Experimental investigation of integrated systems for biohydrogen and biomethane production

Abstract

This thesis study presents two unique systems for biohydrogen (bioH2) and biomethane (bioCH4) production. The first system consists of a single-chamber cylindrical membraneless the microbial electrolysis cell (MEC), while the second system is an MEC-anaerobic digestion system. The system 1 investigates the effects of various parameters on the bioH₂ production, whereas the system 2 examines simultaneous production of the bioH2 and the bioCH4 under different operation conditions. The aluminum electrodes provide the maximum bioH2 production of 854 mg/L at 2.0 V, outperforming other electrodes. The optimum pH value and temperature for bioH2 production in the MEC systems are 6 and 40°C, respectively. The bioH2 production is enhanced by CO2 and N2 sparging, resulting in a 40% and 35% increase, respectively, under improved conditions. The highest H2 efficiency of 92.5% is achieved using an aluminum plate while sparging CO2 gases at a rate of 400 mL/min. The peak productions of the bioH2 and the bioCH4 are 830.9 mL and 720 mL in batch operation mode, respectively, and 843.3 mL and 760 mL in continuous operation mode after 24 hours. During the continuous flow operation, bioH2 production increases by 53% compared to batch mode.