Biohydrogen and biomethane production from food waste using a two-stage dynamic membrane bioreactor (DMBR) system

This study examined a two-stage dynamic membrane bioreactor (DMBR) system for biohydrogen and biomethane production from food waste (FW) in mesophilic condition. The two-stage DMBR system enabled high-rate H₂ and CH₄ production from particulate feedstock by enhanced microorganism retention. Chemical energy in FW was recovered up to 79% as renewable energy. The highest average hydrogen production rate of 7.09 ± 0.42 L/L-d was observed at a hydraulic retention time (HRT) of 8 h in the H₂-DMBR, while the highest CH₄ average production rate of 0.99 ± 0.02 L/L-d was observed at an HRT of 6 d in the CH₄-DMBR. The high specific methanogenic activity of 71.7 mL CH₄/g VSS-d was maintained at the short HRT, which also contributed to the high MPR. The genus Clostridium was dominant in the H₂-DMBR, while bacterial and archaeal populations in the CH₄-DMBR were dominated by the class Clostridia and genera Methanobacterium and Methanosaeta, respectively.