METHANE FERMENTATION METHOD, METHANE FERMENTATION SYSTEM, WASTE MATERIAL RECYCLING METHOD, AND WASTE MATERIAL RECYCLING SYSTEM

摘要

A methane fermentation method whereby a methane-containing biogas can be produced from a raw material containing at least one of glycerin and a fatty acid glycerin ester, the method being characterized by comprising: a first separation step of mixing the raw material with an inorganic acid and separating the resultant mixture into a first oil component and a first glycerin-containing solution; a neutralization step of neutralizing the first glycerin-containing solution with an alkaline substance; a second separation step of separating a second oil component and a precipitated inorganic salt from the neutralized first glycerin-containing solution to produce a second glycerin-containing solution; and a fermentation step of carrying out methane fermentation using the second glycerin-containing solution. According to the present invention, it is possible to produce a methane-containing biogas from a waste material containing glycerin or a waste material containing a fatty acid glycerin ester with high efficiency. Furthermore, it is also possible to dramatically increase the rate of recovery of methane from a glycerin-containing waste material compared with the conventional methods.