nitrification inhibitors (nitrapyrin and chlorate) in combination with compound-specific stable isotope (13C) analysis of bacterial- and Thaumarchaeotal lipid biomarkers. Net nitrification during the sampling period was evident from the concentration dynamics of ammonium, nitrite and nitrate. Measured nitrification rates were high (41–221 nmol N l−1h−1). Ammonium assimilation was always substantially lower than nitrification with nitrification on average contributing 89% (range 73–97%) to total ammonium consumption. 13C-DIC fixation into bacterial and Thaumarchaeotal lipids was strongly reduced by the nitrification inhibitors (27–95%). The inhibitor-sensitive 13C-PLFA pool was dominated by the common PLFAs 16:0, 16:1ω7c and 18:1ω7c throughout the whole sampling period and occasionally also included the polyunsaturated fatty acids 18:2ω6c and 18:3ω3. Cell-specific 13C-DIC fixation activity of the nitrifying bacteria was much higher than that of the nitrifying Thaumarchaeota throughout the whole sampling period, even during the peak in Thaumarchaeotal abundance and activity. This suggests that the contribution of autotrophic Thaumarchaeota to nitrification during winter in the coastal North Sea may have been smaller than expected from their gene abundance. These results emphasize the importance of direct measurements of the actual activity of bacteria and Thaumarchaeota, rather than abundance measurements only, in order to elucidate their biogeochemical importance. The ratio between rates of nitrification versus DIC fixation by nitrifiers was higher or even much higher than typical values for autotrophic nitrifiers, indicating that little DIC was fixed relative to the amount of energy that was generated by nitrification.
37
Veuger, B., A. Pitcher, S. Schouten, J. S. Sinninghe Damsté e J. J. Middelburg. "Nitrification and growth of autotrophic nitrifying bacteria and Thaumarchaeota in the coastal North Sea". Biogeosciences 10, n. 3 (14 marzo 2013): 1775–85. http://dx.doi.org/10.5194/bg-10-1775-2013.
Testo completoAbstract (sommario):
Abstract. Nitrification and the associated growth of autotrophic nitrifiers, as well as the contributions of bacteria and Thaumarchaeota to total autotrophic C-fixation by nitrifiers were investigated in the Dutch coastal North Sea from October 2007 to March 2008. Rates of nitrification were determined by incubation of water samples with 15N-ammonium and growth of autotrophic nitrifiers was measured by incubation with 13C-DIC (dissolved inorganic carbon) in the presence and absence of nitrification inhibitors (nitrapyrin and chlorate) in combination with compound-specific stable isotope (13C) analysis of bacterial and Thaumarchaeotal lipid biomarkers. Net nitrification during the sampling period was evident from the concentration dynamics of ammonium, nitrite and nitrate. Measured nitrification rates were high (41–221 nmol N L−1 h−1). Ammonium assimilation was always substantially lower than nitrification – with nitrification on average contributing 89% (range 73–97%) to total ammonium consumption. 13C-DIC fixation into bacterial and Thaumarchaeotal lipids was strongly reduced by the nitrification inhibitors (27–95 %). The inhibitor-sensitive 13C-PLFA (phospholipid-derived fatty acid) pool was dominated by the common PLFAs 16:0, 16:1ω7c and 18:1ω7c throughout the whole sampling period and occasionally also included the polyunsaturated fatty acids 18:2ω6c and 18:3ω3. 13C-DIC fixation activity of the nitrifying bacteria was much higher than that of the nitrifying Thaumarchaeota throughout the whole sampling period, even during the peak in Thaumarchaeotal abundance and activity. This suggests that the contribution of autotrophic Thaumarchaeota to nitrification during winter in the coastal North Sea may have been smaller than expected from their gene abundance (16S rRNA and amoA (ammonia monooxygenase)). These results emphasize the importance of direct measurements of the actual activity of bacteria and Thaumarchaeota, rather than abundance measurements only, in order to elucidate their biogeochemical importance. The ratio between rates of nitrification versus DIC fixation by bacterial nitrifiers was higher or even much higher than typical values for autotrophic nitrifiers, indicating that little DIC was fixed relative to the amount of energy that was generated by nitrification.
