Effect of endogenous hydrogen utilization on improved methane production in an integrated microbial electrolysis cell and anaerobic digestion: Employing catalyzed stainless steel mesh cathode

Improving the production of methane, while maintaining a significant level of process stability, is the main challenge in the anaerobic digestion process. Recently, microbial electrolysis cell (MEC) has become a promising method for CO₂ reduction produced during anaerobic digestion (AD) and leads to minimize the cost of biogas upgrading technology. In this study, the MEC-AD coupled reactor was used to generate and utilize the endogenous hydrogen by employing biocompatible electrodeposited cobalt-phosphate as catalysts to improve the performance of stainless steel mesh and carbon cloth electrodes. In addition, the modified version of ADM1 model (ADM1da) was used to simulate the process. The result indicated that the MEC-AD coupled reactor can improve the CH₄ yield and production rate significantly. The CH₄ yield was enhanced with an average of 48% higher than the control. The CH₄ production rate was also increased 1.65 times due to the utilization of endogenous hydrogen. The specific yield, flow rate, content of CH₄, and pH value were the variables that the model was best at predicting (with indexes of agreement: 0.960/0.941, 0.682/0.696, 0.881/0.865, and 0.764/ 0.743) of the process with SS-meshes 80/SS-meshes 200, respectively. Employing the catalyzed SS mesh cathode, in the MEC-AD coupled reactor, could be an effective approach to generate and facilitate the utilization of endogenous hydrogen in anaerobic digestion of CH₄ production technology, which is a promising and feasible method to scale up to the industrial level.