scholarly journals Modeling the Photocatalytic Process of Variation in Chemical Oxygen Demand via Stochastic Differential Equations

2013 ◽  
Vol 7 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Adriano F. Siqueira ◽  
Oswaldo L. C. Guimaraes ◽  
Helcio J. Izario Filho ◽  
Domingos S. Giordani ◽  
Ivy dos Santos Oliveira ◽  
...  
Keyword(s):  
Differential Equations ◽  
Chemical Oxygen Demand ◽  
Stochastic Differential Equations ◽  
Combined Treatment ◽  
Oxygen Demand ◽  
Industrial Effluents ◽  
Model Parameters ◽  
Experimental Conditions ◽  
New Approach ◽  
Practical Applications

Several papers in the literature on Advanced Oxidation Processes (AOPs) confirm the process as a viable alternative for the treatment of a variety of industrial effluents. In many of these works, modeling the variations of Chemical Oxygen Demand (COD) as a function of different experimental conditions was performed by techniques such as Design of Experiments, Artificial Neural Networks and Multivariate Analysis. These techniques require both a large number of parameters and a large quantity of experimental data for a systematic study of the model parameters as a function of experimental conditions. On the other hand, the study of Stochastic Differential Equations (SDE) is presently well developed with several practical applications noted in the literature. This paper presents a new approach in studying the variations of COD in AOPs via SDE. Specifically, two effluents, from the manufacture of paints and textiles were studied by combined treatment of the photo-Fenton process and catalytic ozonization.

scholarly journals Treatment of real paracetamol wastewater by fenton process

2017 ◽  
Vol 23 (2) ◽  
pp. 177-186 ◽  
Author(s):  
Gamze Dalgic ◽  
Ilter Turkdogan ◽  
Kaan Yetilmezsoy ◽  
Emel Kocak
Keyword(s):  
Pharmaceutical Industry ◽  
Organic Carbon ◽  
Chemical Oxygen Demand ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Biological Oxygen Demand ◽  
Fenton Process ◽  
Experimental Conditions ◽  
Mass Distributions ◽  
Amino Phenol

The study investigated the pretreatment of real paracetamol (PCT) wastewater of a pharmaceutical industry by Fenton process. At the best experimental conditions (COD/H2O2 = 1/1, Fe+2/H2O2 = 1/70, settling method:centrifuging, pH 6 at settling step), 92.7, 92.7, 95.5, 99.1, 99.9 and 99.4% of chemical oxygen demand (COD), total organic carbon (TOC), 5-day biological oxygen demand (BOD5), PCT, para-amino phenol (PAP) and aniline were removed, respectively. Changes in the concentrations of these parameters were also investigated for both oxidation and settling steps of Fenton process. It was found that COD and TOC were removed at the settling step (precipitation) whereas PCT, PAP and aniline were removed at the oxidation step. Mass balance calculations were also studied to show the mass distributions of COD in different phases (gas + foam, effluent and sludge). Fenton process was found as an effective method for the pretreatment of real PCT wastewater for discharging in a determined collective treatment plant.

scholarly journals Long-term performance of a microbial electrolysis cell operated with periodic disconnection of power supply

RSC Advances ◽  
2018 ◽  
Vol 8 (30) ◽  
pp. 16842-16849 ◽  
Author(s):  
S. A. Hussain ◽  
M. Perrier ◽  
B. Tartakovsky
Keyword(s):  
Chemical Oxygen Demand ◽  
Power Supply ◽  
Oxygen Demand ◽  
Electrolysis Cell ◽  
Microbial Electrolysis Cell ◽  
New Approach ◽  
Microbial Electrolysis ◽  
Long Term Performance ◽  
Term Performance

This study describes a new approach for achieving stable long-term performance and maximizing removal of chemical oxygen demand (COD) in a Microbial Electrolysis Cell (MEC) by periodic disconnection of the MEC power supply.

scholarly journals UV-Irradiated Photocatalytic Degradation of Nitrobenzene by Titania Binding on Quartz Tube

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Thou-Jen Whang ◽  
Mu-Tao Hsieh ◽  
Tjaun-En Shi ◽  
Chun-Hsiung Kuei
Keyword(s):  
Activation Energy ◽  
Physical Properties ◽  
Chemical Oxygen Demand ◽  
Ion Chromatography ◽  
Oxygen Demand ◽  
Tetraethyl Orthosilicate ◽  
Titania Nanoparticles ◽  
Quartz Tube ◽  
Experimental Conditions ◽  
The Matrix

A new method for UV-irradiated degradation of nitrobenzene by titania photocatalysts was proposed, titania nanoparticles were coated on a quartz tube through the introduction of tetraethyl orthosilicate into the matrix. The dependence of nitrobenzene photodegradation on pH, temperature, concentration, and air feeding was discussed, and the physical properties such as the activation energy, entropy, enthalpy, adsorption constant, and rate constant were acquired by conducting the reactions in a variety of experimental conditions. The optimum efficiency of the photodegradation with the nitrobenzene residue as low as 8.8% was achieved according to the experimental conditions indicated. The photodegradation pathways were also investigated through HPLC, GC/MS, ion chromatography (IC), and chemical oxygen demand (COD) analyses.

