Effect of Hydraulic Retention Time on Biohydrogen Production from Glucose in an Internal Circulation Reactor

Abstract

The effect of hydraulic retention time (HRT) on biohydrogen production from glucose in an internal circulation (IC) reactor with granular sludge as inoculants was studied. A maximum hydrogen-production rate (HPR) of 10.78 ± 0.84 L–1d–1 at HRT 2 h and a maximum hydrogen yield (HY) of 1.4 ± 0.21 mol mol–1 glucose at HRT 3 h were achieved. With no external pH adjustment, the effluent pH maintained at 5.16–3.71 under the carbonate buffer in the substrate. Regardless of the different HRTs, ethanol was the predominant metabolite and accounted for 36.59–48.98% of the total soluble microbial products (SMPs), which lead to a total IC reactor energy conversion rate of 11.42 ± 4.15 kJ h–1 L–1 at HRT 2 h based on the hydrogen and ethanol production. This means that the IC reactor was a feasible instrument in improving energy productivity.