Activated Sludge Process

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H N Chang - One of the best experts on this subject based on the ideXlab platform.

  • steady state analysis of the coupling aerator and secondary settling tank in Activated Sludge Process
    Water Research, 1996
    Co-Authors: H N Chang
    Abstract:

    Abstract The steady state analysis of coupling the function of aerator and secondary settling tank in Activated Sludge Process for wastewater treatment is carried out to obtain appropriate responses of output variables and to decide optimum operating parameters. To consider the effect of the secondary settling tank, limit flux theory is applied and the aerator is assumed to be a continuous flow stirred tank reactor. By using Sludge recycle ratio and Sludge waste ratio as the operating parameters, the responses of the output variables—biomass concentration in aerator, dissolved pollutant and solid concentration in effluent—are represented as response surfaces and isoresponse curves. Acceptable operating zone can be obtained from the curves and optimum parameters can be determined. Coupling the function of aerator and secondary settling tank is important to consider the appropriate control of an Activated Sludge Process.

Yu Liu - One of the best experts on this subject based on the ideXlab platform.

  • Chemically reduced excess Sludge production in the Activated Sludge Process.
    Chemosphere, 2003
    Co-Authors: Yu Liu
    Abstract:

    Abstract Excess Sludge production from wastewater biological treatment Process is highly, and the disposal of excess Sludge will be forbidden in a near future, thus increased attention has been turned to look into potential technology for Sludge reduction. Recently, some novel Sludge reduction techniques have been developed based on chemical oxidation and metabolic uncoupling. This paper attempts to review those chemical-assisted Sludge reduction Processes, including Sludge alkaline–thermal treatment, Activated Sludge-ozonation Process, chlorination-combined Activated Sludge Process, Sludge reduction by metabolic uncouplers and high dissolved oxygen Activated Sludge Process. In these combined Activated Sludge Processes, excess Sludge production can be reduced up to 100% without significant effect on Process efficiency and stability. This paper would be useful when one is looking for appropriate environmentally and economically acceptable solutions for reducing or minimizing excess Sludge production from wastewater biological treatment Process.

  • strategy for minimization of excess Sludge production from the Activated Sludge Process
    Biotechnology Advances, 2001
    Co-Authors: Yu Liu, Joohwa Tay
    Abstract:

    Increased attention has been given to minimization of Sludge production from Activated Sludge Process since environmental regulations are being more and more stringent in relation to excess Sludge disposal. In a biological Process, the more organic carbon utilized in carbon dioxide production, the fewer Sludge produced, and vice versa. This paper, therefore, reviews strategies developed for minimization of excess Sludge production, such as oxic-settling-anaerobic Process, high dissolved oxygen Process, uncoupler-containing Activated Sludge Process, ozonation-combined Activated Sludge Process, control of Sludge retention time and biodegradation of Sludge in membrane-assisted reactor. In these modified Activated Sludge Processes, excess Sludge production can be reduced by 20-100% without significant effect on Process efficiency and stability. It is expected that this paper would be helpful for researchers and engineers to develop novel and efficient operation strategy to minimize Sludge production from biological systems.

Henri Spanjers - One of the best experts on this subject based on the ideXlab platform.

  • respirometry in control of the Activated Sludge Process benchmarking control strategies
    Water intelligence online, 2015
    Co-Authors: J B Copp, Henri Spanjers, Peter A Vanrolleghem
    Abstract:

    The respiration rate of Activated Sludge has generated much interest, because it is an essential variable in the Activated Sludge Process and provides information on biomass activity and concentration of waste components. Recognising the need for an extensive evaluation of respirometry in control of the Activated Sludge Process, IWA published Scientific and Technical Report (STR7): Respirometry in Control of the Activated Sludge Process: Principles, which included the biological background, measuring principles, measured and deduced variables, an introduction to control system principles and an overview of proposed and applied control strategies. To complete the work, a second STR: Respirometry in Control of the Activated Sludge Process: Benchmarking Control Strategies was commissioned and, through the generous support of 14 corporate sponsors, a well-defined project was set up with the aim to accomplish an ambitious mission: the development of a simulation protocol (known as the "IWA Simulation Benchmark") and the unbiased evaluation of many respirometry-based control strategies. This Report includes a complete description of the simulation protocol including model plants, simulation procedures and evaluation criteria. Also included in this STR is an overview of the strategy evaluations and a look into the future of respirometry as the basis for control. Finally, to ease the transition from paper to computer, and increase the application of the IWA Simulation Benchmark, a CD is included with many benchmark files and control strategy layouts generated using a variety of simulation platforms including GPS-XTM, STOATTM and WESTTM. This Report will be an invaluable source of information for practitioners and consultants dealing with the operation and control of Activated Sludge Processes, developers of control systems, control software and simulation software, and manufacturers of respirometers and other environmental instruments in all industries dealing with toxic wastes. Scientific and Technical Report No. 11 Also available: Respiromentry in Control of the Activated Sludge Process: Principles

