Application of the Marais - Ekama Activated Sludge Model to Large Plants

1982 ◽  
Vol 14 (6-7) ◽  
pp. 581-598 ◽  
Author(s):  
H A Nicholls
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Activated Sludge ◽  
Large Scale ◽  
Unsteady State ◽  
Activated Sludge Model ◽  
Nitrate Concentrations ◽  
Utilisation Rate ◽  
Oxygen Utilisation ◽  
State Responses

The Marais-Ekama model was used to successfully predict the performance of two 50 000 m3/d five-stage nutrient removing activated sludge plants. The experimental data used to test the model was obtained by monitoring the feed, effluent and contents of each reactor in the process, every two hours for 4 days. In addition, a respirometer was developed to measure the oxygen utilisation rate automatically every 30 minutes. All data collected was found to be valid, as acceptable COD and nitrogen balances across the plants were possible. The data was then compared with the steady state and unsteady state responses of the model. It was found that the model could successfully predict the COD, TKN, Ammonia and nitrate concentrations in the effluent and illustrate some shortcomings in the process layouts. This indicated that the model could be used by designers and operators of large-scale plants to predict performance and highlight problem areas.

Interpretation of Experimental Data with Regard to the Activated Sludge Model No.1 and Calibration of the Model for Municipal Wastewater Treatment Plants

1992 ◽  
Vol 25 (6) ◽  
pp. 167-183 ◽  
Author(s):  
H. Siegrist ◽  
M. Tschui
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Municipal Wastewater Treatment ◽  
Activated Sludge Model

The wastewater of the municipal treatment plants Zürich-Werdhölzli (350000 population equivalents), Zürich-Glatt (110000), and Wattwil (20000) have been characterized with regard to the activated sludge model Nr.1 of the IAWPRC task group. Zürich-Glatt and Wattwil are partly nitrifying treatment plants and Zürich-Werdhölzli is fully nitrifying. The mixing characteristics of the aeration tanks at Werdhölzli and Glatt were determined with sodium bromide as a tracer. The experimental data were used to calibrate hydrolysis, heterotrophic growth and nitrification. Problems arising by calibrating hydrolysis of the paniculate material and by measuring oxygen consumption of heterotrophic and nitrifying microorganisms are discussed. For hydrolysis the experimental data indicate first-order kinetics. For nitrification a maximum growth rate of 0.40±0.07 d−1, corresponding to an observed growth rate of 0.26±0.04 d−1 was calculated at 10°C. The half velocity constant found for 12 and 20°C was 2 mg NH4-N/l. The calibrated model was verified with experimental dam of me Zürich-Werdhölzli treatment plant during ammonia shock load.

Interaction of Rim Seal and Main Annulus Flow in a Low-Speed Turbine Rig

2013 ◽  
Author(s):  
Jesus Pueblas ◽  
Roque Corral ◽  
Sebastian Schrewe
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Large Scale ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Main Stream ◽  
Unsteady State ◽  
Cooling Flow ◽  
Low Pressure Turbine ◽  
Annulus Flow

The influence of the sealing flows on the secondary flows of a low-pressure turbine has been assessed numerically using multi-row steady and unsteady simulations. The experimental data obtained at the Large Scale Turbine Rig (LSTR) at Technische Universität Darmstadt have been used to validate the numerical method and complement the simulations. Steady and unsteady state solutions and experiments are compared to understand the importance of the unsteadiness in the accuracy of numerical simulations. It is concluded that unsteady rotor/stator simulations enhance the prediction of the stator secondary flows, especially in the tip region. The effect of the sealing air is analysed, varying the cooling mass flow for two operating conditions. The penetration of the sealing flow in the main stream increases withthe cooling flow, displacing the horseshoe and passage vortices towards the mid-span.

