scholarly journals Substantiation of the calculation methods of the nitrogen removing (nitrification) in bioreactors with using on the biofilm models

2021 ◽  
Vol 38 (2) ◽  
pp. 18-38
Author(s):  
Oleksandr Ya. Oliynyk ◽  
Sergiy V. Telyma ◽  
Yuriy I. Kalugin ◽  
Yevheniy O. Oliynyk
Keyword(s):  
Influence Factors ◽  
Mathematic Model ◽  
Ammonium Nitrogen ◽  
Surface Velocity ◽  
Ammonium Oxidation ◽  
Waste Waters ◽  
Biofilm Thickness ◽  
Nitrogen Concentrations ◽  
Kinetics Of Reaction ◽  
The Given

The mathematic model and calculations of the waste waters cleaning parameters from the compounds ammonium nitrogen (nitrification) in bioreactors with additional using in theirs volume the fixed biocenosis as the biofilm are presented. The valuation of the different influence factors on the waste waters cleaning parameters is given. The kinetics of reaction according to Monod nonlinear equation is used that allow to calculate the nitrogen concentrations on the external and in the interior biofilm surfaces and to evaluate the efficiency of the biofilm work of the given thickness relative to penetration character of the nitrogen pollutions in it. As showed the biofilm thickness and the flow in it are decreasing as the tearing off velocity of the biomass from its surface is increasing where as at increasing of the nitrogen concentrations these parameters are increasing. At this the substrate flow and the penetration depth into the biofilm are the functions of the substrate concentration on the biofilm surface, velocity of the reaction within it and the diffusive masstransfer. As a main parameter for evaluation of the oxygen influence for control of the process of ammonium oxidation to nitrite the relation of the concentrations oxygen to ammonium nitrogen is proposed. The specific examples and calculations have showed the given relation may be better alternative for control of the nitrification processes in reactor in comparison with oxygen concentration.

Nitrogen cycling in a Venezuelan tropical seasonally flooded forest: soil nitrogen mineralization and nitrification

1994 ◽  
Vol 10 (3) ◽  
pp. 399-416 ◽  
Author(s):  
Barrios E. ◽  
Herrera R.
Keyword(s):  
Soil Nitrogen ◽  
Nitrogen Availability ◽  
Inorganic Nitrogen ◽  
Nitrogen Concentration ◽  
Ammonium Nitrogen ◽  
Wet Season ◽  
Flooded Forest ◽  
Nitrogen Concentrations ◽  
Minimum Stress ◽  
Seasonally Flooded

ABSTRACTSeasonally flooded forests represent a transition between terrestrial and aquatic ecosystems. The Mapire river, a tributary of the Orinoco river, floods its surrounding forests during the wet season (May–December). The soils are very acid and the total nitrogen concentration (0.1%) is only half that found in nearby soils flooded by Orinoco waters. Ammonium-nitrogen predominates in the soil during the flooded period while nitrate-nitrogen concentrations are higher in the dry period. Wide fluctuations in the inorganic nitrogen fractions did not considerably affect the annual course of soil nitrogen.The predominance of mineralization versus nitrification (56 and 5 μgsoil month−1respectively) and possibly the synchronization of nitrogen availability with plant demand could be considered as nitrogen conserving mechanisms.In synchrony with the hydrologic cycle, the seasonally flooded forest studied shows a nitrogencycle where inputs and accumulation are maximized when the system is under minimum stress (dry season). During flooding, the system enters a period of dormancy making minimal use of nutrient and energy to avoid or tolerate anaerobiosis.

The Influence of Volume Surface Ratio of Rectangle Air-Conditioning Duct on Particle Deposition

2011 ◽  
Vol 71-78 ◽  
pp. 3633-3638 ◽  
Author(s):  
Jie Zhang ◽  
Ze Hua Liu ◽  
Yuan Quan Liu ◽  
Hui Min Li ◽  
Yong Fei Ning
Keyword(s):  
Cross Section ◽  
Air Conditioning ◽  
Particle Deposition ◽  
Deposition Velocity ◽  
Vertical Wall ◽  
Influence Factors ◽  
Particle Model ◽  
Random Trajectory ◽  
Air Speed ◽  
The Given

