Fermentative hydrogen production from beet sugar wastewater in a continuous stirred tank reactor (CSTR): Effect of hydraulic retention time (HRT)

The effect of hydraulic retention time (HRT) on the performance of hydrogen production from beet sugar wastewater by anaerobic fermentation using mixed microbial communities was investigated in a continuous stirred-tank reactor (CSTR) in this present study. A CSTR was designed and its performance was determined at various HRT. The goal was to find the optimal HRT for hydrogen production, to minimize the size, mass, and volume of a production model. The bioreactor was tested at 8, 6, and 4 h HRTs under the conditions 6000 mg/L of COD and 35°C of experimental temperature. Biogas and hydrogen yield, effluent pH, VLK, OPR, Liquid fermentation products and biomass concentration were monitored to characterize reactor performance. The highest H2 production (16.2 L/d) and the specific hydrogen production rate (0.22 L/gMLVSS·d) was obtained at 24 kg/m³·d of OLR, respectively. A 6 h HRT will be used in future studies to determine the suitability of the CSTR for fermentative hydrogen production.