Kinetics and reaction engineering aspects of the biodegradation of dichloromethane and dichloroethane

This paper presents some new results on the aerobic degradation of dichloromethane (DCM) and 1,2-dichloroethane (DCA) in a fluidized bed reactor without direct oxygenation. Oxygen was supplied by diffusion through a synthetic membrane. High bacteria concentrations and high degradation rates were obtained. DCM degradation reached 1400 mg (1 h)−1 and DCA degradation up to 600 mg (1 h)−1. Yields for oxygen consumption and biomass production could be established. Haldane kinetics were suitable to describe the influence of DCA and oxygen concentration on the degradation rate of DCA. The DCM degradation rate is only influenced by the substrate concentration. Kinetic parameters for the Haldane model were reached in batch and extended-culture experiments. Extended-culture experiments keep the substrate concentration in the reactor constant and allow a determination of the growth rate by evaluation of the reaction volume.