Premium
Leachate recirculation effects on solid‐state anaerobic digestion of Pennisetum hybrid and microbial community analysis
Author(s) -
Xing Tao,
Kong Xiaoying,
Dong Pengyu,
Zhen Feng,
Sun Yongming
Publication year - 2020
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.6310
Subject(s) - anaerobic digestion , biogas , leachate , pulp and paper industry , methane , pennisetum , methanogen , food science , bioenergy , chemistry , environmental science , agronomy , biofuel , biology , microbiology and biotechnology , environmental chemistry , ecology , organic chemistry , engineering
BACKGROUND A leach‐bed reactor (LBR) with leachate recirculation is a suitable technology for lignocellulosic biomass anaerobic digestion. In this study, the effect of percolate reflux strategies (continuous recirculation and intermittent recirculation) on methane production from Pennisetum hybrid, a type of energy crop, was investigated using a two‐layered LBR. RESULTS Compared to a solid‐state anaerobic digestion batch test, LBRs with percolate recirculation provide a stable process with a short lag phase by avoiding inhibition of volatile fatty acid accumulation and inoculation effect. The results also indicated that continuous reflux led to a lower accumulative methane yield (56.20 L kg −1 VS) compared to intermittent reflux (78.50 L kg −1 VS), resulting from washing effect and poorer distribution on the lower layer. According to microbial analysis, Bacteroidetes, Firmicutes, Proteobacteria and Synergistetes were the most predominant bacterial phyla in each LBR test sample and aceticlastic methanogen (at least >55%) plays a predominant role for methane production in all samples. CONCLUSIONS The results indicate that leachate recirculation could provide stable conditions for methane yield; however, two‐layer reactor designs which cannot guarantee the desired distribution in the lower layer result in a low methane yield. Suitable design of LBRs to maintain a well‐distributed reflux leachate should be further investigated. © 2019 Society of Chemical Industry