| 摘要 |
PURPOSE:To effectively remove a BOD component and nitrogen in waste water by maintaining the concentration of sludge in an aerobic tank at high level and also keeping the high concentration of dissolved oxygen in the aerobic tank by means of high concentration oxygen aeration. CONSTITUTION:Raw water 3 is permitted to flow into an anaerobic tank 1 and concentrated sludge solution containing nitric acid and nitrogen nitrite is introduced from an aerobic tank 2 to the anaerobic tank 1 so that said solution may be stirred and mixed with raw water, and this mixture be denitrified with adsorption of a BOC component into sludge. Next, the mixture in the anaerobic tank 1 is introduced into a precipitation tank 4 to be precipitated and separated into treated water 5 and concentrated sludge, and to permit treated water to flow out. In the meantime, the concentrated sludge is returned to the aerobic tank 2 and its is aerated with high-concentration oxygen 8 at high sludge concentration to decompose the BOD component adsorbed in said sludge and the nitrogen component of the mixed liquid into nitric acid and nitrogen nitrite through oxidation. Then the mixed liquid is again permitted into the anaerobic tank 1. Subsequently, the activity of nitration bacteria is increased and thereby effective waste water treatment is achieved.
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