activated sludge model Articles

  • Guidelines for using activated sludge models

    Mathematical modelling of activated sludge systems is used widely for plant design, optimisation, training, controller design and research. The quality of simulation studies varies depending on the project objectives, finances and expertise available. Consideration has to be given to the model accuracy and the amount of time required carrying out a simulation study to produce the desired ...


    By IWA Publishing

  • Modeling organic nitrogen conversions in activated sludge bioreactors

    For biological nutrient removal (BNR) systems designed to maximize nitrogen removal, the effluent total nitrogen (TN) concentration may range from 2.0 to 4.0 g N/m3 with about 25–50% in the form of organic nitrogen (ON). In this study, current approaches to modeling organic N conversions (separate processes vs. constant contents of organic fractions) were compared. A new conceptual model of ON ...


    By IWA Publishing

  • Multicomponent activated sludge model for reactors in series with recycling

    Multicomponent models containing both substrate and biomass have an advantage over conventional models in seeking better understanding of activated sludge systems. Such models are also useful in the characterisation of wastewater. Studies in recent years have shown that most of the soluble organic matter in the effluent of treatment systems consists of soluble microbial products that arise during ...


    By Inderscience Publishers

  • A systematic approach for model verification: application on seven published activated sludge models

    The quality of simulation results can be significantly affected by errors in the published model (typing, inconsistencies, gaps or conceptual errors) and/or in the underlying numerical model description. Seven of the most commonly used activated sludge models have been investigated to point out the typing errors, inconsistencies and gaps in the model publications: ASM1; ASM2d; ASM3; ASM3 + Bio-P; ...


    By IWA Publishing

  • A comparison of biodegradation kinetic models applied to estrogen removal with nitrifying activated sludge

    The biological degradation of estrone (E1), estradiol (E2) and ethinylestradiol (EE2) was studied in batch experiments at typical concentration levels using nitrifying activated sludge from a membrane bioreactor (MBR). Since first-order, pseudo first-order and Monod-type kinetics were observed. Pseudo first order kinetic was reformulated using only the soluble concentrations S and assuming ...


    By IWA Publishing

  • Virus elimination in activated sludge systems: from batch tests to mathematical modeling

    A virus tool based on Activated Sludge Model No. 3 for modeling virus elimination in activated sludge systems was developed and calibrated with the results from laboratory-scale batch tests and from measurements in a municipal wastewater treatment plant (WWTP). The somatic coliphages were used as an indicator for human pathogenic enteric viruses. The extended model was used to simulate the virus ...


    By IWA Publishing

  • The application of model predictive control of ammonia nitrogen in an activated sludge process

    In this paper a model predictive controller (MPC) for ammonia nitrogen is presented and evaluated in a real activated sludge process. A reduced nonlinear mathematical model based on mass balances is used to model the ammonia nitrogen in the activated sludge plant. An MPC algorithm that minimises only the control error at the end of the prediction interval is applied. The results of the ammonia ...


    By IWA Publishing

  • Integrating activated sludge floc size information in MBR fouling modeling

    Although studied extensively, modeling fouling phenomena in membrane bioreactors (MBRs) remains challenging. It has been well established that cake layer formation and pore blocking have a strong impact on the filtration performance but how to capture that in comprehensive models is not fully defined yet. Since it has been shown that bioflocculation characteristics of activated sludge have a ...


    By IWA Publishing

  • Improving activated sludge classification based on imbalanced data

    A fast and accurate classification method for sewage sludge biological activity classification is of great significance for wastewater treatment. However, the data are often imbalanced and the accuracy of traditional classification algorithms applied to imbalanced small classes of data is very low. Such small classes are crucial application data. Therefore, based on the analysis of eight ...


    By IWA Publishing

  • The Dangers of Uncalibrated Activated Sludge Simulation Packages

    ABSTRACTActivated sludge simulation packages are useful tools, but it can be dangerous to rely on them ifthey are used incorrectly. How dangerous? To determine potential pitfalls, we compared theactivated sludge tank volumes predicted by three simulation packages used directly out-of-theboxwithout calibration. We sought to identify the underlying reason for differences in predictedrequired ...

