PURPOSE: To maintain an excellent denitrifying condition without deteriorating the quality of treated water, by judging the condition of the process on the basis of the concentration of sludge in a denitrification tank, the amount of alkali consumed in a nitrification tank, etc., and obtaining the deviation between the measured value of oxidation-reduction potential and the target value.
CONSTITUTION: In a main controlling system constituted by an oxidation-reduction potential (ORP) meter 21, a comparing circuit 31 and a controlling circuit 32, an actual ORP value p measured by the ORP meter 21 is inputted to the comparing circuit 31 and compared therein with a preset objective ORP value p, and the resulting deviation is inputted to the circuit 32 for controlling organic substance. Said controlling circuit 32 adjusts a means 34 for supplying organic substance either toward an increase when said deviation is plus or toward a decrease when it is minus. On the other hand, the actual value s of the concentration of sludge measured by a sludge densitometer 23 is inputted to a judging circuit 33 and compared therein with the preset lower limit (s) of the concentration of sludge. When the resulting deviation is negative, a signal is inputted to reduce the amount of organic substance to be injected to zero.
BABA KENJI
NOKITA SHIYUNSUKE
OGASAWARA HITOSHI
| JPS5222916A | 1977-02-21 | |||
| JPS558877A | 1980-01-22 |