[Influences of hydraulic retention time on the ethanol type fermentation hydrogen production system in a hybrid anaerobic baffled reactor].

Effect of hydraulic retention time (HRT) on bio-hydrogen production and operational stability of ethanol-type fermentation was investigated in a hybrid anaerobic baffled reactor (HABR) using brown sugar as substrate. The results showed that five HRTs were examined, ranging from 8 to 36 h. At a HRT of 12 h, the highest hydrogen production rate was achieved [13.86 mmol x (h x L)(-1)], with a COD remove rate of 51.51%, and the pH value of five compartments was between 4.22-4.47. The ethanol and acetate were the predominant metabolites. The ratios of ethanol and acetic acid from the 1th compartment to the 5th compartment were 1.90, 1.94, 1.80, 1.77 and 1.91, respectively. The results demonstrated that the best energy production rate was 11.11 kJ x (h x L)(-1), occurred at a HRT of 12 h.