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Kinetic behavior of mixed populations of activated sludge
Author(s) -
Chiu S. Y.,
Fan L. T.,
Kao I. C.,
Erickson L. E.
Publication year - 1972
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260140204
Subject(s) - dilution , steady state (chemistry) , aeration , population , chemistry , kinetics , isothermal process , chromatography , thermodynamics , physics , demography , organic chemistry , quantum mechanics , sociology
The kinetic behavior of heterogeneous microbial populations of sewage origin was studied in a single‐stage isothermal continuous flow completely mixed aeration tank. A series of experiments were carried out at various dilution rates using glucose as the growth limiting substrate. The steady‐state behavior of the system was observed at each dilution rate and the results were found to fit fairly well with the steady‐state equation bayed on the Monod model with an endogenous respiration term included, i.e., μ = μ m S /( K s + S ) − K d . The growth kinetics of cells harvested at steady state for each dilution rate were studied using batch experiments. The multiple response data of the system as functions of time were used to estimate the parameter values in the above kinetic model. It was found that values of the growth parameters changed significantly and systematically with cell population. For example, values of μ m were high at high dilution rates and low at low dilution rates. It was also found that only those batch growth parameters from cells obtained at fairly high dilution rates are comparable with those estimated by the results of steady‐state operations. The results of this investigation suggest that (1) different cell populations pre dominated at different steady‐state dilution rates, with high dilution rates resulting in predominantly fast‐growing organisms and low dilution rates resulting in predominantly slow‐growing cells, and (2) risk exists in any randomly picked batch experiment to predict the steady‐state behavior of the system when heterogeneous microbial populations must be used.