Two-stage anaerobic digestion of sugar beet silage: The effect of the pH-value on process parameters and process efficiency

Publication Type

Journal contribution (peer reviewed)

Authors

Kumanowska, E.; Uruñuela Saldaña, M.; Zielonka, S.; Oechsner, H.

Year of publication

2017

Published in

Bioresource Technology

Pubisher

Elsevier Limited

Band/Volume

217/

ISBN / ISSN / eISSN

0960-8524

DOI

10.1016/j.biortech.2017.09.011

Page (from - to)

876-883

Keywords

acidification, anaerobic digestion, Biogas

The study investigated the influence of the target pH-values 4.5, 5, 5.5 and 6 in the acidification reactor on process parameters, such as substrate-specific methane yield and the intermediates, in the two-stage anaerobic digestion of sugar beet silage. The total specific methane yield (Nl kg⁻¹ COD d⁻¹) increased with an increase in the pH (pH 4.5: 140.58 ± 70.08, pH 5: 181.21 ± 55.71, pH 5.5: 218.32 ± 51.01, pH 6: 256.47 ± 28.78). The pH-value also had an effect on the dominant intermediate in hydrolysate. At the pH-value of 4.5, almost no acidification and microbial activity was observed. At pH 5 and 5.5, butyric acid production dominated, guided by H₂ production. At pH 6 acetic acid was the main product. The absence of H₂ and the highest SMY makes it favorable under practical aspects. © 2017 Elsevier Ltd