Development, identification and validation of a mathematical model of anaerobic digestion of sewage sludge focusing on H2S formation and transfer

• A simplified dynamic anaerobic model focus on H2S formation was developed.
• Model development through sensitivity, collinearity and uncertainty analysis.
• Model implementation was validated with two pilot scale reactors.

Nowadays, there are plenty of models of the anaerobic digestion process, however the impact of this odor emission on these models has received very little attention. Hydrogen sulfide (H2S) has been used as odor trace marker for odor dispersion studies which is formed by microbial action of sulfate reducing bacteria under anaerobic conditions. A mathematical model with focus on the H2S generation with a reduce number of parameters of five stages was developed. The model and parameters were calibrated and validated with experimental data from two pilot scale anaerobic reactors treating sewage sludge. The developed model is able to describe properly the dynamic behavior of this system, particularly, its gas phase composition with an accuracy of 90%, for hydrogen sulfide and carbon dioxide, and 60% for methane, within 99% of confidence.