Tertiary Nitrification Pilot Plants on Parisian Waste Water

1990 ◽  
Vol 22 (1-2) ◽  
pp. 347-352 ◽  
Author(s):  
C. Paffoni ◽  
B. Védry ◽  
M. Gousailles
Keyword(s):  
Waste Water ◽  
Metropolitan Area ◽  
Fixed Bed ◽  
Point Of View ◽  
Operating Conditions ◽  
Research Center ◽  
Daily Output ◽  
Practical Point ◽  
Fixed Bed Reactors

The Paris Metropolitan area, which contains over eight million inhabitants, has a daily output of about 3 M cu.meters of wastewater, the purification of which is achieved by SIAAP (Paris Metropolitan Area Sewage Service) in both Achères and Valenton plants. The carbon pollution is eliminated from over 2 M cu.m/day at Achères. In order to improve the quality of output water, its tertiary nitrification in fixed-bed reactors has been contemplated. The BIOFOR (Degremont) and BIOCARBONE (OTV) processes could be tested in semi-industrial pilot reactors at the CRITER research center of SIAAP. At a reference temperature of 13°C, the removed load is approximately 0.5 kg N NH4/m3.day. From a practical point of view, it may be asserted that in such operating conditions as should be at the Achères plant, one cubic meter of filter can handle the tertiary nitification of one cubic meter of purified water per hour at an effluent temperature of 13°C.

Modeling of spatial distribution of passenger traffi c on interurban bus routes

Innotrans ◽  
2020 ◽  
pp. 31-36
Author(s):  
Alexander V. Martynenko ◽  
◽  
Alexander A. Shevtsov ◽  
Keyword(s):  
Spatial Distribution ◽  
Quantitative Description ◽  
Point Of View ◽  
Practical Point ◽  
Ticket Price ◽  
Passenger Traffic ◽  
Correlation And Regression Analysis ◽  
Classical Gravity ◽  
Bus Service

This paper is devoted to the quantitative description of the spatial distribution of passenger traffic based on the classical gravity model on the example of interurban bus service between Yekaterinburg and other cities of the Sverdlovsk region. The influence of factors such as population, distance between localities, and ticket price on the volume of passenger traffic was studied. As a result of the correlation and regression analysis, it was found that both the distance between localities and the ticket price can be used as a measure of the remoteness of localities. However, the quality of the resulting regression model does not change. The spatial distribution of interurban bus passenger traffic depends on the measure of distance of localities from each other and the size of their population. Moreover, the size of the population is a much more significant factor than the measure of distance. From a practical point of view, this means that when predicting passenger traffic, demographic factors must first be taken into account.

Modeling of transport phenomena in fixed-bed reactors for the Fischer-Tropsch reaction: a brief literature review

2017 ◽  
Vol 33 (2) ◽  
Author(s):  
José R.G. Sánchez-López ◽  
Angel Martínez-Hernández ◽  
Aracely Hernández-Ramírez
Keyword(s):  
Liquid Fuel ◽  
Transport Phenomena ◽  
Fixed Bed ◽  
Reaction System ◽  
Operating Conditions ◽  
Fixed Bed Reactor ◽  
Fuel Production ◽  
Fischer Tropsch ◽  
Fixed Bed Reactors ◽  
The Impact

AbstractCurrently, few processes can be considered practical alternatives to the use of petroleum for liquid fuel production. Among these alternatives, the Fischer-Tropsch synthesis (FTS) reaction has been successfully applied commercially. Nevertheless, many of the fundamentals of this process are difficult to understand because of its complexity, which depends strongly on the catalyst and the reactor design and operating conditions, as the reaction is seriously affected by mass and heat transport issues. Thus, studying this reaction system with transport phenomena models can help to elucidate the impact of different parameters on the reaction. According to the literature, modeling FTS systems with 1D models provides valuable information for understanding the phenomena that occur during this process. However, 2D models must be used to simulate the reactor to correctly predict the reactor variables, particularly the temperature, which is a critical parameter to achieve a suitable distribution of products during the reaction. Thus, this work provides a general resume of the current findings on the modeling of transport phenomena on a particle/pellet level in a tubular fixed-bed reactor.

scholarly journals A Framework of Action for Implementation of Industry 4.0. an Empirically Based Research

