SLUDGE TREATMENT METHOD AND SLUDGE TREATMENT SYSTEM

摘要

Disclosed are a sludge treatment method and a sludge treatment system which efficiently and reliably increase the concentration of sludge, raise the efficiency of methane fermentation of highly concentrated sludge, and use energy effectively and efficiently. The disclosed sludge treatment method involves: a reduced-pressure concentration step in which the raw sludge is foamed under reduced pressure and a foaming gas is added for flotation thickening to obtain a concentrated sludge; a vacuum-forming step in which high-temperature steam is discharged at high speed and a vacuum state is formed with said high-temperature steam as the working fluid; a solubilization step in which the aforementioned concentrated sludge is contacted with the high-temperature steam to obtain a solubilized sludge; a solid-gas separation step in which the aforementioned solubilized sludge is retained and degassed to obtain a degassed sludge; and a methane fermentation step for causing methane fermentation of the aforementioned degassed sludge under anaerobic conditions to obtain digested sludge.