38
Duncan, Elliott G., Cathryn A. O'Sullivan, Anna K. Simonsen, Margaret M. Roper, Mark B. Peoples, Karen Treble e Kelley Whisson. "The nitrification inhibitor 3,4,-dimethylpyrazole phosphate strongly inhibits nitrification in coarse-grained soils containing a low abundance of nitrifying microbiota". Soil Research 55, n. 1 (2017): 28. http://dx.doi.org/10.1071/sr15359.
Testo completoAbstract (sommario):
The effectiveness of the nitrification inhibitor 3,4,-dimethylpyrazole phosphate (DMPP) on sandy soils containing low nitrifying microbial abundance has not been established. Two coarse-grained soils, representative of Western Australia’s agricultural zones, were incubated with 100mgNkg–1 soil, added as either urea, urea+DMPP or urea+nitrapyrin as an alternative nitrification inhibitor for comparative purposes. Ammonium (NH4+) and nitrate (NO3–) concentrations, potential nitrification rates (PNR) and the abundance of ammonia-oxidising bacteria (AOB) and archaea (AOA) were measured over time. Interactions between soil type and inhibitor type altered the extent of nitrification observed in these soils. When N was supplied as urea alone, NH4+-N concentrations decreased from 100mgNkg–1 soil to approximately 20mgNkg–1 soil in the high nutrient soil (Williams) and approximately 60mgNkg–1 soil in the low nutrient soil (Vasse). These differences were reflected in AOB abundance, which was higher (~105genecopiesg–1 soil) in Williams soil than in Vasse soil (<104genecopiesg–1 soil). This difference could have been attributable to differences in soil pH between Williams and Vasse (5.4 vs 4.0 respectively) and/or copper (Cu) availability (~1.5 vs ~0.5mgCukg–1 soil respectively), both of which have been demonstrated to reduce AOB abundance or limit nitrification. On the Williams soil, DMPP limited nitrification, resulting in approximately 80mgNkg–1 soil being retained as NH4+-N. Nitrapyrin was similarly effective for the first 56 days of incubation, but declined considerably in effectiveness between Days 56 and 100. Changes in soil nitrification rates were accompanied by changes in AOB abundance, which was below 103genecopiesg–1 soil when nitrification was impaired. Both DMPP and nitrapyrin inhibit nitrification via chelating Cu and, because these soils contained low Cu concentrations, it may be possible that interactions between DMPP, naturally low abundance of AOB and low Cu availability facilitated the long-term inhibition of nitrification in these soils.
39
Malyan, Sandeep. "Nitrification Inhibitors: A Perspective tool to Mitigate Greenhouse Gas Emission from Rice Soils". Current World Environment 11, n. 2 (25 agosto 2016): 423–28. http://dx.doi.org/10.12944/cwe.11.2.10.
Testo completoAbstract (sommario):
Rice fields are significant contributors of greenhouse gases mainly methane and nitrous oxide to the atmosphere. Increasing concentrations of these greenhouse gases play significant role in changing atmospheric chemistry such as mean air temperature, rainfall pattern, drought, and flood frequency. Mitigation of greenhouse gases for achieving sustainable agriculture without affecting economical production is one the biggest challenge of twenty first century at national and global scale. On the basis of published scientific studies, we hereby assess the use of nitrification inhibitors for greenhouse gas mitigation from rice soil. Biologically oxidation of ammonium to nitrate is termed as nitrification and materials which suppress this process are known as nitrification inhibitors. Soil amendment by addition of certain nitrification inhibitors such as neem oil coated urea, nimin-coated urea; dicyandiamide, encapsulated calcium carbide, and hydroquinone reduce cumulative methane and nitrous oxide emission from rice. Firstly, these inhibitors reduce nitrous oxide emissions both directly by nitrification (by reducing NH4+ to NO3-) as well as indirectly by de-nitrification (by reducing NO3- availability in soil). Secondly, methane emission from rice soil can be reduced by enhancing methane oxidation and suppressing methane production and further by reducing the aerenchymal transportation through rice plant. Application of some of the nitrification inhibitors such as calcium carbide and encapsulated calcium carbide reduce methane production by releasing acetylene gas which helps in reducing the population of methanogenic microbes in the soil. Application of nitrification inhibitors also helps to maintain soil redox potential at higher level subsequently reducing cumulative methane emission from soil. Plant derived organic nitrification inhibitors (neem oil, neem cake, karanja seed extract) are eco-friendly and possess substantial greenhouse gas mitigation potential from rice. In the current scenario of global warming and environmental pollution, application of organic plant derived nitrification inhibitors is much needed for sustainable agriculture.
