Biodegradation of phenol by two competing microbial species in a sequencing batch reactor

Biodegradation of a single pollutant by two competing microbial species has been mathematically described for the case where a sequencing batch reactor is used. The model has been solved numerically to predict the behavior of the reactor under different operating conditions and for different kinetic expressions for biodegradation. Experiments were performed to verify the predictions of the model. Serratia marcescens (ATCC 17991) and Pseudomonas putida (ATCC 31800) were the species used. Experiments were first performed in order to reveal the kinetics of biodegradation for each individual species. The biodegradable substance used was phenol, which was the sole carbon source in the medium. Mixed culture experiments were performed in a 5-liter fill-and-draw reactor. Excellent agreement (both qualitatively and quantatively) was obtained between the experimental data and the model predictions