Using thermophilic anaerobic digestate effluent to replace freshwater for bioethanol production

The possibility of using anaerobic digestate effluent (ADE) to replace freshwater and nutrients for bioethanol production was explored. The ethanol concentration yielded from ADE and post-centrifuged ADE supernatant was 79.60 ± 1.75 g/L and 78.33 ± 1.66 g/L, respectively, with a 24% dry mass (DM) of soft wheat. Ethanol production was enhanced in ADE by as much as 18% in comparison to the production in freshwater (66.61 ± 0.28 g/L, p < 0.01). Without yeast nutrients, ADE fermentation yielded an ethanol concentration of 81.10 ± 2.87 g/L, which was significantly higher than that in freshwater fermentation (59.67 ± 1.79 g/L). Analysis showed that ADE contained rich nitrogen, proteins and minerals. After one-step distillation, the ethanol concentration attained was 700.05 ± 46.20 g/L in ADE as compared to 622.79 ± 32.22 g/L in freshwater (p < 0.05).