To treat more efficiently organic waste by applying the UASB process.
Flowing organic waste 5 formed of a plurality of kinds mixed together and having an adjusted concentration is introduced as an upward flow into an anaerobic fermentation tank 10 in which granules 9 are formed by the self-immobilization of anaerobic microbes, and the anaerobic microbes in the floating state are kept in the tank by filtrating a fermentation liquid 15 flowed out of tank upper section, and the organic waste 5 is methane- fermented under the presence of anaerobic microbes of high concentration and generated gas 17 containing methane gas is recovered. Also, in the case the state in the anaerobic fermentation tank 10 is unstabilized and the granules 9 are not formed, still the anaerobic microbes are kept in the tank to methane ferment efficiently the organic waste 5.
MORO MASASHI
YAMAMOTO TETSUYA
SHIBATA TOSHIYUKI
