Results 221 to 230 of about 11,182 (261)

In-stream nitrification rate prediction

Water Research, 1988
Abstract A simultaneous nitrogen and dissolved oxygen mass balancing technique is used to accurately assess actual in-stream nitrification rate coefficients. These rate coefficients are compared against estimations from observed spatial changes in various bulk fluid nitrogen species concentrations.
John J. Warwick, Pradeep Shetty
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Nitrification Rate in Biological Processes

Journal of the Environmental Engineering Division, 1974
At least four reaction rate equations have been proposed to describe the process of nitrification. A more precise understanding of this reaction rate is needed to optimize the design of the process. The proposed equations which include the Monod, zero-order, first-order, and autocatalytic growth are reviewed.
Ching-San Huang, Ninnian E. Hopson
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Rate constants for nitrification and denitrification in soils

Radiation and Environmental Biophysics, 1976
Rate constants for reactions in flowing solutions in soil can be calculated from extents of reactions as functions of depth, rates of flow, effective biomass of microbes and independent measurements of hydrodynamic dispersion. Constants have been calculated from data in the literature and are shown to be arbitrary unless all of these quantities have ...
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Decomposition rate of dicyandiamide and nitrification inhibition

Communications in Soil Science and Plant Analysis, 1989
Abstract Degradation of dicyandiamide (DCD) was assayed in laboratory studies at 8, 15, and 22 C in a Decatur silt loam and in a Norfolk loamy sand. Dicyandiamide was very short lived at 22 C, with half‐lives of 7.4 and 14.7 days in the Decatur and Norfolk soils, respectively. In the Norfolk soil at 8 C, half‐life increased to 52.2 days.
K. F. Bronson, J. T. Touchton, R. D. Hauck   +2 more
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Measurement of in situ rates of nitrification in sediment

Microbial Ecology, 1980
A method has been developed for the measurement of nitrification rates in intact sediment cores without disturbing the concentration gradients of oxygen and ammonium. N-serve (2-chloro-6-trichloromethyl-pyridine), a specific inhibitor of the autotrophic ammonium oxidation, was injected into a 0-2 cm surface layer of the sediment (20 ppm) and added to ...
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Nitrification Potential and Factors Governing the Rate of Nitrification in Lake Kinneret

Oikos, 1977
number of nitrifying bacteria initially present in the sample. This finding allowed the calibration of the NP measurements in terms of number of nitrifying bacteria. The fluctuations of the NP values were compared with the nitrification actually occurring in the lake. A concomitant decrease of NP in the sediment and increase of the NP in the lake water
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Measurement of nitrification rates in lake sediments: Comparison of the nitrification inhibitors nitrapyrin and allylthiourea

Microbial Ecology, 1984
A method for measuring rates of nitrification in intact marine sediment cores has been modified and adapted for use in freshwater sediments. The technique involves subsampling a sediment core into minicores. Half of these cores are treated with an inhibitor of chemolithotrophic nitrification and, after incubation, differences in ammonia and nitrate ...
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Measurement and Distribution of Nitrification Rates in the Oceans

2011
Nitrification is the process that converts ammonium to nitrate and thus links the regeneration of organic nitrogen to fixed nitrogen loss by denitrification. The first step, oxidation of ammonia to nitrite, is performed by a phylogenetically restricted group of proteobacteria (ammonia-oxidizing bacteria, AOB) and Crenarchaea (ammonia-oxidizing archaea,
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High rate partial nitrification treatment of reject wastewater

Journal of Bioscience and Bioengineering, 2010
Partial nitrification (PN) treatments on reject wastewater were carried out. Dissolved oxygen concentration was limited by controlling air flowrate, which was the main operational strategy in this study. Stable PN performance was obtained during continuous operation for 80 days, with a maximum nitrogen loading rate (NLR) of 4.2 kg-N m(-3) day(-1) and ...
Jiachun, Yang, Li, Zhang, Hira, Daisuke, Sato, Takahiro, Yongguang, Ma, Zhigang, Li, Kenji, Furukawa   +6 more
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A method for the measurement of nitrification rates in water

Water Research, 1978
Abstract This paper describes a very sensitive method for the evaluation of nitrification rates requiring only short incubation times (3–6 h) and applicable to all aquatic media. It is based on the measurement of dark [ 14 C]-bicarbonate incorporation inhibited by N -serve, an inhibitor of nitrification.
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