Dynamic modeling of sulfate reducing biofilms

This paper presents a mathematical model able to simulate the physical, chemical and biological processes prevailing in a sulfate reducing biofilm under dynamic conditions. A mathematical modeling approach for microbial growth and decay is proposed. Complete oxidizers sulfate reducing bacteria, incomplete oxidizers sulfate reducing bacteria and acetate degraders are the microbial groups taken into account in the model. The proposed model is able to simulate the competition among the bacteria growing in the biofilm. The method of characteristics is introduced for the numerical process. As in the qualitative analysis of solutions, where it was first presented, this method seems to be a powerful tool in this situation also. The model has been applied to simulate the sulfate reduction process in a biofilm for several purposes. In particular the effect of the COD/SO42− ratio and the effect of different simulation times on the reactor performances in terms of volume fraction of bacterial species and substrate diffusion trends in biofilm have been assessed.