METHANE FERMENTING METHOD

摘要

PURPOSE:To enhance the precipitating property of sludge by a method wherein methane fermentation sludge containing waste water is introduced into a pressurized float separation tank and the part of treated water is pressurized by a methane fermentation gas and the pressurized treated water is introduced into the pressurized float separation tank under pressure from the lower part thereof. CONSTITUTION:A gas containing methane and carbon dioxide gas exhausted from a methane fermentation tank 1 is pressurized by a compressor 4 and treating water is pressurized by a pressurizing machine 5. Pressurized treating water is sent into a solid-liquid separating pressurized float tank 3 from the lower part thereof through P6. In a discharge liquid flowed into the pressurized float tank 3 from a precipitation tank 2 through P2, a large amount of SS containing methane sludge is mixed but SS is floated by the action of air bubbles in pressurized water. The floated SS is returned to the methane fermentation tank 1 through P5. In addition, the liquid side subjected to solid-liquid separation is discharged out of the system from the lower part of the pressurized float tank 3 through P4.