2020 ◽  
Vol 12 (14) ◽  
pp. 5789 ◽  
Author(s):  
Artur Pollak ◽  
Agata Hilarowicz ◽  
Maciej Walczak ◽  
Damian Gąsiorek
Keyword(s):  
Industry 4.0 ◽  
Point Of View ◽  
Theory And Practice ◽  
Innovative Approach ◽  
Stages Of Development ◽  
Practical Point ◽  
Preparation Stage ◽  
The Face

Background: In the face of changes taking place as a result of the increasing digitization, automation, and robotization of life and the economy, questions regarding the essence of the functioning of modern enterprises and about the emerging new pattern of operation seem to be more and more relevant. Aim of the article: The article focuses on the issues connected with implementation of Industry 4.0 in enterprises, the difficulties involved, and the limitations and challenges that management is facing in the process. Materials and Method: The advantage of the study is its empirical nature. The participants were 39 Industry 4.0 experts from various Polish companies that have participated. At the same time, the aim has been to synthesize theory and practice and to draw attention to potential changes in the area of improvement of the economic results of enterprises that may result from Industry 4.0. Results: The research identified limitations and challenges enterprises may face in connection with the implementation and subsequent stages of development of Industry 4.0 from the practical point of view. Conclusions: Industry 4.0 is an innovative approach to generating a new quality of production. It requires, however, careful and thorough observation of the process already at the preparation stage.

Recent Development of Membrane Processes for Water and Waste Water Treatment

1993 ◽  
Vol 27 (10) ◽  
pp. 141-149 ◽  
Author(s):  
R. Ben Aim ◽  
M. G. Liu ◽  
S. Vigneswaran
Keyword(s):  
Waste Water ◽  
Experimental Study ◽  
Water Treatment ◽  
Waste Water Treatment ◽  
Operating Conditions ◽  
Water Disinfection ◽  
Simultaneous Optimization ◽  
Membrane Processes ◽  
The Relationship

Membranes are presently used at industrial scale for water and waste water treatment, but still for limited production. More knowledge of hydrodynamic phenomena has recently resulted in significant technical improvements (backflush, unsteady flow). However an experimental study performed at lab scale in a rotating membrane device has shown the complexity of the relationship between operating conditions, rejection and filtrate flux. The need for bettering the quality of the water (low turbidity) and waster water (disinfection) may be in favour of the development of membrane processes if efficient models allowing simultaneous optimization of quality and productivity are made available (as was done years ago for deep bed filtration).

scholarly journals Sensitivity of the Superpave mix design method to different methods for determining the maximum specific gravity

DYNA ◽  
2019 ◽  
Vol 86 (211) ◽  
pp. 184-191
Author(s):  
Heraldo Nunes Pitanga HERALDO PITANGA ◽  
Tamyres Karla da Silva ◽  
T.O Silva ◽  
Geraldo Luciano De Oliveira Marques
Keyword(s):  
Particle Size ◽  
Specific Gravity ◽  
Design Method ◽  
Asphalt Binder ◽  
Binder Content ◽  
Asphalt Mixtures ◽  
Point Of View ◽  
Mix Design ◽  
Practical Point

This study aimed to analyze the influence of different methodologies to determine the maximum specific gravity on the Superpave mix design method. The comparative analysis focused on the volumetric parameters, on the choice of the design particle size and, consequently, on the respective design asphalt binder contents of the studied asphalt mixtures. Regarding the particularities of the research, there were no significant differences in the design binder contents obtained using the two adopted methodologies for determining the maximum specific gravity. From a practical point of view, the adoption of any of the methods interfered little with the results of the application of the Superpave mix design method. This fact demonstrates a quality of this method since similar researches based on the Marshall design method evidences the sensitivity of the protocol for determining the asphalt binder content in relation to the used type of maximum specific gravity.

Microbiology and chemical engineering-new possibilities for interdisciplinary cooperation in the development of small anaerobic wastewater treatment plants

2000 ◽  
Vol 41 (1) ◽  
pp. 17-20 ◽  
Author(s):  
M. Kozariszczuk ◽  
W. Wenzel ◽  
M. Kraume ◽  
U. Szewzyk
Keyword(s):  
Waste Water ◽  
Chemical Engineering ◽  
Wastewater Treatment Plants ◽  
Waste Water Treatment ◽  
Fixed Bed ◽  
Interdisciplinary Cooperation ◽  
Reactor Performance ◽  
Fixed Bed Reactors ◽  
Microbiological Methods ◽  
Microbiological Parameters

Anaerobic degradation of waste water in fixed bed reactors is investigated using molasses as an example of complex composed waste water. The results of differently sized rectors are shown to be transferable and can be used for the design of small waste water treatment plants. The assessment of the reactor performance is done not only by material balances but also by applying microbiological parameters. Modern microbiological methods enable the incorporation of biological parameters into reactor design and process control. The results of these measurements lead to a better understanding of the correlation between changing process parameters and the state of the microbial population. Thus new tools are available to maintain stable and save anaerobic processes.

