METHOD FOR TREATING WASTE WATER

Japanese Patent JP3172965

B2

PROBLEM TO BE SOLVED: To highly purify waste water such as sewage water and to decrease the amt. of generation of excess sludge by a method wherein after a raw sludge separated before biological treatment or the raw sludge and a biological sludge extracted from a biological treatment process is methane-fermented, it is oxidized with ozone and is returned to an anaerobic part.
SOLUTION: At first, solid-liq. separation of sewage water 7 is performed in a sedimentation tank 8 and methane fermentation of the precipitated raw sludge 1 is performed in an anaerobic digestion part 2 to reduce biologically the vol. of the sludge and then, the digested residue 3 is oxidized with ozone in an ozone oxidation part 4. The biological sludge is solubilized by an action destroying the cell walls of a fungi and making org. substances into low mol.wt. to make the cell walls of the fungi and the org. substances into BOD. On the other hand, the SS-removed water in the sedimentation tank at the beginning is made to flow into an anaerobic tank 5, where biological denitrification is performed and a part 13 of nitrification-treated water processed once to an aerobic tank 9 is circulated into the anaerobic tank 5 and after water to be treated in the denitrification tank 5 is made to flow into the aerobic tank 9, the active sludge is separated by sedimentation in the final sedimentation tank 10 to obtain a treated water 11.

Katsuyuki Kataoka

JP28201095A

June 04, 2001

October 30, 1995

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Ebara Corporation

C02F3/12; C02F1/78; C02F3/28; C02F3/34; C02F11/00; C02F11/04; C02F11/06; (IPC1-7): C02F3/34; C02F1/78; C02F11/00

JP999296A
JP985299A

Shohei Oguri (8 outside)

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