The invention discloses a combined anaerobic
fermentation method of organic
solid wastes. The organic
solid wastes used for the combined anaerobic
fermentation include domestic wastes, excess
sludge,
feces, kitchen waste, straws, etc. The method comprises the following steps: carrying out different pre-
processing processes to obtain organic materials with a
granularity less than 5 mm; passing through a
cutting pump, adjusting the C / N ratio, adjusting the
water content, etc. to obtain a homogeneous
fermentation substrate with a
solid holdup of 2 to 10%; hydrolyzing and acidifying the fermentation substrate in the presence of a
hydrolase; fermenting for a period of 15 to 25 days under the condition of stirring at a middle temperature of 32-38 DEG C to obtain
biogas, which can be used for
energy supply or output of a
system; aging and desalting the
biogas liquid to obtain a liquid
humic acid fertilizer; and
processing the
biogas residues to a granular
humic acid fertilizer. The fermentation substrate has proper C / N ratio to obviate feedback suppression of the substrate during the fermentation of a single material and simultaneously can enhance the
hydrolysis effects of celluloses,
lignin, hemicelluloses, etc. The method has the advantages of easy flow pattern control, low
energy consumption, and no generation of sewages, and can obtain the high-quality biogas fluid and the high-quality granular
humic acid fertilizer.