The invention relates to agriculture, in particular to the processing of carbon-containing material to obtain a humus-containing product. A method for processing a carbon-containing material to obtain a humus-containing product by exposing it to a mixture of bacteria consisting of the strains Acinetobacter calcoaceticus VKPM (Russian National Collection of Industrial Microorganisms) V-4883, Pseudomonas denitrificans VKPM V-4884, Pseudomonas sp. “longa” VKPM V-4885 in an amount of (6-8)×109, (3-4)×109 and (2-3)×109 cells per 1 L of solution, respectively, in the presence of a phosphorus-containing additive, under aerobic conditions and while stirring, wherein the carbon-containing material is firstly ground to 0.5 mm in a wet mill while sapropel is simultaneously added in an amount of 5-10 wt %, and grinding is carried out for 30 minutes, the resulting mixture is sent into a mixer, into which aluminium industry waste in the form of dust from the cleaning of carbon electrodes with a particle size up to 0.5 mm in an amount of 10-20 wt % and a phosphorus-containing additive in an amount of 0.2-0.6 wt % are fed, mixing is carried out for 5-10 min, the resulting suspension is sent to a fermenter into which an inoculate has been fed beforehand in the form of a mixture of bacteria in an amount of 200-233 L per 1 m3 of suspension, and additionally stirring is performed while air is fed from 0.5 to 2.0 m3/min at a temperature of 15-20° C. for 28-30 h. The invention makes it possible to improve the quality of the target product.