| 摘要 |
<p>PURPOSE:To always permit stable nitrification by exactly knowing the nitrification condition in an aeration tank and controlling the activity or concn. of nitrifying bacteria according to the condition. CONSTITUTION:The ammoniac nitrogen concn. and dissolved oxygen concn. in the aeration tank or in the treated water are measured in a biological nitrification method for waste water by an activated sludge process including the oxidation of the ammoniac nitrogen and org. nitrogen in the waste water to nitrite nitrogen or nitrate nitrogen which is oxidized state nitrogen. The dissolved oxygen concn. is controlled by operating the flow rate of the air in such a manner that the ammoniac nitrogen concn. attains a prescribed value. The activated sludge concn. is controlled by operating the flow rate of discharging the excess sludge in such a manner that the smoothing signal for the dissolved oxygen concn. or the set value of the dissolved oxygen concn. attains a prescribed value. As a result, always stable nitrification is attained.</p> |