  • Modeling Greenhouse Gas Emissions From Activated Sludge Processes

    Dynamic simulation of activated sludge process is a common tool for wastewater treatment design and optimization. Most activated sludge models predict only the uptake of BOD and nutrients, however, they can easily be supplemented with further information regarding greenhouse gas (GHG) production to predict the generation of components such as CO2. Many published anaerobic digestion models contain ...

  • Activated sludge modelling: development and potential use of a practical applications database

    This study aims at synthesizing experiences in the practical application of ASM type models. The information is made easily accessible to model users by creating a database of modelling projects. This database includes answers to a questionnaire that was sent out to model users in 2008 to provide inputs for a Scientific and Technical Report of the IWA Task Group on Good Modelling Practice – ...


    By IWA Publishing

  • Spreadsheet Implementation of Activated Sludge Model #1 for Sequencing Batch Reactors

     KEYWORDS Sequencing Batch Reactor, Simulation Modeling, ASM1, Flow Routing BACKGROUND Many small municipal wastewater treatment plants in North America use sequencing batch reactors (SBR) to provide secondary treatment. SBRs are a fill-and-draw variant of the activated sludge process in which a single reactor is used to mix raw ...

  • Operational cost optimization modeling for conventional activated sludge process

    Energy and solids processing cost accounts for 40% of the total operation and maintenance costs in wastewater treatment facilities. This indicates the potential for saving operation and maintenance costs through the process optimization. The limitations of most cost optimization studies carried out in the past are either these studies could not be applied to existing facilities as the objective ...

  • Simulation Of Simultaneous Nitrification-Denitrification Using Activated Sludge Model No. 1

    The operation of biological wastewater treatment systems performing simultaneous nitrificationdenitrification (SND) was simulated using Activated Sludge Model No. 1 (ASM1). Properties and parameters typical of domestic sewage were used in the simulations. System performance was simulated under a range of conditions to identify an appropriate operating window for the process. Simulation results ...

  • A comparison of biodegradation kinetic models applied to estrogen removal with nitrifying activated sludge

    The biological degradation of estrone (E1), estradiol (E2) and ethinylestradiol (EE2) was studied in batch experiments at typical concentration levels using nitrifying activated sludge from a membrane bioreactor (MBR). Since first-order, pseudo first-order and Monod-type kinetics were observed. Pseudo first order kinetic was reformulated using only the soluble concentrations S and assuming ...


    By IWA Publishing

  • Modeling of organic substrate transformation in the high-rate activated sludge process

    This study describes the development of a modified activated sludge model No.1 framework to describe the organic substrate transformation in the high-rate activated sludge (HRAS) process. New process mechanisms for dual soluble substrate utilization, production of extracellular polymeric substances (EPS), absorption of soluble substrate (storage), and adsorption of colloidal substrate were ...


    By IWA Publishing

  • Model assisted startup of anaerobic digesters fed with thermally hydrolysed activated sludge

    This paper presents the use of the IWA ADM1 to predict and interpret results from two full-scale anaerobic digesters fed with thermal hyrolysate (waste activated sludge with a long upstream sludge age) from a Cambi hydrolysis process operating at 165°C and 6 bar-g. The first digester was fed conventionally—though intermittently, while the second was heavily diluted through a substantial component ...


    By IWA Publishing

  • Influence of reactor configuration on reliability of activated sludge process

    The effect of uncertainty in system parameters and the accuracy of the mathematical model used on the design and reliability of the activated sludge process is investigated by Monte Carlo simulations. Simulations indicate that the coefficient of variation for a reactor volume varies from 0.56 for a single mixed tank reactor to 0.44 for a plug flow reactor. The coefficient of variation for ...


    By Inderscience Publishers

  • Complete solids retention activated sludge process

    In a slaughterhouse's full-scale extended aeration activated sludge wastewater treatment plant (WWTP), operating under complete solids retention time, the evolution of mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) concentration, food to micro-organisms ratio (F/M) and substrate utilization rate (SUR) were studied for over a year. Biomass growth phases ...


    By IWA Publishing

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