Kinetic behavior of mixed populations of activated sludge

Abstract

SummaryThe 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 a t 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 based on the Monod model with anThe 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 p, were high a t high dilution rates and low a t low dilution rates. It was also found that only those batch growth parameters from cells obtained a t 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 predominated 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.

Determination of biokinetic coefficients of an immersed membrane bioreactor

“…Chiu et al [47] have described the continuous culture process as a competitive process, which results in the enrichment of bacterial species at a particular SRT. Those species with higher values of specific growth rate (µ) appeared to be predominant at lower SRT values, while those having lower value of µ were enriched in the system only at high SRT values.…”

The influence of the term Kd for endogenous metabolism on the evaluation of monod kinetics for biotechnological processes

“…In predicting the behavior of the process, mathematic models, together with carefully designed experiments, make it possible to evaluate the behavior of a system more rapidly than with laboratory experiments only. Many papers deal with the kinetic behavior of heterogenous microbial populations of activated sludge processes (Chiu et al, 1972a) (Chiu et al, 1972b) (Gaudy & Gaudy, 1972). Chiu et al, (1972a) showed for instance that kinetic equations including a term k d for endogenous metabolism can better describe the behavior of activated sludge processes than equations without such a term.…”

“…Many papers deal with the kinetic behavior of heterogenous microbial populations of activated sludge processes (Chiu et al, 1972a) (Chiu et al, 1972b) (Gaudy & Gaudy, 1972). Chiu et al, (1972a) showed for instance that kinetic equations including a term k d for endogenous metabolism can better describe the behavior of activated sludge processes than equations without such a term. The purpose of this paper is to present a quantitative simulation of the Monod model Dedicated to Prof.H.Grubitsch on the celebration of his seventieth birthday.…”

ATP pools in activated sludge

“…This approach has been employed both in marine biological and waste water studies (Berland et al, 1972;Brezonik and Patterson, 1971;Holm-Hansen, 1969). Changes in the size of the ATP pool have also been determined in activated sludge in a continuous culture model system with defined growth media (Chiu et al, 1973) or sterilized waste water (Weddle & Abbreviations: COD, chemical oxygen demand. Jenkins, 1971).…”