Effect of hydraulic retention time (HRT) on biohydrogen production from galactose in an up-flow anaerobic sludge blanket reactor

• Published in: International journal of hydrogen energy 2016-12, Vol.41 (46), p.21670-21677
• Main Authors: Sivagurunathan, Periyasamy, Anburajan, Parthiban, Kumar, Gopalakrishnan, Kim, Sang-Hyoun
• Format: Article
• Language: English
• Subjects: Biohydrogen; Clostridium; Gammaproteobacteria; Granules
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2016.06.047

This study investigated the hydrogen fermentation from galactose in up-flow anaerobic sludge blanket (UASB) reactor under mesophilic temperature of 37 °C. The maximum hydrogen production rate (HPR) and hydrogen yield (HY) of 56.8 L/L/d and 2.25 mol/mol galactose added were achieved at a hydraulic retention time (HRT) of 2 h. Further shortening the HRT to 1.5 h, led to the significant drop in the HPR and HY with a value of 48.3 L/L/d and 1.44 mol/mol galactose added, respectively. During the reactor operation, neither external pH adjustment nor recirculation was required, while the pH was maintained in the range of 5.5–6.2 by the carbonate buffer in the nutrient medium. Acetate and butyrate were the major soluble metabolic products (SMPs) formed during the hydrogen fermentation with fewer amounts of lactate and propionate during the peak hydrogen production performances. The results showed that controlling appropriate HRT is prerequisite for the enhancement of hydrogen production performances. •UASB fed with 15 g galactose/L showed the productivity of 56.8 L H2/L/d at HRT 2 h.•HRT influences the microbial community population as well as the performance.•Increased Clostridium populations at 2 h HRT attributed high H2 yield.