40
Myoga, H., H. Asano, Y. Nomura e H. Yoshida. "Effects of Immobilization Conditions on the Nitrification Treatability of Entrapped Cell Reactors Using the PVA Freezing Method". Water Science and Technology 23, n. 4-6 (1 febbraio 1991): 1117–24. http://dx.doi.org/10.2166/wst.1991.0563.
Testo completoAbstract (sommario):
The effects of immobilization conditions, such as freezing temperature, amount of seed sludge, gel size and mixing of other microorganisms with seed sludge, on the nitrification treatability of entrapped cell reactors using the PVA freezing method are discussed. Results indicated that the freezing temperature did not affect nitrification treatability within the range from −20 °C to −80 °C. The amount of seed sludge affected the start-up time and maximum nitrification rate, but the effects were not in proportion to the amount of seed sludge. Regarding the gel size, the maximum nitrification rate of the crushed gel (average gel size is 1mm3) reactor was 1.5 times that of the 3mm cubic gel reactor. Results also indicated that start-up time and maximum nitrification rate were enhanced when seed sludge was mixed with other microorganisms which did not have nitrification ability, before the immobilization procedure.
41
Wu, Di, Xing Wang Wen e Hui Ling Liu. "Inhibition and Recovery of Nitrification during the Process of Sludge Reduction Induced by a Metabolic Uncoupler, 2,6-Dichlorophenol (2,6-DCP)". Advanced Materials Research 937 (maggio 2014): 92–98. http://dx.doi.org/10.4028/www.scientific.net/amr.937.92.
Testo completoAbstract (sommario):
2,6-DCP was found to be an efficient metabolic uncoupler to reduce sludge production. 20mg/L 2,6-DCP could reduce sludge production about 34.62%, however, it also affected nitrification seriously, the nitrification inhibition was about 76.17% compared to control. Environmental factors, temperature and pH, were varied to repair nitrification. The nitrification inhibition was decreased to 45.7% at 28±1 ◦C and pH=8.5±0.2. Nitrification inhabitation was further decreased to 30% when the 2,6-DCP concentration reduced to 10 mg/L, the sludge reduction also decreased to17.9%. The 30-day operation data indicated that 10mg/L 2,6-DCP can also effectively reduced the sludge production about 17.9% with the COD removal efficiency decreased about 6.99% and nitrification inhabitation was about 30.91%. It shouldn’t only consider the sludge reduction when selecting the concentration of metabolic uncoupler. The application of metabolic uncoupler for sludge reduction should be cautious and need further study.
42
Kreuzinger, N., A. Farnleitner, G. Wandl, R. Hornek e R. Mach. "Molecular biological methods (DGGE) as a tool to investigate nitrification inhibition in wastewater treatment". Water Science and Technology 47, n. 11 (1 giugno 2003): 165–72. http://dx.doi.org/10.2166/wst.2003.0601.
