【Paper】
Study on the Performance of Thermophilic Methane Fermentation of Garbage under Once-a-day Feeding conditions
Feng Hong*, Hiroshi Tsuno**, Taira Hidaka** and Jihoon Cheon**
* Department, of Environ. Eng., Graduate School of Eng., Kyoto Univ., CREST of JST
** Department, of Urban and Environ. Eng., Graduate School of Eng., Kyoto Univ., CREST of JST
† Correspondence should be addressed to Feng Hong:
Department, of Environ. Eng., Graduate School of Eng., Kyoto Univ., CREST of JST
（Yoshida-honmachi, Sakyo-ku, Kyoto, 606-8501 Japan）

Abstract
Thermophilic methane fermentation at 55 ℃ was applied to garbage treatment. Continuous feed-and-draw operation was conducted in a complete-mixing type reactor with artificially prepared garbage. Based on calculations of COD, more than 80％ of the garbage was transformed to methane, with 0.4 to 0.5L of methane gas being produced from 1g VS of garbage. Inhibition of methano-genesis by ammonium nitrogen was initiated when its concentration exceeded 2,000mgN/L. Total nitrogen concentration in the garbage treated should be less than 4,000mgN/L, as about half of the total nitrogen was transformed to ammonium nitrogen by anaerobic methane production processes.

Key words: thermophilic methane fermentation, garbage treatment, once-a-day feeding, methane gas production rate, returning solids