Browsing by Author "Sun, Xiaoyan."

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Comparative study on substrate removal kinetics for continuous flow and sequencing batch reactors.
(University of Ottawa (Canada), 1993) Sun, Xiaoyan.; Drosete, R.,
This study has developed a new empirical substrate removal model for continuous flow stirred tank reactor (CFSTR) and sequencing batch reactor (SBR) systems. In this model, an exponential function of volatile suspended solids (VSS) was introduced to express active biomass in substrate utilization kinetics. The proposed empirical substrate removal model is expressed as: dS/dt = $\rm -K\sp\prime X\sb{v}\sp{n}S.$ The kinetic constants K$\sp\prime$ and n in the model were estimated from batch tests. Then, this model was validated for CFSTR and SBR continuous flow systems. The results obtained from batch tests, conducted with sludge from the CFSTR and SBR systems, showed that the exponential model can more accurately express the substrate removal rate in a batch reactor than the conventional first order equation. A comparison of the new exponential and the first order model indicates that the exponential model can more accurately predict the effluent COD concentrations for both CFSTR and SBR continuous flow systems. The first order rate constants (K) for both CFSTR and SBR systems were affected by the reactor sludge age, the influent COD and the biomass concentrations. The kinetic constants K, yield factor (Y), and endogenous decay coefficient $\rm (k\sb{d})$ obtained for SBR system were higher than those for CFSTR. The statistical analysis results indicated that SBR system performed at a higher substrate removal efficiency compared to the CFSTR. Also the sludge grown in the SBR reactors had a better settleability than that produced in the CFSTR. The optimal organic loadings for controlling sludge bulking in the CFSTR and SBR were found to be less than 0.7 mg COD/mg VSS/d and 1.2 mg COD/mg VSS/d, respectively. In addition, the SBR reactor could be operated at an F/M ratio of 1.4 mg COD/mg VSS/d, which was twice the F/M ratio in the CFSTR without a significant decrease in treatment efficiency.