Testo completoAbstract (sommario):
Incomplete nitrification at an activated sludge plant for biological pre-treatment of rendering plant effluents led to a detailed investigation on the origin and solution of this problem. Preliminary studies revealed that an inhibition of ammonia oxidising microorganisms (AOM) by process waters of the rendering plant was responsible for the situation. We were able to show a correlation between the existence of specific AOM and nitrification capacity expressed as oxygen uptake rate for maximal nitrification (OURNmax). Only Nitrosospira sp. was found in the activated sludge of the rendering plant and another industrial wastewater treatment plant with problems in nitrification, while reference plants without nitrification problems showed Nitrosomonas spp. as the predominant ammonia oxidising bacteria. By accompanying engineering investigations and experiments (cross-feeding experiments, operation of a two-stage laboratory plant) with molecular biological methods (DGGE - Denaturing Gradient Gel Electrophoresis) we were able to elaborate an applicable solution for the rendering plant. Laboratory experiments with a two-stage process layout finally provided complete nitrification overcoming the inhibiting nature of process waters from the rendering plant. DGGE analysis of the second stage activated sludge from the laboratory plant showed a shift in population structure from Nitrosospira sp. towards Nitrosomonas spp. simultaneous to the increase of nitrification capacity. Nitrification capacities comparable to full-scale municipal wastewater treatment plants could be maintained for more than two months. As the design of wastewater treatment plants for nitrification is linked to the growth characteristics of Nitrosomonas spp., established criteria can be applied for the redesign of the full-scale plant.
43
Mukhtar, Hussnain, Yu-Pin Lin, Chiao-Ming Lin e Yann-Rong Lin. "Relative Abundance of Ammonia Oxidizing Archaea and Bacteria Influences Soil Nitrification Responses to Temperature". Microorganisms 7, n. 11 (4 novembre 2019): 526. http://dx.doi.org/10.3390/microorganisms7110526.
Testo completoAbstract (sommario):
Ammonia oxidizing archaea (AOA) and bacteria (AOB) are thought to contribute differently to soil nitrification, yet the extent to which their relative abundances influence the temperature response of nitrification is poorly understood. Here, we investigated the impact of different AOA to AOB ratios on soil nitrification potential (NP) across a temperature gradient from 4 °C to 40 °C in twenty different organic and inorganic fertilized soils. The temperature responses of different relative abundance of ammonia oxidizers for nitrification were modeled using square rate theory (SQRT) and macromolecular rate theory (MMRT) models. We found that the proportional nitrification rates at different temperatures varied among AOA to AOB ratios. Predicted by both models, an optimum temperature (Topt) for nitrification in AOA dominated soils was significantly higher than for soils where AOA and AOB abundances are within the same order of magnitude. Moreover, the change in heat capacity ( Δ C P ‡ ) associated with the temperature dependence of nitrification was positively correlated with Topt and significantly varied among the AOA to AOB ratios. The temperature ranges for NP decreased with increasing AOA abundance for both organic and inorganic fertilized soils. These results challenge the widely accepted approach of comparing NP rates in different soils at a fixed temperature. We conclude that a shift in AOA to AOB ratio in soils exhibits distinguished temperature-dependent characteristics that have an important impact on nitrification responses across the temperature gradient. The proposed approach benefits the accurate discernment of the true contribution of fertilized soils to nitrification for improvement of nitrogen management.
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Dollhopf, Sherry L., Jung-Ho Hyun, April C. Smith, Harold J. Adams, Sean O'Brien e Joel E. Kostka. "Quantification of Ammonia-Oxidizing Bacteria and Factors Controlling Nitrification in Salt Marsh Sediments". Applied and Environmental Microbiology 71, n. 1 (gennaio 2005): 240–46. http://dx.doi.org/10.1128/aem.71.1.240-246.2005.
