Accelerated bio-methane production rate in thermophilic digestion of cardboard with appropriate biochar: Dose-response kinetic assays, hybrid synergistic mechanism, and microbial networks analysis

• Published in: Bioresource technology 2019-10, Vol.290, p.121782-121782, Article 121782
• Main Authors: Li, Dunjie, Song, Liuying, Fang, Hongli, Li, Ping, Teng, Yue, Li, Yu-You, Liu, Rutao, Niu, Qigui
• Format: Article
• Language: English
• Subjects: Biochar; Biomethane; Microbial networks analysis; Mono-cardboard digestion; Thermophilic digestion
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2019.121782

[Display omitted] •The CH4 production rate (Kmax) was improved by 40.6% in T1 (0.77 g/gTS sludge).•The acetogenic efficiency improved by 1.7 times after adding moderate biochar.•The biochar enriched potential IET-partners and promoted the microbial synergy.•Excessive biochar caused adverse effects with low CH4 yield and long lag phase. The effect of biochar on the thermophilic digestion of mono-cardboard was investigated. Compared with control group (T0), the maximum rate of biomethane production was significantly improved after the addition of biochar, especially, it has been improved by 40.6% in T1 (0.77 g/gTS sludge) with the methane production of 89.28 mL/gVS. Also, the addition of biochar improved the efficiency of acidogenesis and acetogenesis. However, adverse effects were observed with the biomethane production decreased by 33.98% and the lag phase extended by 35 h in T5 (3.86 g/gTS sludge). Especially, the results showed that the adsorption of biochar played important roles in digestion. In addition, acetoclastic Methanosaeta which considered to be involved in interspecific electron transfer (IET) was enriched after biochar added and the highest diversity of acetogens was obtained in T1. Oppositely, microbial networks analysis showed that the excessive biochar may destroy the diversity of microorganism drastically.