【Paper】
Treatment of Garbage by Two-phase Methane Fermentation
Masaru Sakamoto*, Akihiro Nagano*, Masaharu Suzuki** and Tatsuya Noike***
* Technical Research Laboratories, Sanki Engineering Co., Ltd.
** Department of Fermentation Science, Tokyo University of Agriculture
*** Department of Civil Engineering, Tohoku University
† Correspondence should be addressed to Masaru Sakamoto:
Technical Research Laboratories, Sanki Engineering Co., Ltd.
（1742-7 Shimotsuruma, Yamato, Kanagawa, 242-0001 Japan）

Abstract
We developed a new treatment system for food waste and garbage using a two-phase methane fermentation system with aerobic solubilization. In a continuous 190-day experiment, we found that the aerobic solubilization process could handle a volumetric load of 80 to 100kg-garbage/（m3・day）and that the acidification process could be operated at an HRT of 1.2 day. The maximum volumetric load of the methane fermentation（EGSB）process was 9kgCOD/（m3・day）. In comparison with single-phase methane fermentation, this system has the advantages of shortening the HRT and making possible the discharge of treated water into the sewer system. However, we found that lipid matter accumulated in the acidification tank and suspended solids also accumulated in the EGSB reactor. Analysis of the fatty acids revealed that these originated from lipids contained in meat and seafood.

Key words: garbage, two-phase methane fermentation, methane gas, solubilization, lipid