Abstract—Dry anaerobic digestion has several advantages over liquid anaerobic digestion. However, the digestion would be inhibited at low C/N ratio of substrate such as swine manure. In this study, we tried to prevent the inhibition by adding rice straw into swine manure. Swine manure was co-digested with rice straw in semibatch digesters at 8 (manure only), 20 and 30 of C/N ratio. In only C/N 8, NH4+ concentration exceeded threshold (3000 mg N kg w.w.−1) of ammonia inhibition. Methane production of C/N 8 and C/N 20 decreased during incubation, while C/N 30 showed stable CH4 production. Pyrosequencing results showed that the halophilic bacterial communities were altered to non-halophilic ones by co-digestion of manure with straw. In terms of archaea, acetoclastic methanogen was dominated in C/N 20 and 30. Therefore, adding rice straw into swine manure is effective for prevention of the inhibition and related to structure of microorganisms.

Index Terms—C/N ratio, Dry-thermophilic anaerobic digestion, Rice straw, Swine manure

Cite: Shohei Riya, Kazuhiro Suzuki, Akihiko Terada, Masaaki Hosomi, and Sheng Zhou, "Influence of C/N Ratio on Performance and Microbial Community Structure of Dry-Thermophilic Anaerobic Co-Digestion of Swine Manure and Rice Straw," Journal of Medical and Bioengineering, Vol. 5, No. 1, pp. 11-14, February 2016. Doi: 10.12720/jomb.5.1.11-14