Kinetics of Phenol Degradation by Activated Sludge: Value of Measurements in a Batch Reactor

Kinetic measurements on the degradation of phenol in a batch reactor were done at 20°C using an activated sludge taken from a continuous reactor where the process had shown Monod-type kinetics without substrate inhibition. When employing a sludge sample, adapted to the substrate steady concentration Cs1, for runs with initial substrate concentration Cs0, observed batch rates were as high as expected for Cs0 = Cs1, but lower than expected in runs carried out at Cs0 > Cs11, with indications of a transient inhibitory effect instead of a positive response to the increased substrate concentration. It is concluded that kinetic data collected in a batch reactor are of limited value for the design of a continuous biodegradation process.