Modeling the Impacts of Hydrogen Extraction on Anaerobic Fermentation Systems Using a Modified ADM1 Model

This paper presents a modified ADM1 (mADM1) model for use in assessing the influence of active dissolved H₂extraction on biogas production from anaerobic fermentation reactors, specifically in the context of high-strength brewery wastewater as the feed. The modified model adds regulation factors to account for the varying product stoichiometry of glucose degradation reactions as a function of H₂concentration in anaerobic digestion and incorporates the use of both lactate and ethanol as intermediates. The changes in the model are expected to better predict the effects of H₂removal on the production of H₂in fermentation processes. Both ADM1 and mADM1 were calibrated against experimental data from a fluidized-bed reactor containing encapsulated acidogenic-acetogenic microbial communities treating real brewery wastewater. The calibrated models were validated against another fluidized-bed reactor identical to the calibration reactor with the addition of a hollow-fiber membrane module that was used to reduce dissolved H₂concentrations in the validation reactor. It was found that ADM1 overestimated the H₂production rates of the validation reactor (117 mL/day simulated vs 16.48 mL/day experimental), whereas mADM1 was able to successfully predict fermentation, and specifically the H₂production rate (17 mL/day). The presented model is a first step toward a model that can predict the effects of dissolved H₂removal on fermentation processes.