Treating garbage and wastes to obtain methane

The starch-containing garbage is subjected to an alcohol-producing anaerobic fermentation in the slurry state without sterilizing the garbage in the presence of one or more ethanol-producing yeasts which directly converts starch producing anaerobic fermentation in the presence of CH/sub 4/-producing bacteria. Thus, 3 kg slurry of 10% organic concentration was mixed with 0.5 kg seed culture prepared in advance by mix-culturing Saccharomyces cerevisiae, Saccharomyces diasbtitics, and Candia lipolitica at pH 5 and 30 degrees for 3 days. The mixture was charged into a stainless steel container, stirred at 100 rpm, 30 degrees, and pH 5.0 for 3 days, then from the 4th day onward a continual charging was effected at load of 25 g dried organics per day. The neutralized slurry was gasified in a tank at 60 degrees with residence time of 12 days and pH 7.8. A gas containing 75 volume percent CH/sub 4/ was generated at 35 L/kg slurry.