title: Efficient production of methane from artificial garbage waste by a cylindrical bioelectrochemical reactor containing carbon fiber textiles.
abstract: A cylindrical bioelectrochemical reactor (BER) containing carbon fiber textiles (CFT; BER + CFT) has characteristics of bioelectrochemical and packed-bed systems. In this study, utility of a cylindrical BER + CFT for degradation of a garbage slurry and recovery of biogas was investigated by applying 10% dog food slurry. The working electrode potential was electrochemically regulated at -0.8 V (vs. Ag/AgCl). Stable methane production of 9.37 L-CH4 · L-1 · day-1 and dichromate chemical oxygen demand (CODcr) removal of 62.5% were observed, even at a high organic loading rate (OLR) of 89.3 g-CODcr · L-1 · day-1. Given energy as methane (372.6 kJ · L-1 · day-1) was much higher than input electric energy to the working electrode (0.6 kJ · L-1 · day-1) at this OLR. Methanogens were highly retained in CFT by direct attachment to the cathodic working electrodes (52.3%; ratio of methanogens to prokaryotes), compared with the suspended fraction (31.2%), probably contributing to the acceleration of organic material degradation and removal of organic acids. These results provide insight into the application of cylindrical BER + CFT in efficient methane production from garbage waste including a high percentage of solid fraction.
authors.affiliation: Biotechnology Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko-shi, Chiba-ken 270-1194, Japan. masahiko@criepi.denken.or.jp.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sasaki
authors.forename: Kengo
authors.initials: K
authors.lastname: Sasaki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Watanabe
authors.forename: Masahiko
authors.initials: M
authors.lastname: Morita
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Igarashi
authors.forename: Naoya
authors.initials: N
authors.lastname: Ohmura