Testo completoAbstract (sommario):
ABSTRACT To elucidate the geomicrobiological factors controlling nitrification in salt marsh sediments, a comprehensive approach involving sediment geochemistry, process rate measurements, and quantification of the genetic potential for nitrification was applied to three contrasting salt marsh habitats: areas colonized by the tall (TS) or short (SS) form of Spartina alterniflora and unvegetated creek banks (CBs). Nitrification and denitrification potential rates were strongly correlated with one another and with macrofaunal burrow abundance, indicating that coupled nitrification-denitrification was enhanced by macrofaunal burrowing activity. Ammonia monooxygenase (amoA) gene copy numbers were used to estimate the ammonia-oxidizing bacterial population size (5.6 � 104 to 1.3 � 106 g of wet sediment−1), which correlated with nitrification potentials and was 1 order of magnitude higher for TS and CB than for SS. TS and CB sediments also had higher Fe(III) content, higher Fe(III)-to-total reduced sulfur ratios, higher Fe(III) reduction rates, and lower dissolved sulfides than SS sediments. Iron(III) content and reduction rates were positively correlated with nitrification and denitrification potential and amoA gene copy number. Laboratory slurry incubations supported field data, confirming that increased amounts of Fe(III) relieved sulfide inhibition of nitrification. We propose that macrofaunal burrowing and high concentrations of Fe(III) stimulate nitrifying bacterial populations, and thus may increase nitrogen removal through coupled nitrification-denitrification in salt marsh sediments.
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Xiao, Jing, e Jin Hua Tang. "Nitrogen Removal with Nitrification and Denitrification via Nitrite". Advanced Materials Research 908 (marzo 2014): 175–78. http://dx.doi.org/10.4028/www.scientific.net/amr.908.175.
Testo completoAbstract (sommario):
Biological nitrification and denitrification via nitrite pathway is technically feasible and economically favorable, especially when wastewater with high ammonium concentrations or low C/N ratios is treated. Therefore, it has attracted more and more attention. It is very important to maintain partial nitrification of ammonium to nitrite. In this paper, the factors that influence operation and efficiency of nitrification and denitrification via nitrite are discussed, including DO concentration, carbon source, aeration pattern, PH, temperature and high free ammonia. High ammonia concentration and temperature are prone to accomplish of short-cut nitrification and denitrification, but limit application in practice. Finally, the review discussed the future challenges for application of short-cut nitrification and denitrification.
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He, Feifei, Haohao Yu, Dandan Liu e Zheng Li. "Microorganism community composition analysis coupling with 15N tracer experiments reveals the nitrification rate and N2O emissions in low pH soils in Southern China". Open Life Sciences 17, n. 1 (1 gennaio 2022): 55–63. http://dx.doi.org/10.1515/biol-2022-0010.
Testo completoAbstract (sommario):
Abstract Nitrification in agricultural soil is an important process for food production. In acidic soil, nitrification is however also considered to be a major source of N2O production. The nitrification rate largely depends on the community composition of ammonia-oxidizing organisms. To obtain a view of the nitrification rates and N2O emission situations in low pH soils in Southern China and understand their relations with the microbial community composition, here we conducted 15N tracer experiments and microorganism community composition analysis using four acidic agricultural soil samples collected in Southern China. A single dominant community (relative abundance >68%) of the ammonia-oxidizing bacteria and ammonia-oxidizing archaea was observed in the soils with pH = 4.81–6.02. A low amount of NO 3 – {\text{NO}}_{3}^{\mbox{--}} was produced from the nitrification in the strongly acidic soil (pH = 4.03), and the calculated nitrification rate in this soil was significantly lower than those of other soils with pH = 4.81–6.02. High N2O emissions but low 15N–N2O emissions were observed in the soil with pH = 4.03. Our results suggest that, under aerobic conditions, soil pH is an important factor affecting nitrification through modifying the microorganism composition.
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Petropoulos, Penny, e Kimberley A. Gilbride. "Nitrification in activated sludge batch reactors is linked to protozoan grazing of the bacterial population". Canadian Journal of Microbiology 51, n. 9 (1 settembre 2005): 791–99. http://dx.doi.org/10.1139/w05-069.
