Fermentation drying method of internal mixing type fermentation dryer

摘要

PROBLEM TO BE SOLVED: To obtain compost of excellent quality while reducing a running cost by dispensing with a moisture control agent and reducing an equipment cost by miniaturization. SOLUTION: In a fermentation process, the dehydrated sludge in an internal space 21 is intermittently mixed by intermittently rotating a rotary body 27 while supplying air to the internal space 21, and fermented during this mixing process to form a compost. Before this fermentation process, the rotary body 27 is rotated at a predetermined rotational speed while the internal space 21 is held to a heated state to perform a drying process for mixing and drying the dehydrated sludge charged in a dehydrated sludge charging process to obtain a mixture which has predetermined water content lower than the water content of the dehydrated sludge before charging and is adapted to fermentation in the fermentation process. This mixture is dispersed without being kneaded even if no moisture control agent is sued and air permeability important in the fermentation process is ensured in the mixture. This mixture is fermented uniformly at a high fermentation temperature in the next fermentation process by ensuring air permeability to form particulate compost high in composting effect.