This paper discusses particle deposition in rectangle air-conditioning duct using RSM (Reynold Stress Model) and random trajectory particle model. Particle with nominal diameters of 10-200μm are simulated at each of three nominal air speed: 4m/s, 6m/s and 8m/s, respectively, in the cross-section sizes of 160×120, 500×250, 1000×320mm. In simulation, the paper compares and analyzes the influence factors of particles deposition in volume surface ratio of the given duct. The results show that: 1) particle deposition velocity increases with volume surface ratio; 2) As the inlet air speed increasing, when the particles deposited to floor and vertical wall, the image of dimensionless deposition velocity Vs dimensionless relaxation time shows a coincident trend when the duct cross-section sizes are 500×250, 1000×320mm, but has great differences with the image of 160×120mm.

scholarly journals Methodic tools to optimize marketing expenses of the innovatively active industrial enterprises in Ukraine

2016 ◽  
Vol 14 (1) ◽  
pp. 44-50 ◽  
Author(s):  
Oleg Olefirenko
Keyword(s):  
Mathematic Model ◽  
Machine Building ◽  
Practical Implementation ◽  
Industrial Enterprises ◽  
Managerial Decisions ◽  
Production Distribution ◽  
Market Situation ◽  
The Given ◽  
Rational Process

The efficient sales policy of the machine building innovatively active enterprises is connected with its rational process financing. Optimal determination of innovative production distribution expenses is top-priority element to increase economic subject’s activity profitability and to increase its competitive positions at the market. Thus, planning of costs for innovatively active machine building enterprises sales has to be based on economic and rationally adaptive mathematic tools to industrial enterprises activity specific. Practical implementation of the mentioned task is possible owing to economic and mathematic model to plan costs for innovatively active enterprises production, which preconditions urgency of the given research. Besides the tools investigation is also urgent and it allows to foresee future expenses amounts for sales, demand for production and profit of the innovatively active industrial enterprise, behavior in future depending on market situation. The article deals with scientific and methodic approach to optimize distribution expenses of the innovatively active industrial enterprises in Ukraine. Economic and mathematic modeling methods allowed to formalize models to plan distribution expenses of innovatively active enterprise, demand and profits, that is prerequisite to form prognostications by proper directions. Practical implementation of the suggested scientific and methodic approach on the example of machine building enterprise in Ukraine results in confirmation of models correspondence and establishment of inefficiency to distinguish expenses. It gives evidence about necessity to optimize expenses of enterprise and to introduce active managerial decisions concerning its activity profitability growth

scholarly journals The effect of pulverising aeration on changes in the oxygen and nitrogen concentrations in water of Lake Starzyc

2015 ◽  
Vol 25 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Piotr Wesołowski ◽  
Adam Brysiewicz
Keyword(s):  
Dissolved Oxygen ◽  
Nitrate Nitrogen ◽  
Ecological Status ◽  
Ammonium Nitrogen ◽  
Abiotic Conditions ◽  
The Third ◽  
Long Period ◽  
Nitrogen Concentrations ◽  
Bottom Waters ◽  
Restoration Measures

Abstract Due to poor ecological status of Lake Starzyc, lake restoration measures were undertaken in 2003 to improve aerobic conditions of near-bottom waters and to decrease phosphorus concentrations. To do this, a wind-driven pulverising aerator was installed in the lake. The aim of this study was to analyse variability of oxygen and nitrogen concentrations in lake water near the aerator in the third year of its operation and later on in the three-year-long period of the years 2008–2010. It was found that concentrations of ammonium-nitrogen, nitrate-nitrogen and dissolved oxygen near the aerator did not differ from those in sites 4 and 5, which evidenced similar abiotic conditions in analysed waters. Higher concentrations of dissolved oxygen and lower concentrations of nitrate-nitrogen were found in the years 2008–2010 than in 2005.

