Biohydrogen production from Tequila vinasses in an anaerobic sequencing batch reactor: Effect of initial substrate concentration, temperature and hydraulic retention time

The effect of the temperature (25 and 35 °C), the hydraulic retention time, HRT, (12 and 24 h) and initial substrate concentration on hydrogen production from Tequila vinasse was studied using a sequencing batch reactor. When 25 °C and 12-h HRT were applied, only insignificant biogas quantities were produced; however, using 24 h of HRT and temperatures of 25 and 35 °C, biogas containing hydrogen was produced. A maximum volumetric hydrogen production rate of 50.5 mL H2 L−1 h−1 (48 mmol H2 L reactor - 1 d−1) and an average hydrogen content in the biogas of 29.2 ± 8.8% were obtained when the reactor was fed with 3 g COD L−1, at 35 °C and 12-h HRT. Methane formation was observed when the longer HRT was applied. Results demonstrated the feasibility to produce hydrogen from this waste without a previous pre-treatment.