  • Respirometry in Control of the Activated Sludge Process: Principles
    Water intelligence online, 2015
    Co-Authors: J B Copp, Henri Spanjers, Peter A Vanrolleghem
    Abstract:

    The respiration rate of Activated Sludge has generated much interest, because it is an essential variable in the Activated Sludge Process and provides information on biomass activity and concentration of waste components. Recognising the need for an extensive evaluation of respirometry in control of the Activated Sludge Process, IWA published Scientific and Technical Report (STR7): Respirometry in Control of the Activated Sludge Process: Principles, which included the biological background, measuring principles, measured and deduced variables, an introduction to control system principles and an overview of proposed and applied control strategies. To complete the work, a second STR: Respirometry in Control of the Activated Sludge Process: Benchmarking Control Strategies was commissioned and, through the generous support of 14 corporate sponsors, a well-defined project was set up with the aim to accomplish an ambitious mission: the development of a simulation protocol (known as the ‘IWA Simulation Benchmark’) and the unbiased evaluation of many respirometry-based control strategies. This Report includes a complete description of the simulation protocol including model plants, simulation procedures and evaluation criteria. Also included in this STR is an overview of the strategy evaluations and a look into the future of respirometry as the basis for control. Finally, to ease the transition from paper to computer, and increase the application of the IWA Simulation Benchmark, a CD is included with many benchmark files and control strategy layouts generated using a variety of simulation platforms including GPS-X, STOAT and WEST®. This Report will be an invaluable source of information for practitioners and consultants dealing with the operation and control of Activated Sludge Processes, developers of control systems, control software and simulation software, and manufacturers of respirometers and other environmental instruments in all industries dealing with toxic wastes. This title belongs to Scientific and Technical Report Series ISBN: 9781900222044 (Print) ISBN: 9781780402611 (eBook)

  • Identification and quantification of nitrogen nutrient deficiency in the Activated Sludge Process using respirometry
    Water Research, 2000
    Co-Authors: Z. Ning, Gilles G. Patry, Henri Spanjers
    Abstract:

    Experimental protocols to identify and quantify nitrogen nutrient deficiency in the Activated Sludge Process were developed and tested using respirometry. Respirometric experiments showed that when a nitrogen nutrient deficient Sludge is exposed to ammonia nitrogen, the oxygen uptake rate (OUR) of the Sludge increases while an initial nitrogen nutrient uptake takes place at the same time. Our investigation suggests that this initial nitrogen uptake is metabolically mediated. The protocols developed in this study can be used: (a) to assess whether a Sludge sample is nitrogen nutrient deficient or not; and (b) to estimate the amount of nitrogen required to remedy a nutrient deficient condition in the Sludge. Finally, a respirometry-based strategy to control nutrient addition to the Activated Sludge Process is proposed.

  • Respirometry in control of the Activated Sludge Process
    Water Science and Technology, 1999
    Co-Authors: Henri Spanjers, Peter A Vanrolleghem, Gustaf Olsson, Peter Dold
    Abstract:

    This paper summarises progress of the IAWQ Task Group developing the Scientific and Technical Report (STR) on respirometry in control of the Activated Sludge Process. The significance of respirometry in Activated Sludge systems is explained from a biochemical background. A classification is proposed which includes all respirometric measuring principles described in the literature. The different respiration rates that can be measured are reviewed and some variables that can be deduced from respiration rate are discussed. Some elementary control concepts will be provided that are necessary for the evaluation of respirometry-based control strategies. Finally, a number of respirometry-based control strategies will be classified and discussed.

