Controlling methane and hydrogen production from cheese whey in an EGSB reactor by changing the HRT

• Published in: Bioprocess and biosystems engineering 2020-04, Vol.43 (4), p.673-684
• Main Authors: Ramos, Lucas Rodrigues, de Menezes, Camila Aparecida, Soares, Laís Américo, Sakamoto, Isabel Kimiko, Varesche, Maria Bernadete Amâncio, Silva, Edson Luiz
• Format: Article
• Language: English
• Subjects: Archaea; Bacteria; Biofuels; Bioreactors - microbiology; Biotechnology; Carbohydrates; Cheese; Chemistry; Chemistry and Materials Science; Dairy products; Dominance; Environmental Engineering/Biotechnology; Food Science; Hydraulic retention time; Hydrogen; Hydrogen - metabolism; Hydrogen production; Industrial and Production Engineering; Industrial Chemistry/Chemical Engineering; Methane; Methane - metabolism; Populations; Reactors; Research Paper; Retention time; Sludge; Sludge bed; Whey; Whey - metabolism
• ISSN: 1615-7591; 1615-7605
• DOI: 10.1007/s00449-019-02265-9

This study assessed the effects of hydraulic retention time (HRT; 8 h–0.25 h) on simultaneous hydrogen and methane production from cheese whey (5000 mg carbohydrates/L) in a mesophilic (30 °C) expanded granular sludge bed (EGSB) reactor. Methane production was observed at HRTs from 4 to 0.25 h. The maximum methane yield (9.8 ± 1.9 mL CH 4 /g COD ap , reported as milliliter CH 4 per gram of COD applied) and methane production rate (461 ± 75 mL CH 4 /day L reactor ) occurred at HRTs of 4 h and 2 h, respectively. Hydrogen production increased as methane production decreased with decreasing HRT from 8 to 0.25 h. The maximum hydrogen yield of 3.2 ± 0.3 mL H 2 /g COD ap (reported as mL H 2 per gram of COD applied) and hydrogen production rate of 1951 ± 171 mL H 2 /day L reactor were observed at the HRT of 0.25 h. The decrease in HRT from 8 to 0.25 h caused larger changes in the bacterial populations than the archaea populations. With the decrease in HRT (6 h–0.25 h), the Shannon diversity index decreased (3.02–2.87) for bacteria and increased (1.49–1.83) for archaea. The bacterial dominance increased (0.059–0.066) as the archaea dominance decreased (0.292–0.201) with the HRT decrease from 6 to 0.25 h.