Thermophilic aerobic digestion process for producing animal nutrients and other digested products

A process for thermophilically digesting materials containing a lignocellulose material consisting essentially of the steps of:

• mixing a coarsely divided lignocellulose material with water to form a slurry having a dry solids content of at least about 5% by weight based on the total mixture,
• introducing said slurry into a digester that is sufficiently insulated to prevent substantial heat loss therefrom,
• inoculating said slurry with a bacterial inoculant taken from a mixture containing animal fecal matter digesting at thermophilic temperatures,
• continuously introducing air into said slurry while continuously, mechanically and vigorously agitating said slurry, said air being introduced at a rate sufficient to maintain the dissolved oxygen level in said mixture above about 0.2 mg/l. and said slurry being vigorously agitated at a level effective to promote and raise the temperature of said mixture from ambient temperatures, through mesophilic temperatures, to at least about 55.degree. C. and to maintain the temperature of said mixture at at least 55.degree. C. without the addition of external heat until said lignocellulose material is substantially digested thereby to form a digested product, said air being supplied at a rate sufficient to maintain a dissolved oxygen level in said mixture effective to supply the biological oxygen demand of the slurry before the temperature of said mixture reaches 55.degree. C. and at a rate sufficient to maintain the dissolved oxygen level in said mixture above about 1.0 mg/l. after the temperature of said mixture reaches 55.degree. C.

A process for thermophilically digesting materials containing a lignocellulose material consisting essentially of the steps of:

• mixing a coarsely divided lignocellulose material with water to form a slurry having a dry solids content of at least about 5% by weight based on the total mixture,
• introducing said slurry into a digester that is sufficiently insulated to prevent substantial heat loss therefrom,
• inoculating said slurry with a bacterial inoculant consisting essentially of a culture having the identifying characteristics of deposited strain ATCC 31205 deposited at the American Type Culture Collection,
• continuously introducing air into said slurry while vigorously agitating said slurry, said air being introduced at a rate sufficient to maintain the dissolved oxygen level in said mixture above about 0.2 mg/l. and said slurry being vigorously agitated at a level effective to promote and raise the temperature of said mixture from ambient temperatures, through mesophilic temperatures to at least about 55.degree. C., and to maintain the temperature of said mixture at at least 55.degree. C. without the addition of external heat until said lignocellulose material is digested, thereby to form a digested product, said air being supplied at a rate sufficient to maintain a dissolved oxygen level in said mixture effective to supply the biological oxygen demand of the digesting material before the temperature of said mixture reaches 55.degree. C. and at a rate sufficient to maintain the dissolved oxygen level in said mixture above about 1.0 mg/l. after the temperature of said mixture reaches 55.degree. C.