Effect of cell immobilization, hematite nanoparticles and formation of hydrogen-producing granules on biohydrogen production from sucrose wastewater

This study investigated the effect of granules formation, hematite nanoparticles and biofilm carriers on biohydrogen production from sucrose wastewater in continuous stirring tank reactors operated at 12 h HRT, pH of 5.5 and 35 °C. Granular-based bioreactor was subjected to acid incubation period for 24 h by shifting the pH from 5.5 to 3. Before application of the acid incubation, hydrogen-producing granules (HPGs) diameter and hydrogen production rate (HPR) of 0.5 mm and 4.3 L/L.d, respectively were measured at 10 g-sucrose/L. Application of acid incubation enhanced the granulation process, where the particle size increased to 2.8 mm and higher HPR of 7.8 L/L.d was obtained. Higher sucrose concentration (15–30 g∖L) enhanced HPGs diameter and increased the HPR. At 10 g-sucrose/L, addition of hematite nanoparticles increased the HPR to 5.9 L/L.d higher than 3.87 L/L.d measured in control reactor. Biofilm-based reactor showed HPR of 2.48 L/L.d lower than the control reactor.