BIOLOGICAL TREATMENT DEVICE AND BIOLOGICAL TREATMENT METHOD

摘要

PROBLEM TO BE SOLVED: To provide a biological treatment device and a biological treatment method for waste water by using granular sludge in which various kinds of different environmental conditions can be obtained in a single device.

SOLUTION: Waste water supplied from an inlet pipe 11 to a first nitrification tank 1 is mixed with granular sludge in the tank 1 by air introduced through an aeration pipe 1A and nitrified by nitrifying bacteria in the sludge. Then the water flows through a downflow chamber 5 into a second nitrification tank 2. The water is also nitrified in the tank 2 and flows through a downflow chamber 6 into a denitrification tank 3, where the water is mixed with and denitrified by denitrifying bacteria in the tank 3 by nitrogen supplied from a nitrogen pipe. Then the sludge is settled and separated in a succeeding solid liquid separation tank 4. The treated water is drained through a pipe 12 while the sludge is returned through an opening 8 to the tank 1.

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