Stable operation during pilot-scale anaerobic digestion of nutrient-supplemented maize/sugar beet silage.

Summary, in English

Biogas production from maize/sugar beet silage was studied under mesophilic conditions in a continuous stirred tank reactor pilot-scale process. While energy crop mono-digestion is often performed with very long hydraulic retention times (HRTs), the present study demonstrated an efficient process operating with a 50-day HRT and a corrected total solids (TS(corr)) based organic loading rate of 3.4kg/m(3)d. The good performance was attributed to supplementation with both macro- and micronutrients and was evidenced by good methane yields (318m(3)/tonTS(corr)), which were comparable to laboratory maximum expected yields, plus low total volatile fatty acid concentrations (<0.8g/L). A viscoplastic and thixotropic digester fluid behaviour was observed, and the viscosity problems common in crop mono-digestion were not seen in this study. The effluent also complied with Swedish certification standards for bio-fertilizer for farmland application. Nutrient addition thus rendered a stable biogas process, while the effluent was a good quality bio-fertilizer.

• Author: Nges Ivo Achu; Annika Björn; Lovisa Björnsson
• Department/s: Biotechnology; Environmental and Energy Systems Studies
• Publishing year: 2012
• Language: English
• Pages: 445-454
• Publication/Series: Bioresource Technology
• Volume: 118C
• Links: http://dx.doi.org/10.1016/j.biortech.2012.05.096
• Document type: Journal article
• Publisher: Elsevier
• Topic: Industrial Biotechnology
• Keywords: Biogas; Bio-fertilizer; Energy crops; Macronutrients; Micronutrients
• Status: Published
• ISBN/ISSN/Other: ISSN: 1873-2976