TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Method: The degradation of organic substance is carried out by means of a mesophilic culture is carried out at 32-42 degrees C in the first fermentation step, which is directly connected downstream to the hydrolysis station, by means of at least one parallel or series-connected fermentation container. The further degradation of organic substance is carried out using a thermophilic culture at 45-55 degrees C in the second fermentation step, which is connected downstream to the first fermentation step, by at least two batchwise-fed fermentation container. The transfer of the fermentation substrate from one to other fermentation container is carried out by means of pumping technique by cascading arrangement using open channels and/or by means of different gas pressure over the fermentation substrate in the individual fermentation container. The anaerobic treatment of the fermentation substrate in the first fermentation step is carried out through the use of not completely mixed and short-circuit flows of the fermentation substrate between the respective fermentation substrate inflow to the fermentation substrate inflow excluding apparatus. The first fermentation step is supplied continuously or intermittently with the same daily amounts of fermentation substrate. At least 5% of fermentation container of the second fermentation step present during the drainage is left as a seed culture for the fermentation substrate, which is to be introduced, from the first fermentation step in the fermentation container with the use of different cultures in the two fermentation steps. The fermentation substrate from the first fermentation step is supplied to the completely depleted fermentation container of the second fermentation step after reaching the maximum filling of the fermentation container of the second fermentation step receiving the fermentation substrate from the first fermentation step. Preferred Components: An apparatus with a circular, annular or polygonal base is used as the fermentation container. The fermentation station is connected downstream to the fermentation residue storage, which is uncoupling the fermentation station and the fermentation residue treatment station, with absorption of entire contents of fermentation container of the second fermentation step. The fermentation container of the second fermentation step is provided with additional heating systems for the selective increase of the treatment temperature of the fermentation substrate from the first fermentation step by at least 10 degrees K. EXAMPLE - No suitable example given.