Modelling of full-scale wastewater treatment plants with different treatment processes using the Activated Sludge Model no. 3

2001 ◽  
Vol 44 (1) ◽  
pp. 49-56 ◽  
Author(s):  
M. Wichern ◽  
F. Obenaus ◽  
P. Wulf ◽  
K.-H. Rosenwinkel
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Phosphorus Removal ◽  
Large Scale ◽  
Wastewater Treatment Plants ◽  
Biological Phosphorus Removal ◽  
Activated Sludge Model ◽  
Treatment Processes ◽  
Biological Phosphorus ◽  
P Removal

In 1999 the Activated Sludge Model no. 3 (ASM 3) by the IWA task Group on Mathematical Modeling for Design and Operation of Biological Wastewater Treatment was presented. The model is used for simulation of nitrogen removal. On the basis of a new calibration of the ASM 3 with the easy degradable COD measured by respiration simulation runs of this paper have been done. In 2000 a biological phosphorus removal module by the EAWAG was added to the calibrated version of ASM 3 and is now serving the current requirements for modelling the enhanced biological P-removal. Only little experiences with different load situations of large-scale wastewater treatment plants were made with both new models so far. This article reports the experiences with the simulation and calibration of the biological parameters using ASM 3 and the EAWAG BioP Module. Three different large-scale wastewater treatment plants in Germany with different treatment systems will be discussed (Koblenz: pre-denitrification; Hildesheim: simultaneous denitrification with EBPR; Duderstadt: intermediate denitrification with EBPR). Informations regarding the choice of kinetic and stoichiometric parameters will be given.

Evaluation of the General Activated Sludge Model Proposed by the IAWPRC Task Group

1986 ◽  
Vol 18 (6) ◽  
pp. 63-89 ◽  
Author(s):  
P. L. Dold ◽  
G v. R. Marais
Keyword(s):  
Experimental Data ◽  
Activated Sludge ◽  
Task Group ◽  
Group Model ◽  
Activated Sludge Model ◽  
Activated Sludge System ◽  
Wide Range

This paper reviews the antecedents to the general activated sludge model proposed by the IAWPRC Task Group on modelling of the activated sludge system. Modifications to the Group model are proposed and sets of experimental data from a wide range of single sludge systems are presented to validate the model.

Two-Dimensional Steady-State Analysis of Selected Wastewater State Variables Using ASM3

2021 ◽  
Vol 54 ◽  
pp. 176-186
Author(s):  
Nagwan G. Mostafa ◽  
Ahmed G. Radwan ◽  
Mona M. Galal
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Ammonia Nitrogen ◽  
State Variables ◽  
Steady State Analysis ◽  
Nitrogenous Compounds ◽  
Nitrate Concentrations ◽  
Nitrogen Concentrations ◽  
State Analysis

Performance of activated sludge wastewater treatment plants are mainly dependent on bacterial growth, which is limited by many factors. These factors include availability of suitable substrate, limiting nutrients, environmental conditions, and energy. In activated sludge model no. 3 (ASM3), constituents in wastewater are divided into two main categories: carbonaceous compounds and nitrogenous compounds, which are further subdivided depending on their solubility and biodegradability. These compounds are not mutually independent; hence, the fate of one compound in the biological processes is affected by one or more of the other compounds. In this study, a steady-state analysis was conducted to investigate the effect of initial readily biodegradable substrate, oxygen, ammonia nitrogen, nitrite plus nitrate, and heterotrophic organisms’ concentrations on the effluent concentrations of readily biodegradable COD and nitrogen compounds. The studied ranges of the selected wastewater state variables were identified based on literature surveys including previous studies concerning domestic, industrial, and synthetic wastewaters. The results proved that the effluent readily biodegradable substrate and ammonia nitrogen concentrations are reduced as the initial dissolved oxygen and nitrite plus nitrate concentrations are increased. Moreover, better nitrification-denitrification process is achieved at lower initial readily biodegradable concentration leading to lower nitrite plus nitrate concentrations.

scholarly journals Steady-State Methodology for Activated Sludge Model 1 (ASM1) State Variable Calculation in MBR

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3220
Author(s):  
Ameni Lahdhiri ◽  
Geoffroy Lesage ◽  
Ahmed Hannachi ◽  
Marc Heran
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Operating Parameters ◽  
State Variables ◽  
Activated Sludge Model ◽  
Carbon And Nitrogen ◽  
Conventional Activated Sludge ◽  
Analytical Expressions ◽  
Relevant Factors

