Title:
WATER-WITHDRAWAL TYPE METHANE FERMENTATION METHOD
Document Type and Number:
WIPO Patent Application WO/2011/013655
Kind Code:
A1
Abstract:
Disclosed is a methane fermentation method whereby digestion ratio can be improved and a fermentation tank can be downsized by withdrawing water from digested sludge in the fermentation tank.
In a conventional methane fermentation method, a biomass that is input, as a substrate, into a fermentation tank is digested by microorganisms to generate a digested gas. At the same time, the undigested substrate biomass and microbial cells having proliferated in the course of the fermentation, together with release water, are pushed out as a digested sludge from the outlet of the fermentation tank and discarded. In the method according to the present invention, water is withdrawn from a digested sludge in a fermentation tank to increase the digested sludge (microbial cell) concentration in the fermentation tank and, therefore, the residence time of the sludge in the fermentation tank is prolonged with a decrease in the volume thereof caused by the water withdrawal. As a result, a digestion ratio as high as 90% and downsizing in capacity of the fermentation tank can be achieved. Water can be withdrawn from the digested sludge in the fermentation tank by using, for example, a mechanical concentration device, a gravity-settling tank, or a filter attached to the inner face of the fermentation tank. Among these means, a means for withdrawing water by taking advantage of hydraulic pressure loaded on a filter that is attached to the inner face of a fermentation tank (or an external conducting pipe) is preferred because of the lowest cost.
Inventors:
KOBAYASHI Yoshio (16-22, Jiyugaoka2-Chome,Kumatori-ch, sennan-gun Osaka 23, 〒5900423, JP)
Application Number:
JP2010/062601
Publication Date:
February 03, 2011
Filing Date:
July 27, 2010
Export Citation:
Assignee:
KOBAYASHI Yoshio (16-22, Jiyugaoka2-Chome,Kumatori-ch, sennan-gun Osaka 23, 〒5900423, JP)
International Classes:
C02F11/04; B09B3/00; C02F11/12; C02F11/14; C02F11/18
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