Recovering hydrogen production performance of upflow anaerobic sludge blanket reactor (UASBR) fed with galactose via repeated heat treatment strategy

This study evaluated the effect of repeated heat treatment towards the enhancement of hydrogen fermentation from galactose in an upflow anaerobic sludge blanket reactor with the hydraulic retention time of 6 h and the operation temperature of 37 degrees C. The hydrogen production rate (HPR) and hydrogen yield (HY) gradually increased up to 9.1 L/L/d and 1.1 mol/mol galactose, respectively, until the 33rd day of operation. When heat treatment at 80 degrees C for 30 min was applied, hydrogen production performance was enhanced by 37% with the enrichment of hydrogen producing bacteria population. The HPR and HY were achieved at 12.5 L/L/d and 1.5 mol/mol hexose, respectively, during further 30 cycles of reactor operation. The repeated heat treatment would be a viable strategy to warrant reliable continuous hydrogen production using mixed culture. (C) 2017 Elsevier Ltd. All rights reserved.