Microfiltration Used as a Means of Disinfection Downstream: A Bacterial Treatment Stage on Fixed-Bed Bacteria

1993 ◽  
Vol 27 (7-8) ◽  
pp. 19-27 ◽  
Author(s):  
B. Langlais ◽  
Ph. Denis ◽  
S. Triballeau ◽  
M. Faivre ◽  
M. M. Bourbigot
Keyword(s):  
Fixed Bed ◽  
Suspended Solid ◽  
Poor Quality ◽  
Operating Conditions ◽  
Secondary Effluent ◽  
Effluent Quality ◽  
Filtration Cycle ◽  
Highly Sensitive ◽  
Bacterial Treatment

Conventional methods of disinfecting sewage are all highly sensitive to variations in the effluent quality upstream of the disinfection stage. Microfiltration was tested as a tertiary treatment downstream of biofiltration, simulating very poor biofilter efficiency, to test the limits of the microfiltration process. Despite the poor quality of the secondary effluent (COD between 100 and 400 mgO2/l, BOD5 between 30 and 150 mgO2/l and suspended solid concentrations between 15 and 90 mg/l), the microfiltration process (filtration level : 0.2 µm) eliminated all faecal germs and tenia and ascaris eggs. The total elimination of free amoeba cysts still needs to be confirmed. With the COD and BOD5 reduced by an average of 60 and 70% respectively, the effluent quality is equivalent to level e after microfiltration (COD: 90 mgO2/l and BOD5 = 30 mgO2/l on samples averaged over 24 hours). Turbidity, measured instead of suspended solids at outlet from the microfilter, was 99 % eliminated. The colour remained between 50 and 150 mg Pt.Co/l. Under the operating conditions applied, the minimum filtration cycle was 72 hours for a minimum permeate flow of 80 1/h/m2 of membrane. When microfiltration process was used to treat a secondary effluent of good quality (COD between 14 and 40 mg/l; turbidity between 1.4 and 5.1 NTU) the germ elimination remained the same; the COD removal (31 % average elimination) allowed us to get an effluent with an average COD concentration of 24 mgO2/l. The filtration cycle was much longer (300 hours).

scholarly journals Novel Multiplicity and Stability Criteria for Non-Isothermal Fixed-Bed Reactors

2021 ◽  
Vol 8 ◽  
Author(s):  
Jens Bremer ◽  
Kai Sundmacher
Keyword(s):  
Exothermic Reaction ◽  
Fixed Bed ◽  
Operating Conditions ◽  
Continuous Stirred Tank Reactor ◽  
Stability Criteria ◽  
Fixed Bed Reactors ◽  
Continuous Stirred Tank ◽  
Back Mixing ◽  
State Multiplicity ◽  
New Criteria

With the increasing need to utilize carbon dioxide, fixed-bed reactors for catalytic hydrogenation will become a decisive element for modern chemicals and energy carrier production. In this context, the resilience and flexibility to changing operating conditions become major objectives for the design and operation of real industrial-scale reactors. Therefore steady-state multiplicity and stability are essential measures, but so far, their quantification is primarily accessible for ideal reactor concepts with zero or infinite back-mixing. Based on a continuous stirred tank reactor cascade modeling approach, this work derives novel criteria for stability, multiplicity, and uniqueness applicable to real reactors with finite back-mixing. Furthermore, the connection to other reactor features such as runaway and parametric sensitivity is demonstrated and exemplified for CO2 methanation under realistic conditions. The new criteria indicate that thermo-kinetic multiplicities induced by back-mixing remain relevant even for high Bodenstein numbers. In consequence, generally accepted back-mixing criteria (e.g., Mears’ criterion) appear insufficient for real non-isothermal reactors. The criteria derived in this work are applicable to any exothermic reaction and reactors at any scale. Ignoring uniqueness and multiplicity would disregard a broad operating range and thus a substantial potential for reactor resilience and flexibility.

Sign in / Sign up

Export Citation Format

Share Document