Start-up and continuous operation of continuous stirred-tank reactors (CSTR) using Ethanoligenens harbinense R3

Continuous stirred-tank reactors (CSTR) for bio-hydrogen production were studied using Ethanoligenens harbinense R3, a new anaerobic hydrogen-producing bacterium. The study aimed to assess the start-up and continuous operation characteristics for bio-hydrogen production of the CSTR. At a pH of about 4.5, COD concentration of 6000 mg·L^-1, and a hydraulic retention time (HRT) of 8 h, a hydrogen-producing microbial community could adapt to the environment and operate stably. At the same time, the reduction potential of the bio-hydrogen reactor system remained steady at about -400 mV. The concentration of ethanol could reach 65% of the aqueous terminal production in the system. The total hydrogen production was 399.33 L, and the highest hydrogen production was 15768.8 mL·d^-1 during the stage of the start-up and operation. Organic compounds containing nitrogen could be digested well by the microbes, while inorganic nitrogen had no obvious effects on hydrogen production and bacterium growth. When organic compounds containing nitrogen and phosphorus were added to the culture medium, the total biogas production, the accumulated hydrogen production and total ethanol concentration of the end liquid products were higher than in the control group.