JPS5771695A - Method for treating waste water by microorganism - Google Patents

Abstract

PURPOSE: To enable to perform a stable waste water treatment utilizing special microorganism by a method wherein microorganism is frozen in a low-temperature region, it is then dried by keeping it in room-temperature conditions, is stored in a condition of being shielded from the outside air, and thereafter it is used as required.

CONSTITUTION: Waste water 12 is introduced into a treating tank 2, in which it is contacted to microorganism, then the waste water is fed into a precipitating tank 3, in which the microorganism is separated by precipitation an is drawn out at a bottom part of the tank 3. The supermatent water 13 in the tank 3 is discharged or after-treated. The microorganism 14 drawn out from the tank 3 is returned as return microorganism 14a into the tank 2 via a return line 4, while excesses 14b, 14c of microorganism are directed into a microorganism tank 6 and is temporarily stored therein. Then, the microorganism 15 concentrated by a concentrating means 7 is frozen in a low temperature region of -20°C or below by a freezing means 8. The frozen microorganism 16 is heated to the room-temperature condition in a closed container while evacuating container by a vacuum pump so as to dry the microorganism to a water content of 10% or below. The thus dried microorganism 17 is transferred into a staring container and is left to stand still at a storing plate 10. The dried microorganism 18 thus stored is charged into the tank 2, as required.

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