Combination of microalgae cultivation with membrane processes for the treatment of municipal wastewater

2013 ◽  
Vol 68 (11) ◽  
pp. 2374-2381 ◽  
Author(s):  
Lu Chen ◽  
Jiang Wei ◽  
Weiguo Wang ◽  
Cunwen Wang
Keyword(s):  
Chemical Oxygen Demand ◽  
Membrane Filtration ◽  
Municipal Wastewater ◽  
Oxygen Demand ◽  
Permeate Flux ◽  
Microalgae Cultivation ◽  
New Approach ◽  
Critical Issues ◽  
Uf Membranes ◽  
Residual Solution

The treatment of wastewater by microalgae cultivation has attracted more and more attention. However, the way to harvest microalgae cells from the wastewater and the treatment of the large quantity of residual solution have become critical issues. In this work, a new approach for the treatment of municipal wastewater is presented. The combination of flocculation for removing mainly microalgae and thereafter membrane filtration for chemical oxygen demand (COD) and conductivity reduction of the residual solution after flocculation is discussed. The COD concentration of the wastewater decreased from 260 to 84 mg/L after flocculation by chitosan. Five ultrafiltration (UF) membranes and two nanofiltration (NF) membranes were used for filtration to find a suitable membrane for COD and conductivity reduction. Among the five UF membranes, GR82PE showed the best performance, whose permeate flux and COD retention at 4 bar were 189.66 L/(m2·h) and 43.03%, respectively. NF membranes showed higher COD and conductivity retentions than UF membranes. The COD retention of Desal5-DK reached 98.3% at 20 bar. Lastly, the flux recovery after the filtration test of each membrane is also discussed.

On solving stochastic differential equations

2019 ◽  
Vol 25 (2) ◽  
pp. 155-161
Author(s):  
Sergej M. Ermakov ◽  
Anna A. Pogosian
Keyword(s):  
Monte Carlo ◽  
Markov Chain ◽  
Markov Chain Monte Carlo ◽  
Differential Equations ◽  
Stochastic Differential Equations ◽  
Integral Equations ◽  
Wide Class ◽  
Monte Carlo Methods ◽  
New Approach ◽  
Difference Approximations

Abstract This paper proposes a new approach to solving Ito stochastic differential equations. It is based on the well-known Monte Carlo methods for solving integral equations (Neumann–Ulam scheme, Markov chain Monte Carlo). The estimates of the solution for a wide class of equations do not have a bias, which distinguishes them from estimates based on difference approximations (Euler, Milstein methods, etc.).

scholarly journals McKean–Vlasov type stochastic differential equations arising from the random vortex method

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Zhongmin Qian ◽  
Yuhan Yao
Keyword(s):  
Differential Equations ◽  
Stochastic Differential Equations ◽  
Vortex Dynamics ◽  
Existence And Uniqueness ◽  
Strong Solutions ◽  
Vortex Method ◽  
Wasserstein Distance ◽  
New Approach ◽  
Lipschitz Continuous ◽  
Space Of Distributions

AbstractWe study a class of McKean–Vlasov type stochastic differential equations (SDEs) which arise from the random vortex dynamics and other physics models. By introducing a new approach we resolve the existence and uniqueness of both the weak and strong solutions for the McKean–Vlasov stochastic differential equations whose coefficients are defined in terms of singular integral kernels such as the Biot–Savart kernel. These SDEs which involve the distributions of solutions are in general not Lipschitz continuous with respect to the usual distances on the space of distributions such as the Wasserstein distance. Therefore there is an obstacle in adapting the ordinary SDE method for the study of this class of SDEs, and the conventional methods seem not appropriate for dealing with such distributional SDEs which appear in applications such as fluid mechanics.

Wet Air Oxidation of Toxic Industrial Effluents

1989 ◽  
Vol 21 (4-5) ◽  
pp. 289-295 ◽  
Author(s):  
J. Kálmán ◽  
Z. Izsáki ◽  
L. Kovács ◽  
A. Grofcsik ◽  
I. Szebényi
Keyword(s):  
Activation Energy ◽  
Chemical Oxygen Demand ◽  
Reaction Rate ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Industrial Effluents ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Cod Reduction ◽  
Process Wastewater

The disposal of process wastewater from a wood carbonization factory was studied in a laboratory batch reactor. Chemical oxygen demand (COD) reduction of 92 - 96% was achieved for samples with initial COD concentrations of more than 100 g/l. The samples subjected to wet air oxidation showed no toxic effects in toxicology tests and were readily biodegradable. Effluent containing cyanide was also subjected to wet air oxidation, and a COD reduction of 75% and cyanide removal of 99.99997% was attained. The reaction rate and activation energy of cyanide hydrolysis were determined.

scholarly journals Model Calibration in Option Pricing

2012 ◽  
Vol 16 ◽  
pp. 84
Author(s):  
Andre Loerx ◽  
Ekkehard W. Sachs
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
Option Pricing ◽  
Stochastic Differential Equations ◽  
Model Calibration ◽  
Mathematical Finance ◽  
Adjoint Equations ◽  
Model Parameters ◽  
The Past ◽  
Modeling Process

We consider calibration problems for models of pricing derivatives which occur in mathematical finance. We discuss various approaches such as using stochastic differential equations or partial differential equations for the modeling process. We discuss the development in the past literature and give an outlook into modern approaches of modelling. Furthermore, we address important numerical issues in the valuation of options and likewise the calibration of these models. This leads to interesting problems in optimization, where, e.g., the use of adjoint equations or the choice of the parametrization for the model parameters play an important role. 

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