Kinetics of aerobic sludge stabilization

Benedek, P.; Farkas, Péter; Literathy, P.

doi:10.1016/0043-1354(72)90176-5

Cited by 28 publications

(10 citation statements)

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“…For the thickener in the system considered here, the solids loading rate to the thickener is equal to P , and the zone settling velocity coefficients for thickening are considered to be numerically equal to the corresponding coefficients for the activated sludge (es. ( 8 ) ) .…”

Section: Gravity Thickenermentioning

confidence: 93%

“…The following equation describes the relationship between zone settling velocity and concentration for activated U = Uoexp ( -k , X ) (8) in which U = zone settling velocity of a slurry a t concentration X , L/T; and, Uo and K , are empirically derived coefficients, L/T and…”

Section: Final Settling Tankmentioning

confidence: 99%

“…(16) and (17) ; and, 3) settling data to evaluate the coefficients Uo and k , of eq. (8). Numerical values of coefficiefits for aerobic digestion appear in the literature.s Values for vacuum filter loading and aeration equipment transfer efficiency are usually available from vendors.…”

Section: Process Data Requirementsmentioning

confidence: 99%

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Cost optimization of activated sludge systems

Middleton¹,

Lawrence²

1974

Biotech & Bioengineering

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SummaryActivated sludge is a widely used aerobic biological waste-water treatment process. A rational approach to least cost design of an integrated system is described which includes the following processes : activated sludge reactor, find settling tanks, gravity thickening, and aerobic sludge digestion. Both capital and operation and maintenance costs are considered. Biological reactor design is based on microbial kinetic concepts and continuous culture of microorganisms theory. Biological solids retention time (8,) is utilized as the primary independent design variable to which system performance is related, e.g., effluent quality, ammonia oxidation, and excess sludge production. Liquid-biomass separation is based on the batch flux technique, a rational approach to design of gravity separators (final settling tanks). Trade-offs among reactor volume, clarifier size, recycle pumping capacity, thickener capacity, digester volume, air requirements, and sludge production are discussed. The optimum design is taken as the combination of these parameters within the acceptable design domain, determined by effluent quality criteria, that results in minimum cost. While the method described is general, design of a given treatment system depends on availability, from lab or pilot studies, of system specific numerical values for biological growth coefficients and biomass setting characteristics. A design example illustrates the approach.

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Section: Gravity Thickenermentioning

confidence: 93%

Section: Final Settling Tankmentioning

confidence: 99%

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Cost optimization of activated sludge systems

Middleton¹,

Lawrence²

1974

Biotech & Bioengineering

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“…Due to the use of a daily fill-and-draw flow scheme, the resultant operating system has been termed semi-continuous or semi-batch, both of which are equally applicable; this system is not directly comparable to the classic digester flow schemes described by Benedek et al (2). For this reason, in any assessment of digestion efficiency by an analysis of the rate of mass reduction, the inherent characteristics of the flow scheme in use must be accounted for before the results of the assessment are of any value.…”

Section: Derivation Of Endogenous Decay Coefficientsmentioning

confidence: 98%

“…Benedek et al (2) suggested that this reaction only holds for the batch or plugflow reactor configurations, and if a continuousfeed, completely mixed reactor is used, equation (ii) would have to be modified through a mass balance of solids around the system. The expression of mass reduction would then become:…”

Section: Introductionmentioning

confidence: 99%

Assessment and application of kinetic reaction rates in pilot‐scale semi‐continuous aerobic sludge digestion

Anderson

Mavinic

1992

Environmental Technology

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The aerobic digestion of two different waste activated sludges was examined using a semicontinuous flow scheme and variable raw sludge loading rates. Due to daily perturbations of the system, resulting from sludge withdrawal/addition, the analysis of kinetic decay rates required a modification of the classic methodology, which could account for these external sources of variability in process performance analysis. The resultant kinetic decay coefficients reflected this operational variability, due both to observable and unobservable sources; at the same time, these values were able to describe the dynamic biological processes of the aerobic digester, and reflect the trends seen in volatile mass reduction. It was proposed that these values could subsequently be used in a valid analysis of temperature sensitivity within the digester, such that temperature ranges to be targeted for economical digester performance enhancement could be easily selected.Keywords: aerobic sludge digestion, semi-continuous operation, process variability, kinetic decay rates, Arrhenius temperature sensitivity, mixed liquor pH control INTRODUCTION their approach, and it is generally believed that endogenous metabolism is responsible for the In the field of biological wastewater majority of the mass reduction taking place, treatment, a great deal of research effort has beenIn the aerobic digester, it is assumed that expended in the modelling of aerobic microbial exogenous organic substrates have been depleted, activity, as related to sludge mass accumulation and in order to maintain life functions under in the activated sludge process and the loss of starvation conditions, the sludge mass sludge mass in the aerobic digester. As yet, no organisms must rely on endogenous substrates, real consensus exists pertaining to the "correct" This can be expressed mathematically as: model for these reactions; this is not surprising, given the fact that the reduction of biological dM yi /•) material in the aerobic digester is a function of dt several separate and concurrent physical and biochemical reactions, such as endogenous or, upon integration: metabolism, predation/grazing by the larger zooplankton species, and cryptic growth. The ^_ ^t ^ ^M^ _ ^..ĉ omplexity of the interrelationships between M o these various processes in the aerobic digester, in essence, forces the modellers to simplify where M = quantity of active mass in the system,

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Biodegradability of swine effluents II. Kinetics of pollutants removal

Oliveira

Costa

Rodrigues

et al. 1985

Acta Biotechnologica

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Some aspects of the kinetics of bioremoval of pollutants during biodegradation of swine-breeding waste waters are studied and a biphasic model is proposed. The concentriction of nitrogen and phosphorus compounds during the process is followed. Follotving a previous contribution on the same subject, the aspects of dilution of those effluents are discussed, and it is proposed to treat raw efflucnts, in spite of tho reduction of possible biostatic actions. Dilution will be acceptable only if strong inhibitory effects are observed.

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Kinetics of aerobic sludge stabilization

Cited by 28 publications

References 1 publication

Cost optimization of activated sludge systems

Cost optimization of activated sludge systems

Assessment and application of kinetic reaction rates in pilot‐scale semi‐continuous aerobic sludge digestion

Biodegradability of swine effluents II. Kinetics of pollutants removal

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