  • Respirometry in Control of the Activated Sludge Process: Principles
    1998
    Co-Authors: Henri Spanjers, Peter A Vanrolleghem, Gustaf Olsson, Peter Dold
    Abstract:

    The report describes the principles of measurement of respiration rate, the transformation of measurement data into other types of information, and the application of the obtained information in Process control strategies. Some fundamental concepts on biological respiration and Process control are provided to assist the reader with understanding the principles. A structured overview comprises some eighty control strategies in which respirometry plays a role. An extensive literature list of over 500 references is included and classified into themes. Contents: * Fundamentals of respiration; * Measuring principles; * Measured and deduced variables ; * Elementary control concepts; * Respirometry in control of the Activated Sludge Process; * Summary and perspectives

M. Kümmel - One of the best experts on this subject based on the ideXlab platform.

  • State and parameter estimation for phosphorus removal in an alternating Activated Sludge Process
    Journal of Process Control, 1995
    Co-Authors: Hong Zhao, M. Kümmel
    Abstract:

    Abstract Biological phosphorus removal involved in the advanced Activated Sludge Process requires more efficient on-line monitoring and Process control. However, the substantial complexity of the Process behaviour and the limited availability of reliable on-line measurement challenge the application of advanced Process control techniques. This paper presents an application of state and parameter estimation techniques in an altering Activated Sludge Process with regard to biological phosphorus removal. A simplified model describing the phosphorus dynamics in an alternating Activated Sludge Process is proposed based on insight into the Process with a mechanistic Activated Sludge model. State and parameter estimation problems relating to the non-measurable dynamics of a most important limiting substrate poly-hydroxy-alkanoate (PHA) are formulated and discussed. Several schemes are presented which involve a state estimator designed with the extended Kalman filter algorithm, two specific parameter estimation procedures and an adaptive scheme for simultaneous state and parameter estimation. All these schemes are oriented to practical application and therefore some techniques dealing with the implementation are also provided. Simulations and experimental demonstrations are presented which illustrate the performance of these procedures and schemes.

Mitsumasa Okada - One of the best experts on this subject based on the ideXlab platform.

  • Effect of HRT and MLSS on THM precursor removal in the Activated Sludge Process
    Water Research, 1999
    Co-Authors: Ritchelita P. Galapate, Elly Agustiani, Aloysius U. Baes, Kazuaki Ito, Mitsumasa Okada
    Abstract:

    Abstract This study was conducted to evaluate the effect of hydraulic retention time (HRT) and mixed liquor suspended solids (MLSS) on trihalomethane (THM) precursor removal in the Activated Sludge Process and to determine the effect of chemical properties of the organic components on trihalomethane formation potential (THMFP). A laboratory-scale reactor for the Activated Sludge Process was used with synthetic domestic wastewater as influent. Experimental conditions, HRT and MLSS, were varied and the effluents were evaluated in terms of DOC and THMFP. Hydrophilicity, hydrophobicity and chemical functional groups were analyzed to determine the chemical parameters that may affect THMFP. Optimum removal of THMFP was achieved at HRT 24 h and at MLSS of ca. 2500 mg l −1 . Due to the organic metabolites produced in the Activated Sludge floc, better DOC or THMFP removal was not observed at longer HRTs and larger MLSS. Decrease in DOC did not result in comparable removal of THMFP. This was attributed to two factors: the higher reactivity of the hydrophobic organic carbon (18.5  μ g THMFP mg −1 C) compared to the hydrophilic organic carbon (6.2  μ g THMFP mg −1 C) and the nonremoval of the remaining hydrophobic THM precursors in HRTs longer than 8 h. The Activated Sludge Process preferentially removed the hydrophilic organic substances which was shown to have less potential to form THM. The Activated Sludge Process effluents exhibited similar chemical characteristics compared with various types of treated industrial wastewaters determined in a previous study. The Activated Sludge Process effluents contained larger amounts of the hydrophilic organic substances compared to the hydrophobic fractions. Larger amounts of the carboxylic and phenolic-OH functional groups were determined in the hydrophilic fractions than in the hydrophobic fractions. The equation obtained for THMFP prediction based on bulk parameters and specific functional groups of the treated industrial wastewaters was also found to be applicable on the Activated Sludge Process effluents. The equation suggests that bulk THMFP was influenced by UV 260 and organic nitrogen of both the hydrophilic and the hydrophobic fractions, and phenolic-OH of the hydrophilic fractions.