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

This study investigated the evaluation of a new operational protocol for increasing the membrane lifetime during bioH(2) 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 bioH(2) 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 bioH(2) 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 bioH(2) production was followed by acetate/butyrate pathway. According to the e flow model, NADH(2) 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 bioH(2) production by the spore-forming H-2 producing bacteria viz., Clostridium or Ethanoligenes species. For other OLRs, the error balance of NADH(2) 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.

Automated summary

This study investigated the evaluation of a new operational protocol for increasing the membrane lifetime during bioH(2) production by the anaerobic membrane bioreactor-sequencing batch reactor (AnMBR-SBR). The results showed that increasing the applied organic loading rates (OLR) improved bioH(2) production, with the ferredoxin:hydrogenase system identified as the main route of bioH(2) production.