Investigation on methane yield of wheat husk anaerobic digestion and its enhancement effect by liquid digestate pretreatment

There are few studies on the use of wheat husk for anaerobic digestion until now. In this study, the BMP (biochemical methane potential) of wheat husk without pretreatment and with liquid digestate (LD) soaking pretreatment was investigated. It was demonstrated that wheat husk could be potentially used as a single feeding substrate for anaerobic digestion with a methane yield of 68 mL/g VS and this yield could be enhanced to a maximum of 130.0 mL/g VS using LD soaking pretreatment, which increased the methane production by 91%. Although the particle size (8, 5, 2 mm) and soaking pretreatment time (1, 3, 5 d) affected the biogas production, the influence of particle size was negligible when the pretreatment time was 5 days. Further analysis of the microbial community showed that the LD soaking pretreatment did not change the predominant microbial communities in the digestion. Therefore, LD pretreatment was effective in enhancing the performance of wheat husk anaerobic digestion. (C) 2019 Elsevier Ltd. All rights reserved.