| 摘要 |
PROBLEM TO BE SOLVED: To provide a methane fermentation system and a methane fermentation method in which a removal ratio of an organic material in organic waste water can be improved by increasing efficiency of methane fermentation in methane fermentation equipment while cost is suppressed.SOLUTION: A methane fermentation system 1 includes: methane fermentation equipment 2 that includes an acid forming tank 4 in which introduced organic waste water is treated with a first acid former to form an acid and a methane fermentation tank 5 in which treated water from the acid forming tank 4 is methane-fermented; an aerobic treatment tank 3 in which aerobic sludge including a second acid former is housed and aerobically treated; and a line L5 that supplies a part of the aerobic sludge from the aerobic treatment tank 3 to the acid forming tank 4 or an upper stream thereof. A part of the aerobic sludge housed in the aerobic treatment tank 3 is supplied to the acid forming tank 4 or the upper stream thereof, thereby the second acid former in the aerobic sludge is transferred into the acid forming tank 4, and a persistent substrate that is difficult to be decomposed with only the first acid former in the acid forming tank 4 is decomposed with the second acid former. |
