A new approach to determine the kinetic parameters for nitrifying microorganisms in the activated sludge systems

This work aims at establishing the methodology to determine kinetic parameters describing growth of autotrophs in the activated sludge systems. It is based upon the measurement of oxygen uptake rate (OUR) only. Two Monod kinetic parameters, namely maximum specific growth rate for autotrophic biomass (μmax, A) and half-saturation constant for ammonium ions (KA) were simply and rapidly determined within a single batch OUR test with the use of ammonified wastewater. The obtained mean values of the parameters are μmax, A = 0.675 h−1 and KA = 0.912 mg NH3–N l−1 and they are close to the ones assumed in activated sludge models. It indicates that the methodology of the respiratory batch test elaborated in this study is reliable.

► Activated sludge nitrifiers distinguished by selection of wastewater composition. ► Both Monod kinetic parameters for nitrifiers determined from an individual OUR test. ► No extra data (only OUR) required to determine Monod kinetic parameters. ► OUR curve integration to find half saturation constant instead of simulations.