Effect of temperature and ph on the effective maximum specific growth rate of nitrifying bacteria

For modeling nitrification in wastewater treatment processes it is necessary to determine the dependence of the maximum specific growth rate ( μ A ) of nitrifying bacteria on temperature and pH. A functional relationship for the simultaneous dependence of the effective maximum specific growth rate ( μ A ) minus the decay coefficient, b A) on temperature and pH, obtained from theoretical arguments, was verified via batch experiments with sludge from a local wastewater treatment plant. The parameters for the functional relationship were determined from the experimental data using a nonlinear regression scheme. An optimum pH of approx. 7.8 was determined and the effective maximum specific growth rate was found to be a monotonically increasing function of temperature in the range of 15–25°C.