Modelling sulfate reduction in anaerobic digestion: Complexity evaluation and parameter calibration

A comparative analysis of five different structures of sulfate reduction (SR) models for anaerobic digestion (AD) was conducted to evaluate their accuracy to provide model developers and users with better information to decide on the optimum degree of complexity. The models evaluated differ in terms of the number/type of sulfate reducing bacterial activities considered based on the electron donors used. A systematic calibration of the evaluated models against a large set of experimental data was also conducted using a very recent parameter calibration method. Results indicate that a simple model incorporating both acetate utilizing and hydrogen utilizing sulfate reducing bacterial activities (the M_AH model) achieves a good balance between performance and complexity in terms of prediction errors against experimental data. All the models evaluated provided acceptable predictions except the model including only hydrogen utilizing sulfate reducing bacterial activity. More complex model structures are recommended only if required in specific experimental cases.