Kinetics of degradation of chlorinated aliphatics and hydrocarbons in biofilm reactors

The purpose of the research was to determine kinetic parameters for the biodegradation of organic contaminants at the very low concentrations which are often found in practice (ug/l range). Since several important compounds are degraded by cometabolism, this phenomenon was studied intensively. Experiments have been conducted in a "biodrum" reactor where biofilm samples can be removed easily and the thickness of the biofilm can be determined non-destructively by microscopy. Substrate removal and the simultaneous biofilm growth is modelled by the computer programme Aquasim from EAWAG in Zürich. The modelling takes into account the main processes affecting the different species of the biofilm (growth, decay, hydrolysis, polymer production, attachment, and detachment).