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US 4,565,552 AGranted
Method of producing biogas and compost
OwnerArmand Cottoninventor
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OwnerArmand Cottoninventor
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In the mesophile production of biogas, the temperature of the liquid used during anaerobic, methanogenic, fermentation is raised to the required temperature (about 35.degree. C.) by aerobically prefermenting solid substrate at substantially ambient temperature and of appropriate moisture content to raise its temperature to a temperature greater than that required for the anaerobic, methanogenic, fermentation. Thereafter flooding the fermenting solid substrate with the liquid at substantially ambient temperature to increase the temperature of the liquid by heat exchange, and then removing the liquid and storing it in a heat insulated environment to reduce the moisture content of the solid substrate to a suitable degree. The above steps of aerobic prefermenting and flooding are repeated until the liquid has reached the required temperature, and then leaving the liquid in situ to enable anaerobic methanogenic fermentation to take place. In so doing the supply of external heat for the initial warming up of the substrate may be dispensed with, thereby improving the efficiency of the method.
A method of producing biogas and compost, which comprises the steps of (1) fermenting in an aerobic environment solid fermentable organic matter at substantially ambient temperature and of appropriate moisture content to raise its temperature to a temperature greater than that required for mesophile methanogenic fermentation in an anaerobic environment, (2) flooding the fermenting organic matter with liquid at substantially ambient temperature to increase the temperature of the liquid by heat exchange with the fermenting organic matter, (3) removing the liquid to store it in a heat insulated environment to reduce the moisture content of the matter to a suitable degree, (4) raising the temperature of said matter to said greater temperature by aerobic fermentation, (5) again flooding the matter with the stored liquid to raise the temperature of the latter still further by heat exchange with the fermenting matter, (6) repeating steps (3), (4) and (5) if the liquid flooding the matter has not yet reached the temperature required for mesophile methanogenic fermentation of the matter in an anaerobic environment, (7) leaving the liquid in situ once said required temperature has been reached to enable anaerobic mesophile methanogenic fermentation to take place, and (8) collecting the gas given off during such anaerobic fermentation.
Dependencies are inferred from the claim text.