Abstract: The present invention relates to a treatment process of anaerobically digesting organic wastes under an anaerobic condition for recovering methane from the organic wastes by fermentation effect of anaerobic bacteria. This treatment process is carried out by the charging organic wastes of 50.about.70% water content and seed digestives alternately in strata in a digestion tank and then keeping the interior of said digestion tank under an anaerobic condition.

Abstract: The present invention relates to an anaerobic digestion process of wastes containing cellulose, in which, after liquefying by bringing wastes containing cellulose in slurry state into contact with facultative anaerobic bacteria with pH adjusted between 6.5-8.0 and oxidation-reduction potential controlled between -50-300 mV with oxygen supply, the liquefied slurry is then converted into methane and carbon dioxide by bringing it into contact with obligatory anaerobic bacteria to recover methane efficiently.

Abstract: The present invention relates to an anaerobic digestion process for organic wastes with a high efficiency and an improved recovery rate of methane.This process comprises the following steps: (1) anaerobically digesting organic wastes under simultaneous presence of facultative anaerobic bacteria and obligatory anaerobic bacteria, (2) separating the anaerobically digested slurry obtained from the step (1) into a liquor fraction containing the two groups of bacteria and an undecomposed solid fraction, (3) mixing the liquor fraction obtained from the step (2) with the surplus activated sludge slurry produced by anaerobically treating organic waste water, under anaerobic condition, (4) separating the mixed slurry obtained from the step (3) into a solid fraction containing the surplus activated sludge which has absorbed the two groups of bacteria and a liquor fraction, and recycling back the solid fraction obtained from the step (4) as the sources of the two groups of bacteria and nitrogen to the step (1).

Abstract: Methane gas produced according to an anaerobic digestion of organic wastes is introduced into digested separated water which is alkalized by a photo-culture of algae, whereby impurity carbon dioxide gas is removed by absorption. Accordingly, methane of high concentration is recovered and at the same time, by-product algae is recycled as feedstock, and thereby improving the yield of methane.

Abstract: The present invention relates to a process for digesting garbage or garbage contained wastes, particularly to a microbiological treatment which facilitates the treatment with high efficiency and economics, for the recovery of methane gas, first, by effecting an alcohol fermentation treatment by alcohol fermentative yeasts which can directly convert starch into ethanol without a starch hydrolysis pretreatment in the slurry state, followed by a direct methanization by methane bacteria of the fermented product containing ethanol, without effecting sterilization treatment of garbage or garbage contained wastes.

Abstract: The present invention relates to a process for digestion treatment of organic wastes that are difficult to digest, with a high efficiency and an improved recovery rate of methane.The wastes, before subjected to anaerobic treatment, are heated at 55.degree.-75.degree. C. within an acid or alkaline solution for dissolving digestible ingredients and the insoluble ingredients are eliminated before being transferred to an anaerobic digestion step. By exercising a pre-treatment for dissolving and separating digestible ingredients, the size of the container will be minimized as a result of the shortened time required for digestion and the recovery rate of methane will be improved.