Testo completoAbstract (sommario):
Protozoa feed upon free-swimming bacteria and suspended particles inducing flocculation and increasing the turnover rate of nutrients in complex mixed communities. In this study, the effect of protozoan grazing on nitrification was examined in activated sludge in batch cultures maintained over a 14-day period. A reduction in the protozoan grazing pressure was accomplished by using either a dilution series or the protozoan inhibitor cycloheximide. As the dilutions increased, the nitrification rate showed a decline, suggesting that a reduction in protozoan or bacterial concentration may cause a decrease in nitrification potential. In the presence of cycloheximide, where the bacterial concentration was not altered, the rates of production of ammonia, nitrite, and nitrate all were significantly lower in the absence of active protozoans. These results suggest that a reduction in the number or activity of the protozoans reduces nitrification, possibly by limiting the availability of nutrients for slow-growing ammonia and nitrite oxidizers through excretion products. Furthermore, the ability of protozoans to groom the heterotrophic bacterial population in such systems may also play a role in reducing interspecies competition for nitrification substrates and thereby augment nitrification rates.Key words: nitrification, activated sludge, protozoan grazing, ammonia-oxidizing bacteria, cycloheximide.
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Wang, S. Y., D. W. Gao, Y. Z. Peng, P. Wang e Q. Yang. "Nitrification-denitrification via nitrite for nitrogen removal from high nitrogen soybean wastewater with on-line fuzzy control". Water Science and Technology 49, n. 5-6 (1 marzo 2004): 121–27. http://dx.doi.org/10.2166/wst.2004.0745.
Testo completoAbstract (sommario):
This study is to demonstrate the performance of a new technology for complete nitrogen removal from soybean wastewater with high nitrogen concentrations. Nitrification-denitrification via nitrite was performed in three kinds of operating condition, i.e. nitrification-denitrification via nitrite under traditional SBR process, nitrification-denitrification via nitrite by alternating oxic/anoxic under fixed-time control and nitrification-denitrification via nitrite by alternating oxic/anoxic under on-line fuzzy control.The best one is nitrification-denitrification via nitrite by alternating oxic/anoxic under on-line fuzzy control. It not only improves both nitrification and denitrification rates and decreases total reaction time, but also saves the amount of added carbon source and alkalinity. In addition, reaction time can be shortened and operation cost can be saved by using real-time fuzzy control aeration and mixing time. So this method enhances the efficiency and the stability of nitrogen removal, and reduces operating costs and construction investment in the process of wastewater treatment.
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Nemergut, D. R., e S. K. Schmidt. "Disruption of narH, narJ, and moaE Inhibits Heterotrophic Nitrification in Pseudomonas Strain M19". Applied and Environmental Microbiology 68, n. 12 (dicembre 2002): 6462–65. http://dx.doi.org/10.1128/aem.68.12.6462-6465.2002.
Testo completoAbstract (sommario):
ABSTRACT Interruptions in three nitrate reductase-related genes, narH, narJ, and moaE, inhibited heterotrophic nitrification in Pseudomonas strain M19. No nitrate was detected in the medium, and nitrification proceeded in the presence of a nitrate reductase inhibitor. Heterotrophic nitrification was greatly stimulated by the addition of nitrate.
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Wang, Bing, Yi Xiao, Shou Hui Tong, Lan Fang, Da Hai You, Song Han e Yuan Bo Wang. "Study on De-Nitrification of Improved Step-Feed Progress". Applied Mechanics and Materials 703 (dicembre 2014): 171–74. http://dx.doi.org/10.4028/www.scientific.net/amm.703.171.
Testo completoAbstract (sommario):
Improved step-feed de-nitrification progress combined with biological fluidized bed was introduced in this study. The progress had good performance and capacity of de-nitrification and organic matter. The experiment result showed that the de-nitrification efficiency of the improved biological fluidized bed with step-feed process was higher than the fluidized bed A/O process under the same water quality and the operating conditions. When the influent proportion of each segment was equal, the system showed good nitrogen removal efficiency with the change of influent C/N ratio, HRT and sludge return ratio. The removal rate of TN reached up to 88.2%. It showed that the simultaneous nitrification and de-nitrification phenomenon happened in the aerobic zone. The nitrogen removal mechanism was also studied.