Anaerobic membrane bioreactor for the production of bioH2: Electron flow, fouling modeling and kinetic study

Abstract

This study investigated the evaluation of a new operational protocol for increasing the membrane lifetime during bioH2 production by the anaerobic membrane bioreactor-sequencing batch reactor (AnMBR-SBR) along with a kinetic and membrane fouling study. The certified electron (e-) flow model was applied to investigate the structure of microbial community and metabolism pathway. The AnMBR-SBR was operated under varying applied organic loading rates (OLR). At applied OLR of 0.5 g COD/L.d, the bioH2 production was around 0.39 ± 0.21 L/d, and an increase of applied OLR to 8.0 g COD/L.d led to improve bioH2 production to 14.57 ± 9.06 L/d. At the OLR of 0.5 g COD/L.d, the dominant e- sinks were acetate (52.2) and butyrate (22.5). While significant augmentation in butyrate production (49.9) was observed at OLR of 8.0 g COD/L.d, indicating that bioH2 production was followed by acetate/butyrate pathway. According to the e- flow model, NADH2 balance error at OLR of 0.5 and 1.0 g COD/L.d ranged 3–8, demonstrating the ferredoxin:hydrogenase system as the main route of bioH2 production by the spore-forming H2 producing bacteria viz., Clostridium or Ethanoligenes species. For other OLRs, the error balance of NADH2 ranged from 21 to 24, indicating the activation of non-spore-forming bacteria, e.g., Enterobacter, Escherichia, or Klebsiella species that coincide with the spore-forming bacteria. © 2021 Elsevier B.V.