Browsing by Subject "Continuous bioreactor"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Restricted
    A kinetic study on anaerobic reduction of sulphate, Part I: Effect of sulphate concentration
    (Elsevier, 2002) Moosa, S; Nemati, M; Harrison, S T L
    The kinetics of anaerobic reduction of sulphate was studied in continuous bioreactors. The effects of initial sulphate concentration and its volumetric loading on the kinetics of reaction and activity of sulphate-reducing bacteria were investigated. The increase in initial concentration of sulphate in the range 1.0–Full-size image (<1 K) enhanced the reaction rate from 0.007–Full-size image (<1 K). For a given initial sulphate concentration increasing the volumetric loading rate of sulphate led to a linear increase in volumetric reduction rate. The initial concentration of sulphate did not have a significant effect on maximum specific growth rate (μm), decay coefficient (kd) on bacterial yields (Yx/sulphate and Yx/acetate), with the values of these coefficients being Full-size image (<1 K) bacteria/g sulphate and Full-size image (<1 K) bacteria/g acetate, respectively. The saturation constant (Ks) was an increasing linear function of initial sulphate concentration, with the lowest and highest values being 0.027 and Full-size image (<1 K), respectively. Using the experimental data a kinetic model, incorporating terms for the effects of initial and residual concentrations of sulphate and biomass, was developed.
  • Thumbnail Image
    Item
    Restricted
    A kinetic study on anaerobic reduction of sulphate, part II: incorporation of temperature effects in the kinetic model
    (Elsevier, 2005) Moosa, S; Nemati, M; Harrison, S T L
    The effects of temperature on the kinetics of anaerobic sulphate reduction were studied in continuous bioreactors using acetate as an electron donor. Across the range of temperatures applied from 20 to View the MathML source, the increasing of volumetric loading rate up to 0.08 to View the MathML source resulted in a linear increase in reduction rate of sulphate. The increasing reaction rate showed a lower dependence on volumetric loading rate in the range 0.1–View the MathML source. Further increase in volumetric loading rate above View the MathML source was accompanied by wash out of bacterial cells and a sharp decrease in reaction rate. Despite a similar pattern for dependency of reaction rate on volumetric loading at all temperatures tested, the magnitude of reaction rate was influenced by temperature, with a maximum rate of View the MathML source observed at View the MathML source. The effect of temperature on maximum specific growth rate (μmax) and bacterial yield was insignificant. The values of maximum specific growth rate and yield were View the MathML source and 0.56–0.60 kg bacteria (View the MathML source), respectively. The decay coefficient (kd) and apparent saturation constant (View the MathML source) were both temperature dependent. The increase of temperature resulted in decreased values of View the MathML source, and higher values for kd. Using the experimental data effect of temperature was incorporated in a kinetic model previously developed for anaerobic reduction of sulphate.