Sun, Chihe; Xia, Ao; Fu, Qian; Huang, Yun; Lin, Richen; Murphy, Jerry D.

2019

February

Energy Conversion and Management

Effects of pre-treatment and biological acidification on fermentative hydrogen and methane co-production

Validated

()

Fermentation Hydraulic retention time Biological acidification Biomethane Algae Food waste

185

431

441

A sequential two-stage process comprising biological acidification followed by anaerobic digestion was proposed to enhance gaseous biofuel production from the mixture of rice residue and micro-algae after thermo-chemicial hydrolysis. The maximum specific hydrogen yield of 223.1¿±¿8.8¿mL/g volatile solids (VS) and production rate of 10.4¿±¿0.4¿mL/g VS/h were achieved from hydrothermal acid pre-treated biomass during biological acidification. Increase in hydraulic retention time of biological acidification from 12 to 144¿h significantly affected the distribution of solubilised metabolic products and led to improved biological acidification rates (BARs) from 15.5% to 78.5%. Compared with single stage anaerobic digestion, the first stage acidification phase led to reductions in the lag-phase time and peak time of anaerobic digestion in such a two-stage process. The maximum specific methane production rate of 2.2¿±¿0.03¿mL/g VS/h was achieved with a deep acidification of 144¿h yielding a BAR of 78.5%. Increasing the length of time in biological acidification from 12 to 144¿h contributed to improved energy conversion efficiency of 25.4%–64% after 120¿h of anaerobic digestion. These results demonstrate that biological acidification is feasible to improve bioenergy recovery in two-stage fermentation.

0196-8904

http://www.sciencedirect.com/science/article/pii/S0196890419301943

10.1016/j.enconman.2019.01.118