Analysis on Refractive Property of Complex Optometry System

2014 ◽  
Vol 668-669 ◽  
pp. 1565-1568
Author(s):  
Ji Yan Zhang ◽  
Wen Li Liu ◽  
Lei Yang ◽  
Ming Liang Gao
Keyword(s):  
Influence Factors ◽  
Mathematic Model ◽  
Lens Space ◽  
Back Surface ◽  
Structural Parameter ◽  
Simplified Models ◽  
Accurate Analysis ◽  
Lens Position ◽  
Higher Power ◽  
Lens Power

In optometry, simplified models are usually used to analyze refractive property of optometry system on the assumption that lenses are thin and close enough to each other. However, in fact those lenses do have stated center thickness and lens space between them. The simplified models are not suitable for accurate analysis and system design. In this paper, first, accurate mathematic model for refractive property of single spherical and cylindrical lens is established. Next, accurate model is established for complex optometry system with different kinds of lenses combination. Then, influence factors such as lens structural parameter, lens space and lens position are analyzed for refractive property. Results show that correct lens position is very important for complex optometry system. Parallel light should pass lower power lens first and then higher power lens. When lens power and lens space gets bigger the influence of lens space will be more significant on refractive property. For uncertainty component, uncertainty from front and back surface radii are the biggest, secondary is the refractive index and lens space, and uncertainty from lens thickness is the least.

The Mechanism and Influence Factors of Struvite Precipitation for the Removal of Ammonium Nitrogen

2011 ◽  
Vol 189-193 ◽  
pp. 2613-2620 ◽  
Author(s):  
Hai Ming Huang ◽  
Qian Wu Song ◽  
Chun Lian Xu
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Influence Factors ◽  
Ammonium Nitrogen ◽  
Double Salt ◽  
Normal Operation ◽  
Research Directions ◽  
Struvite Precipitation ◽  
At Home

Struvite (MgNH4PO4∙6H2O) is an insoluble double salt. It can precipitate in places such as pipes, aerators and pumps, which could lead to substantial problems influencing the normal operation of wastewater treatment equipments. At present, removal of ammonium nitrogen from various wastewaters by the formation of struvite has been widely investigated. This paper reviewed the research and application efforts concerning the treatment of ammonium nitrogen by struvite precipitation, which were obtained at home and abroad in recent years. The mechanism and influence factors of struvite precipitation for ammonium nitrogen removal were discussed. Additionally, the problems that still should be resolved and the research directions in future were pointed out.

scholarly journals The Effects of Concentration Gradient of Nitrogen Compounds on the Ammonium-nitrogen and Nitrate-nitrogen Fluxes at Sediment-Water Interface

2021 ◽  
Author(s):  
Han Wang ◽  
Qing Wu ◽  
Yuping Han
Keyword(s):  
Nitrate Nitrogen ◽  
Diffusion Flux ◽  
Ammonium Nitrogen ◽  
Nutrient Concentrations ◽  
Water Interface ◽  
Incubation Experiment ◽  
Concentration Gradients ◽  
Overlying Water ◽  
Average Diffusion ◽  
Nitrogen Concentrations

Abstract The incubation experiments focused on altering concentration gradients of nitrogen between sediment and overlying water to examine the diffusion flux of ammonium-nitrogen (NH4+) and nitrate-nitrogen (NO3-) at sediment-water interface. In this study, the diffusion flux can be estimated based on calculating the average of the net change rate of nutrient concentrations in the overlying water. For the incubation experiment of different TN concentrations in the sediment, the results showed that the diffusion flux of ammonia at sediment-water interface is -52.57~84.57 mg·m-2·d-1, and for nitrate diffusion flux, the changing range during the incubation experiment is -110.13~143.25 mg·m-2·d-1. For the incubation experiment of different nitrogen concentrations in the overlying water, the results of NH4+-N diffusion flux in L, M, H treatment were 3.37, -4.94, -3.84 mg·m-2·d-1, respectively. And the average diffusion flux of nitrate in L (0 mg NO3--N, 0 mg NH4+-N), M (0.5 mg NO3--N, 1.5 mg NH4+-N) and H (1 mg NO3--N, 2.5 mg NH4+-N) treatment were 12.30, 10.39 and 7.11 mg·m-2·d-1. Results highlighted that concentrations gradient of nutrients were indeed an important factor affecting the diffusion flux at sediment-water interface. In addition, the diffusion of nutrients at sediment-water interface in aquatic ecosystem is not only controlled by concentration gradients, some other factors such as incoming water, hydrodynamics, dissolved oxygen content, sediment structure, biological disturbance, horizontal migration and diffusion of nutrients and turbulent diffusion caused by wind and wave, are equally important.

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