The complexity of Activated Sludge Model No. 1 (ASM1) is one of the main obstacles slowing its widespread use, particularly among wastewater treatment plant (WWTP) professionals. In this paper, a simplification procedure based on steady-state mass balances is proposed for the conventional activated sludge process (ASP) configuration, consisting of an aerated bioreactor and a perfect settler (without particular compounds in the outlet). The results do, in fact, show perfect suitability to a membrane bioreactor process (MBR). Both organic carbon and nitrogen removal were investigated. The proposed approach was applied to ASM1, and simple analytical expressions of the state variables were obtained. These analytical expressions were then validated by comparison to simulations given by the original ASM1 (implemented in GPS-X software). A strong match (less than 4% of error overall) was obtained between both results in the steady-state; consequently, these analytical expressions may be useful as tools for quickly estimating the main state variables, feeding the filtration models, or identifying the interaction between operating parameters. Moreover, this enables a sensitivity analysis, covering relevant factors such as kinetics or operating parameters. For instance, the sludge retention time (SRT) effect is lower on XBH and XS at high SRT (˃20 days), while it is more pronounced on XP and XI as their variations with SRT are linear.

MODELING OXIDATION DITCHES USING THE IA WPRC ACTIVATED SLUDGE MODEL WITH HYDRODYNAMIC EFFECTS

1994 ◽  
Vol 30 (2) ◽  
pp. 185-192 ◽  
Author(s):  
Anastasios I. Stamou
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Flow Velocity ◽  
Dispersion Coefficient ◽  
Aerobic Oxidation ◽  
Model Parameters ◽  
Activated Sludge Model ◽  
Average Flow Velocity ◽  
Oxygen Requirements ◽  
Hydrodynamic Effects

A mathematical model is presented to predict the concentrations of the active heterotrophic biomass, the readily biodegradable substrate (soluble COD) and the dissolved oxygen (DO) in a completely aerobic oxidation ditch. The model involves the one-dimensional convection-dispersion equations for biomass, COD and DO. Hydrodynamic effects are represented in the model by the values of the average flow velocity and the dispersion coefficient. Biological processes are described in the model according to the IA WPRC activated sludge model, using typical values for the model parameters at 10°C. The equations are solved with the finite volume method. The application of the model leads to the following conclusions: (i) Steady state biomass concentrations are almost constant throughout the ditch. (ii) Steady state COD concentrations in the ditch are very low, and COD removal efficiency is practically independent of the values of the flow velocity and the dispersion coefficient. The distribution of the COD concentration in the ditch is less uniform, when small values of the dispersion coefficient are used. (iii) The distribution of the DO concentration in the ditch is very sensitive to the values of the flow velocity, the dispersion coefficient and to the capacity of the rotors. DO concentrations increase when the dispersion coefficient decreases or the flow velocity increases. (v) Daily sludge production, oxygen requirements and sludge age are calculated equal to 0.44 g (g COD removed)‒1, 0.56 g (g incoming COD)‒1 and 6.3 days, respectively.

scholarly journals Dynamics of particulate assemblages in metastable liquids: a test of theory with nucleation and growth kinetics

2020 ◽  
Vol 378 (2171) ◽  
pp. 20190245 ◽  
Author(s):  
Irina V. Alexandrova ◽  
Dmitri V. Alexandrov
Keyword(s):  
Experimental Data ◽  
Distribution Function ◽  
Steady State ◽  
Growth Rates ◽  
Fine Particles ◽  
Protein Crystallization ◽  
Growth Time ◽  
Nonlinear Behaviour ◽  
Unsteady State ◽  
State Growth

This manuscript is devoted to the nonlinear dynamics of particulate assemblages in metastable liquids, caused by various dynamical laws of crystal growth and nucleation kinetics. First of all, we compare the quasi-steady-state and unsteady-state growth rates of spherical crystals in supercooled and supersaturated liquids. It is demonstrated that the unsteady-state rates transform to the steady-state ones in a limiting case of fine particles. We show that the real crystals evolve slowly in a more actual case of unsteady-state growth laws. Various growth rates of particles are tested against experimental data in metastable liquids. It is demonstrated that the unsteady-state rates describe the nonlinear behaviour of experimental curves with increasing the growth time or supersaturation. Taking this into account, the crystal-size distribution function and metastability degree are analytically found and compared with experimental data on crystallization in inorganic and organic solutions. It is significant that the distribution function is shifted to smaller sizes of particles if we are dealing with the unsteady-state growth rates. In addition, a complete analytical solution constructed in a parametric form is simplified in the case of small fluctuations in particle growth rates. In this case, a desupercooling/desupersaturation law is derived in an explicit form. Special attention is devoted to the biomedical applications for insulin and protein crystallization. This article is part of the theme issue ‘Patterns in soft and biological matters’.

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